Manmade artificial fibers
Acrylic fibres are polymers formed by addition polymerization of at least 85% by weight of a chemical called acrylonitrile or vinyl chanide. To polymerise vinyl cyanide the double bond between the first two carbon atoms is broken and the molecules attach themselves to each other in a linear chain.
Acrylic is our final fiber. It can be thought of as artificial wool. It is made from the unlikely combination of coal, air, water, oil, and limestone. DuPont first made acrylic fibers in 1944 and began commercial production in 1950. It is spun by either dry spinning or wet spinning.
In dry spinning, the dissolved polymers are extruded into warm air. The fibers solidify by evaporation. In wet spinning, the polymer is dissolved and extruded into a bath and then dried.
In some ways, acrylic imitates wool. It has wool’s warmth and softness but does not absorb water. Instead, acrylic wicks moisture to the surface where it evaporates.
Acrylic is used in knitted apparels such as fleece, socks, sportswear, and sweaters. It is also used to create fake fur, craft yarns, upholstery fabric, carpet, luggage, awnings, and vehicle covers.
The acrylic fibers include acrylic, modacrylic, and other vinyl fibers containing cyanide groups as side chains. Among the major acrylic fibers used in commerce, acrylonitrile is the comonomer containing a cyanide group.
Acrylic fibers are formed from the wet or dry spinning of copolymers containing at least 85% acrylonitrile units. After texturizing, acrylic fibers have a light bulky wool-like hand and overall wool-like aesthetics. The fibers are resilient and possess an excellent acid resistance and sunlight resistance. Acrylics have been used extensively in applications formerly reserved for wool or other keratin fibers.
Common trade names for acrylic fibers include Acrilan, Creslan, Orlon, Sayelle, and Zefran. Since the acrylic fibers are usually texturized, they have a bulky wool-like hand and possess a moderate degree of luster.
The modacrylics generally resemble acrylics and have a warm pleasing hand and good drapability, resiliency and wrinkle resistance. They are more heat sensitive but more flame resistant than acrylics and have generally been used in specialty applications.
Modacrylic fiber trade names include Elura, SEF, Verel, and Zefran. Production of Dynel modacrylic fibers was discontinued in 1975. Modacrylics possess warm wool-like aesthetics and a generally bright luster. The fiber exhibits fair pilling and abrasion resistance. It has good wrinkle resistance and crease retention if the fiber has been properly heating set.
Nytril fibers are made up of polymers containing at least 85% vinylidene dinitrile units, which appear at least every other unit in the polymer chain. The comonomer used in Nytril synthesis is vinyl acetate.
Lastrile fibers are fibers formed from copolymers of acrylonitrile and a diene such as butadiene and contain 10%-50% acrylonitrile units. Lastrile fibers have not been commercially produced.