Acrylic fibers | Properties, Types | Environmental impact

 

Acrylic fibers

Acrylic fibers are synthetic fibers from polymers like polyacrylonitrile with an average weight of about 100000, to about 1900 monomer units. In the United States, a fiber can be called "acrylic", the polymer must contain at least 85% acrylonitrile monomer. Common comonomers are vinyl acetate or methyl acrylate. Dupont produced the first acrylic fibers in 1941 and named Orlon. Since it was first developed in the mid-1940s but was not bulk-production until the 1950s. Strong and warm acrylic fibers are often used for sweaters and tracksuits and for lining boots and gloves as well as decorations in fabrics and carpets. It is produced as a filament, then cut into short staple lengths like wool hair and spun into yarn.

Acrylic fiber properties

i. Acrylic is a luxurious appearance fiber

ii. It is a crisp or soft hand feel

iii. It has a wide range of colors; dyes and prints well

iv. It has excellent drape ability and softness

v. It is shrinking, moth, and mildew-resistant fiber

vi. Low moisture absorbency, relatively fast drying

vii. No pilling problem, it has a little static problem

viii. Most acetate garments require dry cleaning.

ix. Elongation at break is 15%

x. It has good thermal stability.

xi. It has a moisture regain of 1.5-2%.

Types of Acrylic fiber

Modacrylic fiber

Modacrylic fiber is a synthetic copolymeric fiber. Modacrylics are soft, strong, resilient, and dimensionally stable fiber that is derivatives of acrylic fiber. These can be easily dyed, hold good press and shape, and dry quickly. They have outstanding resistance against chemicals and solvents are not attacked by insects or nets and are non-allergenic. Their uses include clothing linings, fur-like outerwear, paint-roller covers, scatter rugs, carpets, workwear, and wig hair.

Modacrylic fibers are used to replace acrylic fibers that are made from acrylonitrile, but much more polymers are added to make copolymers. It is produced by polymerizing the components, dissolving the copolymer in acetone, pumping the solution into a warm air column, and expanding it in hot conditions.

Nytril fiber

The long-chain polymer of vinylidene dinitrile (-CH2-C (CN) 2-) is a manufactured fiber consisting of at least 85% by weight and the vinylidene dinitrile group is less than every other unit in the polymer chain. Nitrile fibers were first sold commercially in 1955 under the Darlan brand. The name was soon changed to Darwin, but production in the United States ceased in the early 1960s. Nytril has created a soft, elastic fabric that does not shrink and is resistant to wrinkles. It was used for sweaters and pile fabrics. Nytril was also used in vomit mixtures to improve dimensional stability in coats and suits. The fibers, however, were difficult to dye and were never popular.

Lastrile

A manufactured fiber where the fiber is a copolymer of acrylonitrile and a witch with at least 10% by weight, but not more than 50% by weight, acrylonitrile (-CH2-CH (CN) -) units.

The acrylic fiber manufacturing process

Polymers are formed by free-radical polymerization in aqueous suspensions. Fiber is produced by dissolving polymers in solvents such as N, N-dimethylformamide (DMF), or aqueous sodium thiocyanate. Evaporation of the solvent in gas (dry spinning) flow. Complete washing, stretching, drying, and crimping processing. Acrylic fibers are usually produced in a variety of dyes, ranging from 0.9 to 15 to a cut main or 500,000 to 1 million filaments tow. In the late 1950s, Courtaulds Ltd. began investigating the production of acrylic fibers later by the process of dissolved polymerization known as Courtelle. Methyl acrylate (6%) and acrylonitrile were polymerized to sodium thiocyanate in a 50% solution to form a dope ready for spinning in a water bath to form Courtelle fibers in different tubular grades. The sodium thiocyanate solution was reconstituted and reused.

Acrylic Fiber's environmental impact

Since acrylic fiber is not biodegradable, its environmental impact is mostly negative. Also, manufacturing processes are to the detriment of acrylic fiber workers and the ecosystems of production facilities. The manufacturing processes used to make acrylic fabrics are highly volatile and the production plants that make up this fiber are at constant risk of exploding if the necessary protection measures fail. Different types of toxic chemicals are used in the production of acrylic fabrics and if these materials are not handled or disposed of properly, they enter the surrounding ecosystems and harm wildlife and human inhabitants. Gases produced in acrylonitrile manufacturing are so harmful that law enforcement requires that they be properly filtered in a closed environment before leaving any manufacturing facility. Unlike polyester and some other synthetic fabrics, recycling acrylic fabric is virtually impossible, which means there is no effective way to dispose of it once the acrylic fabric is made. Acrylic fiber is not biodegradable, so it simply accumulates in the environment and will remain there for hundreds of years until it begins to break down slowly.