Chapter 6 Synthetic and Special Application Fibers

Synthetic Fibers Production: Synthesize polymer from raw materials by addition or condensation polymerization.

Common Properties Heat sensitive: Softens or melts with sufficient heat. Pilling: Formation of tiny balls of fiber on fabric. Static electricity: Soil and lint cling; problems in production & processing; discomfort during use. Oleophilic: Affinity for oil and grease. Chemically resistant Hydrophobic: Low absorbency.

Heat and pressure cause permanent flattening of the yarn.

Common Properties Slick and abrasion resistant Strong and resilient Resistant to most common fiber degradants: sunlight (except for nylon) Flame resistance varies widely Low density Non-biodegradable

Common Manufacturing Processes Melt spun: Used for most synthetics. Drawn: To develop strength, pliability, toughness, and elasticity properties. Heat set: To stabilize yarns or fabrics. PG7YN0 PG7YN0

Identification of Synthetic Fibers Only reliable test is solubility. (According to the book. But in reality, there are others – dye tests and spectroscopic analysis.)

Common Fiber Modifications Fiber shape and size: Melt spun fibers easy to alter. Low-pilling fibers: Reduce flex life by reducing molecular weight slightly. High-tenacity fibers: By drawing, chemical modifications, or combination Low-elongation fibers: Used in blends.

Nylon (Polyamide) Production: Melt spun from condensation polymer made from diamine & acid; cold drawn. Physical structure: Wide variety of types. Chemical structure: Manufactured fiber in which the fiber-forming substance is a long chain synthetic polyamide in which less than 85% of the amide linkages are attached directly to two aromatic rings. ◦ Common types: Nylon 6 & 6,6

Properties Physical: Sheer and durable fabrics; poor cover; hand, texture, luster, etc. can be controlled for end use. Mecanical: High tenacity, good breaking elongation, excellent abrasion resistance. Chemical: Smooth & silky feel; low density; low absorbency; static prone. Appearance retention: Excellent resiliency & elasticity; retains appearance well; pills readily.

Properties Care: easy care ◦ Resistant to chemicals, insects, and mildew; ◦ Color scavenger (Picks up color from other textiles and soil.) ◦ Low melting point ◦ Quick drying ◦ Oleophilic ◦ Degraded quickly by sunlight Environmental impact: Processed from petrochemicals with inherent concerns regarding the environment; little processing after fiber production needed; can be recycled.

Nylon Identification: Nylon dissolves in phenol and formic acid. Fiber modifications: Cross section, size, solution dyed, textured, antistatic, anti-soil, bicomponent, antimicrobial, sunlight resistant, flame retardant, delustered, high tenacity, cross linked, dye affinity. End uses: Furnishings (carpeting, upholstery); apparel; industrial (tire cord, car interiors, ropes, performance apparel, sporting goods).

Polyester Production: Melt spun of condensation polymer from di- acid and di-alcohol, hot drawn. Physical structure: Variety of types. Chemical structure: Manufactured fiber in which the fiber-forming substance is a long chain synthetic polymer composed of at least 85% by weight of an ester of a dihydric alcohol and terephthalic acid. Straight molecular chains with high degree of orientation. Several polymer types.

Polyester Properties Physical: Can resemble most natural fibers; many types. Mechanical: Excellent strength & abrasion resistance; good breaking elongation. Chemical: Low density; low absorbency; static prone; soil release finishes improve wicking; performance and stretch polyester available.

Polyester Appearance retention: Excellent elasticity; excellent resiliency; does not shrink if properly heat set; resists wrinkling. Care: Easy care, quick drying; resists most common fiber degradants; thermoplastic; heavier than nylon & acrylic; oleophilic. Environmental impact: Extensive recycling programs. 6Y7PKyQ7Sfg&feature=related 6Y7PKyQ7Sfg&feature=related Identification: Resistant to most solvents.

Polyester Fiber modifications: Cross section; size; dyeability; solution dyed, textured, tenacity; shrinkage; pill resistant; copolymer; bigeneric; luster; binder staple; flame retardant; antistatic; anti-soil; antimicrobial; delustered; nonpilling. End uses: Apparel; furnishings; industrial (fiberfill, nonwoven fabrics, tire cord, sporting goods, rope, cordage, filters, geotextiles, medical applications).

Olefin Production: ◦ High-pressure system ◦ Low-pressure system ◦ Addition polymer: melt spun; cold drawn ◦ May be gel spun

Olefin Physical structure: Available in many forms. Chemical structure: Manufactured fiber in which the fiber-forming substance is a long chain synthetic polymer composed of at least 85% by weight of ethylene, propylene, or other olefin units except amorphous (noncrystalline) polyolefins qualifying as rubber, polypropylene or polyethylene.

Olefin Properties Physical: Can be modified for end use. Mechanical: Good tenacity, elongation, and abrasion resistance. Chemical: Low regain, good wicking, non- static; light weight; waxy hand, but can be modified; performance fibers. Moisture vapor transport rate (MVRT): Measures the rate moisture vapor moves from the fabric side next to the body to the fabric’s exterior side.

Olefin Appearance retention: Excellent resiliency; good dimensional stability. Care: Unaffected by water borne stains; excellent resistant to most chemicals; low melting point; oleophilic. Environmental impact: Few processing chemicals used; easily recycled; used for environmental applications. Identification: Melt spinnable.

Olefin Fiber modifications: Heat stabilized; light stabilized; modified cross section and size; solution dyed, dye-ability; fibrillated; high tenacity. End uses: Apparel; furnishings; industrial (carpet backing; dye nets, diaper cover stock, filter fabrics, bags, wall panel fabrics, envelopes, banners, geotextiles, ground cover fabrics, protective clothing, substrates for coated fabrics, ropes, twines).

Acrylic Production: Addition polymer or copolymer; dry spun & hot drawn or wet spun & drawn. Physical structure: Cross-sectional shape & size varies; usually staple. Chemical structure: Manufactured fiber in which the fiber-forming substance is a long chain synthetic polymer composed of at least 85% by weight of acrylonitrile units; copolymer or graft copolymer; bicomponent.

Acrylic Properties Physical: Various types; often textured or crimped. Mechanical: Moderate tenacity, abrasion resistance, & breaking elongation. Chemical: Not as synthetic feeling; low density; low regain.

Acrylic Appearance retention: Good resiliency & elasticity; moderate dimensional stability; poor heat settability; pills readily. Care: Follow care instructions; resistant to chemicals, insects, & sunlight. Environmental impact: Chemicals used to produce raw materials, spin fibers, & wash fibers; dyes. Identification: Solubility test.

Acrylic Fiber modifications: Self crimping, solution dyed, bicomponent or copolymer, modified cross section, size, dyeability. End uses: Furnishings; apparel; industrial (craft yarn, tarps, awnings, luggage, vehicle covers, tents, sandbags, precursor of carbon fiber).

Modacrylic Production: Addition copolymer, dry spun, hot drawn. Physical structure: Staple fiber, variable cross section. Chemical structure: Manufactured fiber in which the fiber-forming substance is any long chain synthetic polyamide comprised of less than 85% but at least 35% by weight of acrylonitrile.

Modacrylic Properties Physical: Latent crimp for realistic fake furs; other modifications based on end use. Mechanical: Low abrasion resistance & tenacity, good elongation. Chemical: warm, soft, pills; low regain; moderate density. Appearance retention: Moderate resiliency & dimensional stability; high elastic recovery. Care: Resists most common fiber degradants; flame retardant; heat sensitive; washable or dry cleanable.

Modacrylic Environmental impact: Fewer problems; minor fiber. Identification: Self extinguishes, solubility test. Fiber modifications: Heat sensitivity, solution dyed, dyeability, crimped. End uses: Furnishings; apparel; industrial (protective clothing, filters, wigs, blankets & upholstery in airplanes).

Special Use Fibers

Elastomeric Fibers  Elastomers: A natural or synthetic polymer which, at room temperature, can be stretched repeatedly to at least twice its original length and which, after removal of the tensile load, will immediately and forcibly return to approximately its original length.  Kinds of stretch  Power stretch: holding power with elasticity; fibers with high retractive forces  Comfort stretch: only elasticity desired

Rubber  Manufactured fiber in which the fiber-forming substance is comprised of natural or synthetic rubbers.  Natural rubber: From plant source.  Synthetic rubbers: Synthetic sources.  Properties of both types similar  Excellent elongation & elasticity  Low tenacity influences end use  Poor resistance to aging, sunlight, oil, perspiration, oxidizing agents  Low dyeability, hand, regain

Spandex Wet or dry spun from synthetic polymers. Physical structure: Mono or multifilament; variable sizes. Chemical structure: A manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer consisting of at least 85% of a segmented polyurethane (also known as elastane).

Spandex  Physical: Seldom used alone; no cover yarn needed.  Mechanical: More durable than rubber; improved tenacity & flex life; similar elongation &elasticity; better resistance to body oils, perspiration, chemicals, aging.  Chemical: Low regain; moderate density.  Care: Resistant to cleaning chemicals; thermoplastic.  Uses: Apparel, industrial, furnishings.

Spandex

Elastoester  Manufactured fiber in which the fiber- forming substance is a long-chain synthetic polymer consisting of at least 50% by weight of aliphatic polyether and at least 35% by weight of polyester; elongation of 600%.  Properties: Low tenacity; lower elasticity compared to other elastomers; superior strength retention in wet heat conditions & after treatment with alkalis; better dyeability & print clarity compared to spandex.  Uses: Outerwear & furnishings.

OTHER ELASTOMERICS Elasterell –P ◦ An elastic bicomponent polyester; good inherent stretch with excellent recovery; easy care; active sportswear, leisure; known as multelastester in Europe. Lastol ◦ Elastic cross-linked copolymer olefin; superior stretch and recovery; chemically stable; active wear and easy care stretch apparel.

Fibers with Chemical, Heat, or Fire Resistance Aramid ◦ Manufactured fiber in which the fiber-forming substance is any long-chain synthetic polyamide in which at least 85% of the amide linkages are attached directly to two aromatic rings.

Fibers with Chemical, Heat, or Fire Resistance (cont.) Aramid (cont.) ◦ Processing: Wet or dry spun & drawn. ◦ Physical structure: Staple or filament. ◦ Properties: Exceptional heat and flame resistance & strength; high tenacity & resistance to stretch; resistant to most chemicals; excellent impact & abrasion resistance; regain of 4.5%; usually mass pigmented. ◦ Uses: Industrial fiber; protective apparel uses.

Fibers with Chemical, Heat, or Fire Resistance (cont.) Glass ◦ A manufactured fiber in which the fiber-forming substance is glass (silicon dioxide). ◦ Process: Melt spun, not drawn. ◦ Properties: Incombustible; good strength, but low flex abrasion resistance (brittle); low elongation; high density; nonabsorbent. ◦ Uses: Furnishings and industrial.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  Metal and metallic fibers  Manufactured fiber composed of metal, plastic-coated metal, metal-coated plastic, or a core completely covered by metal.  Processing: Laminating or metalizing.  Types  Gold, silver, brass, etc.  Aluminum: Often coated with plastic film to minimize tarnishing; may be stiff and inflexible.  Stainless steel: Superfine filaments of steel to reduce static potential; strong, stiff, and heavy.  Uses: Apparel, furnishings, and industrial.

Production

Fibers with Chemical, Heat, or Fire Resistance (cont.) Novoloid ◦ Manufactured fiber in which the fiber-forming substance contains at least 35% by weight of cross- linked novolac. ◦ Properties: Outstanding flame resistance; good resistance to sunlight; inert to most chemicals. ◦ Uses: Flame-resistant industrial products.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  PBI  A manufactured fiber in which the fiber-forming substance is a long-chain synthetic aromatic polymer having recurring imidazole groups as an integral part of the polymer chain.  Processing: Dry spun & drawn.  Properties: Good tenacity & breaking elongation; mass pigmented; flame resistant; high regain.  Uses: Heat resistance apparel; furnishings for aircraft, hospitals, & submarines; industrial filters & membranes.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  Sulfar  A manufactured fiber in which the fiber-forming substance is a long-chain synthetic polysulfide in which at least 85% of the sulfide linkages are attached directly to two aromatic rings.  Production: Melt spun; drawn.  Properties: Good tenacity and breaking elongation; excellent elasticity & resistance to acids/alkalis; low regain; moderate density.  Uses: Filtration fabrics; papermaking felts, membranes, rubber reinforcement, & electrical insulation.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  Saran  A manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer composed of at least 85% by weight of vinylidene chloride units.  Production: Melt spun, hot drawn.  Properties: Good weathering properties, resistant to chemicals, tough, durable; good tenacity; low regain; heavy; does not support combustion.  Uses: Competes with olefin for similar end uses.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  Vinyon  A manufactured fiber in which the fiber- forming substance is a long-chain synthetic polymer composed of at least 85% by weight of vinyl chloride units.  Properties: Low tenacity; very sensitive to heat; unaffected by moisture; chemically stable; poor conductor of electricity; does not burn.  Uses: Bonding agents for rugs, papers, & fiberweb fabrics & for other industrial products.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  Vinal  A manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer composed of at least 50% by weight of vinyl alcohol units and in which the total of the vinyl alcohol units and any one or more of the various acetal units is at least 85% by weight of the fiber.  Properties: Strong fiber, weaker when wet; flame resistant; good resistance to chemicals; mass pigmented.  Uses: Protective apparel and industrial goods.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  Fluoropolymer (PTFE)  A manufactured fiber containing at least 95% of a long chain polymer synthesized from aliphatic fluorocarbon monomers; polymerized under pressure and heat with catalyst.  Properties: Average tenacity, low elongation, good pliability; heavy; temperature resistant; resistant to chemicals, sunlight, weathering, & aging; low friction coefficient.  Uses: Industrial, Apparel (Gore- Tex ®)

Fibers with Chemical, Heat, or Fire Resistance (cont.) Carbon ◦ Heat stabilized, cross-linked polyacrylonitrile. ◦ Properties: High strength; rigid; exceptional heat resistance; moderately heavy; high regain; very low coefficient of thermal expansion; chemically inert; biocompatible. ◦ Uses: Reinforcement fibers in resins & metals; bone-grafts; replacement for asbestos.

Fibers with Chemical, Heat, or Fire Resistance (cont.)  Melamine  A manufactured fiber in which the fiber- forming substance is a synthetic polymer composed of at least 50% by weight of a cross-linked melamine polymer.  Properties: Moderate strength; 5% regain; low elongation at break; moderately heavy; fair abrasion resistance; good to excellent resistance to most chemicals.  Uses: Low cost competitor for meta- aramid, PBI, sulfar, and polyimide.

Fibers with Chemical, Heat, or Fire Resistance (cont.) Polyimide (PI or PEI) ◦ Properties: Moderately strong; 20% elongation at break; low regain; moderate specific gravity; good abrasion resistance; good to excellent resistance to most chemicals; moderately high cost. ◦ Uses: Filters, protective clothing, fire block seating.

Fibers with Chemical, Heat, or Fire Resistance (cont.) Polyphenylene Benzobisoxazole (PBO) ◦ Properties: Nonflammable; high temperature resistance; good tenacity; 1.5 density; 2% regain; 3.5% breaking elongation. ◦ Uses: Reinforcing fiber in resins.

Fibers with Chemical, Heat, or Fire Resistance (cont.) Ceramic Fibers ◦ Properties: Composed of metal oxides, metal carbides, metal nitrides, or other mixtures; high thermal resistance; high strength; rigid. ◦ Uses: Reinforcing fibers in resins or other compounds.

Fibers with Chemical, Heat, or Fire Resistance (cont.) Polylactic Acid (PLA) ◦ Fermented & melt spun from cornstarch. ◦ Properties: Luster, drape, and hand of silk, quick drying, good wrinkle resistance, and good flame and ultraviolet light resistance. ◦ Uses: Apparel and industrial applications.