Chemical modification of non-cellulosic polysaccharides

Dr. Katrin Schwikal 1Thuringian Institute of Textile and Plastics Research, Rudolstadt

Chemical modification of non-cellulosic polysaccharides

Katrin Schwikal1, Katrin Petzold-Welcke1, Thomas Heinze1, Bodo Saake2

1 Centre of Competence for Polysaccharide Research, Friedrich Schiller University Jena / TITK- Rudolstadt

2 Institute of Wood Technology and Wood Biology, Johann Heinrich von Thuenen Institute, Hamburg


! For example: acidic, alkaline, hydrophilic, hydrophobic, optical active.

With one matrix – various properties can be obtained

Polymer matrix with functional groups.

Modification with functional groups

Improved... • solubility.

• specific interaction with other polymers and particles (flocculation agents, surface active agents, phase separation agents, viscosity control agents, agents for improving the mechanical properties).

Specific biological activities, sensor functions.


DS = 0.5

DS = 1.0

DS = 2.0

• Mixed substituted derivatives (amphiphile, hybrid ionic, combination of a functional group with a intermediary dilution group ...)

• Degree of the modification and distribution of the functional groups can be adjusted.

Advantages of a polymer analog reaction:

Furthermore, a selective reaction on a specific hydroxyl group is possible, too.

statistical

Distribution of the substituents along the polymer chain

non-statistical

Degree of substitution (DS)(example: two hydroxyl groups)

substituted unit

non-substituted unit

individual hydroxyl functions

Modification with functional groups


Non-cellulosic polysaccharides

O

HOOH

OH

O

OOHO

OOH

OH

O

HOOH

OH

O

OO

HOOH

OH

OOHO

OH

OH

OO

OHO

OH

OH

Amylose

Cellulose

β-D-polyglucose

α-D-polyglucose

fiber forming structure polymer

non-fibre forming storage polymer

O

HOOH

OH

O

OOHO

OOH

O

n

OOHO

OH

OH

Amylopectine

Starch vs. cellulose


OOHO

OHO

O

HOO

OO

HOOH O

OHO

OO

OH3CO

HOOH

COOHOH3CO

HOOH

COOH

n

" Isolation from various resources" Cereal-by-products: wheat and oat spelts, corn spindles, barley

husks (arabinoxylanes) – depending on location up to 50%.

" Pulping-by-products (hard woods – 4-O-methyl glucuronoxylanes).

Xylan" Is one of the polyoses. " To be found in the supporting connective tissue

of plant cells.

41,627.3

27.1

cellulose

polyoses

lignin

accessory component

Birch:

*Grammel, R., Forstbenutzung. Verlag Paul Parey, Hamburg und Berlin, 1989.




Cellulose

Xylan

OOHO

OHO

O

HOO

OO

HOOH O

OHO

OO

RR

OOHO

OHO

O

HOOH

OO

HOOH O

OHO

OHO

OH

OH

OH

OH

O

HOOH

OOO

HOOH

OO

OHβ-D-Polyglucose

β-D-Polyxylose

similar stereochemical configuration

Supporting connective tissue of plant cells- supports plant water circulation- connect cellulose and lignin

With the exception:pentose hexose

R: polysaccharide substituents


Adjustable degree of substitution (DS)

Adjustable distribution of the substituents along the polymer chain

OOHO

OH

Functional polymers

PolysacchridePolysacchride esteresterPolysacchridePolysacchride etherether

OxidatedOxidatedproductsproducts

O

HOOH

OH

O

O

Reactive OH-groups

COOH

CH3C

O

O-Na+

N CH3

CH3OH H3C

Cl

CH3

O n

Xyl-O-SO3-Na+

O

Hydrophilic Hydrophobic Other special functionalities

O

O

O

OOO

O

NO

O

H

OO

Cross-linkable

Physiological active

Complexing Chiral


OORO

O

OHNCl

OOHO

OH

NO

Cl

2-Hydroxypropyltrimethylammonium xylan (HPMA xylan)

R = H; CH2CHOHCH2N(CH3)3+Cl-

Schwikal K., Heinze Th., Ebringerová A., Petzold K. Macromol. Symp. 2006, 232, 49-56.

Activation with NaOH

4-O-methyl-glucurono xylan from birch wood

The degree of substitution

0.06

0.10

0.14

0.19

0.00

0.05

0.10

0.15

0.20

0.15 0.25 0.35 0.50

EPTA/AXU

DS The molar degree of substitution

(MS) is easily adjustable to values between 0.06 and 0.19.

MS


-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 2 4 6 8 10 12 14

pH-value

Cha

rge

[equ

/mol

]

" The all in all surface charges of GX and the HPMAGX with a MS of 0.06 in water at pH 6-8 is negative.

" Surface charge of cationic modified birch xylans in water:

0.19

0.14

0.1

0.06

birch xylan

HPMA 4-O-methylglu-curono xylanswith MS =

-0.07

-0.02

0.030.07

0.14

SurfacechargebetweenpH 6-8

≡

O

HOO

OO

HOO

O

N

OH

OH3CO

HOOH

O O

O

HOOH

O

Cl

Na

+-

+

-

-

+-

Due to the methylglucuronicside chains in the polymer, the resulted structure have a zwitterionic character.



Practical example: xylan as paper strength additive

Strong association of xylan to the cellulose microfibrilles in the natural environment.1

After removing xylan - stability decreased. 2

The pulp surface is weakly anionic charged.

" New biopolymer-based products are suitable by modification of the xylan.

" Cationic xylan derivatives should be able to increase the paper strength properties.

" They should be capable to improve the fine and filler retention.

+

OH

HO

HOOH

OH

OH

-OOCCOO-

HO

HO

--+

1Chanzy H., Dube, M., Marchessault R. H., Tappi 1978, 61(7), 81.2Laine, J., Pap. Puu 1997, 79(8), 551, Mobarak F., El-Ashmawy, A.E. Fahmy, Y. Cell. Chem. Technol. 1973, 7, 325Mobarak F., El-Ashmawy, A.E. Augustin, H. Cell. Chem. Technol. 1973, 11, 109.



Adsorption behaviour on model surfaces via SPR*

prismpolarized light reflected light

adsorbed HPMA xylanHPMA xylan

sensor surfacewith gold film andsurface coating

• At a specific angle - the free electrons in the metal (gold) couple resonant with the incident photons – and induce a plasma wave that extends out in the interface.# surface plasmon

• Any change in the interface (thickness, refraction index) lead to a change of the resonant frequency.

• The angle there the minimum intensity was detected shift.

*surface plasmon resonance spectroscopyKaya A., Drazenovich D. A.; Glasser W. G., Schwikal K., Heinze Th., Esker A. R. The 235th ACS National Meeting, New Orleans, LA, United States, April 6-10, 2008.

Surface coating with self-assembled monolayers (SAMs) and cellulose


HPMA xylan

SAM-COOHHS(CH2)10COO-

=HS

Au Au

S S S S

Au

S S S S


SPR-measurements*

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

0.4

0.3

0.2

0.1

0

Γ/m

g•m

-2

16012080400

Concentration /mg•L-1

A3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

0.4

0.3

0.2

0.1

0

Γ/m

g•m

-2

16012080400


A

16012080400


16012080400


0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

16012080400


0.3

0.2

0.1

0

Γ/m

g•m

-2

16012080400


B0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

16012080400


0.3

0.2

0.1

0

Γ/m

g•m

-2

16012080400


B

Γ/m

g•m

-2Γ/

mg•

m-2

Γ/m

g•m

-2Γ/

mg•

m-2

model cellulose surface SAM-OH surface

" Generally, all samples have low affinity to the model cellulose and SAM-OH surfaces.

" Hydrophilic interactions do not play any significant role in the adsorption.* in cooperation with Abdulaziz Kaya, Alan R. Esker, Viginia-Tech-University, USA



0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

16012080400


D0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

16012080400


D

Γ/m

g•m

-2Γ/

mg•

m-2

MS = 0.06 (●), MS = 0.10 (▼), MS = 0.14 (►), MS = 0.19 (■), MS = 0.34 (▲),4-O-methyl-glucurono xylan from birch wood (◄).

SAM-COO- surface

electrostatic interactions

HPMA-4-O-methylglucuronoxylans with:

" Absence of adsorption for birch xylan indicates the importance of electrostatic interactions in the adsorption process.

" The decrease in adsorption at higher DS values are most probably caused by flat conformation of HPMA chains on the SAM-COOH surface.

" Adsorption has a maximum at HPMAGX MS = 0.10.

" Adsorption has a maximum at HPMAGX MS = 0.10.

MS = 0.1


SPR-measurements

Heinze T., Hornig S., Michaelis N., Schwikal K., ACS Symposium Series, 2010, 1019(9), 195–221.


2025303540455055

0 3 6 9c [g*10*kg-1]

Tens

ile-In

dex

[Nm

*g-1

]

0.19

0.14

0.1

0.06

Birch xylan

" HPMA xylan increased the tensile strength of spruce sulfite pulp and birch kraftpulp.

" Spruce sulfite pulp up to 50%; birch kraft pulp up to 60%." Optimum at MS = 0.1.

Tensile strength after adding xylan and xylan derivatives:

HPMA-4-O-methylglucuronoxylans with:

MS = 0.19MS = 0.14MS = 0.10MS = 0.064-O-methyl-glucurono xylan from birch wood

2025303540455055

0 3 6 9

c [g*10*kg-1]

Tens

ile-In

dex

[Nm

*g-1

]

Spruce sulfite pulp Birch kraft pulp

Adjustable degree of cationic groups – optimized product.



6

23

O

+Na-OOCH2COO

OH

O

OOHO

OOH

OCH2COO-Na+

+Na-OOCH2C

Statistical distribution:

Non-statistical distribution:HPLC5

" Distribution of the functional groups within the repeating unit Can be calculated from the 1H-NMR-spectra (hydrolyzed sample).1

" Distribution of the functional groups along the polymer chain.

The substituent distribution

Analytical tools:

Capillary Electrophoresis4

Enzymatic Degradation3

GC/FID2

1 Reuben J., Conner H.T. Carbohydr. Res. 1983, 115, 1–13.2 Zeller S. G., Griesgraber G. W., Gray G. R. Carbohydr. Res. 1991, 211, 41–45.3 Horner S., Puls J., Saake B., Klohr E.-A., Thielking H. Carbohydr. Polym. 1999, 40, 1–7.4 Tüting W., Albrecht G., Volkert B., Mischnick P. Starch/Stärke 2004, 56, 315–3215 Lazik W., Heinze Th., Pfeiffer K., Albrecht G., Mischnick P. J. Appl. Polym. Sci. 2002, 86,

743–752.


Values from HPLC analysis of carboxymethylcelluloses after hydrolysis with HClO4

Synthesis procedure for e.g. a carboxymethylation1. Dissolving the polymer (e.g. in

Dimethylacetamide/LiCl for cellulose; Dimethylsulfoxide for starch and xylan)

2. Solid NaOH particles3. ClCH2COO-Na+

A selective activationof the polymer fiberresulted

Non-statistical distribution

For example non-statistical distributed CMC1: " Tends to the formation of small, more compact

complex aggregates." Specific adsorption - multiple reloading of colloidal

BaSO4-particles.

Synthesis via forming a reactive microstructure � state of the art

Different properties despite the same degree of substitution:


1Kötz J., Bogen I., Heinze U., Heinze T., Klemm D., Lange S., Kulicke W.-M. Das Papier 1998, 52(12) 704-712.


CMS from Hylon VII, DS = 1.02via reactive microstructure

0

0.1

0.2

0.3

0.4

0.5

0.6

Glc Mono-CMGlc Di-CMGlc Tri-CMGlc

Mol

e fra

ctio

n Statistical values for linear polymers (Spurlin) for DS = 1.02

Hylon VII (amylose content: 70%)

Synthesis via forming a reactive microstructure*

DSCM NMR O-2 O-3 O-6 Σ 0.53 0.11 0.42 1.05 0.64 0.11 0.26 1.01

Via reactive microstructureVia conventional heterogeneous synthesis

Increased reactivity on position O-6 compared to heterogeneous methods.


OORO

OCH2COO-Na+

OR

R = H, CH2COO-Na+

*Dissolution in DMSO, NaOH-particlesAGU:NaOH:ClCH2COO-Na+ zu 1:17:10


Potato starch (amylose content: 28%)

Synthesis via forming a reactive microstructure

0

0.1

0.2

0.3

0.4

0.5

0.6

Glc Mono-CMGlc

Di-CMGlc Tri-CMGlc

Tetra-CMGlc

Mol

e fra

ctio

n

CMS from potato starch, DS = 1.10via reactive microstructure

Statistical values for linear polymers(Spurlin) for DS = 1.10

For starches with a higher amylopectine content an additional tetra-substitution was detected.1


1Heinze T. , Liebert T., Heinze U., Schwikal K. Cellulose, 2004, 11(2) 239-245

AGU:NaOH:ClCH2COO-Na+ zu 1:17:10


0.00.20.40.60.81.01.2

0.5 1 2 3 4 10Molares Verhältnis

ClCH2COONa:Anhydroxyloseeinheit

DS

Xylan dissolved in aqueous NaOH -subsequent addition of Propan-2-ol

Anhydroxylose unit (AXU):NaOH 1:4,1, 70 min, 65°C, 25% NaOH

OORO

OCH2COO-Na+

R = H, CH2COO-Na+

Activation of the xylan in solution*

Xylan suspended in Propan-2-ol -subsequent addition of aqueous NaOH

Anhydroxylose unit (AXU):NaOH - 1:ClCH2COONa, 5 h, 55°C, 15% NaOH

Activation of the xylan in suspension

*multiple synthesis steps (2 X) CMX (DS = 1.09) - product with a DS = 1.91 results.


Alternative routes for non-cellulosic polysaccharides:

Molar ratioClCH2COONa: anhydroxylose unit

Petzold K., Schwikal K., Heinze T. Carbohyd. Polym., 2006, 64, 292–298.


0,0

0,2

0,4

0,6

0,8

1,0

0,0 0,5 1,0 1,5 2,0

Mol

frakt

ione

n

DSHPLC

Xylose Mono-O-CMX Di-O-CMX

HPLC-data analysis1,2 of the carboxymethyl xylans:

0,0

0,2

0,4

0,6

0,8

1,0

0,0 0,5 1,0 1,5 2,0M

olfra

ktio

nen

DSHPLC

Xylose Mono-O-CMX Di-O-CMX

Activation of the xylan in suspensionActivation of the xylan in solution

ci = Mole fraction of xylose (i = 0); mono- (i = 1); di- (i = 2) carboxymethyl xylose

k = carboxymethyl group content per AXU (k = 0;1;2)DS = degree of substitution

( ) ( ) k2ki DS/21DS/2

k2

c −−⎟⎟⎠

⎞⎜⎜⎝

⎛=

1Spurlin H.M. J. Am. Chem. Soc. 1939, 61, 2222-2227.2 Heinze U., Heinze Th., Klemm D. Macromol. Chem. Phys. 1999, 200, 896-902.

Petzold K., Schwikal K., Günther W., Heinze Th. Macromol. Symp. 2006, 232, 27-36.

Structural characterization



Synthesis conditions: Anhydroxylose unit:ClCH2COO-Na+:NaOH - 1:2:2, 5 h, 55°C, propan-2-olproducts: DS = 0.81 (4% NaOH), DS = 0.82 (6% NaOH), DS = 0.84 (10% NaOH), DS = 1.01 (15% NaOH), DS = 0.60 (20% NaOH).

Di-O-carboxymethyl xylose

Mono-O-carboxymethyl xylose

Xylose

4% 6% 10% 15% 20%

-0,30

-0,20

-0,10

0,00

0,10

0,20

Δ ci(s

purli

n)

NaOH

Activation of the xylan in suspension

1. xylan/propan-2-ol. 2. aqueous NaOH.

050

100150200250300350400

2 3 4 5 6 7 8 9 10 15% NaOH

NT

U

1% Xylan3% Xylan

Non-statisticaldistribution




... and in starch chemistry?

" It is a well known fact that reaction conditions can be influence sample properties

• Even at low degrees of substitution (MS = 0.03-0.11)1 different properties (swelling, solubility and viscosity) of HPMA- starches varied, despite the same MS when different reaction conditions were used (Slurry process, Paste process, Semi-dry process, Extrusion process).

• Vihervaara et al.:2 different distributions of cationic groups throughout the granule depending on process.

" In starch chemistry the method �first slurry and then activation� is very common.

• Tüting et al.3 discuss the distribution pattern along the polymer chain of different carboxymethyl starches (Waxy mais, potato and High amylose) prepared with a slurry method (isopropanol/NaOH).

• Waxy maize CMS– best agreement with the statistic calculated patterns (Spurlin, Reuben).

• potato and high amylose CMS – more differences.

1S. Radosta, W. Vorwerg, A. Ebert, A.H. Begli, D. Grülc, M. Wastyn Starch/Stärke 2004, 56, 277–287.2T. Vihervaara, H. H. Bruun, R. Backman, M. Paakkanen Starch/Stärke 1990, 42, 64-68.3Tüting W., Albrecht G., Volkert B., Mischnick P. Starch/Stärke 2004, 56, 315–32.


" In general:• Type of starch

• Water/slurry ratio

• Slurry medium

• NaOH concentration

• Reaction temperature...

...are influence swelling of the starch - and may have an influence on the distribution pattern along the polymer chain.


More detailed studies can be a helpful tool to design starch derivatives with a target adjusted distribution and

properties, too.


Many thanks for�

Thank you for your attention!

Prof. Allan Esker and Dr. Abdulaziz Kaya

Documents

Chemical modification of non-cellulosic polysaccharides