Classification

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HistoryPolymers were discovered long before anyone understood what they were. It wasn’t until 1920 that German chemist Hermann Staudinger(1881–1965) made his macromolecular hypothesis, suggesting that polymers are actually giant molecules formed by the permanent attachment of countless smaller molecules. Through careful experiments, he proved his hypothesis to be correct and was rewarded with the 1953 Nobel Prize in Chemistry.

Fiber structure and elasticity

- Wool garments will easily stretch and recover during use, but their cotton counterparts have very little ‘give’.

- The difference is largely due to the degree of alignment of the polymer chains along the fiber axis.

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Fiber structure and elasticity

In cotton fiber:

- The cellulose molecules exist as fully extended chains aligned sufficiently close in register to enable crystallization to occur within the fiber.

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- The crystalline material is difficult to deform and this, together with the already extended configuration of the molecules, makes cotton fires hard to stretch.

- All the molecules in the cross-section of the fiber take a share of the imposed stress, and consequently cotton fibers will withstand a high tensile force before breaking.

- But crystalline materials is also brittle and cotton fibers are easily fractured on bending, a property that is associated with a reduced resistance to abrasion

Fiber structure and elasticity

In protein chains in wool fiber

Physical and chemical forces between two polypeptide chains1. Hydrogen bridges between peptide groups (polar bond)2. Cystine bridge (covalent bond)3. Salt bridge between two amino acids (ionic bond)4. Hydrophobic bond between a valine and an isolyeine rest (non-polar bond)

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Fiber structure and elasticity

In protein chains in wool fiber

- Coiled configuration of the protein chains and the way in which they are crosslinked through cystine disulfide links gives elasticity.

- Disulfide linkages also form bridges between coils within the same molecule, and so the fiber becomes an extensive molecular grid structure.

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Fiber structure and elasticity

In protein chains in wool fiber

- When the fibers are stretched the coils straighten out, but on release of the tensile force the crosslinks cause the chains to spring back to their original helical arrangement.

- Wool fibers can therefore undergo considerable reversible extension. With this molecular configuration there is very little crystallization and any strain is distributed unevenly between molecules, which leads to a lower breaking strength.

- Wool is therefore weak but highly extensible; the balance between the tensile strength and elasticity of wool makes it a very desirable textile fiber.

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Amorphous and Crystalline Material

Crystalline is the highly organized state in polymer. It resists the penetration of chemical reagents and dyes.

Amorphous is the disorganized state in polymer.

The crystalline and ordered orientation are less and the fiber molecules are more accessible.

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Amorphous (non-crystalline)Non Orientated

Semi-crystalline,Non-Orientated but Sections Ordered

Orientated semi-crystalline

Regenerated Fibers

- For many years textile chemists dreamed of discovering how such properties could be obtained by design through synthetic routes.

- The first step towards making fibers synthetically was the discovery of how to dissolve waste cellulose and regenerate it into the form of a fiber.

fibers have been regenerated from natural cellulose dissolved in one of three solvents. : - Carbon disulphide can dissolve cellulose in the form of wood pulp to give cellulose xanthate (viscose fibers)- a solution of cuprammonium hydroxide, which gave the now obsolete fiber cupro (cuprammonium rayon)- NMMO wood can dissolve cellulose at high temperature and pressure to produce TENCEL (LYOCELL).

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Cellulose Sheet Steeping Pressing &

Shredding Aging Xanthation Ripening &Filtration Spinning

Cell-OH + NaOH → Cell-ONa + H2O 25oC, 1-4 hr

To obtainsodium cellulosate

To obtain low viscositysodium cellulosate

Degree of Polymerization: 200-600 ( Fe, Mn, high temp., 1-2 hr)

Hydrosis Oxidation

To obtainsodium cellulose

xanthatate

Cell-OH + OH → Cell-O- + H2OCell-O- + CS2 → Cell-OCS2-

Toxic!

To obtain viscose solution & remove CS2

Cell-OCS2Na + H2O → Cell-OH + NaOH + CS2

Conventional Preparation of Viscose Rayon

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Conventional Preparation of Viscose Rayon

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Conventional Preparation of Viscose Rayon

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Rayon Fiber Characteristics- Highly absorbent- Soft and comfortable- Easy to dye- Drapes well

Some Major Rayon Fiber Uses- Apparel: Accessories, blouses, dresses, jackets, lingerie,

linings, millinery, slacks, sportshirts, sportswear, suits, ties, work clothes

- Home Furnishings: Bedspreads, blankets, curtains, draperies, sheets, slipcovers, tablecloths, upholstery

- Industrial Uses: Industrial products, medical surgical products, nonwoven products, tire cord

- Other Uses: Feminine hygiene products

LYOCELL

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LYOCELL manufacturing process

- A new form of cellulosic fiber that manufactured using a solvent spinning process.

- has all the advantages of rayon, and in many respects is superior: high strength in both dry and wet states, and high absorbency

- the closed-loop manufacturing process is far more environmentally friendly than that used to manufacture rayon, although it is also more costly.

Making Synthetic fibers

JG R JG R JG R JG R

Repeat Unit

JG =Joining Group

R = Monomer Unit

The general pattern of synthetic fiber construction which the repeat unit is first made by joining two simple compounds together and repeating the process at both ends of the new molecules so formed.

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Monomer Polymer

CO2HHO2CHO

OHO O

HO OH2C

H2C O

nTerephthalic acid

Ethyleneglycol

Poly(ethylene terephthalate

HO OH

O O

4H2N NH24

Adipic Acid 1,6-Diaminohexane Nylon 6,6HO N

HNH

HO O

4 4n

CO2HHO2C

Terephthalic acid

NH2H2N

1,4-Diamino benzene

Kevlar

OHO

OHN

HN H

n

HOOH

Ethyleneglycol

H2COCN NCO

4,4-diisocyantophenylmethane Spandex

H2C

HN

HN

OHO

OO

H2C

H2C O H

n

Urethane linkage

H

Ester

Amide

Polyesters, Amides & Urethanes

NomenclatureStep growth polymers

Nylon Fibers

Nylon was the first truly synthetic fiber to be commercialized (1939). Nylon was developed in the 1930s by scientists at Du Pont, headed by an American chemist Wallace Hume Carothers (1896-1937).

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Applications of Nylon

History Nylon was first used for fishing line, surgical sutures, and toothbrush bristles. DuPont touted its new fiber as being "as strong as steel, as fine as a spider's web," and first announced and demonstrated nylon and nylon stockings to the American public at the 1939 New York World's Fair.

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Polyester Fibers

HOH2C-CH2 OH + HO-C-

O

-C-OH

O

-H2O

-O-CH2-CH2-O-C- -C-O-

O O

Ester linkage

Joining group

Ethylene glycol

Terephthalic acid

Polyester fiber developed by J R Whinfield and J R Dickinson in the 1950s.

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N C N O CH2CH2CH2CH2O Cm

HCO

H

H

N C NH

HHOHCO H

CO

NCH2CH3

CH2CH3

*

n

PTMGMDI

EDA(Extender)

DEA(Terminator)

Soft SegmentHard Segment

MDI

Prepolymer

- Polyurethane fiber is manufactured from glycol and diisocyanate as raw material with a special spinning method.

Elastofibers : Spandex (Polyurethane) Elastofibers : Spandex (Polyurethane)

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initial: amorphous chains are kinked, cross-linked.the crosslinks act as anchor points between the chains and prevent chain slippage.“Entropy” is the part of the driving force for elastic deformation.

final: chains are straighter, still cross-linked

deformation is reversible (elastic)!

Chain growth polymers

polypropylene

C=C

CH3H

H H

+ C=C

HH

CH3H

C C C C0

H

CH3

H

H CH3

H

H

H

H

+ C=C

H

H

H

CH2

C

H

CH3

CH2

CCH2

H

CH3

CCH2

CH3

H

C

*H

CH3 n

CH3

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Olefin fibers

- The name means "oil-like," and refers to the oily or waxy texture of this class of plastic resins.

- Polyolefin is the largest class of organic thermoplastic polymers.

- They are non-polar, odorless, nonporous materials that are often used in consumer goods, structural plastics, food packaging and industrial products.

- Some of fibers based on alkenes monomers are useful textile fibers.

- Polypropylene prepared from propane is a similar but more robust polymer that does have uses for textiles.

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History

1839 Vulcanised Sulfur rubbber (C. Goodyear) 1862 Celluloid (Parkes)1868 nitrocellulose (J.W. Hyatt) 1885 Rayon (Chardonnet), Cellopane1909 phenol-formaldehyde resin (L.H. Baekeland)

(1910 Korea-Japan Annexation)(1919 Foundation of Kyungsung textile industry by Sungsoo Kim,Cotton manufacturing)

1922 Polymer concept by H. Staudinger1927 cellulose actate and poly(vinyl chloride)

Buna S (butadiene-styrene rubber) (Bayer Co.) 1928 poly(methyl methacrylate) Industrialization (O. Rohm). 1930 polystyrene 1931 Neoprene rubber (DuPont Co. W. H. Carothers) 1935 nylon 66 (W.H. Carothers). 1936 PANN, SAN and poly(vinyl acetate)1937 polyethylene (O. Bayer).

History

1938 nylon 6, epoxy resin, and LDPE. 1941 PET (J.R. Whinfield와 J.T. Dickinson).1942 PAN fibers DuPont).

(1945 End of the World War II, Independence of Korea) (1943 rubber shose "말표“ by “국제고무”)(1947 Spinning of Nylon 66 by Korea Nylon)

1948 ABS resin. 1950 Outbreak of Korean war

Determination of the cause of tire deterioration : Ozone → start R&D on antiozonant

1952 Ziegler catalyst for low pressure polymerization of ethylene.1953 Novel prize winning by Hermann Staudinger

(Work on macromolecules) 1955 Stereoregular polymerization using Ziegler catalyst by G. Natta

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TEXTILE PROCESS (ex. Synthetic fiber)

SpinningYarn

processing Fabrication Dyeing Sewing

MeltDryWet

TexturingTwistingCovering

WeavingKnitting

DyeingPrinting

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Spinneret

Ozanam invented a method in which a solution of real silk could be spun into fibers by extruding through small orifices (1862). His invention which was called the spinneret.

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Synthetic Fiber spinning Process:

Using heat to melt polymer to a viscosity suitable for extrusion.

ex. PET, Nylon, and PP

Melt Spinning

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Synthetic Fiber spinning Process:

used for easily dissolved polymers. Polymer solution is extruded through a spinnerette into gas or vapor.

ex. Spandex, cellulose acetate

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Dry Spinning

Synthetic Fiber spinning Process:

Wet spinning : Polymer solution is extruded into a precipitation bath. ex. Viscose rayon, Acrylics

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Wet Spinning

Shape of fiber cross-section

- The cross sectional shape of synthetic fiber is a function of both the method of production and the dimensions of the spinneret orifice.

- Orifices can be circular , crenellated,trilobal,convex, triangular and hollow.

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Absorbent fibers

- Modification of both the external and internal surface areas of fibers can also powerfully affect the absorption of water (Super absorbing polymer: SAP)

- Applications : swabs and babies.

Viloft and Courcel are thin walled fibers which can absorb an amazing 120 to 380% of their own mass of water.

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Hydrogel

Drawing of synthetic filaments

If a synthetic fiber is stretched after formation the disorderedpolymer chains straighten and become extended along the fiberaxis.

Filament

slow Fast Take up

stretch

Draw ratio = Final lengthOriginal length

Random orientation, amorphous

Some orientation and crystalline

Further orientation

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Conversion of filaments to staple

- The purpose of blending with natural fibers the synthetic fibers will be cut to correspond closely with the staple length of the natural fiber.

- Generally Helical bladed cutters are used for these short fibers.

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Imparting texture to synthetic fibers : Texturizing (False-twisting)

Since the advent of thefirst synthetic fibersefforts have beencontinually made to meetconsumer demands forsynthetic fabrics withgreater comfort in wearand pleasanter handle,more akin to thoseassociated with fabricsmade from natural fibers.ex. Crimp, loftiness,bulkiness, insulation,appearance, moisturetransportation

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Imparting texture to synthetic fibers : Texturing (False-twisting)

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HEATER

FR1

원사

FR2

FR3

Cheese

WR

Friction Unit

After Oiling

I/L

TMS (Tension Monitoring System)

Cooling Plate

Yarn Cutter

Yarn Detector

Imparting texture to synthetic fibers

- Develop loftiness and bulkiness through crimp formation

- Improve appearance and insulation properties

- Greater air space in the fiber allows moisture to be transportedmore easily from the body to the surrounding air, thus helpingto overcome the discomfort often associated with thehydrophobic nature of synthetic fibers worn close to the skin

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Texturing device

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가연기구 : belt, pin, disk

Yarn Count (or Yarn number)

- The yarn count expresses the thickness of the yarn, and must be known before calculating the quantity of yarns for a known length of fabric.

- The yarn count number indicates the length of yarn in relation to the weight.

Three systems of yarn count are currently in use:

1) Fixed weight

2) Fixed length

3) Tex systems

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Yarn Count (or Yarn number)

1) The fixed weight system

Worsted Spun: English and American

hank 560 yards

Linen: lea 300 yards (ie: 1 lea linen has 300 yards, a 5 lea linen has 1500 yards)

Cotton: hank 840 yardsSpun Silk: hank 840 yards

- It is based on the length of the yarn per lb. weight. - ex. English count (Ne) : Number of hanks (840yd) per pounds- The greater the length of the yarn weighing 1 lb., the finer it is,

and the higher the count number.

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2. The fixed length system

- This system in used to number continuous filament yarns, reeled silk and man-made extruded yarns such as rayon, nylon and polyester.

- It is based on a fixed yarn length to a variable weight and is measured in deniers or tex.

- The coarser the yarn, the higher the denier or tex becomes

Yarn Count (or Yarn number)

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Denier : the weight in grams per 9000 meters. Thus: 9000 meters of 30 denier yarn weighs 30 grams.

Tex : the weight in grams per 1 kilometer (1000 meters) of yarn. For example, a yarn numbered 10 Tex weighs 10 grams per kilometer.

Yarn Twist : The degree of twist needed to hold the fibers together and develops the satisfactorily strength, compactness, compressibility and lusture.

T = (TPM)Number of twistLength (m)

S-twist: when the fiber slope from left to right.Z-twist: when the fiber slope from right to left.

Yarn Twist

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