MANUFACTURED CELLULOSIC FIBERS/ PROTEIN FIBERS Chapter 5.
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Transcript of MANUFACTURED CELLULOSIC FIBERS/ PROTEIN FIBERS Chapter 5.
MANUFACTURED CELLULOSIC FIBERS/
PROTEIN FIBERS
Chapter 5
Identification of Regenerated Fibers
Manufactured regenerated fibers: From naturally occurring polymers; regenerated fibers – cannot be used in their natural state, but are chemically processed into a solution that is then extruded through a spinneret Cellulosic: Rayon, lyocell Protein: Azlon – soy silk, silk latte
Derivative cellulosic Fibers: chemically changed derivative of cellulose known as esters Acetate, triacetate
Rayon
Production: Wet spun rayon (viscose); high wet modulus (HWM) rayon.
Physical structure: Naturally bright Can be solution dyed Regular rayon: Serrated cross section. HWM rayon: Rounder cross section and better
performance.
Chemical Composition and Molecular Arrangement of Rayon
Manufactured fiber of regenerated cellulose in which substitutes have replaced not more than 15 percent of the hydrogens of the hydroxyl groups.
Rayon Properties
Physical: Fluid drape, soft hand; control luster, length, diameter.
Mechanical: Regular: Weak, especially wet. HWM: Stronger; adequate
breaking elongation.
Chemical: Absorbent, dyes well, high regain, smooth, soft, good heat & static conductor.
Rayon
Appearance retention: Moderate Regular: poor resiliency, progressive shrinkage HWM: less wrinkling, accepts durable press & dimensional stability
finishes, can be mercerizedCare:
Regular: limited washability (wrinkling, loss of sizing, excessive shrinkage) dry clean
HWM: greater washability, less wrinkling, shrinkage may be controlled
Rayon
Environmental effects: Similar to other cellulosics.Environmental impact: Tree harvesting, processing of
wood pulp, chemicals (acid rain), recycling, water & chemicals in finishing, dry cleaning.
Identification: Burns readily, striations, may be crimped.
Rayon
Common modifications: Staple, solution dyed, acid dyeable, cross sections & sizes, high tenacity, HWM, optically brightened, flame retardant, high absorbency.
Uses: Apparel, furnishings, industrial (medical, nonwovens, disposables).
Lyocell
Production: Wet spun with the solvent recycled.
Physical structure: Staple and filament; rounded cross section, but can be modified.
Chemical structure: Manufactured fiber composed of solvent spun cellulose.
Lyocell Properties
Physical: Size, luster, denier related to use.Mechanical: Strong (4.8-5.0 g/d), 18% weaker
when wet; adequate breaking elongation; poor resistance to abrasion (fibrillates).
Chemical: Good regain (11.5%), no static, soft hand.
Lyocell
Appearance retention: Moderate, dimensional stability moderate.
Care: Dry cleaned; unacceptable changes in hand and color if washed in regular cycle.
Acetate/Triacetate
Production: Dry spun; Triacetate no longer produced in the U.S.
Physical structure: Staple and filament; lobular cross-section, can be modified.
Chemical Composition and Molecular Arrangement of Acetate/Triacetate
Manufactured fiber in which the fiber forming substance is cellulose acetate. Where, not less than 92% of the hydroxyl groups are acetylated, the term triacetate may be used as a generic description of the fiber; modified cellulose.
Acetate Properties
Physical: Control cross section, luster, denier for end use.
Mechanical: Weak, especially when wet; adequate breaking elongation; poor resistance to abrasion.
Chemical: Lower regain (acetate 6%, triacetate 3.2%), static, resistant to weak acids, alkalis, and bleach.
Acetate/Triacetate
Appearance retention: Poor resiliency for acetate, better for triacetate. Dimensional stability moderate for both; elasticity low for both.
Care: Both can be dry cleaned and are thermoplastic and heat sensitive.
Identification: Slight striations.Environmental effects: Resistant to
moths, mildew, & bacteria; less than other cellulosics unless sunlight resistant type (SLR).
Acetate/Triacetate
Environmental impact: Tree harvest; processing of wood pulp; solvent reclaimed & reused, dry cleaning.
Common fiber modifications: Solution dyed, cross section & fiber sizes, textured, sunlight & weather resistant, flame retardant.
Uses: Apparel, furnishings, industrial.
Other Regenerated Fibers
Alginate fiber: Polysaccharides processed from brown seaweed; used for wound dressings.
Regenerated protein fibers Soysilk®: from soybean waste;
durable, good drape, good comfort; apparel
Silk Latte®: from milk protein; soft hand, dyeable; apparel
Bamboo: Soft, silky hand; similar to high quality ramie.
Soy Silk and Bamboo
Properties (Other Fibers)
Identification: Round cross-section, resistant to most organic solvents.
Environmental effects: Resistant to moths, similar sunlight resistance to rayon & cotton.
Environmental impact: Some made from waste from other industries; small amounts produced.
Common fiber modifications: Few at present.
Uses: Apparel, furnishings, industrial.