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Acrylic fibers are
synthetic fiber
Synthetic fibers or synthetic fibres (in British English; see spelling differences) are fibers made by humans through chemical synthesis, as opposed to natural fibers that are directly derived from living organisms, such as plants (like cotton) ...
s made from a
polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
(
polyacrylonitrile
Polyacrylonitrile (PAN), also known as polyvinyl cyanide and Creslan 61, is a synthetic, semicrystalline organic polymer resin, with the linear formula (C3H3N)n. Though it is thermoplastic, it does not melt under normal conditions. It degrades bef ...
) with an average
molecular weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...
of ~100,000, about 1900 monomer units. For a fiber to be called "acrylic" in the US, the polymer must contain at least 85%
acrylonitrile
Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. In terms of its molecular ...
monomer
In chemistry, a monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization.
Classification
Mo ...
. Typical comonomers are
vinyl acetate
Vinyl acetate is an organic compound with the formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate and ethene-vinyl acetate copolymers, important industrial polymers.
Production
The worldwide production capacity of v ...
or
methyl acrylate
Methyl acrylate is an organic compound, more accurately the methyl ester of acrylic acid. It is a colourless liquid with a characteristic acrid odor. It is mainly produced to make acrylate fiber, which is used to weave synthetic carpets. It is al ...
.
DuPont
DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in ...
created the first acrylic fibers in 1941 and trademarked them under the name Orlon. It was first developed in the mid-1940s but was not produced in large quantities until the 1950s. Strong and warm acrylic fiber is often used for sweaters and tracksuits and as linings for boots and gloves, as well as in furnishing fabrics and carpets. It is manufactured as a filament, then cut into short staple lengths similar to wool hairs, and spun into yarn.
Modacrylic A modacrylic is a Organic compound#Synthetic compounds, synthetic copolymer. Modacrylics are soft, strong, resilient and dimensionally stable. They can be easily dyed, show good press and shape retention, and are quick to dry. They have outstanding ...
is a modified acrylic fiber that contains at least 35% and at most 85%
acrylonitrile
Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. In terms of its molecular ...
.
Vinylidene chloride
1,1-Dichloroethene, commonly called 1,1-dichloroethylene or vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula CHCl. It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water, ...
or
vinyl bromide
Vinyl bromide is a simple vinyl halide. It is a colorless liquid. It is produced from ethylene dibromide. It is mainly used as a comonomer to confer fire retardant properties to acrylate polymers.
Reactions and applications
It reacts with magne ...
used in modacrylic give the fiber flame retardant properties. End-uses of modacrylic include faux fur, wigs, hair extensions and protective clothing.
Production
The polymer is formed by
free-radical polymerization
In polymer chemistry, free-radical polymerization (FRP) is a method of polymerization by which a polymer forms by the successive addition of free-radical building blocks (repeat units). Free radicals can be formed by a number of different mechanis ...
in aqueous suspension. The fiber is produced by dissolving the polymer in a solvent such as
N,N-dimethylformamide
Dimethylformamide is an organic compound with the formula ( CH3)2NC(O)H. Commonly abbreviated as DMF (although this initialism is sometimes used for dimethylfuran, or dimethyl fumarate), this colourless liquid is miscible with water and the major ...
(DMF) or aqueous
sodium thiocyanate
Sodium thiocyanate (sometimes called sodium sulphocyanide) is the chemical compound with the formula NaSCN. This colorless deliquescent salt is one of the main sources of the thiocyanate anion. As such, it is used as a precursor for the synthes ...
, metering it through a multi-hole
spinneret
A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and are ...
and coagulating the resultant filaments in an aqueous solution of the same solvent (wet spinning) or evaporating the solvent in a stream of heated inert gas (dry spinning). Washing, stretching, drying and crimping complete the processing. Acrylic fibers are produced in a range of
deniers, usually from 0.9 to 15, as cut staple or as a 500,000 to 1 million filament
tow
Towing is coupling two or more objects together so that they may be pulled by a designated power source or sources. The towing source may be a motorized land vehicle, vessel, animal, or human, and the load being anything that can be pulled. Th ...
. End uses include sweaters, hats, hand-knitting yarns, socks, rugs, awnings, boat covers, and upholstery; the fiber is also used as "
PAN" precursor for
carbon fiber
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
. Production of acrylic fibers is centered in the Far East, Turkey, India, Mexico, and South America, though a number of European producers still continue to operate, including Dralon and Fisipe. US producers have ended production (except for specialty uses such as in friction materials, gaskets, specialty papers, conductive, and stucco), though acrylic tow and staple are still spun into yarns in the USA.
In the late 1950s, Courtaulds Ltd began investigating the production of an acrylic fiber later to be called "courtelle" by a process of solvent polymerisation. Methyl acrylate (6%) and acrylonitrile were polymerised in a 50% solution of sodium thiocyanate to produce a dope ready for spinning into a waterbath to produce "courtelle" fiber in various grades of denier. The sodium thiocyanate solution was reconcentrated and re-used. The reaction was a continuous process, with about 5% of reactants being recycled. This recycling process resulted in the build-up of pollutants in the process, as did the recycling of the solvent. A great deal of research in the chemical engineering laboratory in Lockhurst Lane, Coventry, and on the pre-production pilot plant at Little Heath overcame the recycling problems and resulted in the process becoming a commercial success at a new production plant in Grimsby.
Textile uses
Acrylic is lightweight, soft, and warm, with a
wool
Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool.
As ...
-like feel. It can also be made to mimic other fibers, such as cotton when spun on short staple equipment. Some acrylic is extruded in colored or pigmented form; other is extruded in "ecru", otherwise known as "natural," "raw white," or "undyed." Pigmented fiber has the highest lightfastness. Its fibers are very resilient compared to both other synthetics and natural fibers. Some acrylic is used in clothing as a less expensive alternative to
cashmere, due to the similar feeling of the materials. Some acrylic fabrics may fuzz or
pill
Pill or The Pill may refer to:
Drugs
* Pill (pharmacy), referring to anything small for a specific dose of medicine
* "The Pill", a general nickname for the combined oral contraceptive pill
Film and television
* ''The Pill'' (film), a 2011 fil ...
easily, though there are low-pilling variants. Acrylic takes color well, is washable, and is generally hypoallergenic. End-uses include socks, hats, gloves, scarves, sweaters, home furnishing fabrics, and awnings. Acrylic can also be used to make fake fur and to make many different knitted clothes.
As acrylic is a synthetic fiber, the larvae of
clothes moth
Clothes moth or clothing moth is the common name for several species of moth considered to be pests, whose larvae eat animal fibres (hairs), including clothing and other fabrics.
These include:
* ''Tineola bisselliella'', the common clothes moth ...
s are unable to digest it. However, acrylic fibers that are blended with wool or soiled may be eaten as a consequence of having blended fibers.
Acrylic is the "workhorse" hand-crafting fiber for crafters who
knit
Knitting is a method by which yarn is manipulated to create a textile, or fabric. It is used to create many types of garments. Knitting may be done by hand or by machine.
Knitting creates stitches: loops of yarn in a row, either flat or i ...
or
crochet
Crochet (; ) is a process of creating textiles by using a crochet hook to interlock loops of yarn, thread (yarn), thread, or strands of other materials. The name is derived from the French term ''crochet'', meaning 'hook'. Hooks can be made from ...
; acrylic yarn may be perceived as "cheap" because it is typically priced lower than its natural-fiber counterparts, and because it lacks some of their properties, including softness and propensity to felt. The fiber requires heat to "relax" or set the shape of the finished garment, and it isn't as warm when wet as alternatives like
wool
Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool.
As ...
. Some hand-knitters also complain that the fiber "squeaks" when knitted, or that it is painful to knit with because of a lack of "give" or stretch in the yarn. On the other hand, it is machine-washable and extremely color-fast. This makes it useful in certain items, like garments for babies, which require constant washing. However it is much more flammable than its natural fiber counterparts, so caution should be used when making items for babies and children.
Microplastic release
A team at Plymouth University in the UK spent 12 months analyzing what happened when a number of synthetic materials were washed at different temperatures in domestic washing machines, using different combinations of detergents, to quantify the
microfibre
Microfiber (or microfibre) is synthetic fiber finer than one denier or decitex/thread, having a diameter of less than ten micrometers. A strand of silk is about one denier and about a fifth of the diameter of a human hair.
The most common ty ...
s shed. They found that acrylic was responsible for releasing nearly 730,000 tiny synthetic particles (
microplastics
Microplastics are fragments of any type of plastic less than in length, according to the U.S. National Oceanic and Atmospheric Administration (NOAA) and the European Chemicals Agency. They cause pollution by entering natural ecosystems from a v ...
) per wash, five times more than polyester-cotton blend fabric, and nearly 1.5 times as many as pure
polyester
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...
. Research by ecologist Mark Browne showed synthetic fibre waste over coastlines at a global scale, with the greatest concentration near sewage outflows. Of the man-made material found on the shoreline, 85% were microfibers and matched the types of material (such as nylon and acrylic) used in clothing.
Single clothes wash may release 700,000 microplastic fibres, study finds , Environment
''The Guardian'' (2016-09-27). Retrieved on 2017-01-26.
See also
*List of fabrics
Fabrics in this list include fabrics that are woven, braided or knitted from textile fibres.
A
* Aertex
* Alençon lace
* Antique satin
* Argentan lace
* Argentella lace
* Armenian needlelace
B
* Bafta cloth
* Baize
* Ballistic nylon
* ...
References
{{DEFAULTSORT:Acrylic Fiber
Synthetic fibers
Plastics