Rayon, Lyocell, and Acetate Fibers

• Study notes for the Exam 2 Review

Rayon and Lyocell

• Rayon is an inexpensive cotton substitute derived from cellulose sources like cotton linters, beech trees, and bamboo
• Rayon is soft and absorbent
• Rayon weakens significantly when wet
• Rayon lacks the resilience of synthetics, but drapes well, providing comfort
• Rayon/Viscose is oldest manufactured fiber. It is cheap, absorbent, and used in disposable products like sponges, wipes, and diapers
• Lyocell, known generically and as Tencel commercially, also uses cellulose, specifically from eucalyptus
• Lyocell involves wet spinning where the material is dissolved, spun into a chemical bath to coagulate, and the solvent is recycled in a closed-loop process
• Lyocell is stronger and more resilient than rayon, offering environmental benefits, but is a bit more expensive

Acetate

• Acetate is a thermoplastic, regenerated from cellulose, meaning it can be softened by heat and remolded
• Acetate is very shiny, often requiring delustering to reduce shine, and is also cheap to produce
• Acetate demonstrates weakness, particularly when wet, necessitating dry cleaning due to poor resiliency
• Acetate uses dry spinning where resin is dissolved, solvent evaporates with warm air, and fiber solidifies
• Acetate is not a long lasting plastic

Nylon

• Nylon is a fully synthetic fiber known for abrasion and tear resistance
• Nylon is oleophilic (attracts oils), hydrophobic (repels water), and thermoplastic
• Nylon offers elasticity, as seen in pantyhose and seatbelts, and employs melt spinning, the least expensive method
• Nylon melt spinning involves melting resin, spinning fiber into air, and fiber solidifying during cooling

Polyester

• Polyester known as the great imitator, uses PET or PETE
• Trademarked names include Coolmax for wicking moisture from the surface and Hollofil for insulation uses

Olefin

• Olefin is made from polypropylene (PP) and polyethylene
• Olefin is slippery, strong, and lightweight, and heat sensitive (most)

Acrylic/Modacrylic

• Acrylic serves as a wool substitute that is bulked and crimped
• Acrylic is hypoallergenic, easy to care for, doesn't attract insects, and resists felting, but at a disadvantage is thermoplastic and extremely flammable
• Acrylic is soft; also used for fake fur and stuffed animals
• Acrylic is hydrophobic and prone to pilling due to static electricity
• Acrylic is solution dyed and used in eyeglass lenses
• Modacrylic, a first synthetic that doesn't melt or burn (SEF), simulates fur and hair and easily dyed and is chemical resistant

Elastomers

• Elastomers can stretch twice their original length and snap back to size
• Neoprene: rubber between two layers of fabric.
• Neoprene us stretchy and used for form-fitting materials. The rubber is surrounded by cotton/poly
• Rubber (natural/latex synthetic) is inexpensive but breaks down when exposed to oxygen, detergent, chlorine, sweat, and oil
• Spandex, also known as Lycra is easy to care for that doesn't degrade, dries quickly, and is resilient

Other Synthetics

• PVC/ Vinyl/ “fake/vegan leather"/Pleather: waterproof, clear but flexible, for: backpacks, cosmetic bags, umbrella, shower curtain, housing siding, car upholstery
• Polyurethane: dense rubbery plastic. Crocs, roller skates
• Polystyrene: Styrofoam, packing peanuts, bike helmets, not strong. Extremely lightweight
• Silicone: cookware. Watch bands. Rubbery but lasts longer that polyurethane. Prosthetics. Can be dyed. Very flexible. Heat resistant

Fiber Properties

• Important to understand fiber properties such as thermoplasticity, hydrophilicity, and oleophobicity, as well as which fibers excel in abrasion resistance, tenacity, absorbency, and resilience
• Rayon is more heat sensitive when compared to Olefin
• Nylon excels in abrasion resistance, while Acetate is the least resistant
• Nylon offers high tenacity, in contrast Rayon offers the least
• Rayon demonstrates high absorbency, in contrast Olefin is the least
• Nylon is highly resilient, in contrast Acetate is the least Polyester is thermoplastic, oleophilic, and hydrophobic Polyester offers excellent thermal retention and abrasion resistance with low elongation and elastic recovery Polyester can be recycled, and is a resilient, and easy-care

Practice Exam Questions/Study Material

• Alterations to nitrogen and phosphorus cycles surpass carbon cycle changes dramatically
• Phosphorus increase is a lead water quality detractor resulting in algal blooms and oxygen deficiency (dead zone) in bodies of water, such as Lake Erie and the Mississippi River which flows into the Gulf of Mexico
• Spandex addition at 5% enhances the stretch properties of fabrics
• Acetate should always be dry-cleaned
• Cotton Linters are used to make regenerated fibers
• Wet spinning (acrylic, lyocell, rayon, spandex) is the most economical spinning method when compared to dry and melt spinning
• Wet spinning is the most complex, oldest, raw materials are dissolved by chemicals, spun into a bath, when coagulated fibers solidify
• Dry spinning (acetate, acrylic, modacrylic, and spandex) solvent recovery is required, fiber solidifies when the solvents are evaporated
• Melt spinning (nylon, olefin, polyester, saran) least expensive process, fibers solidify on cooling
• Polar fleece is made of recycled polyester
• Nylon is a color scavenger
• Environmental concerns for nylon, polyester and olefin: they persist, use energy and oil, cause greenhouse gas release
• Nylon used in seatbelts, airbags, lingerie, raincoats and swimwear
• Polyester used in bottles, blankets, tarps, rugs, curtains, shirts, socks and pants
• Olefin is used in vehicle interiors, wallpaper and carpeting