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Chapter 5

Chapter 5. Manufactured Cellulosic Fibers/ Protein fibers. Identification of Regenerated Fibers .

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Chapter 5

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  1. Chapter 5 Manufactured Cellulosic Fibers/ Protein fibers

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Rayon • Appearance retention: Moderate • Regular: poor resiliency, progressive shrinkage • HWM: less wrinkling, accepts durable press & dimensional stability finishes, can be mercerized • Care: • Regular: limited washability (wrinkling, loss of sizing, excessive shrinkage) dry clean • HWM: greater washability, less wrinkling, shrinkage may be controlled

  7. 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.

  8. 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).

  9. 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.

  10. 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.

  11. Lyocell • Appearance retention: Moderate, dimensional stability moderate. • Care: Dry cleaned; unacceptable changes in hand and color if washed in regular cycle.

  12. Acetate/Triacetate • Production: Dry spun; Triacetate no longer produced in the U.S. • Physical structure: Staple and filament; lobular cross-section, can be modified.

  13. 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.

  14. 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.

  15. 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).

  16. 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.

  17. 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.

  18. Soy Silk and Bamboo

  19. 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.

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