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ABSTRACT
BILGEN, MUSTAFA. Wrinkle Recovery for Cellulosic Fabric by Means of Ionic Crosslinking. (Under the direction of Peter Hauser and Brent Smith.)
When treated with formaldehyde-based crosslinkers, cellulosic fabrics show
improved mechanical stability, wrinkle recovery angles and durable press performance,
but N-methylol treatment also causes fabrics to lose strength and later to release
formaldehyde, a known human carcinogen. We have discovered that ionic crosslinks can
stabilize cellulose using high or low molecular weight ionic materials which do not release
hazardous reactive chemicals, but at the same time provide improved wrinkle recovery
angles as well as complete strength retention in treated goods. We have varied
polyelectrolyte, the ionic content of fabrics, and various features of the application
procedure to optimize the results and to develop an in-depth fundamental physical and
chemical understanding of the stabilization mechanism.
WRINKLE RECOVERY FOR CELLULOSIC FABRIC BY MEANS OF IONIC CROSSLINKING
by
MUSTAFA BILGEN
A thesis submitted to the Graduate Faculty of North Carolina State University
in partial fulfillment of the requirements for the Degree of
Master of Science
TEXTILE CHEMISTRY
Raleigh
2005
APPROVED BY:
Dr. Peter Hauser (Chair) Dr. Brent Smith (Co-Chair)
Dr. Charles Boss (Minor)
ii
DEDICATION
This thesis is dedicated to my family and my wife, Nicole, who supported me with
constant love and caring and inspired my interest in studying textile chemistry.
iii
BIOGRAPHY
Mustafa Bilgen was born in December 1, 1978 in Erdemli, Turkey. He graduated
from Erzurum Science High School in June 1995. He received the Bachelor of Science
degree in Textile Engineering from Department of Engineering and Architecture, Uludag
University, Bursa, Turkey in July 1999.
After he graduated he worked as a dyeing and finishing supervisor in Akay Textile
Dyeing & Finishing Company for one year before he started to help his father for taking
care of the family business.
He came to North Carolina State University in January 2004, to continue his education
and started his master program in Textile Chemistry under the direction of Dr. Brent
Smith and Dr. Peter Hauser.
iv
ACKNOWLEDGEMENTS
I would like to thank to the National Textile Center and North Carolina State University
for their financial support. I also would like to thank to my advisors, Dr. Hauser and Dr.
Smith, for their crucial help and patience during my research and preparation of my thesis.
v
LIST OF CONTENTS
LIST OF TABLES ------------------------------------------------------------------------------- viii LIST OF FIGURES --------------------------------------------------------------------------------x 1. INTRODUCTION -------------------------------------------------------------------------------1 2. LITERATURE REVIEW ----------------------------------------------------------------------3
2.1 Cellulose chemistry ---------------------------------------------------------------------------3 2.2 Cellulosic fabric’s nature of wrinkling -----------------------------------------------------5 2.3 Durable Press finishing of cotton -----------------------------------------------------------6
2.3.1 Urea-Formaldehyde derivatives--------------------------------------------------------7 2.3.2 Melamine-Formaldyhe derivatives ----------------------------------------------------7 2.3.3 Methylol derivatives of cyclic ureas --------------------------------------------------8 2.3.4 Effects of formaldehyde based DP finishes on cellulose ---------------------------9
2.4 Recent developments in non-formaldehyde DP applications ------------------------- 10 2.5 Ionic crosslinking --------------------------------------------------------------------------- 14 2.6 Preparation of quaternized polymers ----------------------------------------------------- 16
2.6.1 Chitosan and its reaction with CHTAC --------------------------------------------- 16 2.6.2 Reaction of Cellulose with CHTAC------------------------------------------------- 18
2.7 Carboxymethylation of cellulose---------------------------------------------------------- 20 2.8 Proposed Research-------------------------------------------------------------------------- 21
3. EXPERIMENTAL PROCEDURES ------------------------------------------------------- 23 3.1 Test Materials-------------------------------------------------------------------------------- 23 3.2 Equipments ---------------------------------------------------------------------------------- 25 3.3 Application procedures--------------------------------------------------------------------- 25
3.3.1 Pad dry cure ---------------------------------------------------------------------------- 25 3.3.2 Pad batch-------------------------------------------------------------------------------- 26 3.3.3 Exhaustion ------------------------------------------------------------------------------ 26
3.4 Analysis and physical property tests------------------------------------------------------ 26 3.4.1 Nitrogen analysis ---------------------------------------------------------------------- 27 3.4.2 FT-IR analysis-------------------------------------------------------------------------- 27 3.4.3 1H- NMR analysis --------------------------------------------------------------------- 27 3.4.4 Wrinkle recovery angles -------------------------------------------------------------- 28 3.4.5 Tensile strength ------------------------------------------------------------------------ 28 3.4.6 Whiteness index------------------------------------------------------------------------ 28 3.4.7 Stiffness --------------------------------------------------------------------------------- 28
3.5 Reaction of cellulose with chloroacetic acid -------------------------------------------- 29 3.6 Reaction of Cellulose with CHTAC------------------------------------------------------ 32 3.7 Synthesis of compounds ------------------------------------------------------------------- 35
3.7.1 Molecular weight determination of chitosan --------------------------------------- 35 3.7.2 Depolymerization of chitosan and characterization ------------------------------- 37 3.7.3 Reaction of chitosan with CHTAC -------------------------------------------------- 39 3.7.4 Reaction of glycerin and ethylene glycol with CHTAC -------------------------- 51
vi
3.7.5 Reaction of cellobiose and dextrose with CHTAC -------------------------------- 53 3.8 Preparation of fabric samples-------------------------------------------------------------- 53 3.9 Crosslinking of carboxymethylated cellulosic fabric----------------------------------- 54
3.9.1 Treatment with cationic chitosan ---------------------------------------------------- 54 3.9.2 Treatment with cationic glycerin ---------------------------------------------------- 54 3.9.3 Treatment with cationic cellobiose, cationic dextrose and cationic ethylene glycol------------------------------------------------------------------------------------------- 55 3.9.4 Treatment with calcium chloride and magnesium chloride ---------------------- 55
3.10 Crosslinking of cationic cellulosic fabric----------------------------------------------- 57 3.10.1 Treatment with PCA and BTCA --------------------------------------------------- 57 3.10.2 Treatment with EDTA, NTA and HEDTA --------------------------------------- 59 3.10.3 Treatment with oxalic acid, citric acid and malic acid -------------------------- 59
4. RESULTS & OBSERVATIONS AND DISCUSSION---------------------------------- 60 4.1 Wrinkle recovery angles of conventional durable press finished fabrics ------------ 60 4.2 Wrinkle recovery angles of polycation treated anionic cellulosic fabrics ----------- 60
4.2.1 Wrinkle recovery angles of cationic chitosan treated fabrics -------------------- 60 4.2.2 Application of paired t-test analysis on cationic chitosan treatments ----------- 68 4.2.3 Wrinkle recovery angles of cationic glycerin treatments ------------------------- 71 4.2.4 Wrinkle recovery angles of cationic cellobiose and cationic dextrose treated fabrics ------------------------------------------------------------------------------------------ 76 4.2.5 Wrinkle recovery angles of calcium chloride and magnesium chloride treated fabrics ------------------------------------------------------------------------------------------ 76 4.2.6 Discussion of wrinkle recovery angles for polycation treatments --------------- 79
4.3 Wrinkle recovery angles of polyanion treated cationic cellulosic fabrics ----------- 82 4.3.1 Wrinkle recovery angles of PCA and BTCA treated fabrics--------------------- 82 4.3.2 Wrinkle recovery angles of EDTA, NTA and HEDTA treated fabrics --------- 87 4.3.3 Wrinkle recovery angles of oxalic acid, citric acid and malic acid treatments 89 4.3.4 Discussion of wrinkle recovery angles for polyanion treatments---------------- 90
4.4 Strength data--------------------------------------------------------------------------------- 92 4.4.1 Tensile strength of conventional durable press finished fabric ------------------ 92 4.4.2 Strength data of polycation treated anionic cellulosic fabrics-------------------- 93 4.4.3 Strength data of polyanion treated cationic cellulosic fabrics-------------------- 96 4.4.4 Discussion of strength data of untreated and treated fabrics --------------------- 98
4.5 CIE whiteness index data -----------------------------------------------------------------101 4.5.1 CIE whiteness index of conventional durable press treated fabric -------------101 4.5.2 CIE whiteness index of polycation treated anionic cellulosic fabrics----------102 4.5.3 CIE whiteness index of polyanion treated cationic cellulosic fabrics----------104 4.5.4 Discussion of whiteness index of untreated and treated fabrics ----------------106
4.6 Stiffness data -------------------------------------------------------------------------------108 4.6.1 Stiffness of conventional durable press treated fabrics --------------------------109 4.6.2 Stiffness data of polycation treated anionic cellulosic fabrics ------------------109 4.6.3 Stiffness data of polyanion treated cationic cellulosic fabrics ------------------111 4.6.4 Discussion of stiffness data of untreated and treated fabrics--------------------113
vii
5. CONCLUSIONS ------------------------------------------------------------------------------116 6. RECOMMENDATIONS FOR FUTURE WORK--------------------------------------118 7. LIST OF REFERENCES--------------------------------------------------------------------121 8. APPENDIX-------------------------------------------------------------------------------------126
8.1 Wrinkle recovery angles ------------------------------------------------------------------126 8.2 Breaking strength --------------------------------------------------------------------------133 8.3 CIE whiteness index -----------------------------------------------------------------------137 8.4 Stiffness -------------------------------------------------------------------------------------141 8.5 Nitrogen analysis---------------------------------------------------------------------------145
viii
LIST OF TABLES
Table 3.2 Results for carboxymethylation of cellulosic fabrics ------------------------------ 32 Table 3.3 Scheme of intrinsic viscosity measurement for the low viscosity chitosan ----- 36 Table 3.4 Properties of the Low Viscosity chitosan.------------------------------------------- 37 Table 3.5 The intrinsic viscosity and Mv of depolymerized chitosans----------------------- 39 Table 4.1 Paired t-test results for dry wrinkle recovery angles of cationic chitosan treated
fabrics ------------------------------------------------------------------------------------------ 69 Table 4.2 Paired t-test results for wet wrinkle recovery angles of cationic chitosan treated
fabrics ------------------------------------------------------------------------------------------ 70 Table 4.3 Paired t-test results for dry/wet wrinkle recovery angles of Ca++ and Mg++
treated fabrics --------------------------------------------------------------------------------- 79 Table 4.4 Paired t-test results for dry/wet wrinkle recovery angles of PCA and BTCA
treated fabrics --------------------------------------------------------------------------------- 87 Table A.1 Dry and wet wrinkle recovery angles for molecular weight of 3.2 x 104g/mole
cationic chitosan treated fabrics -----------------------------------------------------------126 Table A.2 Dry and wet wrinkle recovery angles for molecular weight of 1.4 x 105g/mole
cationic chitosan treated fabrics -----------------------------------------------------------127 Table A.3 Dry and wet wrinkle recovery angles for molecular weight of 6.11 x 105g/mole
cationic chitosan treated fabrics -----------------------------------------------------------127 Table A.4 Dry and wet wrinkle recovery angles for molecular weight of 1.4 x 105g/mole
cationic chitosan treated fabrics by exhaustion method --------------------------------128 Table A.5 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics----128 Table A.6 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics by
exhaustion method---------------------------------------------------------------------------129 Table A.7 Dry and wet wrinkle recovery angles for cationic cellobiose and cationic
dextrose treated fabrics ---------------------------------------------------------------------129 Table A.8 Dry and wet wrinkle recovery angles for calcium chloride and magnesium
chloride treated fabrics ---------------------------------------------------------------------130 Table A.9 Dry and wet wrinkle recovery angles for PCA treated fabrics------------------130 Table A.10 Dry and wet wrinkle recovery angles for BTCA treated fabrics --------------131 Table A.11 Dry and wet wrinkle recovery angles for EDTA treated fabrics --------------131 Table A.12 Dry and wet wrinkle recovery angles for NTA treated fabrics ----------------132 Table A.13 Dry and wet wrinkle recovery angles for HEDTA treated fabrics ------------132 Table A.14 Dry and wet wrinkle recovery angles for oxalic, malic and citric acid treated
fabrics -----------------------------------------------------------------------------------------133 Table A.15 Breaking strength data for molecular weight of 3.2 x 104g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------134 Table A.16 Breaking strength data for molecular weight of 1.4 x 105g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------134
ix
Table A.17 Breaking strength data for molecular weight of 6.11 x 105g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------135
Table A.18 Breaking strength data for cationic glycerin treated fabrics -------------------135 Table A.19 Breaking strength data for calcium chloride and magnesium chloride treated
fabrics -----------------------------------------------------------------------------------------136 Table A.20 Breaking strength data for PCA treated fabrics ---------------------------------136 Table A.21 Breaking strength data for BTCA treated fabrics -------------------------------137 Table A.22 Whiteness index data for molecular weight of 3.2 x 104g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------138 Table A.23 Whiteness index data for molecular weight of 1.4 x 105g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------138 Table A.24 Whiteness index data for molecular weight of 6.11 x 105g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------139 Table A.25 Whiteness index data for CG treated fabrics-------------------------------------139 Table A.26 Whiteness index data for calcium and magnesium chloride treated fabrics -140 Table A.27 Whiteness index data for PCA treated fabrics -----------------------------------140 Table A.28 Whiteness index data for BTCA treated fabrics---------------------------------141 Table A.29 Stiffness data for molecular weight of 3.2 x 104g/mole cationic chitosan
treated fabrics --------------------------------------------------------------------------------142 Table A.30 Stiffness data for molecular weight of 1.4 x 105g/mole cationic chitosan
treated fabrics --------------------------------------------------------------------------------142 Table A.31 Stiffness data for molecular weight of 6.11 x 105g/mole cationic chitosan
treated fabrics --------------------------------------------------------------------------------143 Table A.32 Stiffness data for cationic glycerin treated fabrics ------------------------------143 Table A.33 Stiffness data for calcium chloride and magnesium chloride treated fabrics 144 Table A.34 Stiffness data for PCA treated fabrics --------------------------------------------144 Table A.35 Stiffness data for BTCA treated fabrics ------------------------------------------145 Table A.36 Nitrogen analysis data for molecular weight of 3.2 x 104g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------146 Table A.37 Nitrogen analysis data for molecular weight of 1.4 x 105g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------146 Table A.38 Nitrogen analysis data for molecular weight of 6.11 x 104g/mole cationic
chitosan treated fabrics ---------------------------------------------------------------------147 Table A.39 Nitrogen analysis data for cationic glycerin treated fabrics--------------------147
x
LIST OF FIGURES
Figure 2.1 Molecular structure of a cellulose polymer chain -----------------------------------4 Figure 2.2 Crystalline and amorphous structure of cellulose -----------------------------------4 Figure 2.3 Molecular structure of DMDHEU-----------------------------------------------------8 Figure 2.4 Molecular structure of BTCA-------------------------------------------------------- 12 Figure 2.5 Reaction of chitosan with CHTAC in alkaline conditions ----------------------- 17 Figure 2.6 Reaction of cellulose with CHTAC in alkaline conditions----------------------- 19 Figure 2.7 Molecular structure of carboxymethyl cellulose ---------------------------------- 20 Figure 3.1 Reactions of cellulose with CAA that impart an anionic character ------------- 30 Figure 3.2 Reactions of cellulose with CHTAC that impart a cationic character ---------- 34 Figure 3.3 Huggins plot of ήsp/c versus c for the cationic chitosan -------------------------- 37 Figure 3.4 Reaction of chitosan with CHTAC-------------------------------------------------- 41 Figure 3.5 Conductometric titration curve of cationic chitosan ------------------------------ 43 Figure 3.6 FTIR spectrum of deacetylated chitosan ------------------------------------------- 46 Figure 3.7 FTIR spectrum of cationic chitosan------------------------------------------------- 47 Figure 3.8 1H-NMR spectrum of deacetylated chitosan --------------------------------------- 48 Figure 3.9 1H-NMR spectrum of O-substituted and N-substituted cationic chitosan ----- 50 Figure 3.10 Reaction of glycerin with CHTAC ------------------------------------------------ 52 Figure 3.11 Crosslinked anionic cellulose with calcium -------------------------------------- 56 Figure 3.12 Crosslinked cationic cellulose with BTCA --------------------------------------- 58 Figure 4.1 Effect of carboxyl content and concentration on dry wrinkle recovery angles of
cationic chitosan treated fabrics ------------------------------------------------------------ 62 Figure 4.2 Effect of carboxyl content and concentration on wet wrinkle recovery angles of
cationic chitosan treated fabrics ------------------------------------------------------------ 62 Figure 4.3 Effect of carboxyl content and concentration on %Nitrogen content of cationic
chitosan treated fabrics ---------------------------------------------------------------------- 64 Figure 4.4 The relationship between %Nitrogen content of the fabrics and dry/wet wrinkle
recovery angles ------------------------------------------------------------------------------- 65 Figure 4.5 Effect of molecular weight of chitosan and concentration on dry wrinkle
recovery angles of cationic chitosan treated fabrics ------------------------------------- 67 Figure 4.6 Effect of molecular weight of chitosan and concentration on wet wrinkle
recovery angles of cationic chitosan treated fabrics ------------------------------------- 67 Figure 4.7 Effect of carboxyl content and concentration on dry wrinkle recovery angles of
cationic glycerin treated fabrics ------------------------------------------------------------ 72 Figure 4.8 Effect of carboxyl content and concentration on wet wrinkle recovery angles of
cationic glycerin treated fabrics ------------------------------------------------------------ 72 Figure 4.9 Effect of carboxyl content and concentration on %Nitrogen content of cationic
glycerin treated fabrics----------------------------------------------------------------------- 74 Figure 4.10 The relationship between %Nitrogen content of the fabrics and dry/wet
wrinkle recovery angles --------------------------------------------------------------------- 75
xi
Figure 4.11 Effect of carboxyl content on dry wrinkle recovery angles of calcium and magnesium treated fabrics------------------------------------------------------------------- 77
Figure 4.12 Effect of carboxyl content on wet wrinkle recovery angles of calcium and magnesium treated fabrics------------------------------------------------------------------- 78
Figure 4.13 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of PCA treated fabrics ----------------------------------------------------------------------- 83
Figure 4.14 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles of PCA treated fabrics ----------------------------------------------------------------------- 84
Figure 4.15 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of BTCA treated fabrics --------------------------------------------------------------------- 85
Figure 4.16 Effect of% Nitrogen fixed and concentration on wet wrinkle recovery angles of BTCA treated fabrics --------------------------------------------------------------------- 86
Figure 4.17 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of EDTA treated fabrics --------------------------------------------------------------------- 88
Figure 4.18 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles of EDTA treated fabrics --------------------------------------------------------------------- 89
Figure 4.19 Effect of treatment on dry wrinkle recovery angles ----------------------------- 91 Figure 4.20 Effect of treatment on wet wrinkle recovery angles ----------------------------- 92 Figure 4.21 Effect of carboxyl content and concentration on breaking strength of the
cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics-------------- 94 Figure 4.22 Effect of carboxyl content and concentration on breaking strength of the
cationic glycerin treated fabrics ------------------------------------------------------------ 95 Figure 4.23 Effect of carboxyl content and concentration on breaking strength of the
calcium and magnesium treated fabrics --------------------------------------------------- 95 Figure 4.24 Effect of %Nitrogen content and concentration on breaking strength of the
PCA treated fabrics--------------------------------------------------------------------------- 97 Figure 4.25 Effect of %Nitrogen content and concentration on breaking strength of the
BTCA treated fabrics ------------------------------------------------------------------------ 97 Figure 4.26 Effect of treatment on breaking strength------------------------------------------ 99 Figure 4.27 Correlation between wet wrinkle recovery angles of cationic chitosan
(molecular weight of 1.4 x 105g/mole) treatment and tensile strength ---------------100 Figure 4.28 Correlation between wet wrinkle recovery angles of PCA treatment and
tensile strength -------------------------------------------------------------------------------101 Figure 4.29 Effect of carboxyl content and concentration on whiteness index of the
cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics-------------103 Figure 4.30 Effect of carboxyl content and concentration on whiteness index of the
cationic glycerin treated fabrics -----------------------------------------------------------103 Figure 4.31 Effect of carboxyl content and concentration on whiteness index of the
calcium chloride and magnesium chloride treated fabrics -----------------------------104 Figure 4.32 Effect of %Nitrogen fixed and concentration on whiteness index of the PCA
treated fabrics --------------------------------------------------------------------------------105
xii
Figure 4.33 Effect of %Nitrogen fixed and concentration on whiteness index of the BTCA treated fabrics --------------------------------------------------------------------------------106
Figure 4.34 Effect of treatment on whiteness index ------------------------------------------108 Figure 4.35 Effect of carboxyl content and concentration on stiffness of the cationic
chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics -----------------------110 Figure 4.36 Effect of carboxyl content and concentration on stiffness of the cationic
glycerin treated fabrics----------------------------------------------------------------------110 Figure 4.37 Effect of carboxyl content and concentration on stiffness of the calcium
chloride and magnesium chloride treated fabrics----------------------------------------111 Figure 4.38 Effect of %Nitrogen fixed and concentration on stiffness of the PCA treated
fabrics -----------------------------------------------------------------------------------------112 Figure 4.39 Effect of %Nitrogen fixed and concentration on stiffness of the BTCA treated
fabrics -----------------------------------------------------------------------------------------113 Figure 4.40 Effect of treatment on stiffness----------------------------------------------------115
1
1. INTRODUCTION
The textile market has shown an interest in the demand for easy care, wrinkle-
resistant for cellulosic fabrics over the years. Untreated cellulose has poor recovery,
because cellulose is stabilized by hydrogen bonds within and between cellulose chains.
Moisture between the polymer chains can invade the cellulose structure and can
temporarily release the stabilizing hydrogen bonds and hydrogen bonds in cellulose
experience frequent breaking and reforming when extended and newly formed hydrogen
bonds tend to hold cellulose chain segments in new positions when external stress is
released. Preventing wrinkling of cellulosic fabric can be accomplished by the
crosslinking of polymer chains, thus making intermolecular bonds between chains that
water cannot release. In a typical durable-press (DP) treatment, some hydrogen bonds are
replaced with covalent bonds between the finishing agent and the fiber elements. Because
covalent bonds are much stronger than hydrogen bonds, they can resist higher external
stress. Hence, treated cellulose has a higher initial modulus and better elastic recovery.
After the external force is released, the energy stored in the strained covalent bonds
provides the driving force to return chain segments back to their original positions.
Formaldehyde-based cellulose crosslinking was a very important textile chemical
breakthrough of the 1930's, and is still the basis for a vast array of modern finished cotton
products today. N-methylol crosslinkers have the biggest use in durable press finishing.
They give fabrics crease resistance, shrinkage control, anti-curl, and durable press, but
2
they also impart strength loss and release formaldehyde, a known human carcinogen. [1]
Today’s textile industry has for a long time been searching for durable press finishes that
can give same results as formaldehyde based finishes, but cause less strength loss and no
formaldehyde release. For example, polycarboxylic acids and citric acid have been used
with varying degrees of success. [2, 3]
We have developed multiple methods of forming ionic crosslinks to give non-
wrinkle effects to cellulosic fabric. [4] These includes, (1) treatment of cellulose with an
anionic material and reacting with a polycation, (2) treatment of cellulose with a cationic
material and then application of a polyanion, (3) treatment of cellulose with a
precondensate of an ionic reactive material and a polyelectrolyte of the opposite charge.
The performance of crosslinkers can be measured by dry and wet wrinkle recovery angle
(WRA). Dry WRA is important for outerwear clothing to help resist dry wrinkling during
wearing, but wet WRA is more important for bedding which is almost never ironed and
must resist wrinkling during laundering. We observed simultaneous enhancements of both
wet and dry WRA as well as significant strength gain and excellent washing durability.
Polyelectrolytes are strongly bond and thus do not desorb during laundering. The
chemicals are common industrial reactants and do not have unusual safety or
environmental issues. Processes use existing equipment and no high temperature curing is
necessary. In addition, ionic crosslinks may have other important advantages, such as
antimicrobial activity and enhanced dyeability.
3
2. LITERATURE REVIEW
2.1 Cellulose chemistry
We can only understand chemical as well as physical properties of cellulose by the
knowledge of both chemical nature of the cellulose molecules and their structural and
morphological arrangement in the solid, mostly fibrous, state. For example reactivity of
the functional sites in the cellulose molecules and structural characteristics of polymers
such as; inter- and intramolecular interactions, and size of crystallites and fibrils. These
structural characteristics of the cellulosic polymers influence the physico-mechanical
properties utilized in the textile industry. The largest part of the cellulosic polymers used
for textile substrates comes from cotton.
Cotton is a soft fiber that grows around the seeds of the cotton plant. The fiber is
most often spun into thread and used to make a soft, breathable textile. Cotton is a
valuable crop because only about 10% of the raw weight is lost in processing. [5] Once
traces of wax, protein, etc. are removed, the remainder is a natural polymer of pure
cellulose. This cellulose is arranged in a way that gives cotton unique properties of
strength, durability, and absorbency. After scouring and bleaching, cotton is 99% pure
cellulose. [6] Cellulose is a macromolecule made up of anhydroglucose units united by 1,
4, oxygen bridges as shown in Figure 2.1. The anhydroglucose units are linked together as
beta-cellobiose; therefore, anhydro-beta-cellobiose is the repeating unit of the polymer
chain. The number of these repeat units that are linked together to form the cellulose
polymer is referred to as the degree of polymerization and is between 1000 and 15000. [7]
4
O
O
OH
HH
H
H H
OHOH
OH
OO
OH
HH
H
H H
OH
OH
O
O
OH
HH
H
H H
OH
OH
O
OHOH
HH
H
H
HOH
OH
nCellulose
Figure 2.1 Molecular structure of a cellulose polymer chain
The cellulose chains within the cotton fibers tend to be held in place by hydrogen
bonding. These hydrogen bonds occur between the hydroxyl groups of adjacent molecules
and are more prevalent between the parallel, closely packed molecules in the crystalline
areas of the fiber as shown in Figure 2.2. [8]
Figure 2.2 Crystalline and amorphous structure of cellulose
The chemical characters of the cellulose molecules are determined by the
sensitivity of the three-hydroxyl groups, one primary and two secondary, in each repeating
cellobiose unit of cellulose, which are chemically reactive groups. These groups can
undergo substitution reactions in procedures designed to modify the cellulose fibers such
5
as esterification and etherification or in the application of dyes and finishes for
crosslinking. The hydroxyl groups also serve as principal sorption sites for water
molecules. Directly sorbed water is firmly chemisorbed on the cellulosic hydroxyl groups
by hydrogen bonding. [8] Of particular interest in the case of cellulosic fibers is the
response of their strength to variations in moisture content. Generally, in the case of
regenerated and derivative cellulosic fibers, strength decreases with increasing moisture
content. In contrast, the strength of cotton generally increases with increased moisture.
The contrast seen between the fibers in their response to moisture is explained in terms of
intermolecular hydrogen bonding between cellulose chains and their degree of
crystallinity. [8]
2.2 Cellulosic fabric’s nature of wrinkling
The textile market has shown an interest in the demand for easy care, wrinkle-
resistant for cellulosic fabrics over the years. Improvements in crease angle recovery
property are obtained by chemical treatments, which improve the ability of fibers to
maintain configurations in which they are treated. [9] Untreated cellulose has poor
recovery, because hydrogen bonds in cellulose experience frequent breaking and
reforming when extended, and newly formed hydrogen bonds tend to hold cellulose chain
segments in new positions when external stress is released. In a typical durable-press
treatment, some hydrogen bonds are replaced with covalent bonds between the finishing
agent and the fiber elements. Because covalent bonds are much stronger than hydrogen
bonds, they can resist higher external stress. Hence, treated cellulose has a higher initial
6
modulus and better elastic recovery. After the external force is released, the energy stored
in the strained covalent bonds provides the driving force to return chain segments back to
their original positions. However, chemical treatment on cellulose also causes the loss of
mechanical properties. [10] The classical explanation to this problem is that traditional
crosslinks are too rigid to allow cellulose chain segments to move.
2.3 Durable Press finishing of cotton
Durable press is shaping a garment and then treating it in such a way that after
wearing and washing it will return to its pre-set shape. In order to produce non-wrinkle
cellulosic fabrics the durable press finishing has been developed.
The original process for the production of crease resistant fabrics was developed in 1928.
[11] DP finishes have been marketed ever since. Durable press is accomplished by resin
treatments. The main purpose of resin treatments is to overcome a serious drawback of
cellulosic fabrics, for example their ease of wrinkling, which requires ironing after
washing. [12] Ideally, a DP finished fabric will wash and dry to a completely smooth
state. The usual method of production of crease resistant fabric consists of padding fabric
trough a crosslinking agent along with a catalyst and other additives, drying at 100-110oC
followed by curing at 155-175oC for 2-3 minutes. [13] The resulting fabric has the ability
of recovering from creases both when fabric is wet and dry. The selection of crossslinking
agents for DP finishing is important. There are a large number of cross linker available.
Some of the most common reagents are urea-formaldehyde derivatives, melamine-
7
formaldehyde derivatives and methylol derivatives. All of these reagents used for DP of
cellulosic fabric with varying degrees of success.
2.3.1 Urea-Formaldehyde derivatives
The first widely used crosslinking agent for DP finishing was urea-formaldehyde
adducts. These products are mostly prepared at the finishing plant; also precondensate are
available in the market. The treatment of fabrics with urea-formaldehyde resin involves
padding the fabric through precondensate and an acid catalyst, drying, curing and
washing. The advantages of urea-formaldehyde resins are the low cost and high
efficiency. The disadvantages are poor stability of the agent, poor durability and imparting
chlorine retention to the fabric. The chlorine retention is due to the presence of the –NH
groups which react with chlorine from the bleach or laundry bath. [14, 15, 16] The
reaction of –NH groups and chlorine produces hydrochloric acid and it is a strong acid
that causes tendering and yellowing of cellulose.
2.3.2 Melamine-Formaldyhe derivatives
The most commonly used melamine product is trimethylol melamine. It has good
stability and durability. Trimethylol-melamine is more expensive than urea-formaldehyde.
It picks up and retains chlorine, it also yellows the bleached fabric but the fiber
degradation due to strong acid is avoided because of basicity of the compound. [17, 18]
8
2.3.3 Methylol derivatives of cyclic ureas
These compounds are also referred to as fiber reactants, because they only react
with the cellulose instead of themselves. As a result insoluble resin on the surface of the
fabric is absent hence the finished fabric have a softer hand. The members of this group
are:
(a) Dimethylol ethylene urea (DMEU) has high reaction efficiency and low price. [19] It
can produce high wrinkle recovery angles at low add-ons. The finish with DMEU is
sensitive to acids and can be destroyed by acid treatment during laundering. (b)
Dimethylol propylene urea (DMPU) is suitable for white goods, since it does not produce
yellowing on heating. [20] Another advantage of it is that not giving any odor. But the
finish is not susceptible to chlorine retention damage. It is more expensive than others in
the group. (c) Dimethylol dihydroxy ethylene urea (DMDHEU) as shown in Figure 2.3. It
is the most commonly used DP finish agent and gives excellent crease angle recovery.
[21, 22]
NN
O
OHOH
OHOH
DMDHEU
Figure 2.3 Molecular structure of DMDHEU
9
It shows some chlorine retention therefore it is not recommended for white goods. It does
not effect the lightness of the dyes hence it is dominating the colored garments durable
press finishing.
2.3.4 Effects of formaldehyde based DP finishes on cellulose
Formaldehyde-based N-methylol reagents are the most common DP reagents. But
these reagents produce losses in tensile strength of cotton due to depolymerization of
cellulose chains. Cellulose depolymerization occurs with a polycarboxylic acid or a Lewis
acid, which are catalysts for formaldehyde based resins. As a result they cause a high
degree of depolymerization. A direct correlation between tensile strength loss of the
treated cotton and the molecular weight of cellulose was found. [23] Severe tensile
strength loss is a major disadvantage of DP finished cotton fabrics, and it continues to be
the major obstacle for DP applications. Most of the studies of mechanical strength of
durable press finished cotton fabrics in the past have focused on changes in the gross
properties of cotton fabrics, such as tensile strength and abrasion resistance. Another
disadvantage of N-methylol reagents is later formaldehyde release. In recent years there
have been extensive efforts to find non-formaldehyde alternatives due to increasing
concern with health risks associated with formaldehyde. On the other hand, the final
textile products not only have to be eco-friendly, but also have to be produced by clean
technologies. Crosslinking of cellulose with N-methylol crosslinking agents to impart
wrinkle-resistance, shrink proofing, and smooth drying properties by virtue of chemical
reaction with cellulosic hydroxyl groups to form covalent crosslinks in the interior of
10
cellulosic fibers have successfully been done. However, at the present time, presence of
formaldehyde in the finished product, working atmosphere, as well as in wastewater
streams is considered as highly objectionable due to the mutagenic activity of various
aldehydes, including formaldehyde. [24]
2.4 Recent developments in non-formaldehyde DP applications
Extensive research has attempted to develop nonformaldehyde crosslinking agents
to replace N-methylol compounds that release formaldehyde during production and
storage, which is proven to be carcinogenic. [25] Durable press finishing, used to
overcome wrinkling problems in cotton fabric for some years, involves chemical
crosslinking agents that covalently crosslink with hydroxyl groups of adjacent cellulose
polymer chains within cotton fibers. This crosslinking not only results in the fabric's
wrinkle resistance, but also in discoloration and impairment of fabric strength and of other
mechanical properties. The early chemical agents used for crosslinking with cellulose
were mostly formaldehyde and formaldehyde derivatives, which can form ether bonds
with cellulose. DMDHEU is the most widely used crosslinking agent because it provides
good durable press properties at a lower cost and an acceptable level of detrimental effects
on fabric strength and whiteness compared to other N-methylol agents. However, fabric
treated with DMDHEU tends to release formaldehyde vapors during processing, storage,
and consumer use. Because formaldehyde is toxic to human beings, several attempts have
been made to replace it with formaldehyde-free crosslinking agents.
11
Several polycarboxylic acids have served as durable press agents. Carboxylic
groups in polycarboxylic acids are able to form ester bonds with hydroxyl groups in
cellulose. The main advantages of polycarboxylic acids are that they are formaldehyde-
free, do not have a bad odor, and produce a very soft fabric hand. BTCA (1.2,3,4-
butcnetetracarboxylic acid) is the most effective polycarboxylic acid for use as a durable
press agent as shown in Figure 2.4. In the presence of sodium hypophosphite monohydrate
as catalyst, BTCA provides almost the same level of durable press performance and finish
durability with laundering as the conventional DMDHEU reactant, but its high cost may
be an obstacle to a mill's decision to use it as a replacement for the conventional durable
press reactant. As with DMDHEU, fabrics treated with polycarboxylic acids generally
lose their strength, [26] probably due to excess crosslinking with cellulose chains. This
may be tackled by using long-chain polycarboxylic acids, which can be obtained through
copolymerization of two unsaturated polycarboxylic acids.
BTCA satisfies many desirable requirements such as durability to laundering and
durable press performance. Crosslinking of cellulose molecules with BTCA increases
fabric wrinkle resistance at the expense of mechanical strength. [27]
12
COOH
COOH
COOH
COOH
BTCA
Figure 2.4 Molecular structure of BTCA
Severe tensile strength loss diminishes the durability of finished cotton garments.
The factors involved in strength loss of cotton fabric treated with BTCA include acid
catalyzed degradation of cellulose molecules and their crosslinking. The common
catalysts for polycarboxylic acids are phosphorous-containing compounds, although their
use has disadvantages such as high cost, strength loss and raises some environmental
concerns. In order to decrease strength retention other catalysts have been proposed;
among these is boric acid, [28] which was added to increase strength of the treated fabrics.
With this treatment, durable press properties were similar to those obtained with sodium
hypophosphite; moreover the mechanical resistance improved.
A previous study [29] indicated that cellulosic fabric treated with a copolymer
made with maleic and acrylic acids possesses the same level of wrinkle resistance as with
BTCA, while tensile strength retention improves slightly. Another disadvantage of
polycarboxylic acid finishing is yellowing of the treated fabric. It is proposed that the use
of a copolymer between acrylic and maleic acids as a durable press finishing agent can
improve crease angle recovery for cotton fabric. [29] However, the copolymer treatment
does not provide as good tensile strength and whiteness as DMDHEU.
13
Chitosan citrate has been evaluated as non-formaldehyde durable press finish to
produce wrinkle-resistance and antimicrobial properties for cotton fabrics. [30] The
carboxylic groups in the chitosan citrate structure were used as active sites for its fixation
onto cotton fabrics. The fixation of the chitosan citrate on the cotton fabric was done by
the padding of chitosan citrate solution onto cotton fabrics followed by a dry - cure
process. The factors affecting the fixation processes were systematically studied. The
antimicrobial activity and the performance properties of the treated fabrics, including
tensile strength, wrinkle recovery, wash fastness and whiteness index, were evaluated. The
finished fabric shows adequate wrinkle resistance, sufficient whiteness, high tensile
strength and more reduction rate of bacteria as compared to untreated cotton fabric.
A non-polluting system of applying an easy-care finish to cotton fabrics has been
proposed. [31] The new formulation is based on an aqueous system of BTCA-chitosan-
sodium hypophosphite and was applied by the traditional pad-dry-cure method to an
Egyptian poplin. The variables studied were the concentrations of BTCA and chitosan, the
time and temperature of polymerisation. The study also included a comparison with other
traditional or recommended systems. The treated fabric was tested for crease recovery
angle, resistance to traction, elongation to breakage, rigidity, wetability, whiteness,
nitrogen content and dyeability. It was concluded that the new formulation gave
comparable if not better results than the traditional treatments.
14
2.5 Ionic crosslinking
Ionic crosslinking has been used in the polymer industry for various applications.
It is an alternative to covalent crosslinks. It is well known that the thermal resistance,
durability, abrasion resistance, chemical resistance, etc., of a polymer are improved by
crosslinking. For example, acrylic copolymer sizes have been used for improving the
weaving properties of polyester filament warps. [32] Acrylic sizes produce good abrasion
resistance, high strength, good adhesion and easy removability. But when exposed to high
humidity many of the acrylics absorb water and cause blocking on the beam. In order to
improve the stability of acrylic sizes divalent cations are used for reduction of the
moisture regain. Calcium and magnesium ions were used [32] for reducing the water
sensitivity of sizes. These cations form ionic crosslinks between the polymer chains and
stabilize the structure against moisture. Also these crosslinks improved the strength
properties of the polymer film.
The copolymer of propylene and maleic anhydride is also crosslinked by ionic
bonding. It is considered that the ionic crosslinking by maleic anhydride groups is
possible by using not only of magnesium hydroxide but also of other metal compounds.
Magnesium 12-hydroxy stearate, zinc oxide, and zinc sulfide were chosen for ionic
crosslinking. Accordingly, by changing the kind and content of the metal compounds, the
viscosity can be freely controlled. Considering also other rheological characteristics, these
ionically crosslinked compounds are assumed to show ideal flow processabilities except
for the extrudate appearance [33,34]
15
A series of siloxane-based liquid-crystalline elastomers were synthesized by using
ionic crosslinking agents containing sulfonic acid groups. The ions aggregated in domains
forces the siloxane chains to fold and form an irregular lamellar structure. Ionic
aggregates and liquid crystalline segments may be dispersed among each other to form
multiple blocks with increasing ionic crosslinking content. [35]
In a previous work [36] a vulcanized carboxylated nitrile rubber compound was
prepared using a mixed crosslinking system employing a mixture of zinc peroxide and
sulphur accelerators as vulcanizing agents to produce ionic and covalent structures.
Because of the existence of carboxyl groups in the polymeric chain, crosslinked polymers
of ionic nature can be obtained when a bivalent metal oxide, such as zinc oxide, is used as
a crosslinking agent. Ionic vulcanized compounds with properties equal to or better than
those produced using sulphur accelerators can also be obtained in the same way using
metal peroxides.
Polyurethanes are a versatile class of materials; their end applications dictate the
structure and morphology during synthesis. From the prepolymer stage through chain
extension and in the required cases of final crosslinking, there are many ways to influence
the final characteristics of the polyurethanes. Crosslinked networks are obtained through
ionic crosslinking and the different approaches produce cationic, anionic and Zwitter ionic
polyurethanes. These networks find a variety of applications as coatings, adhesives,
shoe soles, and vibration damping materials. [37]
16
2.6 Preparation of quaternized polymers
Conversion to quaternary ammonium salts gives products whose degree of
ionization is pH-independent. Such polymers can be prepared by reaction of polymers
with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHTAC).
2.6.1 Chitosan and its reaction with CHTAC
Chitosan is the deacetylated form of chitin, poly [β-(1→4)-2-deoxy-D-
glucopyranose], is the second most abundant natural polymer next to cellulose. Chitosan
is a linear copolymer composed mainly β-(1→4)-2-amino-2-deoxy-D-glucopyranose and
partially β-(1→4)-2-acetamido-2-deoxy-D-glucopyranose residues. [38] Chitosan can be
dissolved in diluted acids by being protonated to soluble polyammonium salt. Hydroxyl
and amino groups of chitosan can react with epoxides by a ring opening reaction in either
present of a base or neutral conditions. These reactions were performed previously. [4, 39]
Kim at al performed the reaction between chitosan and CHTAC at neutral conditions.
They proved by FTIR and H1-NMR that the product they produced had a degree of
substitution larger than 60% and substitutions formed at NH2 sites. Because the hydroxyl
groups of chitosan are not sufficiently nucleophilic under neutral conditions, N-substituted
cationic chitosan can be obtained under neutral conditions.
On the other hand; in alkali conditions the hydroxyl groups of chitosan are
nucleophilic therefore reaction of chitosan and CHTAC produce O-substituted cationic
chitosan. Hasem at al performed the reaction under highly alkaline (pH=11-12) conditions
and they believe that the product was O-substituted cationic chitosan and soluble at
17
neutral conditions. Both of the products have cationic properties and can be used as a
cationic polyelectrolyte to form ionic crosslinks and anti-microbial finish for cellulosic
fabrics. [30, 40] Figure 2.5 shows the reaction of chitosan with CHTAC in alkaline
conditions.
O
O
NH2
HH
H
H H
OHOH
OH
OO
NH2
HH
H
H H
OH
OH
O
O
NH2
HH
H
H H
OH
OH
O
OHNH2
HH
H
H
HOH
OH
n
O
O
NH2
HH
H
H H
OHOH
O
OO
NH2
HH
H
H H
OH
O
O
O
NH2
HH
H
H H
OH
O
O
OHNH 2
HH
H
H
HOH
O N+
CH3
CH3
CH3O H
N+
CH3
CH 3
CH3O H
N+
CH 3
CH3
CH 3O H
N+
CH3
CH3CH3O H
n
Chitosan
N+
CH3
CH3
CH3
ClO H
N+
CH3
CH3
CH3O
Na OH
3-chloro- 2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride
N+
CH3
CH3
CH3O
+
Cationic chitosan
Cl Cl
Cl
Cl Cl
Cl
Cl
(EPTAC)(CHTAC)
Figure 2.5 Reaction of chitosan with CHTAC in alkaline conditions
18
2.6.2 Reaction of Cellulose with CHTAC
The cationization of cellulose with using CHTAC has been previously studied.
[41,42,43] The process basicly takes place in two stages. From practical point this occurs
in a single process. Sodium hydroxide (NaOH) is the base catalyst. The cationic character
of cellulose is independent from pH. In the first stage the epoxide form of CHTAC formed
in the presence of NaOH. In the second stage this epoxide reacts with a hydroxyl group in
the cellulose.
The reaction efficiency for cationization of cellulose is low due to hydrolysis
reaction of CHTAC. Hydrolyzed CHTAC is no longer reactive therefore the efficiency is
less than perfect. There are many ways to perform the reaction for example, pad-batch,
pad-steam, exhaust, and pad-dry-cure methods. [42] All of these procedures give different
values of efficiency. The pad-batch process is consist of padding the fabric through a
mixture of NaOH and CHTAC solution at room temperature and followed by holding at
room temperature for 24 hours. The exhaustion procedure was studied at 75oC for 90
minutes. The mole ratio of NaOH and CHTAC varied. Also different solvent systems
were experimented such as; water, acetone, ethanol, isopropanol, and methanol. The
highest cationization level was obtained with acetone. The pad-steam application was
consist of padding the fabric through the mixture of CHTAC and NaOH and steaming at
100oC for 30 minutes. The pad-dry-cure method investigated at using different drying and
curing times and temperatures. The mole ratio of NaOH and CHTAC was also varied. The
best conditions for this application was after padding the fabrics drying at 35oC for 5
minutes followed by curing at 110oC for also 5 minutes. The exhaust method gave under
19
10% substitution, pad-batch and pad steam methods are more efficient, and they produced
about 25% substitution. The pad-dry-cure methods give fixations around 85%. The
efficiencies for all the methods decreased when increasing in concentration of CHTAC.
The optimum mole ratio was determined as 1.8 or greater. [42]
O
O
O H
HH
H
H H
OHOH
O H
OO
O H
HH
H
H H
OH
O H
O
O
O H
HH
H
H H
OH
O H
O
O HO H
HH
H
H
HOH
O H
n
O
O
O H
HH
H
H H
OHOH
O
OO
O H
HH
H
H H
OH
O
O
O
O H
HH
H
H H
OH
O
O
O HO H
HH
H
H
HOH
O N+
C H 3
C H 3
C H 3O H
N+
C H 3
C H 3C H 3O H
N+
C H 3
C H 3
C H 3O H
N+
C H 3
C H 3
C H 3O H
n
Cellulose
N+
C H 3
C H 3
C H 3O
+
Cationic cellulose
Cl
Cl Cl
Cl
Cl
N+
C H 3
C H 3
C H 3
C lO H
N+
C H 3
C H 3
C H 3O
N a O H
3 -chloro- 2 -hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride
Cl Cl
(EPTAC)(CHTAC)
Figure 2.6 Reaction of cellulose with CHTAC in alkaline conditions
20
2.7 Carboxymethylation of cellulose
Carboxymethylcellulose (CMC) is a derivative of cellulose that can be formed by
its reaction with alkali and chloroacetic acid. The CMC structure is based on the β-(1→4)-
D-glucopyranose polymer of cellulose as shown in Figure 2.7. Different preparations may
have different degrees of substitution. [44] CMC molecules are somewhat shorter, on
average, than native cellulose with uneven derivatization giving areas of high and low
substitution. This substitution is mostly 6-O-linked, followed in order of importance by 2-
O, 2,6-di-O- then 3-O-, 3,6-di-O-, 2,3-di-O- lastly 2,3,6-tri-O-.linked. It appears that the
substitution process is a slightly cooperative (within residues) rather than random process
giving slightly higher than expected unsubstituted and trisubstituted areas.
O
O
OH
HH
H
H H
OHOH
O
OO
OH
HH
H
H H
OH
O
O
O
OH
HH
H
H H
OH
O
O
OHOH
HH
H
H
HOH
O
O
O
O
O
O
O
O
On
Figure 2.7 Molecular structure of carboxymethyl cellulose
CMC molecules are most extended (rod-like) at low concentrations but at higher
concentrations the molecules overlap and coil up. The average chain length and degree of
substitution are of great importance. At low pH, CMC may form cross-links through
carboxylic acid and free hydroxyl groups.
21
Cellulosic fabrics can react with several materials, which impart an anionic
character to it, for example, chloroacetic acid (CAA) and chlorosulfonic acid [4] and
sodium, 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate [45].
In a perivious study [4] carboxymethylation process was experimented first padding the
cellulosic fabric through sodium hydroxide solution, which opens the struchture of
cellulose, drying at a mild temperature and then padding through chloroacetic acid
solution and holding the fabric in a plastic bag at 70oC for 1 hour.
2.8 Proposed Research
Today’s textile industry has for a long time been searching for durable press finishes that
can give the same advantages as formaldehyde based finishes, but cause less strength loss
and no formaldehyde release.
We have developed multiple methods of forming ionic crosslinks to give non-
wrinkle effects to cellulosic fabric. These include, (1) treatment of cellulose with an
anionic material and reacting with a polycation, (2) treatment of cellulose with a cationic
material and then application of a polyanion, (3) treatment of cellulose with a
precondensate of an ionic reactive material and a polyelectrolyte of the opposite charge.
Methods 1 and 2, which we studied in this research, involve a pretreatment step for the
cellulosic fabric, but the third method is very similar to commercial DP applications. The
performance of crosslinkers can be measured by dry and wet wrinkle recovery angle
(WRA). Dry WRA is important for outerwear clothing to help resist dry wrinkling during
use, but wet WRA is more important for bedding which is almost never ironed and must
22
resist wrinkling during laundering. We observed simultaneous enhancements of both wet
and dry WRA. In addition, ionic crosslinks may have other important advantages, such as
antimicrobial activity and enhanced dyeability.
Cellulose can react with several materials, which impart an anionic character to it,
such as chloroacetic acid (CAA). On the other hand, cellulose can also react with cationic
materials that impart cationic character to it, for instance 3-chloro-2-hydroxypropyl
trimethyl ammonium chloride (CHTAC). Our work is based on Methods 1 and 2, the first
consisting of the reaction of cellulose with CAA, which producing partially
carboxymethylated cellulose, followed by a treatment with a polycation, such as,
cationized chitosan, cationized glycerine, cationized ethylene glycol, cationized dextrose
or cationized D-celobiose. We also observed WRA improvements with divalent cations
such as Ca++ and Mg++. Method 2 consists of the reaction of cellulose with CHTAC to
produce cationic cellulose, followed by the application of polyanion, such as,
polycarboxylic acids (PCA), 1,2,3,4-butanetetracarboxylic acid (BTCA),
ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid, trisodium salt, monohydrate
(NTA), ethylenediamine di(o-hydroxyphenylacetic acid (HEDTA), oxalic acid, citric acid,
or malic acid.
Both methods gave promising results with excellent washing durability.
Polyelectrolytes are strongly bond and thus do not desorb during washing. These
chemicals are common industrial reactants and there is also no unusual safety or
environmental issues. No high temperature curing is necessary. The processes utilize
existing equipment and similar processes are already widely used.
23
3. EXPERIMENTAL PROCEDURES
The materials, equipments and experimental procedures used in this study are
described in this section. The fabric is characterized, and the chemicals are identified their
manufacturers and chemical names. The equipment is described, and manufacturers are
named. Also the synthesis of experimental products and their application are presented.
The test procedures are listed, and detailed descriptions can be found in the appropriate
references.
3.1 Test Materials
The materials that used in this project are given in the table below including
names, brief descriptions and manufacturers.
Table 3.1 Test materials and chemicals Name or Group
Description Manufacturer
Cotton fabric Plain weave, style 400, 102 g/m2, 44”- 45”, 78 X 76, ISO 105/F02
Testfabrics Inc
Cationic agent
3-chloro-2-hydroxypropyl trimethyl (CHTAC) ammonium chloride, 69% solution
Dow Chemical
Oxidation agent
Sodium nitrate, 97.25%,m.p. 306°C, b.p. 380°C
Acros Organics
Base Sodium hydroxide, 50% aqueous solution Fisher Chemicals
Calcium chloride dehydrate, 77-80% CaCl2 Fisher Chemicals Salts Magnesium chloride hexahydrate, 99%
MgCl2 Fisher Chemicals
Ethylene glycol dimethyl ether 99+%, b.p. 84
oC -86oC Fisher Chemicals
Alcohols Glycerol, 99+%, b.p. 290°C Fisher Chemicals
24
Table 3.1 Test materials and chemicals continued CROSSLINK RB 105, Aqueous solution of polycarboxylic acids
BioLab Water Additives
CROSSLINK RB 120, 1,2,3,4-Butanetetracarboxylic acid
BioLab Water Additives
HEDTA, Ethylenediamine di(o-hydroxyphenylacetic) acid, trisodium salt
Lynx Chemical Group, LLC
NTA, Nitrilotriacetic acid, trisodium salt monohydrate, 92-94% aqueous solution
Hampshire Chemical Corporation
Polyanions
EDTA, Ethylenediaminetetraacetic acid, tetrasodium salt, 39% aqueous solution
BASF Corporation
Chitosan, medium viscosity with nominal degree of deacetylation of 91.5%
Vanson HaloSource, Inc.
Dextrose, D-(+)-Glucose, anhydrous Acros organics
Polysaccharides Cellobiose, D (+)-Cellobiose, 98% ,m.p.
239°C Acros Organics
Monochloro acetic acid, 99 + % Aldrich Chemical Company, Inc.
Oxalic acid anhydrous 98%, m.p. 189°C Acros Organics
DL-Malic acid 99%, m.p. 130°C to 132°C Acros Organics
Acids
Citric acid anhydrous 99%, m.p. 153°C to 154.5°C
Acros Organics
Ion exchange resin
Amberlite IRA-402 (Cl- form), 200g, 1.25 meq/mL, 4.1 meq/g
Fisher Chemicals
25
3.2 Equipments
Stirring was performed using a Fisher Hot Plate. A Fisher Scientific Co. model
600-pH meter was equipped with a standard combination pH electrode. Intrinsic viscosity
and viscosity average molecular weight determinations and cationization reactions were
performed in a water bath with an electrical temperature controller and a heavy-duty
stirrer. Application of finishes and ionic materials were performed using a 14-inch
Laboratory padding machine manufactured by Werner Mathis AG. Fabrics were dried and
cured, to their original dimensions on 7 X 12 inch metal pin frames, in a forced air oven
manufactured by Werner Mathis AG.
3.3 Application procedures
The ionic crosslinkers were applied to untreated and ionic cellulosic fabrics by
using three kinds of procedure. The procedures are given below.
3.3.1 Pad dry cure
Approximately 7 X 12 inch fabric samples were used. The fabrics dipped into the
various concentrations of aqueous polyelectrolyte solutions, followed by squeezing to a
wet pick up of approximately 100%. Then the wet fabric samples were pinned to the
original 7 X 12 inch dimensions, dried at 85oC for 5 minutes and cured at 140oC for 1.5
minutes. Finally the treated samples were washed using 2g/L nonionic wetting agent at
100oC for 10 minutes, rinsed with hot and cold water, centrifuged and dried at room
temperature for 24 hours.
26
3.3.2 Pad batch
The same size samples as in pad dry cure application were used. The fabrics were
padded through the ionic crosslinker solutions and squeezed to a wet pick up of
approximately 100%. Then the wet fabrics put into plastic bags, sealed and hold for 18
hours at room temperature. Followed by washing and drying the treated samples as
described above.
3.3.3 Exhaustion
The samples were put into 500mL glass beaker. Ionic crosslinker solution was
charged into the beaker. The bath ratio of fabric weight to weight of the bath was 1:15.
Then the beakers were located into a water bath and temperature raised to 95oC with a rate
of approximately 2oC/minutes and hold for 1 hour. The solution was stirred using an
electrical stirrer. Finally the samples were washed and dried as described previously.
3.4 Analysis and physical property tests
Including nitrogen, Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear
Magnetic Resonance (NMR) were performed. Physical properties of untreated and treated
cellulosic fabrics including wrinkle recovery angles; tensile strength, stiffness and
whiteness index were also tested. The precise procedures are given below.
27
3.4.1 Nitrogen analysis
The nitrogen analysis was performed using a Leuco CHN analyzer. The analysis
performed using EDTA as standard and 3 independent samples approximately 0.1g each.
3.4.2 FT-IR analysis
FTIR analysis needs only a small sample size and it doesn’t take a long time
therefore it is one of the most useful techniques in polymer characterization. All IR
spectra in this work were obtained by using a Nicolet 510P FT-IR spectrophotometer. The
data collection parameters were 2.0 cm-1 resolution and 64 scans. The samples were
prepared as KBr pellets and were scanned against a blank KBr pellet backround. The
spectra contain absorbance on the y-axis and wavelength on the x-axis.
3.4.3 1H- NMR analysis
Nuclear Magnetic Resonance spectroscopy is a powerful technique for
determining the structure of simple inorganic to complex biochemical compounds. [46]
The usefulness of this technique in chemistry can be attributed to the very detailed
information obtained by NMR. For example in IR spectroscopy the spectroscopic features
are correlate with groups of atoms but in NMR spectroscopy the features correlates with
the individual atoms. Therefore much more detailed information can be obtained. The 1H-
NMR analysis was performed using GE NMR 300Ω (300 MHz) spectrometer at room
temperature and sodium 3-(trimethylsilyl) propane sulfonate was used as an internal
reference.
28
3.4.4 Wrinkle recovery angles
Wrinkle recovery angles were measured according to AATCC Standard Test
Method 66 option 2, Wrinkle Recovery of Fabrics: Recovery Angle Method. The wrinkle
recovery angles were recorded as the added total of warp and weft averages.
3.4.5 Tensile strength
The tensile strength of untreated and treated fabrics was determined with a
Syntech tensile strength tester according to ASTM Test Method D5035. Cellulosic fabrics
were tested only at warp direction and the breaking load (Lb) of the fabrics recorded.
3.4.6 Whiteness index
Using Spectraflush SF600X a double beam spectrophotometer, manufactured by
DataColor, CIE standard illuminant D65 and 1964 10o observer the CIE Whiteness Index
measurements of the cellulosic fabrics were performed according to AATCC test method
110, whiteness of textiles. Six measurements were obtained for each sample and average
value was calculated and recorded.
3.4.7 Stiffness
Stiffness measurements of fabrics were determined according to ASTM D 1388-96
Option A, Cantilever Test method. The bending length (cm) and the flexural rigidity (mg
X cm) of the fabrics were calculated and recorded. The fabrics were tested in the warp
direction.
29
3.5 Reaction of cellulose with chloroacetic acid
Cellulosic fabric was treated with anionic and cationic materials to produce ionic
cellulose. This approach gave us the opportunity of forming ionic crosslinks with using
both cationic and anionic polyelectrolytes.
The optimum conditions for carboxymethylation of cotton using CAA and
determination of carboxyl content were extracted from previous work. [4] Cotton fabric
samples were soaked in 20% NaOH aqueous solution for 10 minutes at room temperature
and squeezed to a wet pick up of approximately 100%. The samples were dried at 60oC
for 10 minutes. Then, the alkali treated samples were steeped in aquous solutions of
sodium salt of CAA with concentrations of 0, 0.5, 1, 1.5, and 2.5M, for 5 minutes and
squeezed to approximately 100% wet pick up. Sodium salt of CAA was prepared with
sodium carbonate. After the samples are packed in polyethylene bags and held at 70oC for
1 hour, they were washed several times with water (hot and cold), acidified with 0.2M
acetic acid and washed with distilled water to adjust pH of 7. Finally, they were dried at
RT for 24 hours.
Figure 3.1 shows the production of anionic cellulose in three steps. Note that the
crosslinks are bonded to cellulose through a very stable ether linkage.
30
O
O
OH
HH
H
H H
OHOH
OH
OO
OH
HH
H
H H
OH
OH
O
O
OH
HH
H
H H
OH
OH
O
OHOH
HH
H
H
HOH
OH
n
O
O
OH
HH
H
H H
OHOH
O
OO
OH
HH
H
H H
OH
O
O
O
OH
HH
H
H H
OH
O
O
OHOH
HH
H
H
HOH
O
O
O
O
O
O
O
O
On
Cellulose
ClO
O
Na
Na OH
Chloroacetic acid (Sodium salt)
+
Anionic cellulose
Figure 3.1 Reactions of cellulose with CAA that impart an anionic character
31
The carboxylic acid group content of the partially carboxymethylated cellulosic
fabrics were determined. [4] Cotton fabrics were cut into small pieces, 100mL of 0.5%
aqueous HCl solution prepared and fabric samples were steeped in it for 16 hours. The
samples were then filtered off and washed several times with distilled water until free
from HCl and having a pH of 7. Silver nitrate drop test was performed and it showed no
presence of chloride. The samples were dried at 105oC for 3 hours. Accurate weight of
samples (exactly 0.2g each) was soaked in 25mL of 0.05N aqueous NaOH solutions at
room temperature for 4 hours. First, a blank solution (solution without any sample) was
titrated with 0.05N aqueous HCl solution. Phenolphthalein pH indicator was used. The
volume of HCl solution (mL) spent was recorded for the blank. Then, each of the
solutions with different carboxymethylated samples was titrated in the same way as the
blank. The carboxyl contents of samples were calculated as follows:
mmols carboxymethyl content per 100 grams = 100 Χ (Vblank - Vsample)HCl Χ NHCl / 0.2
Where Vblank is the volume of HCl used for titration of blank solution, Vsample is the
volume of HCl used for titration of sample solution, and NHCl is the normality of
HCl titrant. Finally, we obtained five different carboxymethylation: 6.2, 30.2, 60.7, 87.1,
and 114.5 mmols of carboxymethyl groups per 100g of fabric, as determined by titration.
Table 3.2 shows the summary of the titration process.
32
Table 3.2 Results for carboxymethylation of cellulosic fabrics (Vblank=23.8ml)
Treatment CAA concentration
(M)
Sample no
Weight of sample
(g)
Vsample Carboxyl content
mmol/100g None
0 0 0.243 23.5 6.24
Carboxymethylation
0.5 1 0.258 22.25 30.21
Carboxymethylation
1 2 0.256 20.7 60.73
Carboxymethylation
1.5 3 0.253 19.45 87.12
Carboxymethylation
2.5 4 0.26 17.85 114.54
3.6 Reaction of Cellulose with CHTAC
Cationic cellulose was produced by cold pad batch treatment of fabrics with
mixtures of different mole ratios of CHTAC, cationization reagent, and NaOH. [42] We
used four different mol ratios, 0.46 /0.95, 1.28 /1.53, and 1.83 /2.2 respectively. Aqueous
solutions of each reactant were prepared separately as follows: A known amount of NaOH
was charged into a 1L beaker and filled with distilled water to 500mL and cooled to RT.
In the same way, a known amount from CHTAC solution was charged into another beaker
and filled with distilled water to 500mL. These two solutions were mixed in a 1000mL
beaker and cooled to RT in ice and immediately applied onto cotton as follows: fabrics
were padded through the CHTAC/NaOH solutions, squeezed to a wet pick up of
approximately 100% and rolled on to a beam. The fabrics were then covered with plastic
to stop air interaction and held overnight at RT. Finally, fabrics were
33
washed with a nonionic wetting agent at boiling temperature for 10 minutes, centrifuged
and dried at RT for 24 hours. Application with the last mole ratio (1.83/2.2) was repeated
multiple times in order to accomplish higher degrees of cationization.
The possible reaction mechanism is shown in Figure 3.2. Note that the crosslinks
are also bonded to cellulose through a very stable ether linkage. Percent nitrogen fixed
onto cellulosic fabric used for quantitatively characterization of cationic cellulose. The
level of nitrogen fixed for each treatment was determined by Nitrogen analysis. The
nitrogen levels of untreated and treated fabrics were as follows: 0.24%, 0.45%, 0.73%,
1.15% and 1.54% respectively.
34
O
O
OH
HH
H
H H
OHOH
OH
OO
OH
HH
H
H H
OH
OH
O
O
OH
HH
H
H H
OH
OH
O
OHOH
HH
H
H
HOH
OH
n
O
O
OH
HH
H
H H
OHOH
O
OO
OH
HH
H
H H
OH
O
O
O
OH
HH
H
H H
OH
O
O
OHOH
HH
H
H
HOH
O N+
CH3
CH3
CH3OH
N+
CH3
CH3CH3OH
N+
CH3
CH3
CH3OH
N+
CH3
CH3
CH3OH
n
Cellulose
N+
CH3
CH3
CH3O
+
Cationic cellulose
Cl
Cl Cl
Cl
Cl
N+
CH3
CH3
CH3
ClOH
N+
CH3
CH3
CH3O
Na OH
3-chloro-2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride
Cl Cl
(EPTAC)(CHTAC)
Figure 3.2 Reactions of cellulose with CHTAC that impart a cationic character
35
3.7 Synthesis of compounds
All the compounds synthesized in this research are given below with detailed
procedures and characterization methods.
3.7.1 Molecular weight determination of chitosan
The viscosity average molecular weight (Mv) of chitosan can be determined by the
Mark Houwink equation, [47] where [ή] is intrinsic viscosity determined from a Huggins
plot and k and α are empirical coefficients dependent on the DD of chitosan.
[ή]=k Mvα
Wang and coworkers established the functional relationships for k and α as a function of
%DD of chitosan when chitosan is dissolved in 0.2M CH3COOH/0.1M CH3COONa
aqueous solution at 30oC.
k=1.64 * 10-30 * (%DD)14
α=-1.02 * 10-2 * (%DD) + 1.82
The Mv of chitosan was determined by the method of Wang et al. [47] A known amount
of thoroughly dried chitosan was dissolved in 0.2M CH3COOH/0.1M CH3COONa
aqueous solutions and a series of dilute solutions were prepared. A Cannon-Ubbelohde
semi- micro Viscometer (size 1, No. J536, Viscometer Constant=0.00745 mm2/s2 (cSt/s)
36
was charged with 3mL of each solution and equilibrated to 30oC in a water bath. Three
flow times were recorded at each concentration and averaged. Specific viscosity
(ήsp) were calculated according to the following equation,
ήsp= (t – ts)/ ts
Where t is a sample flow time and ts is a solvent flow time. The result of viscosity
measurements is reported in Table 3.3.
Table 3.3 Scheme of intrinsic viscosity measurement for the low viscosity chitosan. c (g/mL) Solvent 0.002499 0.001999 0.001499 0.000999 0.000499
time (sec) 89.75 320.56 265.19 211.99 161.8 122.47
ήsp 2.571699 1.954763 1.362006 0.802786 0.364568
ήsp/c 1029.091 977.8706 908.6095 803.5891 730.5977
The intrinsic viscosity [ή] was determined by the extrapolating the linear
regression of plots of ήsp/c versus c, where c is concentration of chitosan solution (g/mL),
to zero concentration as shown in Figure 3.3. The DD obtained from the manufacturer
certificate of analysis of the chitosans. Also DD was used to calculate k and α, which were
used together with [ή] to calculate Mv of chitosans using the Mark-Houwink equation.
Table 3.4 shows the properties of the chitosan.
37
Figure 3.3 Huggins plot of ήsp/c versus c for the cationic chitosan
Table 3.4 Properties of the Low Viscosity chitosan.
Chitosan %DD k α [ή] Mv
Low Viscosity
93.5 0.006400389 0.8663 658.73 6.11*105
3.7.2 Depolymerization of chitosan and characterization
The hydrolytic fragmentation of chitosan with HCl, and the oxidative
fragmentation with NaNO3 and H2O2
are the possible chemical methods. [48] HCl
fragmentation can be done at 65oC. Oxidative reactions take place at room temperature.
The number of chain scission depended on the concentration, time and temperature of the
chemical reagents. A previous work done by M. R. Kasaai showed that the rates of
y = 154254x + 658.73R2 = 0.9867
0
200
400
600
800
1000
1200
0 0.001 0.002 0.003
Concentration (g/mL)
intr
insi
c vi
s. /
conc
entr
atio
n
38
fragmentation with HCl and NaNO3 are higher than with H2O2. Also he examined the
chemical structure of chitosan and of its fragments by 1H-NMR spectroscopy. The
fragmentation process with H2O2 and NaNO3 did not alter the chemical structure and
degree of acetylation significantly. However, in acid hydrolysis, the degree of acetylation
decreased somewhat with fragmentation. The polydipersity of the fragments by the
chemical methods were similar and similar to the original one. Higher values of chain
scission were obtained with oxidative fragmentation with NaNO3 in shorter duration. The
initial rate of hydrolysis and oxidation with NaNO3were faster than the others. Also
oxidative degradation of chitosan with NaNO3 can be easily performed at room
temperature and desirable fragments can be achieved in relatively shorter durations.
Therefore we choose the oxidative degradation of chitosan with NaNO3.
The chitosan fragmentation is studied at 7.25 X 10-4M and 2.9 X 10-3M
concentrations of NaNO3 in a filtered initial chitosan solution (1% chitosan was dissolved
in 0.1M aqueous acetic acid solution). Reaction performed at room temperature with
constant stirring for various times. After the reaction, chitosan is recovered from the
reaction mixture as follows: The reaction mixture is neutralized with 1N NaOH to
precipitate the depolymerized chitosan. The chitosan is recovered by vacuum filtration
and remaining solid chitosan washed several times with distilled water to pH 7. Polymer is
collected in a drying bottle and dried at 70oC overnight in an air forced oven. Final drying
was done in a vacuum oven at 70oC for 24 hours.
A known amount from each recovered depolymerized chitosan was dissolved in
0.2M CH3COOH/0.1M CH3COONa aqueous solution at 30oC. The intrinsic viscosities
39
and the viscosity average molecular weight of depolymerized chitosan were determined
by the same method used to determine the molecular weight of original chitosan but with
different viscometer. The viscometer that was used is a Cannon Ubbelohde semi-micro
Viscometer (size 75, No. N177, Viscometer constant = 0.00745 mm2/s2 (cSt/s)). Table 3.5
summarizes the results of depolymerization of chitosan.
Table 3.5 Intrinsic viscosity and Mv of depolymerized chitosan
NaNO3
concentration (M)
Time (minutes) Intrinsic viscosity Viscosity average
molecular weight
350 310.52 2.5 X 105
460 221.4 1.7 X 105
7.25 X 10-4
695 184.21 1.4 X 105
465 70.678 4.6 X 104
690 56.055 3.5 X 104
2.9 X 10-3
1410 51.045 3.2 X 104
3.7.3 Reaction of chitosan with CHTAC
The optimum condition for quaternization of chitosan has been extracted from
[40]. Three different molecular weights of chitosan were cationized as follows: 41.75g of
original chitosan with a molecular weight of 611000g/mole were added into 300g CHTAC
in a 2L glass beaker (1:4 mole ratio) and stirred for 10 minutes. 60mL of NaOH (50%)
40
was added drop wise into slurry to adjust the pH of 10 to 11. 1L of deionized water was
added to create a reaction medium to produce a better contact between quat and chitosan
molecules. The slurry was constantly stirred at 60oC for 20 hours in a water bath. Then,
the temperature was raised to 95oC and stirring was resumed for another 4 hours. The
product was then cooled to room temperature, filtered, and pH adjusted to 7 with acetic
acid. Figure 3.4 shows the possible reaction between chitosan and quat molecules.
The resulting reaction mixture was recovered by drying; the product had a high
degree of cationization and was easily redissolved in water at RT. With the same
procedure chitosans with molecular weight of 1.4 x 105g/mole and 3.2 x 104g/mole were
also cationized.
The solid content of each reaction mixture was determined by drying a known amount of
product at 70oC for 48 hours in an air forced oven. The solid content of each product was
used to prepare the polyelectrolyte solutions prior to crosslinking process.
41
O
O
NH2
HH
H
H H
OHOH
OH
OO
NH2
HH
H
H H
OH
OH
O
O
NH2
HH
H
H H
OH
OH
O
OHNH2
HH
H
H
HOH
OH
n
O
O
NH2
HH
H
H H
OHOH
O
OO
NH2
HH
H
H H
OH
O
O
O
NH2
HH
H
H H
OH
O
O
OHNH2
HH
H
H
HOH
O N+
CH3
CH3
CH3OH
N+
CH3
CH3
CH3OH
N+
CH3
CH3
CH3OH
N+
CH3
CH3CH3OH
n
Chitosan
N+
CH3
CH3
CH3
ClOH
N+
CH3
CH3
CH3O
Na OH
3-chloro-2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride
N+
CH3
CH3
CH3O
+
Cationic chitosan
Cl Cl
Cl
Cl Cl
Cl
Cl
(EPTAC)(CHTAC)
Figure 3.4 Reaction of chitosan with CHTAC
42
3.7.3.1 Characterization of cationic chitosan by conductometric titration method
The amount of substitution on chitosan was obtained. Reaction between chitosan
and quat was done under alkali conditions, therefore it was expected that the product
could have some OH- ions as counter ions of quaternary ammonium salts. The OH- ions
must be exchanged to Cl- ions for characterization of degree of substitution (DS) by
conductometric titration. For this procedure, an ion-exchange column was prepared. [49]
Ion-exchange resin (Amberlite IRA-402 (Cl- form), 200g, 1.25 meq/mL, 4.1 meq/g) was
stirred in 1L of 12%(with volume) NaOH solution for 16 hours, filtered over a glass filter
and thoroughly washed with distilled water until neutral. The resin was stirred in 1L of
3M HCl solution for 3 hours and washed with deionized water until pH of 7. This fresh
ion exchange resin was charged into a 500mL burette.
Using the dialysis method, a known amount of cationic chitosan sample was
purified and dried as follows: 10mL of cationic chitosan mixture was charged into a 20cm
of cellulose acetate membrane with a molecular weight separation of 6000-10000 and
stirred in 3L of deionized water for 72 hours, water was changed every 12 hours, followed
by precipitating the chitosan in 1L of acetone. Then a small amount of pure cationic
chitosan was dried at 70oC for 24 hours in a vacuum oven. The pure cationic chitosan was
then transferred into a glass beaker and dissolved in 200mL of deionized water. The
cationic chitosan solution was allowed to flow down through the column. It was collected
in a beaker, precipitated in 1L of acetone and dried in a vacuum oven at 70oC for 16
hours. The DS of cationic chitosan was obtained by titration of the halide (Cl-) with
aqueous silver nitrate (AgNO3) solution. [50] The process was as follows: 0.1344g from
43
the dried cationic chitosan was dissolved in 100mL of deionized water and
conductometrically titrated with 0.017N AgNO3 solution. Titration was conducted at a
constant temperature (23.5oC). The titration curve for cationic chitosan is shown in Figure
3.5.
360
400
440
480
520
0 4 8 12 16 20 24 28 32
Volume of silver nitrate (mL)
Con
duct
ivity
(uS/
cm)
Figure 3.5 Conductometric titration curve of cationic chitosan
The amount of silver nitrate used at the bending point (22.3mL) equals to the amount of
Cl- ions on the cationic chitosan derivative. 1mL of 0.017N AgNO3 is equal to 1mg NaCl,
therefore 0.1g of the cationic chitosan contains 3.81588 X 10-4 moles of Cl- ions. The
percentage degree of substitution was calculated by the equation below:
DS = 100 Χ (MW Χ NCl-) / m
44
Where MW is the molecular weight of each repeating unit of the cationic chitosan when
the DS is 1 (314.89 g/mol), NCl- is the number of moles of Cl- ions in the cationic chitosan
(2.6523 Χ 10-4), and m is the mass of cationic chitosan sample in grams (0.1344g). Finally
the DS of cationic chitosan was calculated as 89%.
3.7.3.2 Characterization of cationic chitosan by FTIR analysis
In order to characterize the products, we obtained Fourier Transform Infrared
Spectroscopy (FTIR) spectrums. For the IR measurements pure cationic chitosan samples
were prepared by using the dialysis method as described previously. The samples were
prepared as KBr pellets and scanned against a blank KBr pellet background. Deacetylated
chitosan shows medium to strong absorption peaks in the range of 1650 to 1580 cm-1. The
major IR functional group frequencies relevant to chitin and chitosan are shown in Table
3.6.
45
Table 3.6 Major IR functional group frequencies relevant to chitin and chitosan [46] Frequencies Intensity Functional group Assignment 3420-3250 s Alcohol –OH OH stretch (solid & liquid)
3460-3280 m Primary amine –NH2 NH stretch; broad band, may have
some structures
350-3050 vs Ammonium, NH4+ NH stretch; broad band
3200-3000 v br Amino acid –NH3 NH3+ antisym stretch
2990-2850 m-s Aliphatic alkyl CH antisym stretch
2830-2810 m Primary amine –NH2 CH stretch
2750-2350 m-s, br Amine hydrohalides -
NH3+
NH3+ stretch, several peaks
1680-1630 vs Secondary amide C=O Carbonyl stretch (Amide I)
1650-1580 m-s Primary amine –NH2 NH2 deformation
1610-1560 vs Carboxylic acid slat –COO- COO- antisym stretch
1565-1475 vs Secondary amide –NH- NH deformation (Amide II)
1440-1260 m-s, br Alcohol C-OH in plane bend
1430-1390 s Ammonium, NH4+ NH2 deformation ; sharp peak
1400-1310 s Carboxylic acid salts –
COO-
COO- sym stretch; broad band
1310-1250 m Trans amide linkage C-N stretch (Amide III)
1240-1070 s-vs Ether –C-O-C C-O-C stretch; antisym stretch
1200-1015 s-vs Alcohol –C-O-H C-O stretch
1150-1070 vs Aliphatic ethers C-O-C antisym stretch
1120-1030 s Primary aliphatic amine C-
NH2
C-N stretch
860-760 vs- br Primary aliphatic R-NH2 NH2 wag
680-620 s Alcohol –C-O-H C-O-H bend
s=strong; m=medium; w=weak; v=very; br=broad; sym;symmetric; antisym=antisymmetric
46
The peaks (1646 cm-1 and 1599 cm-1) shown in Figure 3.6 respond to C=O of secondary
amide and NH2 of primary amine groups. [46]
0.0
0.2
0.4
0.6
0.8
1.0
1.2
5001000150020002500300035004000Wavenumbers (cm-1)
Abs
orba
nce
1646 1599
Figure 3.6 FTIR spectrum of deacetylated chitosan
The cationic chitosan spectrum shows a new strong peak at 1479 cm-1 in Figure 3.7. It is
induced from the C-H bond of (2-hydroxyl-3-trimethylammonium) propyl group, which
was a product of CHTAC and chitosan reacting at highly alkaline conditions.
47
0.0
0.2
0.4
0.6
0.8
1.0
1.2
5001000150020002500300035004000
Wavenumbers (cm-1)
Abs
orba
nce 1479
Figure 3.7 FTIR spectrum of cationic chitosan
3.7.3.3 1H-NMR spectrums of deacetylated and cationized chitosan
The Figure 3.8 shows the 1H-NMR spectra of deacetylated chitosan. The H-1 peak
is appeared at 4.84ppm and the H-2 peak appeared at 3.05ppm. The remaining protons H-
3, 4, 5, and 6 appeared as a group peak between 4.05ppm and 3.55ppm. The spectra
showed a clear separation of peaks.
48
Figure 3.8 1H-NMR spectrum of deacetylated chitosan
49
In order to characterize the O-substitute chitosan the N-substituted chitosan was
used as reference, because the N-substituted chitosan has only quaternary ammonium salts
on the NH2 site of chitosan, which proven by Kim et. al. [39] The O-substituted chitosan
spectra, the bottom spectra in Figure 3.9, showed a strong peak at 3.21 ppm and the
spectra of N-substituted chitosan, the top spectra in Figure 3.9, also showed a similar peak
at 3.19 ppm. Both of these peaks come from the CH3 groups of the quaternary ammonium
salt. Unlike the chitosan spectra both of the cationized chitosan spectra didn’t show a clear
separation of peaks. We believe that it is due to introducing a complex ammonium salt
group into the chitosan’s structure. Therefore both spectra didn’t give us the opportunity
of calculating the degree of substitution by using the intensities of the peaks. It is clearly
seen from the peaks that the spectrum of N-substituted chitosan is different than O-
substituted chitosan.
The H-2 peak shown in the spectrum of N-substituted chitosan is assigned at 2.91 ppm
with an intensity of 2.43. The same peak on O-substituted spectra assigned at 2.89 ppm
with an intensity of 0.97. The decrease in intensity for H-2 peak was significant, which
indicated that the ammonium salt groups were attached more on the O-position than on
the N-position of the chitosan. Note that the H-2 peak didn’t disappear because there was
still some substitution on NH2 site of the chitosan. The peak “H-1” in the O-substituted
derivative decreased compared to that in the N-substituted cationic chitosan. The peak did
not disappear. This indicated that O-substituted chitosan contains some substitutions over
NH2 site.
50
Figure 3.9 1H-NMR spectrum of O-substituted (above) and N-substituted (below) cationic chitosan
51
3.7.4 Reaction of glycerin and ethylene glycol with CHTAC
Reaction of alcohols with quat can be performed at mild temperatures and using
high mole ratios. Glycerin was cationized using the following method: 1156g (4 moles)
from CHTAC was charged into a 2L beaker, 228mL of 50%NaOH solution was added
dropwise to adjust pH of the CHTAC 10 to 11 and 46.05g (0.5 moles) from glycerin was
added into highly alkaline CHTAC solution. Note that glycerin to CHTAC mole ratio was
1:8. The mixture was stirred 10 minutes at RT, transferred into a preheated water bath and
stirred at 60oC for 20 hours. A viscose and yellowish mixture was collected at the end.
The resulting reaction product was cooled off to room temperature, filtered, and pH
adjusted to 7 with acetic acid. The reaction of glycerin with CHTAC is shown in Figure
3.10.
With a similar procedure, ethylene glycol is also cationized. This time the mole
ratio was kept at 1:4. The following procedure was followed: 272g (1 mole) from CHTAC
was charged into a 500mL of beaker. 60mL of 50%NaOH solution was added dropwise in
order to raise the pH of the quat solution to 10-11 and followed by adding 15.51g (0.25
moles) from ethylene glycol into highly alkaline CHTAC solution. The reaction was
performed with the same method that described for glycerin.
52
Glycerin
N+
CH3
CH3
CH3
ClOH
N+
CH3
CH3
CH3O
Na OH
3-chloro-2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride
N+
CH3
CH3
CH3O
+
Cationic Glycerin
Cl Cl
Cl
(EPTAC)(CHTAC)
OH
OH
OH
O
O
O
N+
CH3
CH3
CH3
OH
N+
CH3
CH3
OH
N+
CH3
CH3
OH
CH3CH3
Cl
Cl
Cl
Figure 3.10 Reaction of glycerin with CHTAC
53
3.7.5 Reaction of cellobiose and dextrose with CHTAC
The similarity of the molecular structure of cellobiose, dextrose and chitosan we
used the cationization method of chitosan for reaction of CHTAC with both cellobiose and
dextrose. The procedure was as follows: 50g (0.18 moles) from CHTAC solution was
charged into a 250mL beaker and pH adjusted to 10-11 with 10mL of NaOH solution and
followed by adding 15.5g (0.045 moles) from cellobiose into highly alkaline quat solution.
The mixture stirred for 10 minutes at room temperature and transferred into a preheated
water bath. The mixture stirred at 60oC for 20 hours. Then the temperature raised to 95oC
and stirring continued for another 4 hours. Finally the reaction mixture was cooled off to
room temperature and pH adjusted to 7 with acetic acid.
With the same procedure dextrose was also cationized. For this procedure 90g
(0.32 mole) from CHTAC solution was charged into a 250 mL beaker and pH adjusted to
10-11 with 90mL of NaOH. Followed by adding 15g (0.08 mole) from dextrose into the
quat solution. The reaction performed using the same method described for cellobiose.
3.8 Preparation of fabric samples
For each crosslinker solution 5 samples, 1 untreated fabric sample and 4 ionic
cellulosic fabrics having different levels of ionic content, were prepared for treatment. The
samples were marked for determination of warp and weft directions of the fabric,
identification of the level of ionic content of the samples and concentration of crosslinker
solution that used to treat each sample. The sample size kept constant for all treatments
and was 7 X 12 inch.
54
3.9 Crosslinking of carboxymethylated cellulosic fabric
Untreated fabric having a carboxymethyl content of 6.2mmol/100g and
carboxymethylated cellulosic fabrics with anionic contents of 30.2, 60.7, 87.1, and
114.5mmole/100g, were treated with cationized chitosan, cationized glycerine, calcium
chloride, magnesium chloride, cationized ethylene glycol, cationized dextrose and
cationized D-cellobiose. All of these treatments are given below.
3.9.1 Treatment with cationic chitosan
Crosslinking with cationic chitosan was studied using pad-dry-cure, cold pad-
batch and exhaustion procedures. Fabrics with five different anionic levels were used. The
procedure was same for different molecular weight of cationized chitosans. For pad dry
cure and pad batch application 400mL of blank (0%) and three different concentrations of
polyelectrolyte, 1, 3, and 6 % with weight, solutions were prepared. Cationic chitosan
dissolved in deionized water at pH of 7. For exhaustion method 400mL of 6% with weight
cationic chitosan solution and 1:15 bath ratio was used.
3.9.2 Treatment with cationic glycerin
Crosslinking with cationic glycerine was studied using pad-dry-cure and
exhaustion methods. Fabrics with five different anionic levels were used. For this method
400mL of blank (0%) and three different concentrations of crosslinker, 1, 3, and 6 % with
weight, solutions were prepared. Cationic glycerine was also dissolved in deionized water
at pH of 7. For exhaustion method 12% with weight, of 400g solution was used. The
55
temperature rose to 95oC with a 2oC/minute grade and hold for 90 minutes and followed
by hot and cold washing of the samples and drying at room temperature for 24 hours.
3.9.3 Treatment with cationic cellobiose, cationic dextrose and cationic ethylene glycol
These treatments were studied as a prescreening study in order to identify if the
polyelectrolytes can impart crease angle recovery to anionic cellulosic fabric. Treatments
with cationic cellobiose, cationic dextrose, and cationic ethylene glycol were studied using
anionic cellulosic fabrics with two different carboxyl content, 30.2 and 60.7mmole/100g.
The concentrations of cationic crosslinkers were 6% with weight of the bath. All
treatments were applied using the pad dry cure procedure and followed by washing and
drying as described previously.
3.9.4 Treatment with calcium chloride and magnesium chloride
Calcium and magnesium are divalent atoms and they can be used as cationic
crosslinker agents. Treatments of calcium chloride and magnesium chloride performed
using pad dry cure procedure. The solutions were prepared as follows: 29.5g (0.2 mole)
from calcium chloride dihydride dissolved in 400mL of deionized water. It yielded to
0.5M of aqueous CaCl2 solution. With the similar way 0.5M magnesium chloride
hexahydrate solution was prepared by dissolving 40.6g from magnesium chloride in
400mL of deionized water. Fabrics with five different anionic levels were used. The pad
dry cure application method was applied and followed by washing and drying as described
above. Figure 3.11 shows the reaction of calcium with anionic cellulose.
56
O
O
OHH
H
H
H
H
OHOH
O
O
O
OHH
H
H
H
H
OH
O
O
O
OHH
H
H
H
H
OH
O
O
OH
OHH
H
HH
H
OH
O
O
O
O
O
O
O
O
O
Ca
O
O
OHH
H
H
H
H
OHOH
O
O
O
OHH
H
H
H
H
OH
O
O
O
OHH
H
H
H
H
OH
O
O
OH
OHH
H
HH
H
OH
O
O
O
O
O
O
O
O
O
Ca++
++
Anionic cellulose chain Anionic cellulose chain
Divalent calcium ion
Divalent calcium ion
Figure 3.11 Crosslinked anionic cellulose with calcium
57
3.10 Crosslinking of cationic cellulosic fabric
Various polyelectrolytes were used. Polyanion types were PCA, BTCA, EDTA,
NTA, HEDTA, oxalic acid, citric acid, and malic acid. The approach was to form ionic
crosslinks between cationic cellulose chains by reacting them with a polyanion. All of
these crosslinkers improved crease angle recovery of cotton with varying degrees of
success, but we accomplished higher WRA with PCA and BTCA treatments.
3.10.1 Treatment with PCA and BTCA
Untreated and cationized cotton fabrics with varying levels (0, 0.19, 0.28, 0.46,
and 0.57) of percent fixed nitrogen were used. Aqueous solutions of PCA and BTCA with
concentrations of 1, 3, and 6% with weight of the solution were prepared. The pH of the
solutions were adjusted to 6-7 with 50% NaOH solution, as the pH of both crosslinker
solutions were initially under 2, which may reduce the strength of cellulose. The
application procedure for treatments was pad dry cure method. After the treatments,
fabrics were washed and dried as described previously. The crosslinked cationic cellulose
with BTCA is shown in Figure 3.12.
58
O
O
OHH
H
H
H
H
OHOH
O
O
O
OHH
H
H
H
H
OH
O
O
O
OHH
H
H
H
H
OH
O
O
OH
OHH
H
HH
H
OH
O
N+
CH3CH3
CH3
OH
NCH3CH3
CH3
OH
N+
CH3CH3
CH3
OH
NCH3
CH3
CH3
OHO
O
OHH
H
H
H
H
OHOH
O
O
O
OHH
H
H
H
H
OH
O
O
O
OHH
H
H
H
H
OH
O
O
OH
OHH
H
HH
H
OH
O
N+
CH3CH3
CH3
OH
NCH3 CH3
CH3
OH
N+
CH3CH3
CH3
OH
NCH3
CH3
CH3
OH
COO
COO
COO
COO
Cl
Cl
Cl
Cl
- -
--
+ +
+ +
Cationic cellulose chain Cationic cellulose chain
BTCA
Figure 3.12 Crosslinked cationic cellulose with BTCA
59
3.10.2 Treatment with EDTA, NTA and HEDTA
Treatments were studied using five different %N fixed fabrics and three different
concentrations, 1%, 3%, and 6% with weight of the solution, of HEDTA, NTA, and
EDTA solutions. The pH of the solutions was adjusted to 7 with acetic acid. The pad dry
cure application procedure was used. The treated fabrics were washed and dried as
described above.
3.10.3 Treatment with oxalic acid, citric acid and malic acid
These treatments were performed as a prescreening study in order to identify if the
polyelectrolytes can impart crease angle recovery to anionic cellulosic fabric. Treatments
were studied using 2 different %N fixed fabrics (0.46 and 0.57) and 0.5M of crosslinker
solutions. The solutions were prepared as follows: 9g (0.1 mole) oxalic acid dissolved in
200mL of deionized water, 13.4g (0.1 mole) malic acid dissolved in 200mL of deionized
water and 19.2g (0.1 mole) citric acid dissolved in 200mL of deionized water. The pad dry
cure procedure was used. The treated fabrics were washed and dried as described above.
60
4. RESULTS & OBSERVATIONS AND DISCUSSION
In this section the results of the physical property measurements of the untreated
and treated fabrics are represented using figures. A detailed discussion for each property is
also stated.
4.1 Wrinkle recovery angles of conventional durable press finished fabrics
In order to compare the wrinkle recovery angles of ionic crosslinked fabrics the
crease angle recovery test was performed on the DMDHEU treated cellulosic fabric. The
dry/wet wrinkle recovery angles were 276/266 degrees respectively.
4.2 Wrinkle recovery angles of polycation treated anionic cellulosic fabrics
Wrinkle recovery angle data are presented for polycation treated anionic fabrics.
Carboxyl content on the cellulosic fabrics is given on the x-axis while dry/wet wrinkle
recovery angles are given on the y-axis.
4.2.1 Wrinkle recovery angles of cationic chitosan treated fabrics
The wrinkle recovery angles of untreated, carboxymethylated and cationic
chitosan treated samples are given in Tables A.1, A2 and A3 of the Appendix. The result
of DMDHEU treated fabric is also included in the tables. Standard deviation of crease
angle recovery measurements was between 3o and 12o for cationic chitosan treated fabrics.
As an example, the crease angle recovery measurements of 1.4 x 105g/mole cationic
61
chitosan treated fabrics are presented here. The relationship between carboxyl content of
the fabric, cationic chitosan concentration and dry/wet wrinkle recovery angles is shown
in Figure 4.1 and 4.2. The cationic chitosan is symbolized by CC. A correlation between
wet wrinkle recovery angles and carboxyl content of the fabrics for the treatments was
observed. Increase in carboxyl content increased the wrinkle recovery angles of treated
fabrics because high numbers of carboxylic groups on the cellulose form more ionic
crosslinks with cationic sites of the quaternized chitosan, therefore a higher crease angle
recovery was obtained. Both wet and dry wrinkle recovery angles were enhanced with an
increase in carboxyl content of the fabric treated. The effect of the cationic chitosan
concentration is not significant. On average the 3% crosslinker concentration seems to be
the most effective concentration. The treatments show wet wrinkle recovery angles
between 240 and 280o and dry wrinkle recovery angles between 180o and 230o. The
difference of wet crease angle recovery between blank samples and treated fabrics was up
to 120o, a very significant increase and up to 70o for dry wrinkle recovery angles.
62
120
160
200
240
0 30 60 90 120
Carboxyl content (mmol/100g)
Dry
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%CC3%CC6%CC
Figure 4.1 Effect of carboxyl content and concentration on dry wrinkle recovery angles of
cationic chitosan treated fabrics
120
160
200
240
280
0 30 60 90 120
Carboxyl content (mmol/100g)
Wet
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%CC3%CC6%CC
Figure 4.2 Effect of carboxyl content and concentration on wet wrinkle recovery angles of
cationic chitosan treated fabrics
63
The cationic crosslinker contains nitrogen, thus the nitrogen content of the treated
fabrics is proportional with the number of ionic crosslinks formed between the anionic
cellulose chains. The cationic chitosan treated fabrics are analyzed for % nitrogen
content. The results of three molecular weights of chitosan treatments are given in Table
A.36, A.37 and A.37 of the Appendix. The data of the fabrics treated with the molecular
weight of 1.4 x 105g/mole cationic chitosan is shown in Figure 4.3. The cationic chitosan
is symbolized by CC. The relationship between cationic chitosan concentration, carboxyl
content of the fabrics and % nitrogen fixed after treatment is presented here. The untreated
fabric was contained approximately 0.24% nitrogen, as the cotton fabric naturally contains
some impurities such as protein matter, pectin, minerals, and waxes. The fabric was
scoured and bleached, but it has been known that there is still some impurity residue on
the fabric. The carboxymethylation process did not significantly affect the nitrogen
content of the fabric. Anionic fabrics contained approximately 0.25% nitrogen. Anionic
fabrics treated with cationic polyelectrolyte showed a presence of various degrees of %
nitrogen fixation. The % nitrogen contents of the treated fabrics are changed by carboxyl
content of the fabrics and the crosslinker concentration. Fabrics with higher carboxyl
contents contain higher levels of nitrogen. The difference is more significant for fabrics
having 87.1mol/100g and 114.5mmol/100g carboxyl groups. The treatment with 6%
polyelectrolyrte concentration produced greater nitrogen fixation than the 3% cationic
chitosan treatment for high carboxyl levels. The 3% treatment showed slightly higher
nitrogen content for 30.2 mmol/100g carboxyl level than the 6% treatment, yet it is in the
expected standard deviation range. The 3% cationic chitosan treatment also produced
64
higher nitrogen fixation than the 1% treatment. The maximum nitrogen fixation was
0.54% and was obtained with the application of 6% cationic chitosan on the fabric
containing 114.5 mmol/100g carboxyl content.
0.20
0.30
0.40
0.50
0.60
0 30 60 90 120
Carboxyl content (mmol/100g)
%N
itrog
en c
onte
nt
0%1%CC3%CC6%CC
Figure 4.3 Effect of carboxyl content and concentration on %Nitrogen content of cationic chitosan treated fabrics
The wrinkle recovery angles of treated fabrics versus their nitrogen contents are
also plotted. Figure 4.4 shows the relationship between nitrogen level of the fabrics and
dry/wet wrinkle recovery angles. Wrinkle recovery angle is symbolized by WRA. The
data obtained with carboxymethylated fabrics are presented here. A correlation between
wet wrinkle recovery angles and % nitrogen content was observed. The correlation was
obtained with the coefficient of determination (R2) of 0.73 for wet wrinkle recovery
65
angles. The dry wrinkle recovery angle data of the treated fabrics did not show a good
correlation with the % nitrogen content, as most of the ionic crosslinks were formed while
the fabric was wet. Increases in % nitrogen content led to increases in wet crease angle
recovery for treated fabrics. As previously mentioned, the nitrogen content of the fabrics
is proportional with the number of the ionic crosslinks, therefore fabrics having greater
nitrogen contents are expected to produce higher wrinkle recovery angles than others. The
data obtained with cationic chitosan treatments indicated that fabrics with greater nitrogen
contents also produced higher crease angle recovery.
R2 = 0.7391
180
200
220
240
260
280
0.2 0.3 0.4 0.5 0.6
%Nitrogen content
Wrin
kle
reco
very
ang
les
(deg
rees
)
Wet WRADry WRA
Figure 4.4 The relationship between %Nitrogen content of the fabrics and dry/wet wrinkle
recovery angles
66
Several laundry washings were applied to the cationic chitosan treated fabrics
using a commercial detergent, Tide, and % nitrogen content of the fabric were tested. The
% nitrogen content was initially 0.67%, after one laundry washing it was 0.68% and was
0.59% after five laundry washings and 0.40% after ten laundry washings.
The anionic cellulosic fabrics were treated with three different molecular weights
of cationic chitosan. Regardless of molecular weight of the polycation, significant
increases in both dry and wet wrinkle recovery angles were observed, but the results show
that wet wrinkle recovery angles are higher than dry wrinkle recovery angles. The effects
of different molecular weights of cationic chitosan and carboxyl content of the fabrics on
wrinkle recovery angles are compared in Figures 4.5 and 4.6. These figures are produced
from the data obtained with 6% cationic chitosan concentration.
The change in molecular weight of cationic chitosan did not make a significant difference
on wrinkle recovery angles of the treated fabrics. Yet the results show that the lowest
molecular weight (3.2 x 104g/mole) cationic chitosan gave better results for dry wrinkle
recovery angles than other treatments.
67
160
200
240
0 30 60 90 120
Carboxyl content (mmol/100g)
Dry
wrin
kle
reco
very
ang
les
(deg
rees
) 611000g/mol140000g/mol32000g/mol
Figure 4.5 Effect of molecular weight of chitosan and concentration on dry wrinkle
recovery angles of cationic chitosan treated fabrics
150
200
250
0 30 60 90 120
Carboxyl content (mmol/100g)
Wet
wrin
kle
reco
very
ang
les
(deg
rees
) 611000g/mol140000g/mol32000g/mol
Figure 4.6 Effect of molecular weight of chitosan and concentration on wet wrinkle
recovery angles of cationic chitosan treated fabrics
68
Cationic chitosan was also applied on three levels of anionic fabrics using the exhaustion
method. The data is given in Table A.4 of the Appendix. The results show reasonably high
wet crease angle recovery, but dry wrinkle recovery angles are very low. The wet wrinkle
recovery angles are between 191o and 232o while the dry angles are between 120o and
135o. The fabric having 30.2mmole/100g carboxyl content treated by cold pad batch
method also showed a similar result. The wet wrinkle recovery angle measured as 248o
while the dry was only 147o. These results indicated that a curing step is needed in order
to obtain both high wet and dry wrinkle recovery angles.
4.2.2 Application of paired t-test analysis on cationic chitosan treatments
Given two paired sets of n measured values, the paired t-test determines whether
they differ from each other in a significant way under the assumptions that the paired
differences are independent and identically normally distributed. [51]
Paired t-test was applied to the cationic chitosan treatments using the statistics software,
StatCrunch.
This statistic has “n-1” degrees of freedom (DF: the number of degrees of freedom
in a problem, distribution, etc., is the number of parameters which may be independently
varied). If we define µ as the mean of the differences in wrinkle recovery angles between
two different molecular weights of cationic chitosan treated fabrics and then we set our
hypothesis (Ho) as “µ=0”, which implies that the difference in wrinkle recovery angles is
not significant. We can reject or accept the Ho using the results of the paired t-test.
69
If; Lower Limit< µ <Upper Limit, and then we “do not reject Ho”. For all other cases we
“reject Ho”, which means that the difference is significant.
Table 4.1 shows the paired t-test results of the dry wrinkle recovery angles of different
molecular weights of cationic chitosan treatments for 95% Confidence Interval (CI). The
calculated µ values of cationic chitosan treatments are contained in the 95% Confidence
Interval. Therefore we are 95% confident with accepting Ho, thus stating that the
differences are not significant.
Table 4.1 Paired t-test results for dry wrinkle recovery angles of cationic chitosan treated fabrics
95% CI Difference Mean of
Sample Difference (µ)
Standard Error of means
DF
Lower
Limit
Upper
Limit
6.11 x 105g/mol – 1.4 x 105g/mol
not significantly different 6.3333335 2.61254 14 0.7299794 11.9366
6.11 x 105g/mol – 3.2 x 104g/mol
not significantly different -6.266667 3.24619 14 -13.22906 0.69572
1.4 x 105g/mol – 3.2 x 104g/mol
not significantly different -12.6 2.69355 14 -18.3771 -6.8228
70
Table 4.2 shows the paired t-test results of wet wrinkle recovery angles of different
molecular weights of cationic chitosan treatments for 95% CI. The calculated µ values of
cationic chitosan treatments are contained in the 95% Confidence Interval. Therefore we
are 95% confident with accepting Ho, therefore stating that the differences are also not
significant.
Table 4.2 Paired t-test results for wet wrinkle recovery angles of cationic chitosan treated fabrics
95% CI
Difference Mean of
Sample Difference (µ)
Standard Error of means DF Lower
Limit
Upper
Limit
6.11 x 105g/mol – 1.4 x 105g/mol
not significantly different 0.0666666 3.57433 14 -7.59952 7.73285
6.11 x 105g/mol – 3.2 x 104g/mol
not significantly different 0.1333333 2.89805 14 -6.082379 6.34904
1.4 x 105g/mol – 3.2 x 104g/mol
not significantly different 0.0666666 2.89411 14 -6.140582 6.27391
71
4.2.3 Wrinkle recovery angles of cationic glycerin treatments
The wrinkle recovery angles of resin treated, untreated, carboxymethylated and
cationic glycerin treated samples are shown in Table A.5 of the Appendix. Standard
deviation of wrinkle recovery angle measurements in warp direction was 9 degree while it
was 4 degree in weft direction. The effect of carboxyl content and cationic glycerin
concentration on dry and wet wrinkle recovery angles are presented in Figure 4.5 and 4.6.
Cationic glycerin symbolized by CG. A correlation between wet wrinkle recovery angles
and carboxyl content of the fabrics was also observed. It is believed to be the increase in
the amount of crosslinks between the cellulose chains while increase in the
carboxymethylation level of the fabrics. The wet and dry wrinkle recovery angles were
enhanced with an increase in carboxyl content of the fabric treated. Wet wrinkle recovery
angles were higher than dry wrinkle recovery angles. Treatment of anionic cotton with
cationic glycerin showed wet wrinkle recovery angles between 240 and 280o and dry
wrinkle recovery angles between 180 and 230o. The average difference of wet wrinkle
recovery angles between blanks (0% polycation) and treated fabrics was 120o while it was
55o for dry crease angle recovery.
The cationic glycerin was also applied to the fabrics by exhaustion method. The results are
shown in Table A.6 in the appendix. The data also showed a better wet crease angle
recovery than dry. The wet wrinkle recovery angles are between 180 and 229o, the dry
wrinkle recovery angles are between 131 and 206o. These results imply that pad dry cure
application improves the durable press properties of cellulosic fabrics better than
exhaustion method.
72
120
160
200
240
0 30 60 90 120
Carboxyl content (mmol/100g)
Dry
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%CG3%CG6%CG
Figure 4.7 Effect of carboxyl content and concentration on dry wrinkle recovery angles of
cationic glycerin treated fabrics
120
160
200
240
280
0 30 60 90 120
Carboxyl content (mmol/100g)
Wet
wrin
kle
reco
very
ang
les
(deg
rees
)
0%1%CG3%CG6%CG
Figure 4.8 Effect of carboxyl content and concentration on wet wrinkle recovery angles of
cationic glycerin treated fabrics
73
The cationic glycerin treated fabrics were also analyzed for % nitrogen content.
The results of three molecular weights of the treatment are given in Table A.39 of the
Appendix. The relationship between cationic glycerin concentration, carboxyl content of
the fabrics and % nitrogen fixed after treatment is presented in Figure 4.9. The cationic
glycerin is symbolized by CG. The % nitrogen contents of the treated fabrics are also
affected by carboxyl content of the fabrics and the crosslinker concentration. Fabrics with
higher carboxyl contents contain higher levels of nitrogen. The difference is more
significant for fabrics having higher carboxyl contents. The treatment with 6% and 3%
polyelectrolyte concentrations produced greater nitrogen fixation than the 1% treatment,
but the difference between 3% and 6% varied as the carboxyl content of the fabrics were
changed. The maximum nitrogen fixation was 0.44% and it was obtained with application
of 3% cationic glycerin on the fabric containing 114.5 mmol/100g carboxyl content.
74
0.20
0.30
0.40
0.50
0 30 60 90 120
Carboxyl content (mmol/100g)
%N
itrog
en c
onte
nt
0%1%CG3%CG6%CG
Figure 4.9 Effect of carboxyl content and concentration on %Nitrogen content of cationic
glycerin treated fabrics
The wrinkle recovery angles of cationic glycerin treated fabrics and their nitrogen
contents are shown in Figure 4.10. The relationship between nitrogen level of the fabrics
and dry/wet wrinkle recovery angles of carboxymethylated and cationic glycerin treated
fabrics are presented here. Correlations between wet wrinkle recovery angles (WRA) and
% nitrogen content were determined. The correlations were obtained with the coefficients
of determination (R2) of 0.48 for wet wrinkle recovery angles (WRA) and 0.51 for dry
WRA. Increases in % nitrogen content showed increases in dry/wet crease angle recovery
for treated fabrics. As previously mentioned, the nitrogen content of the fabrics is
proportional with the number of the ionic crosslinks, therefore fabrics having greater
nitrogen contents are expected to produce higher wrinkle recovery angles than others. The
75
data obtained with cationic glycerin treatment also indicated that fabrics with greater
nitrogen contents also produced greater crease angle recovery than the others.
R2 = 0.4888
R2 = 0.5187
180
200
220
240
260
280
0.2 0.3 0.4 0.5
%Nitrogen content
Wrin
kle
reco
very
ang
les
(deg
rees
)
Wet WRADry WRA
Figure 4.10 The relationship between %Nitrogen content of the fabrics and dry/wet
wrinkle recovery angles
Several laundry washings were also applied using a commercial detergent to the
cationic glycerin treated fabric and % nitrogen content of the fabric were tested. The %
nitrogen content was initially 0.36%, after one laundry washing it was 0.36% and was
0.31% after five laundry washings and 0.24% after ten laundry washings.
76
4.2.4 Wrinkle recovery angles of cationic cellobiose and cationic dextrose treated
fabrics
As a prescreening study, we treated anionic fabrics with cationic cellobiose and
cationic dextrose. These polycations were investgated to identify if they could improve the
crease angle recovery of cellulosic fabrics. Table A.7 of the Appendix shows the results of
wrinkle recovery angle measurements of the untreated, carboxymethylated and treated
fabrics. The results show that even with 6% of polyelectrolyte solution the increase in
wrinkle recovery angles are lower than those obtained with cationic chitosan and cationic
glycerin treatments. The dry wrinkle recovery angles of cationic cellobiose treatments are
slightly higher than cationic dextrose treated fabrics while the wet wrinkle recovery angles
are almost identical.
4.2.5 Wrinkle recovery angles of calcium chloride and magnesium chloride treated
fabrics
The wrinkle recovery angles of untreated, carboxymethylated, calcium and
magnesium treated samples are shown in Table A.8 of the Appendix. Calcium (Ca++) and
magnesium (Mg++) are divalent metal atoms. Due to the two positive charges, they
potentially can form ionic crosslinks with the carboxymethyl groups on adjacent cellulose
polymer chains. The effects of carboxyl content of the fabrics on dry and wet wrinkle
recovery angles are shown in Figure 4.11 and 4.12. The treatments of anionic cellulosic
fabrics with calcium chloride and magnesium chloride also provide a significant
improvement in dry and wet wrinkle recovery angles for the treated fabrics. The results
77
obtained from both treatments were approximately the same. Calcium chloride treated
fabrics showed up to 244o dry and 232o wet crease angle recovery and the magnesium
chloride treated fabrics created a maximum of 232o dry and 237o wet wrinkle recovery
angles. The cellulosic fabric containing 114.5 mmole/100g carboxyl content was also
treated with 0.5M sodium chloride. The results of measurements are 165o for dry and 185o
for wet wrinkle recovery angles. Lower wrinkle recovery angles of sodium chloride
treated fabrics indicated that divalent metal atoms are needed in order to obtain high
crease angle recovery because they can form ionic crosslinks due to double positive
charges on them.
120
160
200
240
0 30 60 90 120
Carboxyl content (mmol/100g)
Dry
wrin
kle
reco
very
ang
les
(deg
rees
)
0%0.5M Ca++0.5M Mg++
Figure 4.11 Effect of carboxyl content on dry wrinkle recovery angles of calcium and
magnesium treated fabrics
78
120
160
200
240
0 30 60 90 120
Carboxyl content (mmol/100g)
Wet
wrin
kle
reco
very
ang
les
(deg
rees
)
0%0.5M Ca++0.5M Mg++
Figure 4.12 Effect of carboxyl content on wet wrinkle recovery angles of calcium and
magnesium treated fabrics
The paired t-test is applied to the data obtained with calcium and magnesium
treatments as previously described. [53] Table 4.3 shows the paired t-test results of
dry/wet wrinkle recovery angles of calcium and magnesium treatments for 95% CI. The
calculated µ values of these treatments are contained in the 95% confidence interval.
Therefore we are 95% confident with accepting Ho, therefore stating that the differences
between Ca++ and Mg++ treatments are not significant.
79
Table 4.3 Paired t-test results for dry/wet wrinkle recovery angles of Ca++ and Mg++ treated fabrics
95% CI Difference Mean of
Sample Difference(µ)
Standard Error DF
Lower
Limit
Upper
Limit
Dry WRA of Ca++ and Mg++
not significantly different 0.8 4.25910 4 -11.02517 12.6251
Wet WRA of Ca++ and Mg++
not significantly different -1.2 4.90306 4 -14.81307 12.4130
4.2.6 Discussion of wrinkle recovery angles for polycation treatments
The polyelectrolyte type, anionic content of the fabrics and application procedure
are the three major affects that influence the durable press properties of the treated fabrics.
Ionic crosslinks between cellulose chains stabilize the structure; therefore, fabrics resist
wrinkling. The treatments with cationic chitosan using different molecular weights,
concentrations and different application procedures produced different results. It was
expected that the smaller molecular weight cationic chitosan is able to produce higher
wrinkle recovery angles, but the change in molecular weight didn’t make a significant
difference. The result indicated that a wider range of molecular weight difference might
be needed. On average, the cationic chitosan produced from the chitosan having a
molecular weight of 3.2 x 104g/mole created slightly higher improvements for dry wrinkle
80
recovery angles than the other treatments. The results obtained by pair t-test also showed
that there is not a significant difference in wrinkle recovery angles between the three
different molecular weights of cationic chitosan treatments. The treatments with the
concentrations of 3% and 6% improve the wrinkle recovery angles more than treatment
with 1% concentration. There is also no significant difference between 3% and 6%
concentrations, but there was a slight increase in wrinkle recovery angles with increase in
the carboxyl content of the fabrics. It is believed to be result of having more ionic
crosslinks between cellulose chains, because each of the carboxyl groups can form an
ionic bond with the cationic sites of the crosslinkers.
With the pad batch and exhaustion treated fabrics a reasonably high wet crease
angle recovery was gained, but dry wrinkle recovery angles were very low. For some
cases, the dry angles were measured less than the untreated fabric. Yet, the fabric treated
with pad dry cure application method produced very high wet crease angle recovery and
reasonably high dry wrinkle recovery angle. Cationic glycerin treatment also showed high
wrinkle recovery angles. Just like the cationic chitosan treatment, the wet crease angle
recovery was higher. Both dry and wet wrinkle recovery angles were slightly higher than
cationic chitosan treatments. The different crosslinker concentrations produced
approximately the same results.
Fabrics treated with the exhaustion procedure showed lower crease angle recovery
than those treated with pad dry cure application. This implies that the curing step is
needed in order to accomplish high improvements in crease angle recovery of the treated
fabrics. The treatments with cationic cellobiose and cationic dextrose also improved the
81
crease angle recovery of the anionic cellulosic fabrics, although, the increases in wrinkle
recovery angles are not as high as cationic glycerin treatment. Calcium and magnesium
treatments produced the highest dry wrinkle recovery angles. The wet crease angle
recovery of the treated fabrics was lower than cationic chitosan and cationic glycerin
treatments. Increases in carboxyl content produced higher dry wrinkle recovery angles but
for wet crease angle recovery the 60.7mmole/100g carboxyl content gave the best result.
Unlike the DMDHEU treatment, for most of the polyelectrolyte treatments, the wet
wrinkle recovery angles were higher than dry crease angle recovery. This is the result of
forming the crosslinks at the wet stage of the fabric. If the ionic links were formed when
the fabric is dry then the dry crease angle recovery would be higher than the wet wrinkle
recovery angles. Hence, the treatments by exhaustion and pad batch procedures showed
high improvements in wet wrinkle recovery angles, but the dry crease angle recovery was
very poor. The fabrics treated with pad dry cure procedure produced significant
improvements in dry wrinkle recovery angles because of the curing step. When high
temperature was applied to the treated ionic fabrics, some of the ionic crosslinks between
the cellulose chains break and reform. This produces a higher dry crease angle recovery.
For example, a single divalent atom either calcium or magnesium, has higher mobility
between the cellulose polymer chains. Therefore, when fabrics were cured at high
temperatures, some of the ionic crosslinks may break and reform. Thus, when a force is
applied to the treated fabric while the fabric is dry the cellulose chains are able to recover.
As a result, higher dry wrinkle recovery angles are obtained. Hence, the dry crease angle
82
recoveries of calcium and magnesium treatments were higher than chitosan and glycerin
treatments.
4.3 Wrinkle recovery angles of polyanion treated cationic cellulosic fabrics
The effects of %Nitrogen fixed on the fabrics and crosslinker concentration on
wrinkle recovery angles of the treated fabrics are presented here. %Nitrogen fixed on the
cellulosic fabrics is given on the x-axis and dry or wet wrinkle recovery angles are given
on the y-axis.
4.3.1 Wrinkle recovery angles of PCA and BTCA treated fabrics
The results can be found in Tables A.9 and A.10 in the appendix. They illustrate
an increase in both dry and wet wrinkle recovery angles. Both of the treatments showed
that the wet wrinkle recovery angles are higher than dry. The effect of %Nitrogen fixed on
cellulosic fabric and PCA concentration on dry and wet wrinkle recovery angles are
shown in Figure 4.13 and 4.14. The untreated fabric treated with 6%PCA showed a dry
crease angle recovery of 192o. Such high value for untreated fabric appeared only one
time, therefore we believe it is not a result of the treatment, but it may be resulted from the
differences in fabric structure and measurement errors. A correlation between wet wrinkle
recovery angles and %Nitrogen fixed was also obtained for both treatments. Higher
%Nitrogen fixed onto cellulose produces a higher crease angle recovery. It should be
noted that a similar correlation has been obtained for polycation treated anionic fabrics.
An increase in concentration of the PCA also showed a positive affect on crease angle
83
recovery performance of the treated cationic fabrics. PCA treatments produced wet
wrinkle recovery angles between 140o and 235o while the dry crease angle recovery was
between 160o and 190o. Standard deviation of the wrinkle recovery angle measurements is
between 4o and 9o. On average, the difference of wet wrinkle recovery angles of the
blanks and treated fabrics are between 30o and 80o. The maximum wet wrinkle recovery
angle was obtained with 6% polyanion concentration applied onto the fabrics containing
1.54 %Nitrogen fixed.
120
140
160
180
200
0.2 0.6 1 1.4
%Nitrogen fixed
Dry
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%PCA3%PCA6%PCA
Figure 4.13 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles
of PCA treated fabrics
84
120
160
200
240
0.2 0.6 1 1.4
%Nitrogen fixed
Wet
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%PCA3%PCA6%PCA
Figure 4.14 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles
of PCA treated fabrics
For BTCA treatments the effect of %Nitrogen fixed on cellulosic fabric and
crosslinker concentration on dry and wet wrinkle recovery angles are shown in Figure
4.15 and 4.16. A correlation between wet wrinkle recovery angles and %Nitrogen fixed
was also obtained for BTCA treatments. Treatment of higher %Nitrogen fixed fabrics
produced higher wrinkle recovery angles. An increase in concentration of the BTCA also
resulted in higher crease angle recovery performance of the treated cationic fabrics.
BTCA treatments produced wet wrinkle recovery angles between 140o and 235o while the
dry crease angle recovery was between 155o and 185o. Standard deviation of the
measurements is in the range of 6o and 11o. On average, the difference of wet wrinkle
recovery angles of the blanks and treated fabrics are between 20o and 80o. The maximum
85
wet wrinkle recovery angles were also obtained with 6% polyanion concentration applied
onto the fabrics containing 1.54 %Nitrogen fixed.
120
140
160
180
200
0.2 0.6 1 1.4
%Nitrogen fixed
Dry
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%BTCA3%BTCA6%BTCA
Figure 4.15 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles
of BTCA treated fabrics
86
120
160
200
240
0.2 0.6 1 1.4
%Nitrogen fixed
Wet
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%BTCA3%BTCA6%BTCA
Figure 4.16 Effect of% Nitrogen fixed and concentration on wet wrinkle recovery angles
of BTCA treated fabrics
Dry wrinkle recovery angles of the treated fabrics decrease while the wet crease
angle recovery increases. The wrinkle recovery angles of the treated fabrics were slightly
higher for polycarboxylic acid treatments. The paired t-test is also applied to the data
obtained with PCA and BTCA treatments as previously described. [53] Table 4.4 shows
the paired t-test results of dry/wet wrinkle recovery angles of PCA and BTCA treatments
for 95% CI. The calculated µ values of these treatments are contained in the 95%
Confidence Interval. Therefore we are 95% confident with accepting Ho, therefore stating
that the differences are not significant.
87
Table 4.4 Paired t-test results for dry/wet wrinkle recovery angles of PCA and BTCA treated fabrics
95% CI Difference Mean of
Sample Difference(µ)
Standard Error DF Lower
Limit
Upper
Limit
Dry WRA of PCA and BTCA
not significantly different 6.5333333 3.24824 14 -3.136188 16.2028
Wet WRA of PCA and BTCA
not significantly different 5.8 2.56013 14 0.3090588 11.2909
4.3.2 Wrinkle recovery angles of EDTA, NTA and HEDTA treated fabrics
These chelating agents have multiple anionic charges on their molecules;
therefore, they are expected to form ionic crosslinks with cationic sites of cellulose
polymer chains. This was also a prescreening study to identify if these molecules can
improve the durable press properties of cationic cellulosic fabric. The data can be obtained
from Tables A.11, A.12 and A.13 of the Appendix. As an example, the effect of EDTA
concentration and %Nitrogen content of the cationic fabrics on wrinkle recovery angles of
the treated fabrics is given in Figures 4.17 and 4.18 below. Wet wrinkle recovery angles
of the treated fabrics are higher than dry wrinkle recovery angles. The wet wrinkle
recovery angles are significantly lower than PCA and BTCA treatments. Both dry and wet
88
wrinkle recovery angles are under 190o, which indicates that these chelating agents don’t
have an advantage over PCA and BTCA.
120
140
160
180
200
0.2 0.6 1 1.4
%Nitrogen fixed
Dry
wrin
kle
reco
very
ang
les
(deg
rees
)
0%1%EDTA3%EDTA6%EDTA
Figure 4.17 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles
of EDTA treated fabrics
89
120
140
160
180
200
0.2 0.6 1 1.4
%Nitrogen fixed
Wet
wrin
kle
reco
very
ang
les
(deg
rees
) 0%1%EDTA3%EDTA6%EDTA
Figure 4.18 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles
of EDTA treated fabrics
4.3.3 Wrinkle recovery angles of oxalic acid, citric acid and malic acid treatments
As a prescreening study, we treated cationic fabrics with oxalic acid, malic acid
and citric acid. These acids have more than one anionic carboxyl group, therefore, they
can form ionic crosslinks with the cationic groups of the cellulose polymer chains. These
polyanions were analyzed to determine if they can improve the crease angle recovery of
cationic cellulosic fabrics. The results of wrinkle recovery angle measurements of the
untreated fabric, cationized fabrics and polyanion treated fabrics are shown in Table A.14
of the Appendix. The wet wrinkle recovery angles are under 205o and the dry wrinkle
recovery angles are under 160o. The results show that even with the 0.5M polyelectrolyte
solution, the increases in wrinkle recovery angles are lower than those obtained with PCA
and BTCA treatments.
90
4.3.4 Discussion of wrinkle recovery angles for polyanion treatments
We experimented with eight different polyanions, all of which improved the
wrinkle recovery angles of the cationic fabrics with varying degrees. Two of those
polyanions produced improvements in wrinkle recovery angles that surpassed the other
six. These two polyelectrolytes are PCA and BTCA. The chelating agents EDTA, NTA
and HEDTA treated cationic fabrics resulted in 20-30% increase in crease angle recovery.
On the other hand, BTCA and PCA increased 20-50% in wrinkle recovery angles. BTCA
has four carboxyl groups on its molecule. PCA, on the other hand has hundreds of
carboxylic groups that are available to form ionic crosslinks with the cationic cellulose
chains. Therefore, it is expected that PCA treated fabrics would have better durability. The
comparision of the polyanion treatments with the polycation treatments demonstrates that
the polycation treatments such as cationic chitosan and cationic glycerin improved the
durable press properties of the fabrics better than PCA and BTCA treatments. This could
be due to the bulky structure of quat molecules that attached on the chitosan or glycerin.
Hence, not only ionic attraction between the opposite charges, but also secondary forces
such as wan der walls forces may have affected the crosslinks between the cellulose
chains. The cationization process of the cellulose is also much more difficult than the
carboxymethylation, due to low efficiency of the reaction of cellulose with quat.
Therefore, polycation treatments of anionic cellulose are preferable.
The summary of the effects of treatment on dry and wet wrinkle recovery angles of
the treated fabrics is shown in Figures 4.19 and 4.20. The DMDHEU treatment produced
the highest dry wrinkle recovery angles (276 degrees), followed by magnesium and
91
calcium treatments. The lowest wrinkle recovery angles were obtained with BTCA treated
cationic fabrics. Cationic chitosan and cationic glycerin treatments produced greater wet
wrinkle recovery angles than other polyelectrolyte treatments and were slightly lower than
the crease angle recovery (266 degrees) of DMDHEU treated fabric. Calcium and
magnesium treatments produced higher wrinkle recovery angles than PCA and BTCA
treatments. The lowest wet crease angle recoveries were obtained with BTCA treatment.
Figure 4.19 Effect of treatment on dry wrinkle recovery angles
92
Figure 4.20 Effect of treatment on wet wrinkle recovery angles 4.4 Strength data
Strength tests were studied with anionic fabrics treated with cationic chitosan,
cationic glycerin, calcium chloride and magnesium chloride and cationic cotton treated
with PCA and BTCA. Other treatments did not give significant wrinkle recovery angle
improvements therefore the strength test was not applied to them.
4.4.1 Tensile strength of conventional durable press finished fabric
The DMDHEU treated fabric was tested for breaking strength in warp direction in
order to compare with the polyelectrolyte treated samples. The result breaking strength
was 14.53lb.
93
4.4.2 Strength data of polycation treated anionic cellulosic fabrics
The data for untreated and treated fabrics can be found in Table A.15, A.16, A.17,
A.18 and A.19 of the Appendix showing the breaking load (lb) of the fabrics in warp
direction. Strength testing of 350 treated samples revealed tensile strength increases of up
to 58%. Standard deviation of strength tests for treated samples was between 2-5Lb. The
effects of carboxyl content of the fabrics and polycation concentration on the breaking
strength of the treatments are shown in Figures 4.21, 4.22 and 4.23. As an example the
data obtained from the molecular weight of 1.4 x 105g/mole chitosan is given below. For
cationic chitosan treatments the concentrations of 3% and 6% crosslinker showed the
highest strength gains, though the difference between the two wasn’t significant. In some
cases, 6% treatment produced a lower strength gain than 3% treatment. The strength data
of three different molecular weights of cationic chitosan treatments did not show a
significant difference. The cationic glycerin treatment produced a better strength gain and
a better correlation between crosslinker concentration and the strength gain. The
maximum breaking load was obtained with the 3% treatment on 114.5mmole/100g fabric.
The calcium chloride and magnesium chloride treatments also showed some strength gain
but not as high as cationic chitosan and cationic glycerin treatments. The breaking
strengths of the treated fabrics are in the range of 41.6Lb and 55.1Lb. The maximum
breaking strength was obtained at 55.1Lb for magnesium chloride treated fabric
containing114.5mmol/100g carboxyl content while it was 52.2Lb for calcium chloride
treated fabric containing 87.1mmol/100g carboxyl content. There was also no correlation
between the strength and carboxyl content of the treated fabrics.
94
30
40
50
60
70
0 30 60 90 120
Cabrboxyl content (mmol/100g)
Bre
akin
g lo
ad (L
b)
0%1%CC3%CC6%CC
Figure 4.21 Effect of carboxyl content and concentration on breaking strength of the
cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics
95
30
40
50
60
70
80
0 30 60 90 120
Carboxyl content (mmol/100g)
Bre
akin
g lo
ad (L
b)
0%1%CG3%CG6%CG
Figure 4.22 Effect of carboxyl content and concentration on breaking strength of the
cationic glycerin treated fabrics
30
40
50
60
0 30 60 90 120
Carboxyl content (mmol/100g)
Bre
akin
g lo
ad (L
b)
0%0.5M Ca++0.5M Mg++
Figure 4.23 Effect of carboxyl content and concentration on breaking strength of the
calcium and magnesium treated fabrics
96
4.4.3 Strength data of polyanion treated cationic cellulosic fabrics
Cationic cellulosic fabrics treated with PCA and BTCA resulted in slight increase
in breaking strength. The data can be found in Tables A.20 and A.21 of the Appendix. The
effect of %Nitrogen fixed on fabrics and polyelectrolyte concentrations on the breaking
strength of the treated fabrics are presented in Figures 4.24 and 4.25. The breaking load
measurements are between 40Lb and 50Lb. Both polyanion treatments showed
approximately the same strength gain. The tensile strength test was applied to 150 samples
and only three samples showed strength losses of 7, 12 and 13% compared to the initial
fabric. The difference in strength gain was not significant between the PCA and BTCA
treatments. The 3% and 6% PCA treatments produced higher strength gains than 1% PCA
treatment. On the other hand, for BTCA treatments, 1% and 3% concentrations showed
higher strength gain than 6% concentration treatment. These treatments increased the
strength of the cellulosic fabric less than polycation treatments. On average polycation
treatments produced 24% more strength gain than polyanion treatments.
97
30
40
50
60
0.2 0.6 1 1.4
%Nitrogen fixed
Bre
akin
g lo
ad (L
b)
0%1%PCA3%PCA6%PCA
Figure 4.24 Effect of %Nitrogen content and concentration on breaking strength of the
PCA treated fabrics
30
40
50
60
0.2 0.6 1 1.4
%Nitrogen fixed
Bre
akin
g lo
ad (L
b)
0%1%BTCA3%BTCA6%BTCA
Figure 4.25 Effect of %Nitrogen content and concentration on breaking strength of the
BTCA treated fabrics
98
4.4.4 Discussion of strength data of untreated and treated fabrics
The ionic crosslinking process has a great ability to increase the strength of the
treated fabrics. This strength gain is proportional with number of ionic crosslinks between
the cellulose polymer chains. Unlike covalent bonds formed by treatment of fabric with
N-methylol based resins in conventional durable press finishing, the ionic crosslinks
increase the flexibility of the polymer chains, because the ionic crosslinked samples were
produced significantly higher elongation at breaking load than untreated and DMDHEU
treated fabrics. The average elongation of 5 untreated fabric samples at peak load was
5.2mm, while it was 2.52mm for DMDHEU treated fabrics and 26.8mm for 6% cationic
glycerin treated fabric containing 114.5 mmole/100g carboxyl groups. The flexible
polymer chains have mobility to line up and become firmer under an applied force. This
lining up of the polymer chains provides resistance against much higher forces. Hence, the
result is much higher increases in strength gain of treated fabrics.
Considering the strength loss by cationization of the fabrics, the data obtained from
polyanion treatments showed that there is a significant strength gain of up to 34%.
Cellulosic fabrics treated with strong acids could decrease the strength of the fabric. Thus
we neutralized the acids before the crosslinking process, with the intention of halting the
strength reducing effects of the strong carboxylic acids. The strength gain by polyanion
treatments was lower than polycation treatments, likely due to the acid treatments and
strength loss of the cationic fabrics. Treatments of anionic fabrics with various polycations
provided a strength gain up to 58%, a very significant improvement.
99
The summary of the strength data of the treated fabrics is shown in Figure 4.26. The
DMDHEU treatment decreased the tensile strength of the fabrics more than 50%, which is
a very significant strength loss. On the other hand the ionic crosslinked fabrics showed
strength gains up to 58%. The maximum strength gain obtained with cationic glycerin
treatment.
Figure 4.26 Effect of treatment on breaking strength
Figures 4.27 and 4.28 show the wet wrinkle recovery angles of cationic chitosan and PCA
treated samples versus breaking strength data. The correlations with the coefficients of
determination (R2) of 0.78 for cationic chitosan treatments and 0.49 for PCA treatments
100
are obtained. The correlation coefficients are calculated as 0.71 for cationic glycerin
treatments and 0.42 for BTCA treatments.
R2 = 0.78
200
220
240
260
280
40 50 60 70
Breaking load (Lb)
Wet
wrin
kle
reco
very
ang
les
(deg
rees
)
Figure 4.27 Correlation between wet wrinkle recovery angles of cationic chitosan
(molecular weight of 1.4 x 105g/mole) treatment and tensile strength
101
R2 = 0.49
130
150
170
190
210
230
250
30 35 40 45 50 55 60
Breaking load (Lb)
Wet
wrin
kle
reco
very
ang
les
(deg
rees
)
Figure 4.28 Correlation between wet wrinkle recovery angles of PCA treatment and
tensile strength
4.5 CIE whiteness index data
The CIE whiteness index measurements were applied to cationic chitosan, cationic
glycerine, calcium chloride and magnesium chloride treated anionic fabrics and PCA and
BTCA treated cationic fabrics.
4.5.1 CIE whiteness index of conventional durable press treated fabric
The whiteness index of DMDHEU treated fabric measured as 51.04 while it was
62.58 for untreated fabric. There was approximately 12% decrease in whiteness index for
resin treated fabric. It has known that the decrease in whiteness is due to high curing
temperature and presence of acid catalyst for the resin, because such conditions degrade
the cellulose and yellows the fabric.
102
4.5.2 CIE whiteness index of polycation treated anionic cellulosic fabrics
The CIE whiteness index data showed that all the treatments decrease the
whiteness of the fabric except calcium and magnesium chloride treatments. The data can
be found in Tables A.22, A.23, A.24, A.25 and A.26 of the Appendix. The effect of
carboxyl content of the fabrics and polyelectrolyte concentrations on the whiteness index
of the treated fabrics are presented in Figures 4.29, 4.30 and 4.31. The cationic chitosan
treatments decreased the whiteness index of the fabrics the most, due to the color of the
cationic chitosan. As previously mentioned, the color of the chitosan changes into a dark
brown color after reaction with quat. The greatest decrease was obtained with the
molecular weight of 3.2 x 104g/mole cationic chitosan. Treatments with higher
concentrations of crosslinker produced the lowest whiteness index. The cationic glycerin
treatments also created some decreases in whiteness index, but not as low as cationic
chitosan treatments with values between 50 and 60. The calcium and magnesium
treatments had almost no effect on whiteness of the fabrics. In some cases, they slightly
improved the whiteness index.
103
30
40
50
60
70
0 30 60 90 120
Carboxyl content (mmol/100g)
CIE
Whi
tene
ss In
dex
0%1%CC3%CC6%CC
Figure 4.29 Effect of carboxyl content and concentration on whiteness index of the
cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics
30
40
50
60
70
0 30 60 90 120
Carboxyl content (mmol/100g)
CIE
Whi
tene
ss In
dex
0%1%CG3%CG6%CG
Figure 4.30 Effect of carboxyl content and concentration on whiteness index of the
cationic glycerin treated fabrics
104
30
40
50
60
70
0 30 60 90 120
Carboxyl content (mmol/100g)
CIE
Whi
tene
ss In
dex
0%0.5M Ca++0.5M Mg++
Figure 4.31 Effect of carboxyl content and concentration on whiteness index of the
calcium chloride and magnesium chloride treated fabrics
4.5.3 CIE whiteness index of polyanion treated cationic cellulosic fabrics
The results can be found in Tables A.27 and A.28 of the appendix. The effect of
%Nitrogen content of the fabrics and polyelectrolyte concentrations on the whiteness
index of the treated fabrics are presented in Figures 4.32 and 4.33. The blank cationic
fabrics showed significant decreases in whiteness compared to untreated fabrics. Both of
the treatments reduced the whiteness of the fabrics with various degrees. The decreases
are quite similar to the cationic chitosan treatment results. The strong acidic nature of
these polycarboxylic acids yellows the cellulose, especially when the fabrics are
introduced to high temperatures. Although, BTCA decreased the whiteness index values
105
of the treated fabrics slightly more than PCA, the difference was not significant. An
increase in cationic levels of the fabric and concentration of the polyanion produced
higher decreases in the whiteness index of the treated fabrics.
30
40
50
60
70
0.2 0.6 1 1.4
%Nitrogen fixed
CIE
Whi
tene
ss In
dex
0%1%PCA1%PCA6%PCA
Figure 4.32 Effect of %Nitrogen fixed and concentration on whiteness index of the PCA
treated fabrics
106
30
40
50
60
70
0.2 0.6 1 1.4
%Nitrogen fixed
CIE
Whi
tene
ss In
dex
0%1%BTCA3%BTCA6%BTCA
Figure 4.33 Effect of %Nitrogen fixed and concentration on whiteness index of the BTCA
treated fabrics
4.5.4 Discussion of whiteness index of untreated and treated fabrics
The summary of the CIE whiteness index data of treated fabrics is shown in Figure
4.34. The whiteness index of DMDHEU treated fabric was 51.04, approximately 12%
decrease compared to untreated fabric. Cationic glycerin, calcium and magnesium
treatments produced higher whiteness index values than resin treatment but cationic
chitosan, PCA and BTCA treatments decreased the whiteness index of the treated fabrics
more than conventional resin treatment. The whiteness index of polyelectrolyte treated
fabrics decreases as the concentration of crosslinker increases. We also observed that the
decrease in whiteness index was higher for BTCA treatment. The change is more
significant for treatments of fabrics having higher levels of cationic or anionic content.
107
Hence, the density of the crosslinks between the cellulose polymer chains is higher. The
whiteness index of untreated fabric dropped from 62.58 to as low as 32.42 for cationic
chitosan treatments. The decrease is due to color change of cationic chitosan. Light
yellowish color of chitosan changes into dark brown color after the cationization reaction.
Though, the molecular weight of 3.2 x 104g/mole showed very low whiteness index values
for treatments with 3 and 6% concentrations with results of 51.77 for cationic glycerin
treatments, 37.25 for PCA treatments and 31.82 for BTCA treatments. The treatments
with calcium chloride and magnesium chloride did not decrease the whiteness index of the
fabrics significantly. In some cases they slightly increased the whiteness of the treated
fabrics.
108
Figure 4.34 Effect of treatment on whiteness index
4.6 Stiffness data
The stiffness test was applied to the fabrics treated with cationic chitosan, cationic
glycerin, calcium chloride, magnesium chloride, PCA and BTCA. The data is given in the
figures below. The figures show the ionic content of the fabric on the x-axis and the
flexural rigidity of the treated fabrics on the y-axis. The untreated fabric produced a
flexural rigidity of 21.47mg x cm and the flexural rigidity of the N-methylol treated fabric
measured as 39.04mg x cm.
109
4.6.1 Stiffness of conventional durable press treated fabrics
The bending length and flexural rigidity of the DMDHEU treated fabric was
measured as 1.5cm / 39.04mg x cm while it was 1.2cm / 21.4mg x cm for untreated fabric.
4.6.2 Stiffness data of polycation treated anionic cellulosic fabrics
The results containing the bending length and flexural rigidity of the untreated,
cationized and treated fabrics can be found in Tables A.29, A.30, A.31, A.32 and A.33 of
the appendix. The effect of carboxyl content of the fabrics and polyelectrolyte
concentrations on the stiffness of the treated fabrics are presented in Figures 4.35, 4.36
and 4.37. The cationic chitosan treatments showed higher flexural rigidity values for
treated fabrics. The rigidity of the fabrics increased significantly after the
carboxymethylation process. Molecular weight of 3.2 x 104g/mole cationic chitosan
produced the highest flexural rigidity values. Molecular weight of 1.4 x 105g/mole and
6.11 x 105g/mole cationic chitosan treated fabrics showed slightly lower rigidity values
than 3.2 x 104g/mole cationic chitosan treatment. For all cases though, cationic chitosan
treatments showed significantly higher rigidity values than other treatments. The rigidity
values of treated fabrics are in the range of 47mg x cm to 730mg x cm. The cationic
glycerin treated fabrics showed lower flexural rigidity values than cationic chitosan
treatments. The flexural rigidity values are between 45mg x cm and 165mg x cm. On the
other hand, the calcium chloride treated fabrics showed flexural rigidity between 80mg x
cm and 200mg x cm, while it was between 90 to 240mg x cm for magnesium chloride
treatments.
110
0
50
100
150
200
250
300
0 30 60 90 120
Carboxyl content (mmole/100g)
Flex
ural
rigi
dity
(mg
x cm
)
0%1%CC3%CC6%CC
Figure 4.35 Effect of carboxyl content and concentration on stiffness of the cationic
chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics
0
50
100
150
200
250
300
0 30 60 90 120
Carboxyl content (mmole/100g)
Flex
ural
rigi
dity
(mg
x cm
)
0%1%CG3%CG6%CG
Figure 4.36 Effect of carboxyl content and concentration on stiffness of the cationic glycerin treated fabrics
111
0
50
100
150
200
250
300
0 30 60 90 120
Carboxyl content (mmole/100g)
Flex
ural
rigi
dity
(mg
x cm
)
0%0.5M Ca++0.5M Mg++
Figure 4.37 Effect of carboxyl content and concentration on stiffness of the calcium
chloride and magnesium chloride treated fabrics
4.6.3 Stiffness data of polyanion treated cationic cellulosic fabrics
The results of stiffness measurements of PCA and BTCA treated fabrics are given
in Tables A.34 and A.35 of the appendix. The effect of %Nitrogen content of the fabrics
and polyelectrolyte concentrations on stiffness of the treated fabrics are presented in the
Figures 4.38 and 4.39. The cationized cellulosic fabrics also showed significantly higher
flexural rigidity values compared to the untreated fabric. The rigidity of the fabrics
increased while increasing the cationic level of the fabrics. The maximum rigidity was
obtained with 0.57 %Nitrogen fixed fabric. The treatments with polyanions reduced the
rigidity of the cationized fabrics. The crosslinked fabrics’ rigidity values are slightly
higher than that of the untreated fabric. Both the PCA and BTCA treatments produced
112
similar flexural rigidity values. For the PCA treatments, the flexural rigidity values are
between 22 and 73mg x cm, while for BTCA treatments they were between 23 and 72mg
x cm.
0
50
100
150
200
250
300
0.2 0.6 1 1.4
%Nitrogen fixed
Flex
ural
rigi
dity
(mg
x cm
)
0%1%PCA3%PCA6%PCA
Figure 4.38 Effect of %Nitrogen fixed and concentration on stiffness of the PCA treated
fabrics
113
0
50
100
150
200
250
300
0.2 0.6 1 1.4
%Nitrogen fixed
Flex
ural
rigi
dity
(mg
x cm
)
0%1%BTCA3%BTCA6%BTCA
Figure 4.39 Effect of %Nitrogen fixed and concentration on stiffness of the BTCA treated fabrics
4.6.4 Discussion of stiffness data of untreated and treated fabrics
The summary of the stiffness data of treated fabrics is shown in Figure 4.40. The
flexural rigidity of the DMDHEU treated fabric was measured as 39.04mg x cm while it
was 21.4mg x cm for untreated fabric. The stiffness of resin treated fabric is lower than
most of the ionic crosslinked fabrics. But in some cases, for example the PCA and BTCA
treated cationic fabrics having 0.19% and 0.28% fixed nitrogen showed lower flexural
rigidity than DMDHEU treated fabric.
The ionic crosslinking process increases the stiffness of the treated fabric. After
the fabric is carboxymethylated or cationized it shows significantly high flexural rigidity
114
values compared to the untreated fabric, because ionic cellulose molecules have
substitutions on their molecules either with chloroacetic acid or CHTAC. Cellulose
molecules are most extended at low concentrations of ionic groups but at higher
concentrations the molecules overlap and coil up and then, at high concentrations, they
form entangled structures. Increasing ionic strength causes the polymer to become more
coiled. This new molecular structure makes the fabric stiffer. Following application, ionic
crosslinking in this case, reduces the rigidity of the ionic cellulosic fabric by some degree.
The end product, crosslinked cellulosic fabric, shows rigidity values that are still higher
than the initial fabric. The increase in the flexural rigidity is higher for higher cationic or
anionic content of the fabrics. Increases in the concentration of the crosslinker also make
the fabrics stiffer. In the case of anionic fabrics treated with polycations, the cationic
chitosan treatments produced the highest increase in stiffness. Calcium and magnesium
treated fabrics also produced high rigidity values, though are not as high as cationic
chitosan treated fabrics. Cationic glycerin treatments also showed significantly high
flexural rigidity values, but are still lower than cationic chitosan treatments. On the other
hand, the polyanion treated cationic fabrics showed flexural rigidity values that are
slightly higher than the initial fabric. The flexural rigidity values are almost identical for
PCA and BTCA treated fabrics. These treatments resulted with significantly low rigidity
values compared to polycation treated anionic fabrics.
115
Figure 4.40 Effect of treatment on stiffness
116
5. CONCLUSIONS
Ionic crosslinking of cellulose for durable press finish can be a potential solution
for today’s textile industry, which is searching for durable press finishes that can give the
same advantages as formaldehyde based finishes without causing strength loss and
formaldehyde release. There are many alternatives for forming ionic crosslinks, for
example, making cellulose anionic with chloro acetic acid and reacting with a polycation
or producing cationic cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium
chloride and then reacting with a polyanion. In both ways, the polymer chains are bound
at as many sites as possible with having an excellent washing durability. These treatments
produce improvements in both dry and wet wrinkle recovery angles with significant
increases in tensile strength. Increases up to 140o were obtained in wet wrinkle recovery
angles and up to 100o in dry wrinkle recovery angles, while including a considerable
strength gain in treated fabrics. The DMDHEU treatment decreased the tensile strength of
the fabrics more than 50%, a considerable strength loss and a major problem. On the other
hand the ionic crosslinked fabrics improved tensile strength of treated fabrics up to 58%, a
very significant strength gain. The whiteness index of resin treated fabric was 51.04, an
approximately 12% decrease compared to untreated fabric. Treatments with cationic
glycerin, calcium and magnesium did not cause significant decrease in whiteness index of
treated fabrics. The difference was between 2% and 20%. Cationic chitosan treatments
showed over 25% decreases in whiteness of the treated fabrics. The stiffness values of the
treated fabrics were significantly higher than initial fabric. The BTCA and PCA
117
treatments showed similar stiffness values to that of the DMDHEU treatment. The other
polyelectrolyte treatments produced significantly higher stiffness values than DMDHEU
treated fabric.
In addition, ionic crosslinks may have other important advantages, such as
antimicrobial activity and enhanced dyeability. The chemicals are common industrial
reactants and do not have unusual safety or environmental issues. The processes use
existing equipment that are widely used in the textile industry and have no need for high
temperature curing.
118
6. RECOMMENDATIONS FOR FUTURE WORK
This research focused on effects of altering polyelectrolyte types, ionic content of
the fabrics and application process on wrinkle recovery angles, tensile strength, whiteness
and stiffness of the treated fabrics.
In terms of polyelectrolyte types, we observed that small molecular weight
molecules such as cationic glycerin could give same advantages as high molecular weight
polyelectrolyte without causing significant decreases in whiteness of the treated fabrics. In
addition, it is expected that smaller molecules have higher mobility between the cellulose
polymer chains; therefore they could form ionic crosslinks either in the same cellulose
chain or between two different chains. The nitrogen analysis after several laundry
washings showed there was no significant difference in loss of polyelectrolyte between
cationic chitosan treatment and cationic glycerin treatment. Thus treatments with small
molecular weight polyelectrolyte are recommended for future work.
In the case of ionic content of the fabrics, four ionic levels have been tested and an
optimum level was observed. The wrinkle recovery angles and strength data of the treated
fabrics were not significantly different for levels 3 and 4. Meanwhile, treated fabrics
having lower levels of ionic contents produced higher whiteness and lower stiffness
values than the fabrics having higher ionic contents. Therefore, it is recommended to work
with just three different levels of ionic contents. Working with different fabric and fiber
types may also vary the results. For example, a tight fabric structure can produce lower
improvements than a loose fabric, as the tight weave inhibits movements causing the
119
fibers to take on more pressure, and therefore more wrinkling occurs. Fiber thickness also
affects the crease angle recovery of the fabric. For example, a fabric made of thicker fibers
may show lower crease angle recovery improvements, as the cellulose chains have greater
force difference due to stretching under an applied force and they wrinkle more.
The application process consisted of producing anionic and cationic cellulose
followed by the application of a polyelectrolyte of the opposite charge. The treatments of
anionic cellulosic fabrics with various polycations showed greater improvements.
Therefore, polycation application is preferable. A one-step treatment can also be applied,
such as making a precondensate by adding an ionic material to a polyelectrolyte of the
opposite charge and then reacting this precondensate with the fabric. This method is much
easier and faster, as it avoids the production of ionic fabric prior to ionic crosslinking and
is similar to conventional durable press finishes. In order to accomplish higher dry wrinkle
recovery angles, a solvent system can be used instead of water to apply polyelectrolytes.
The selected solvent should easily dissolve the polyelectrolytes and open the structure of
cellulose.
The ionic crosslinking process may have some effects on the microstructure of the
cellulose polymer chains, such as changes in the crystalline structure of the polymer
chains and internal structure of the cellulose. A further understanding of the molecular
changes after the ionic crosslinking process is recommended. Ionic crosslinking may
increase the crystalline part of the cellulose structure. The strength data obtained from
treated fabrics showed significant strength gain. This strength gain may be due to an
increase in the amount of crystalline part of cellulose structure. There are instrumental
120
techniques to determine the crystallinity level of the polymer. X-Ray diffraction analysis
can be performed to identify the changes in the crystallinities and the internal structures as
a result of ionic crosslinking.
121
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11. Butnaru R., Muresanu A. and Mitu S. Influence of crease resist finish treatments upon the comfort indices in cotton-type textiles. Cellulose Chemistry and Technology 1986 May;20(3):349-355. 12. Ibrahim N.A. and El Alfy EA. Concurrent dyeing and finishing II. Combined dyeing and easy-care finishing of aminized cotton with acid dyestuffs and N-methylol compounds. Cellulose Chemistry and Technology 1987 Sep;21(5):507-512. 13. Vaidya A.A. and Trivedi S.S. Textile Auxiliaries and Finishing Chemicals. Ahmedabad: R.C. Vora; 1975. 90-100. 14. Bajaj P., Chakrapani S. and Jha N.K. Flame retardant durable-press finishes for cotton and polyester/cellulose blends. Textile Research Journal 1984 Sep;54(9):619-630. 15. Shin Y., Hollies N.R.S. and Yeh K. Polymerization-crosslinking of cotton fabric for superior performance properties. I. A preliminary study. Textile Research Journal 1989 Nov;59(11)635-642. 16. Hamalainen C., Mard H.S. and Cooper A.S. Comparison of application techniques for deposition of resins in cotton fibres. American Dyestuff Reporter 1972 ;71(2):30-38. 17. Vail S.L. and Verburg G.B. Chemical and physical properties of cotton modified by N-methylol agents. III. Observations on polymerization and crosslinking of melamine- based reagents with cotton. Textile Research Journal 1973 Jan;43(2):67-74. 18. Nair P. Resin finishing of polynosic/cotton blended fabric by poly-set process. Cellulose Chemistry and Technology 1982 Sep;16(5):491-502. 19. Reinhardt R.M. and Harper R.J. Comparison of aftertreatments to lower formaldehyde release from cottons crosslinked with various finishing agents. Journal of Coated Fabrics 1984 April;13(4):216-227. 20. Sarma G.V., Gupta R.C. and Verma B.C. Performance report of BIL-treated all cotton durable press shirts in a pilot service test. Journal of the Textile Association 1973 May;34(3):115-122. 21.Turner J.D. Articles with durable press produced by low temperature treatment. Textile World 2001 March;151(3):50-53. 22. Yang C.Q., Qian L. and Lickfield G.C. Mechanical strength of durable press finished cotton fabric Part IV: Abrasion resistance. Textile Research Journal 2001 June;71(6):543-548.
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23. Charles Q. Yang and Weishu Wei. Mechanical Strength of Durable Press Finished Cotton Fabric Part II: Change in Cellulose Molecular Weight. Textile Research Journal 2000 Oct;70(10):910-915. 24. Ibrahim N. A., Abo Shosha M. H., Elnagdy E. I. and Gaffar M. A. Eco Friendly Durable Press Finishing of Cellulose Containing Fabrics. Journal of Applied Polymer Science 2002 June;84(12):2243–2253. 25. Day M.P. and Collier B.J. Prediction of formaldehyde release from durable press treated fabrics. Textile Chemist and Colorist 1997 Jan;29(1):33-36. 26. Xu W. and Li Y. Cotton fabric strength loss from treatment with polycarboxylic acids for durable press performance. Textile Research Journal 2000 Nov;70(11):957-961. 27. Charles Q. Yang and Weishu Wei. Mechanical strength of durable press finished cotton fabric. Part II: Comparison of crosslinking agents with different molecular structures and reactivity. Textile Research Journal 2000 Feb;70(2):143-147. 28. Srichharussin W., Ryo Aree W., Intasen W. and Poungraksakirt S. Effect of Boric Acid and BTCA on Tensile Strength Loss of Finished Cotton Fabrics. Textile Research Journal 2004 June;74(6):475-480. 29. Udomkichdecha W., Kjttinaovarat S., Tianasoonthornroek U. and Potlyaraj P. Acrylic and maleic acids in nonformaldehyde durable press finishing of cotton fabric. Textile Research Journal 2003 May;73(5):401-406. 30. Aly A.S., Hashem A. and Hussein S.S. Utilization of chitosan citrate as crease-resistant and antimicrobial finishing agent for cotton fabric. Indian Journal of Fiber & Textile Research 2004 June;29(2):218-222. 31. Achwal W.B. Chitosan and its derivatives for textile finishing. Colourage 2003 ;50(8): 51-76. 32. Gary A. Ungefug and Stephan B. Cello. Ionic Crosslinking of Acrylic Sizes. Textile Chemist and Colorist 1983 Oct;15(10):193-196. 33. Fujiyama M., Kondou M., Ayama K. and Inata H. Rheological Properties of Ionically and Covalently Crosslinked Polypropylene Type Thermoplastic Elastomers. Journal of Applied Polymer Science 2002 July;85(4):762–773. 34. Mitsuyoshi F., Kazuhiro Y., Kazuhiko A. and Hitoshi I. Rheological Properties of Ionically Crosslinked Poly(propylene)-Type Thermoplastic Elastomers. Journal of Applied Polymer Science 2002 Dec;86(11):2887–2897.
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35. Fanbao M., Baoyan Z., Lumei L. and Baoling Z. Liquid-crystalline elastomers produced by chemical crosslinking agents containing sulfonic acid groups. Polymer 2003 June;44(14):3935–3943. 36. Ibarra L. and Alzorriz M. Vulcanization of carboxylated nitrile rubber (XNBR) by a mixed zinc peroxide–sulphur system. Polymer International 2000 Jan;49(1):115-121. 37. Sriram V., Aruna P., Naresh M. D. and Radhakrishnan Ganga. AB Crosslinked Polyurethanes Through Ionic Crosslinking: Influence of Crosslinking Networks on Physico Chemical properties. Journal of Macromolecular Science Part A: Pure Application Chemistry 2001 Sep;38(9):945–959. 38. Roberts G.A.F. Chitin Chemistry. London: Macmillan Press Ltd.; 1992. 94-112. 39. Kim, Y., Choi, H., and Yoon, J. Synthesis of a Quaternary Ammonium Derivative of Chitosan and Its Application to a Cotton Antimicrobial Finish. Textile Research Journal 1998 June;68(6):428. 40. El Hilw Z.H. Development of an ecological system for the easy-care finishing of cotton. Tinctoria 2004 March;101(3):29-35. 41. Kittinaovarut S. Acrylic and citric acid in nonformaldehyde durable press finishing on cotton fabric. AATCC Review 2003;3:62-64. 42. Hasem M., Hauser P. and Smith B. Reaction Efficiency for Cellulose Cationization Using 3-Chloro-2-Hydroxypropyl Trimethyl Ammonium Chloride. Textile Research Journal 2003 Nov;73(11):1017-1023. 43. Shore John, editor. Colorants and Auxiliaries Organic chemistry and application properties. Hampshire: Hobbs The Printers; 2002. 664-666. 44. Timell T.E. editor. Proceedings of the Eighth Cellulose Conference. II. General Papers. New York: John Wiley & Sons; 1975. 811-830. 45. Tae K., Kim S., Han Y. and Young A.S. Effect of reactive anionic agent on dyeing of cellulosic fibers with a Berberine colorant. Dyes and Pigments 2004 March;60(3):121-127. 46. Lamber J.B., Shurrel H.F., Lightner D.A. and Cooks R.A. Introduction to Organic Spectroscopy. New York: Macmillan Publishing Company; 1987. 22-70.
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126
8. APPENDIX
8.1 Wrinkle recovery angles
The wrinkle recovery angles of the untreated fabric, carboxylated fabrics,
cationized fabrics, conventional durable press finished fabric and polyelectrolyte treated
fabrics and their relationships with ionic content of the fabrics and polyelectrolyte
concentration are given in the tables below.
Table A.1 Dry and wet wrinkle recovery angles for molecular weight of 32000g/mole cationic chitosan treated fabrics (dry/wet)
CC treatment > pad batch concentration Resin treatment 272/266
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 138/125 184/168 172/172 178/168
30.2 160/149 212/236 242/250 226/255
60.7 163/145 220/244 234/246 222/257
87.1 162/153 224/248 232/248 230/242
114.5 166/159 220/250 234/254 208/268
127
Table A.2 Dry and wet wrinkle recovery angles for molecular weight of 140000g/mole cationic chitosan treated fabrics (dry/wet)
CC treatment > pad batch concentration Resin treatment 272/266
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 138/125 186/185 172/182 183/193
30.2 160/149 204/234 208/246 211/256
60.7 163/145 212/244 218/258 214/256
87.1 162/153 228/246 222/260 209/260
114.5 166/159 212/260 207/264 215/266
Table A.3 Dry and wet wrinkle recovery angles for molecular weight of 611000g/mole cationic chitosan treated fabrics (dry/wet)
CC treatment > pad batch concentration Resin treatment 272/266
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 138/125 170/172 164/166 168/164
30.2 160/149 208/246 212/252 212/250
60.7 163/145 210/249 215258 218/256
87.1 162/153 222/252 218/262 230/258
114.5 166/159 233/242 234/237 230/244
128
Table A.4 Dry and wet wrinkle recovery angles for molecular weight of 140000g/mole cationic chitosan treated fabrics by exhaustion method (dry/wet)
CC treatment > batch concentration Resin treatment 272/266
COO- content
(mmols/100g)
0%(Blank) 6%
30.2 160/149 135/216
87.1 162/153 123/191
114.5 166/159 120/232
Table A.5 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics (dry/wet)
Cationic glycerin treatment > pad batch concentration Resin treatment: 272/266
COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 138/125 188/185 174/183 185/192
30.2 160/149 216/250 206/256 207/257
60.7 163/145 201/256 208/262 212/265
87.1 162/153 215/259 215/258 204/265
114.5 166/159 214/269 227/266 224/273
129
Table A.6 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics by exhaustion method (dry/wet)
Cationic glycerin treatment > batch concentration Resin treatment: 272/266
COO- content
(mmol/100g)
0% (Blank) 12%
6.2 138/125 131/180
30.2 160/149 192/202
60.7 163/145 197/214
87.1 162/153 206/215
114.5 166/159 200/229
Table A.7 Dry and wet wrinkle recovery angles for cationic cellobiose and cationic
dextrose treated fabrics (dry/wet)
Cationic cellobiose and dextrose treatment > pad batch concentration Resin treatment: 272/266
COO- content
(mmol/100g)
0% (Blank) 6% cationic
cellobiose
6% cationic dextrose
30.2 160/149 212/214 202/216
60.7 163/145 208/214 205/215
130
Table A.8 Dry and wet wrinkle recovery angles for calcium chloride and magnesium
chloride treated fabrics (dry/wet)
Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 272/266
COO- content
(mmol/100g)
0% (Blank) 0.5M Calcium
Chloride
0.5M Magnesium
Chloride
6.2 138/125 175/152 183/167
30.2 160/149 211/203 221/206
60.7 163/145 133/232 230/237
87.1 162/153 226/225 219/210
114.5 166/159 244/203 232/201
Table A.9 Dry and wet wrinkle recovery angles for PCA treated fabrics (dry/wet)
Polycarboxylic acids treatment > pad batch concentration Resin treatment 272/266
%N fixed 0%(Blank) 1% 3%
6%
0.24 138/125 172/144 158/150 192/132
0.45 155/158 175/191 168/191 172/178
0.73 157/145 185/178 188/195 184/187
1.15 150/154 184/207 184/202 174/222
1.54 153/152 182/222 170/226 170/232
131
Table A.10 Dry and wet wrinkle recovery angles for BTCA treated fabrics (dry/wet)
BTCA treatment > pad batch concentration Resin treatment: 272/266
%N fixed 0%(Blank) 1% 3%
6%
0.24 138/125 170/138 162/150 156/138
0.45 155/158 162/180 174/193 185/180
0.73 157/145 184/178 184/186 181/178
1.15 150/154 172/201 160/209 158/194
1.54 153/152 186/204 158/208 168/233
Table A.11 Dry and wet wrinkle recovery angles for EDTA treated fabrics (dry/wet)
EDTA treatment > pad batch concentration Resin treatment: 272/266
%N fixed 0%(Blank) 1% 3%
6%
0.24 138/125 162/134 191/128 176/137
0.45 155/158 166/168 166/158 161/161
0.73 157/145 163/168 184/187 173/182
1.15 150/154 145/183 157/174 157/179
1.54 153/152 136/189 134/182 165/185
132
Table A.12 Dry and wet wrinkle recovery angles for NTA treated fabrics (dry/wet)
NTA treatment > pad batch concentration Resin treatment: 272/266
%N fixed 0%(Blank) 1% 3%
6%
0.24 138/125 170/131 167/136 168/138
0.45 155/158 171/178 193/178 166/180
0.73 157/145 191/169 174/167 170/169
1.15 150/154 164/170 170/172 163/176
1.54 153/152 147/182 134/186 153/192
Table A.13 Dry and wet wrinkle recovery angles for HEDTA treated fabrics (dry/wet)
HEDTA treatment > pad batch concentration Resin treatment: 272/266
%N fixed 0%(Blank) 1% 3%
6%
0.24 138/125 182/136 176/130 186/130
0.45 155/158 173/170 167/160 175/158
0.73 157/145 187/170 184/187 191/186
1.15 150/154 148/180 146/178 157/182
1.54 153/152 160/188 161/183 139/186
133
Table A.14 Dry and wet wrinkle recovery angles for oxalic, malic and citric acid treated fabrics (dry/wet)
Oxalic acid, malic acid and citric acid treatment > pad batch concentration
Resin treatment: 272/266
%N fixed 0% (blank) 0.5M Oxalic
acid
0.5M Malic
acid
0.5M Citric
acid
1.15 150/154 160/178 154/170 160/182
1.54 150/152 106/186 140/188 154/204
8.2 Breaking strength
The breaking strength of the untreated fabric, carboxylated fabrics, cationized
fabrics, conventional durable press finished fabric and polyelectrolyte treated fabrics and
their relationships with ionic content of the fabrics and polyelectrolyte concentration are
given in the tables below.
134
Table A.15 Breaking strength data for molecular weight of 32000g/mole cationic chitosan
treated fabrics (lb)
CC treatment > pad batch concentration Resin treatment: 14.53
COO- content
(mmols/100g)
0%(Blank) 1% 3%
6%
6.2 39.01 41.76 45.7 46.1
30.2 53.32 63.68 63.6 59.8
60.7 45.99 62.6 65.8 62.1
87.1 44.8 61.1 57.5 62.6
114.5 51.23 49.8 66.4 70.1
Table A.16 Breaking strength data for molecular weight of 140000g/mole cationic chitosan treated fabrics (lb)
CC treatment > pad batch concentration Resin treatment: 14.53
COO- content
(mmols/100g)
0%(Blank) 1% 3%
6%
6.2 39.01 48.85 49.06 50.02
30.2 53.32 47.07 58.16 55.54
60.7 45.99 50.3 62.37 56.6
87.1 44.8 56.95 64.4 62.37
114.5 51.23 59.54 67.64 62.9
135
Table A.17 Breaking strength data for molecular weight of 611000g/mole cationic chitosan treated fabrics (lb)
CC treatment > pad batch concentration Resin treatment: 14.53
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 39.01 46.9 46 47.9
30.2 53.32 62.7 64.9 55.6
60.7 45.99 65.6 53.6 58.8
87.1 44.8 66.9 62.2 58.6
114.5 51.23 57.8 57.3 53.2
Table A.18 Breaking strength data for cationic glycerin treated fabrics (lb)
Cationic glycerin treatment > pad batch concentration Resin treatment: 14.53
COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 39.01 52.67 56.4 55.16
30.2 53.32 58.85 66.53 64.67
60.7 45.99 66.2 67.26 66.3
87.1 44.8 62.17 70.78 66.96
114.5 51.23 65.45 73.53 66.93
136
Table A.19 Breaking strength data for calcium chloride and magnesium chloride treated fabrics (lb)
Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 14.53
COO- content
(mmol/100g)
0% (Blank) 0.5M Calcium
Chloride
0.5M Magnesium
Chloride
6.2 39.01 43.8 44.3
30.2 53.32 51.8 42.8
60.7 45.99 47.2 41.6
87.1 44.8 52.2 47.7
114.5 51.23 51.7 55.1
Table A.20 Breaking strength data for PCA treated fabrics (lb)
Polycarboxylic acids treatment > pad batch concentration Resin treatment: 14.53
%N fixed 0%(Blank) 1% 3%
6%
0.24 39.01 39.31 41.01 41.86
0.45 41.47 36.08 46.15 45.68
0.73 36.32 39.5 45.53 45.66
1.15 36.2 40.78 47.41 46.35
1.54 35.38 52.75 50.94 49.22
137
Table A.21 Breaking strength data for BTCA treated fabrics (lb)
BTCA treatment > pad batch concentration Resin treatment: 14.53
%N fixed 0%(Blank) 1% 3%
6%
0.24 39.01 40.01 39.08 41.12
0.45 41.47 41.9 41.84 38.64
0.73 36.32 40.11 40.84 39.54
1.15 36.2 44.75 45.05 39.85
1.54 35.38 54.52 52.43 50.09
8.3 CIE whiteness index
The CIE whiteness index of the untreated fabric, carboxylated fabrics, cationized
fabrics, conventional durable press finished fabric and polyelectrolyte treated fabrics and
their relationships with ionic content of the fabrics and polyelectrolyte concentration are
given in the tables below.
138
Table A.22 Whiteness index data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics
CC treatment > pad batch concentration Resin treatment: 51.04
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 62.58 49.35 42.44 40.51
30.2 60 41.32 33.35 28.55
60.7 59.64 37.44 26.12 20.46
87.1 58.71 34.44 6.58 4.34
114.5 57.84 21.11 2.5 2
Table A.23 Whiteness index data for molecular weight of 1.4 x 105g/mole cationic
chitosan treated fabrics
CC treatment > pad batch concentration Resin treatment 51.04
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 62.58 57 56.97 55.75
30.2 60 54.5 53.31 52.12
60.7 59.64 53.91 50.27 49.56
87.1 58.71 51.59 46.77 44.28
114.5 57.84 47.49 41.1 33.42
139
Table A.24 Whiteness index data for molecular weight of 6.11x 105g/mole cationic chitosan treated fabrics
CC treatment > pad batch concentration Resin treatment: 51.04
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 62.58 56.4 55.21 54.48
30.2 60 51.02 49 45.62
60.7 59.64 50.59 47.04 42.59
87.1 58.71 53.23 45.44 41.13
114.5 57.84 42.11 36.8 35
Table A.25 Whiteness index data for CG treated fabrics
CG treatment > pad batch concentration Resin treatment 51.04
COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 62.58 60.75 59.78 57.73
30.2 60 56.18 55.76 56.7
60.7 59.64 55.94 53.76 56.8
87.1 58.71 56.27 53.3 57.2
114.5 57.84 54.79 51.77 53.63
140
Table A.26 Whiteness index data for calcium and magnesium chloride treated fabrics
Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 51.04
COO- content
(mmol/100g)
0% (Blank) 0.5M Calcium
Chloride
0.5M Magnesium
Chloride
6.2 62.58 60.98 60.29
30.2 60 61.02 60.94
60.7 59.64 62.8 62.21
87.1 58.71 63.6 61.54
114.5 57.84 60.52 60.77
Table A.27 Whiteness index data for PCA treated fabrics
Polycarboxylic acids treatment > pad batch concentration Resin treatment 51.04
%N fixed 0%(Blank) 1% 3%
6%
0.24 62.58 58.23 59.37 61.40
0.45 61.18 53.63 54.87 52.65
0.73 59.53 51.08 51.50 51.75
1.15 55.4 40.84 41.34 43.57
1.54 44.75 37.25 39.5 37.96
141
Table A.28 Whiteness index data for BTCA treated fabrics
BTCA treatment > pad batch concentration Resin treatment 51.04
%N fixed 0%(Blank) 1% 3%
6%
0.24 62.58 58.81 58.80 59.42
0.45 61.18 48.01 50.18 43.75
0.73 59.53 47.89 45.65 41.17
1.15 5534 43.19 43.15 39.13
1.54 44.75 38.21 31.82 39.69
8.4 Stiffness
The stiffness of the untreated fabric, carboxylated fabrics, cationized fabrics,
conventional durable press finished fabric and polyelectrolyte treated fabrics and their
relationships with ionic content of the fabrics and polyelectrolyte concentration are given
in the tables below.
142
Table A.29 Stiffness data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)
CC treatment > pad batch concentration Resin treatment: 1.5/39.04
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 1.2/21.4 1.7/60.4 1.8/65 1.8/65.7
30.2 1.4/45.5 1.76/86.5 1.9/113.3 1.9/105.2
60.7 1.7/93.7 1.88/107.5 2.2/173.8 2.2/175
87.1 1.9/119.9 2.26/207.2 2.3/217.3 2.4/242
114.5 2.4/254.7 3/497 2.37/259.9 3.3/730.8
Table A.30 Stiffness data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)
CC treatment > pad batch concentration Resin treatment: 1.5/39.04
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 1.2/21.4 1.62/48 1.67/51.8 1.63/49.6
30.2 1.4/45.5 1.57/62.1 1.54/57.8 1.47/51.5
60.7 1.7/93.7 1.4/47.2 1.52/57.9 1.57/65.3
87.1 1.9/119.9 1.5/59.6 1.53/61.2 1.51/63.1
114.5 2.4/254.7 1.7/97.8 1.52/67 1.97/159.5
143
Table A.31 Stiffness data for molecular weight of 6.11x 105g/mole cationic chitosan treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)
CC treatment > pad batch concentration Resin treatment: 1.5/39.04
COO- content
(mmol/100g)
0%(Blank) 1% 3%
6%
6.2 1.2/21.4 1.63/49.7 1.68/54.3 1.69/57.3
30.2 1.4/45.5 1.72/79.7 1.83/103.1 1.56/57.4
60.7 1.7/93.7 1.82/97.2 1.71/81.1 1.75/87.8
87.1 1.9/119.9 1.91/113.7 1.68/78.7 1.76/92.1
114.5 2.4/254.7 2/144.5 2.38/243 2.1/171.3
Table A.32 Stiffness data for cationic glycerin treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)
Cationic glycerin treatment > pad batch concentration Resin treatment: 1.5/39.04
COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 1.2/21.4 1.63/45.1 1.65/51 1.64/53.5
30.2 1.4/45.5 1.72/76.9 1.8/97.4 1.57/57.8
60.7 1.7/93.7 1.8/91.9 1.71/82 1.77/89.2
87.1 1.9/119.9 1.89/109.5 1.68/79.1 1.79/97.3
114.5 2.4/254.7 2/145.5 2.1/164.5 2.1/165.8
144
Table A.33 Stiffness data for calcium chloride and magnesium chloride treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)
Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 1.5/39.04
COO- content
(mmol/100g)
0% (Blank) 0.5M Calcium
Chloride
0.5M Magnesium
Chloride
6.2 1.2/21.4 1.98/88.2 2.0/91.4
30.2 1.4/45.5 1.93/108.5 1.76/81.0
60.7 1.7/93.7 1.82/90.8 187/99.2
87.1 1.9/119.9 2.1/148.1 1.91/113.7
114.5 2.4/254.7 2.3/198.8 2.4/240.5
Table A.34 Stiffness data for PCA treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)
Polycarboxylic acids treatment > pad batch concentration Resin treatment: 1.5/39.04
%N fixed 0%(Blank) 1% 3%
6%
0.24 1.2/21.4 1.66/52.1 1.7/55.9 1.75/58.5
0.45 1.35/33.7 1.25/22.5 1.3/25.8 1.28/24.4
0.73 1.777.4 1.31/28.3 1.34/29.9 1.35/31.3
1.15 1.87/114.1 1.43/48.4 1.49/54.7 1.41/47.4
1.54 2.35/241.4 1.4/49.1 1.51/61.3 1.61/43.6
145
Table A.35 Stiffness data for BTCA treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)
BTCA treatment > pad batch concentration Resin treatment: 1.5/39.04
%N fixed 0%(Blank) 1% 3%
6%
0.24 1.2/21.4 1.66/52.1 1.69/54.9 1.65/49
0.45 1.35/33.7 1.27/22.9 1.35/28.6 1.32/26.7
0.73 1.777.4 1.33/29.9 1.35/30.9 1.35/31.3
1.15 1.87/114.1 1.43/48.4 1.49/55.2 1.45/51.6
1.54 2.35/241.4 1.4/48.6 1.5/59.5 1.6/71.6
8.5 Nitrogen analysis
The %Nitrogen content of the untreated and polycation treated fabrics and their
relationships with ionic content of the fabrics and polyelectrolyte concentration are given
in the tables below.
146
Table A.36 Nitrogen analysis data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics (%Nitrogen)
Cationic chitosan treatment > pad batch concentration COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 0.24 0.3 0.31 0.34
30.2 0.25 0.25 0.29 0.3
60.7 0.25 0.32 0.34 0.36
87.1 0.25 0.32 0.41 0.48
114.5 0.26 0.47 0.56 0.67
Table A.37 Nitrogen analysis data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics (%Nitrogen)
Cationic chitosan treatment > pad batch concentration COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 0.24 0.24 0.24 0.25
30.2 0.25 0.26 0.28 0.27
60.7 0.25 0.27 0.30 0.3
87.1 0.25 0.30 0.32 0.42
114.5 0.26 0.38 0.47 0.54
147
Table A.38 Nitrogen analysis data for molecular weight of 6.11 x 104g/mole cationic chitosan treated fabrics (%Nitrogen)
Cationic chitosan treatment > pad batch concentration COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 0.24 0.27 0.26 0.3
30.2 0.25 0.27 0.34 0.28
60.7 0.25 0.3 0.33 0.36
87.1 0.25 0.29 0.42 0.43
114.5 0.26 0.36 0.53 0.57
Table A.39 Nitrogen analysis data for cationic glycerin treated fabrics (%Nitrogen)
Cationic glycerin treatment > pad batch concentration COO- content
(mmol/100g)
0% (Blank) 1% 3%
6%
6.2 0.24 0.25 0.25 0.28
30.2 0.25 0.26 0.29 0.27
60.7 0.27 0.25 0.31 0.33
87.1 0.25 0.34 0.34 0.36
114.5 0.26 0.37 0.44 0.39