... areformedwithstructuresasoutlinedin Figure 1-3."-'ABABABABABNALTERNATINGCOPOLYMERIVAABABABBBAIVRANDOMCOPOLYMERBB BB BIVAA~AA ~A& apos;"GRAFTCOPOLYMER'vA A ... 1-1.Classificationof natural and man-madefibers.FIBERCLASSIFICATION Textile fibersare normally brokendownintotwomainclasses,natural and man-madefibers.Allfiberswhichcomefromnatural ... inedbelowschemat-ically:12 Textile Fibers, Dyes, Finishes, and Processes Stepgrowth:n nnA~IAA~lAAAA~Chaingrowth:nA~ (A) nnA~ (A) nnA~ (A) nTheaveragenumberofmonomerrepeatingunitsin a polymerchain(n)isoftenreferredtoalsoasthedegreeofpolymerization,DP.TheDPmustexceedanaverage20unitsinmostcasestogive a polymerofsufficientmolecularsizetohavedesirablefiber-formingproperties.Theoverallbreadthofdistributionofmolecularchainlengthsinthepolymerwillaffecttheultimatepropertiesofthe fibers, withwidepolymersizedis-tributionsleadingtoanoverallreductionoffiberproperties.Althoughthepolymersfromnaturalfibers and regeneratednaturalfibersdonotundergopolymerizationbythemechanismsfoundforsynthetic fibers, mostnaturalpolymershavecharacteristicrepeatingunits and highdegreesofpolymerization and arerelatedtostepgrowthpolymers.BasicpolymericstructuresforthemajorfibersaregiveninFigure1-4.FiberSpinningAlthoughnaturalfiberscomein a morphologicalformdeterminedbynature,regenerated and syntheticman-madefiberscanbe"tailor-made"dependingontheshape and dimensionsoftheorifice(spinningjet)thatthepolymerisforcedthroughtoformthefiber.Thereareseveralmethodsusedtospin a fiberfromitspolymer,includingmelt,dry,wet,emulsion, and suspensionspinning.Meltspinningistheleastcomplexofthemethods.Thepolymerfromwhichthefiberismadeismelted and thenforcedthrough a spinneret and intoairtocausesolidification and fiberformation.Dry...