Nylon (Textiles industry) organic chemistry assignment

[NYLON] December 3, 2014

ACKNOWLEDGEMENT

The Most Gracious and Most Merciful, finally we manage to complete our first

assignment on this particular subject, Organic and Instrumental Chemistry for Engineers

(CBE422). We wish to express our gratitude to all those who had taking part in the making of

this assignment.

Our special thanks to Miss Julia Tan regarding her valuable guidance and advice

about this assignment. We also would like to thank her for showing us some example that

related to the topic of our assignment. We were really grateful to have her as our lecturer for

this subject.

Not to forget, we would also like to thank to our families and friends for their

understandings and supports on us in order to complete this assignment. Without the help of

the particular people mentioned above, we would face many difficulties while doing this

assignment. Thank you to all of you once again.

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Contents

ACKNOWLEDGEMENT...........................................................................................................................1

Contents................................................................................................................................................2

1.0 Introduction...............................................................................................................................3

1.1 History.........................................................................................................................................3

1.2 Introduction to Nylon..................................................................................................................4

2.0 Properties of Nylon..........................................................................................................................5

2.1 Physical Properties.......................................................................................................................6

2.2 Chemical Properties.....................................................................................................................7

3.0 Nylon Production Technology..........................................................................................................8

3.1 Method used to produce Nylon.................................................................................................10

3.1.1 Production method of Nylon 6............................................................................................11

3.1.2 Manufacturing Process of Nylon 6, 6..................................................................................12

4.0 Advantages and Disadvantages of Nylon.......................................................................................13

4.1 Advantages................................................................................................................................14

4.2 Disadvantages............................................................................................................................14

5.0 Application of Nylon......................................................................................................................15

5.1 Most important uses of Nylon...................................................................................................15

5.2 Common application of Nylon.............................................................................................16

References...........................................................................................................................................17

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1.0 Introduction

1.1 History

Nylon was introduced in 1940, is the

first all-synthetic fibre made commercially and

opened up the entire field. Wallace H.

Carothers was the person who discovered

polyamides in year 1931. Commercial

production of nylon 6, 6 began in the 28th

October 1938. First, polyamides were

introduced as fibre forming polymers. The

Bristles on Dr West’s Miracle Tuft toothbrush

is the first commercial application.

Next following years, nylon stocking

became available and thus in 1941, nylon

mouding powders began commercial

production. In the 1940’s, nylon 6 was

developed; largely as a consequence of patent

that existed on Nylo 6, 6. Nylon mouldings

were not widely used until the 1950’s. During 1981, the U.S production was up to 1.18 x

106t, where 59 per cent of it was used for home furnishing, mostly carpets. 20 percent for

apparel accounted and another 11 per cent for tire cord.

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Figure 1 Wallace H. Carothers, the Nylon founder


1.2 Introduction to Nylon

Nylon is polyamides which is a polymer where the repeating units are held together

by amide links. The formula for amide group is – CONH2. An amide link has this structure:

The repeating units:

Nylon 6, 6 is the product resulting from the polymerization reaction of adipic acid and

hexamethylene diamine because each of the raw material chains contains six carbon atoms.

Nylon 6 is the homopolymer of caprolactam, and the newly developed aramid fibre, Kevlar,

an aromatic polyamide, poly-p-phenylene terephthalamide.

Nylon is a family of plastics. The common grades of nylon is Nylon 6 and Nylon 6,6

(the number refers to the number of methyl groups). In condition where the separation of

amide group increase, the polarity of the amide group decreases, thus the moisture

absorbance decreases. Due to more flexibility and mobility in the methyl unit sections of the

chain, the resistance to thermal deformation is lowered.

Comparison the Nylon 6 and Nylon 6, 6 properties are not that different. But we can

see the relationship when comparing the Nylon 6, 6 and Nylon 6, 12. Nylon 6, 12 has lower

modulus, longer elongation, lower strength, lower thermal distortion temperature, lower

hardness and lower melting point than Nylon 6, 6. However, Nylon 6/12 can absorb half as

much water on Nylon 6/6. Thus the property of Nylon 6, 6 is better in dry condition. While,

Nylon 6,12 is much more consistent when it is used in applications in which water may be

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present.

In general, Nylon has very good physical properties. But moisture gives significant

effect on the properties. It was very good heat resistance, chemical resistance, and wear

resistance. Its price is between moderate to high price and it is fair to easy processing.

2.0 Properties of Nylon

The majority of the nylon tends to be partial Crystals and is ingredients that are

generally very difficult to heat resistance and good chemistry. Different types provide

different properties with gravity, melting point and moisture content tends to reduce as

increasing numbers of nylon. Nylons can be used in high temperature environment. Heat

allows stable system performance is maintained at temperatures up to 185oC.

Physical Value

Tensile Strength: 90 - 185 N/mm2

Notched Impact Strength: 5.0 - 13.0 Kj/m2

Thermal Coefficient of Expansion: 80 x 10-6

Max. Continued Use Temperature: 150 - 185 oC (302 - 365 oF)

Melting Point: 190 - 350 oC (374 - 662 oF)

Glass Transition Temp. (Nylon 66): 45 oC (113 oF)

Density: 1.13 - 1.35 g/cm3

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2.1 Physical Properties

1. Composition: The nylons are polyamides with recurring amide groups. They contain

carbon, oxygen, nitrogen and hydrogen elements.

2. Strength: Nylon has good tenacity and the strength is not lost with age. Nylon has a high

strength to weight ratio. It is one of the lightest textile fibres is at the same time also one of

the strongest. It is one of the fibres which are added at the points of wear such as knees and

seats of jeans and toes and heels of socks. The strength of the nylon fabric is lost when wet.

Nylon has excellent abrasion resistance.

3. Elasticity: Nylon has good elasticity which makes it much suitable for the apparel

purposes. The excellent elasticity would mean that the nylon materials return to their original

length and shreds the wrinkles or creases. Nylon like other fibres has its own limit of

elasticity. If stretched too much, it will not completely recover its shape. The high elongation

and excellent elastic recovery of nylon contributes to the outstanding performance in hosiery.

Nylon hosiery recovers to its original shape at knees and ankles instead of bagging.

4. Resilience: Nylon fabrics have excellent resilience. Nylon fabrics retain their smooth

appearance and the wrinkles from the usual daily activities can be removed easily.

5. Drapability: Fabrics of nylon filament yarn have excellent draping qualities. The drape of

the fabrics made from nylon can be varied depending on the yarn size. The light weight sheer

fabrics of nylon night gowns have high-draping quality. The medium-weight dress fabrics

can drape very nicely.

6. Heat Conductivity: The heat conductivity of the nylon fabrics vary depending upon the

fabric construction, the type of nylon (staple/filament) used in the construction etc. For

instance, the filament nylon used in the open construction would be cooler when compared to

the same filament used in a closed construction. In a closed or tight construction the air

circulation through the fabric is limited. The heat and moisture of the body will not readily

pass the fabric construction, which makes the wearer feel very warm. Such fabrics are good

for winter apparel, such as wind-breakers, but are not suitable for summer garments. On the

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other hand the fabrics with open construction permits the air circulation which makes the

wearer feels cool.

7. Absorbency: Nylon fabrics have low absorbency. The low absorbency of the fabrics tends

to be advantageous and also disadvantageous. The main advantage of the nylons low

absorbency is that the water remains on the surface of the fabrics and runs off the smooth

fabric and hence dries quickly. This property makes the nylon fabrics suitable for raincoats

and shower curtains. Nylon’s low absorbency has a disadvantage in that the fabric feels

clammy and uncomfortable in warm, humid weather.

8. Cleanliness and Wash ability: Nylon fabrics are easy care garments. Nylon fabrics are

smooth, non-absorbent and dry quickly. Dirt doesn’t cling to this smooth fibre, which can be

washed easily or can be even cleaned by using a damp cloth. Nylon whites are commonly

referred as colour scavengers and should be washed separately to avoid greying. They easily

pick up colour and dirt from the wash water. Nylons, washed with other fabrics pick up

colour (even from the palest pastels) and develop a dingy grey appearance that is extremely

difficult to remove. In addition to retaining their appearance during wear, garments made

from nylon fabrics retain their appearance and shape after washing. Hot water should be

avoided during washing as the hot water may cause wrinkling in some fabric constructions.

2.2 Chemical Properties

1. Effect of Bleaches: The nylon fabrics are white and generally do not require bleaching.

The nylon fabrics which pick up colour or develop greying should be bleached with oxidising

bleaches such as hydrogen peroxide.

2. Shrinkage: Nylon fabrics retain their shape and appearance after washing. It has good

stability and does not shrink.

3. Effect of Heat: Nylon should always be ironed at low temperatures. Using hot iron will

result in glazing and then melting of the fabric.

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4. Effect of Light: Nylon fabrics have low resistance to sun light. They are not suitable for

curtains or draperies as it is weakened by the exposure to sun light.

5. Resistance to Mildew: Nylon fabrics have absolute resistance to the development of

mildew.

6. Resistance to Insects: Nylon is resistance to the moths and fungi.

7. Reaction to Alkalis: Nylon has excellent resistance to alkali's but the frequent and

prolonged exposures to alkalis will weaken the nylon fabrics.

8. Reaction to Acids: Nylon is less resilient to the action of acids and is damaged by strong

acids.

9. Affinity for Dyes: Nylon can be easily dyed with a wider range of dyes. The dyed fabrics

retain their colour and have good resistance to fading.

10. Resistance to Perspiration: Nylon fabrics are resistant to perspiration

3.0 Nylon Production Technology

Nowadays, nylon being produced constantly to fulfil for the demand of developing and modern country. Nylon produced in the various type to make the particular products . one of the product that make the Nylon as its main material is Nylon Filament Yarn (NFY) .

Nylon is a generic term for the long chain synthetic polyamides. The two most important polyamides is Nylon 6 and Nylon 6,6 . Nylon 6 is manufactured by self-condensation of 6-amino caproic acid obtained from caprolactam. Like all other polyamides Nylon 6 is capable of being formed into a filament in which the polymer molecules are oriented, at large, in the direction of the axis. It can also be cut to small length to get staple fibres . Nylon Filament Yarn can be manufactured with varied degree of orientation such a s low oriented yarn , partially oriented yarn and full oriented yarn . Nylon Filament Yarn is produced as multi filament yarn or mono filaments in a wide range of deniers. It is also available in bright, semi-dull and dull lustres.

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NFY has excellent orientation and crystallites characteristics which imparts it with good mechanical properties. NFY has good fatigue resistance and better resistance to the effect of prolonged heating for applications at a temperature lower than its melting point. It is highly resistance to chemical degradation and strains . It has excellent biological resistance.

Nylon-6 and Nylon-6, 6 are two synthetic polyamides which are being manufactured on a commercial scale. The two polyamides have similar properties. Nylon-6,6 has higher melting point and fatigue resistance compared to Nylon 6 , and therefore may be preferred for application such as tyre cord or carcass . However , process to manufacture Nylon 6 is simpler than that for Nylon 6,6 , and is superior resistance for light degradation .Also nylon-6 has advantage over Nylon-6,6 in respect of dye ability , elastic recovery , and thermal stability and thus , for end uses like textile and carpet manufacture it may be preferred over nylon-6,6.

The manufacturing process for Nylon Filament Yarn can be broadly divided into following production steps which is 1) polymerization of caprolactam to manufacture nylon chips . 2) extraction and drying of chips 3) melt spinning of chips to manufacture spun yarn 4)processing of spun yarn and 5) recycling of Nylon waste .

There is an history behind this development of technology . The commercial production of Nylon 6 was started in Germany in 1940 and during world war 2 . Ply-caproamide or nylon-6 fibres ware manufactured and sold under the name of Perlon L . Over period of time , the process has been developed to manufacture physically and chemically modified fibres suitable for special purposes .There are couples of examples for that such modified yarns such as crimpled and bulked yarn , modified cross-section yarn , mono-filaments , high count yarn , abrasion resistant yarn and etc. .

Nylon 6 is the linear addition polymer of caprolactam or 6-amino-caproic-acid . The polymerization process for Nylon 6 can be batch or continuous , however , the main process for its manufacture is continuous polymerization . Three reversible , hydrolysis , polycondensation , and polyaddition are the main steps in nylon 6 production .

The first steps is hydrolysis reaction to open the caprolactam ring , forming ε−¿amino caproic acid . This reaction proceeds in molten caprolactam in the presence of a small weight percent water . Althoush the reaction will proceed with only caprolactam and water present , a material such as phosphoric acid is added at low concentration to act as a chain stabilizer and help achieve the desired final viscosity .

Polyaddition is the reaction which is mainly responsible for the growth of the linear polymer chains . It is the most important reaction as soon as a certain amount of end groups has been made available by the hydrolysis of caprolactam .

Thus , the polymer dissolves in the unreacted caprolactam . The polymer end groups affect the stability and final molecular weight of the polyimide. Organic acids such as acetic acid can be added as chain stabilizers. Monofunctional organic amines can also be added .

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The linear polymer chain formed in the polyaddition reaction can further increase its molecular weight via a polycondensation reaction . The reactive end groups polycondensate forming linear chain molecules and by-product water. Thus, two linear chain molecule condense producing a longer chain molecule with higher molecular weight. In other words , the polycondensation is regarded as the most important reaction in the last phase of nylon 6 formation in which the distribution of polymer chain length is adjust . Caprolactam can also be polymerized in-situ in a mold . A typical procedure uses the sodium salt of caprolactam as a catalyst.

For producing the Nylon , it have to go through the particular process . Nylon 6 and Nylon 6,6 batch and continuous processes.

About Nylon 6 processes , the ring-opening polymerization of caprolactam to nylon 6 can be accomplished by both hydrolytic and anionic mechanisms . However , Nylon 6 can produced almost exclusively by hydrolytic polymerization of caprolactam because it is easier to control and better adapted for large-scale operation . The polymerization process for nylon via the hydrolytic mechanism can be batch or continuous .

Besides, about Nylon 6,6 continuous process , to solve the limitations inherent in the batch process, the continuous polymerization process was developed . The main steps of continuous process include salt preparation, and polymerization . Solid phase polymerization is an additional step used to increase molecular weight of the polymer without damaging properties of the polymer.

3.1 Method used to produce Nylon

The term nylon refers to a family of polymers called linear polyamides. There are two

common methods of making nylon for fibre applications. In one approach, molecules with an

acid (COOH) group on each end are reacted with molecules containing amine (NH2) groups

on each end. The resulting nylon is named on the basis of the number of carbon atoms

separating the two acid groups and the two amines. Thus nylon 6, 6 which is widely used for

fibre is made from adipic acid and hexamethylene diamine. The two compounds form salt,

known as nylon salt, and an exact 1:1 ratio of acid to base. This salt is then dried and heated

under vacuum to eliminate water and form the polymer.

In another approach, a compound containing an amine at one end and an acid at the

other is polymerized to form a chain with repeating units of (-NH-[CH2]n-CO-)x. if n=5, the

nylon is referred to as nylon 6, another common form of this polymer. The commercial

production of nylon 6 begins with caprolactam uses a ring-opening polymerization.

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In both cases, the polyamide is melt spun and drawn after cooling to give the desired

properties for each intended use. Production of nylon industrial and carpet fibres begin with

an aqueous solution of monomers and proceeds continuously through polymerization,

spinning, drawing, or draw-texturing.

3.1.1 Production method of Nylon 6

Toyo Royan developed the photochemical route in Japan that avoids the conventional

oxidation narration step with a simplified process. The letter success was largely due to the

development of 20 KW mercury lamps that conseme power less than 4.5 KWH per kg of

oxime.

By the nature of the polymerization, the process is differs from that for Nylon 6, 6.

The similar process is the step wise condensation of caprolactam with no net removal. More

difficulty will arise, but however, in the thermal equilibrium between the monomer and

polymer are at the melting and spinning temperatures. 10% monomer is retained in this

process, so the fibres have to be water washed the soluble caprolactam monomer. While the

molecular weight controlled by the addition of monofuntional acid.

Final product are produced with a molecular weight at range 12,000-16,000 is

extruded as a ribbon onto chilling rolls. Then it is extruded to a chipper for producing small

chips suitable for storage and rehandling.

The chips are melted when the nylon fibres are produced, metered through high

pressure pumps, filtered and passed through a melt spinneret. On air cooling, the extruded

filaments will harden immediately and can be wound on bobbins at speed of 750 meters per

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Figure 2 A step of manufacturing Nylon

Figure 3 Nylon filaments (raw)


minute or higher. The thread will stretch to about 4 times than its original length in cold

drawing to give the fibre desirable textile properties.

Figure 4 Caprolactam synthesis

Figure 5 Stage condensation of caprolactum

3.1.2 Manufacturing Process of Nylon 6, 6

1. The process starts with the production of two chemicals; hexamethylene diamine and

adipic acid. Both contain 6 carbon atoms from coal.

2. Then, these chemicals are combined to form the nylon salt.

3. The nylon salt is dissolved in water and sent to the spinning mill.

4. By heating it in large evaporators, the nylon salt solution is made into a concentrated

solution.

5. Next, the concentrated solution is heated in an autoclave under the pressure and

temperature.

6. The polymerization takes place by combining the two chemicals into polymers which

are likes giant chain.

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7. Similar to nylon 6, the molten polymer is processed in a manner.

Figure 6 Manufacturing Nylon 6, 6

4.0 Advantages and Disadvantages of Nylon

Nylon fibers can be produced in a variety of cross-section and fineness. Composite

fibers, having unique appearance and tactile feeling, can also be produced by combining with

other types of fibers. Heat storage or warmth retention fibers consisting of extremely fine

filament yarns in which carbonaceous material converting the light to heat are inserted. Anti-

static nylon fibers are inhibiting electro-static charge. Transparent nylon fibers are exhibiting

more transparent and beautiful colors. Thus a wide variety of nylon fibers are available

giving much more performances and fabric hand.

Almost all nylon fibers are filament yarns ranging from very fine to coarse denier to

be used for clothing such as sport wear, lingerie, pantyhose; home furnishing as carpets; and

industrial uses such as fishing nets, ropes, and tire cords. Staple fibers are used, in the yarns

blended with wool and acrylic fibers, for clothing; home furnishing such as carpets,

upholstery; and other fields of sundries.

4.1 Advantages

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1. One of the very strong fibers. Extremely resistant to abrasion and flexing.

2. The specific gravity is 1.14 Very light, i.e., 80% of that of silk fibers, and 70% of that of cotton fibers.

3. Since nylon fibers absorb little water even though they are wetted., they dry fast and simple in laundering.

4. Excellent in elasticity and resistant to wrinkle.

5. If properly set, nylon textiles little shrink/ extend or little deform their shape due to thermo plasticity.

6. Resistant to chemicals and oil. Non-attackable by sea water.

7. Non-attackable by molds and insects.

8. Used in many military applications.

4.2 Disadvantages

Some of the disadvantage of nylon includes that:

1. It has a tendency to fade easily and stain. It is also highly sensitive to light and heat.

2. Good quality nylon fiber is much more expensive than some other types of material.

3. Nylon is famous of its properties that is easy to dye with bright color is the major

factor of it prone to staining. Permanent stains are result from food stain that mainly

contains oil and grease. Cleaning product that contain bleach or acid that are created

to remove stains from fabrics.

4. Prolonged exposure to direct sunlight also causes the nylon to fade and wear out.

5. Nylon fibers melt if exposed to extreme temperature.

6. Cheap nylon is also available. However it tends to lose its bounce, brightness and

color very quickly.

Other disadvantages are the physical weakness of the material:

7. It has high moisture pick-up with related dimensional stability and require UV

stabilization.

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8. It has high shrinkage and molded sections.

9. Apart from that it has high moisture absorptivity degrades electrical and mechanical

properties.

10. It is also easily attack by oxidizing and strong acid or base.

11. It also has high notch sensitivity.

5.0 Application of Nylon

Nylon fibres are wide used in textiles, fishing line as well as carpet. Nylon films is

used for food packaging, offering toughness and low gas permeability, and coupled with its

temperature resistance, for boil-in-bag food packaging.

Moulding and extrusion compounds find many applications as replacements for metal

a parts, for instance in car engine components. Intake manifolds in nylon are tough, corrosion

resistant, lighter and cheaper than aluminium as well as offer better air flow due to a smooth

internal bore instead of a rough cast one. Its self-lubricating properties make it useful for

gears and bearings.

Electrical insulation, corrosion resistance, toughness are as well make nylon a better

choice for high load parts in electrical applications as insulators, switch housings and the

ubiquitous cable ties. Another major application is for power tool housings.

5.1 Most important uses of Nylon

1. Because of it has high strength fibre. It is used in making fishing nets, ropes,

parachutes and type

2. For making elastic hosiery, crinkled nylon fibres are used.

3. Used for making fabrics in textile industry

4. Widely used as plastic for making machine parts. To increase the strength, it is

blended with wool

5.2 Common application of Nylon

1. Fabric, carpeting, sportswear

2. Sports and recreational equipment

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Figure 7 Fishing net


3. Electrical connectors

4. Gear, slide, cams, and bearings

5. Cable ties and film packaging

6. Fluid reservoirs

7. Fishing line, brush bristles

8. Automotive oil pans

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Figure 8 Heavy Nylon JecketFigure 9 Fabric (net form) Figure 10 Nylon tubing


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Figure 11 Nylon fabric Figure 12 Toothbrush Figure 13 Nylon rope


References

Benefits of Nylon. http://benefitof.net/benefits-of-nylon/

Bhishm Khanna (May 2013). What are the uses of Nylon?http:// www.preservearticles.com/201101032306/uses-of-nylon.html

Mazharul Islam Kiron (August 2011). Characteristics of Nylon Fabrics | Physical and Chemical Properties Nylon Fabrics. http://textilelearner.blogspot.com/2011/08/characteristics-of-nylon-fabrics_745.ht KqRMwGzB ml#ixzz3

Draw a flow chart and explain the manufacturing process of Nylon 6.https://bookstreet.in/questions/draw-a-flow-chart-and-explain-the-manufacturing-process-of-nylon-6-10-marks-1602

Dr. Plotkin, J. S. (2009). PERP Program - Nylon 6 And Nylon 6,6. Retrieved from http://www.chemsystems.com/about/cs/news/items/PERP%200708S6_Nylon%206.cfm

Fry, Bill. Working with Nylon -Speaking of Plastics Manufacturing Series(Society of Manufacturing Engineers (SME), 1999)

George T. Austin. Shreve’s Chemical Process Industries(McGraw-Hill Book Company, 1984)

Hoelderich, W. F., & Dahlhoff, G. (February, 2001). DEVELOPING TECHNOLOGY. Retrieved from http://pubs.acs.org/subscribe/archive/ci/31/i02/html/02dahlhoff.html

Jim Clark. (2004). Polyamides - nylon and Kevlar.http://www.chemguide.co.uk/organicprops/amides/polyamides.html

Nylon (Polyamide).http://www.bpf.co.uk/plastipedia/polymers/polyamides.aspx

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Figure 14 Carpet made from Nylon


Polymer Technology & Services, LLC. A GUIDE TO NYLONptsllc.com/intro/nylon_intro.aspx.

Sambhar Pati. Flow sheet manufacturing diagram of Nylon 6, 6.http://blog.oureducation.in/flow-sheet-manufacturing-diagram-of-nylon-66/

Steve Dashew. Materials used for Ropes: Nylon (polyamide)http://www.christinedemerchant.com/rope_material_nylon.html

The University of York (May 2013). The Essential Chemical Industry Onlinehttp:// http://www.essentialchemicalindustry.org/polymers/polyamides.html

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Nylon (Textiles industry) organic chemistry assignment