polystyrene

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polystyrene

(pŏl'ēstī`rēn), widely used plasticplastic,
any organic material with the ability to flow into a desired shape when heat and pressure are applied to it and to retain the shape when they are withdrawn. Composition and Types of Plastic
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; it is a polymerpolymer
, chemical compound with high molecular weight consisting of a number of structural units linked together by covalent bonds (see chemical bond). The simple molecules that may become structural units are themselves called monomers; two monomers combine to form a dimer,
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 of styrene. Polystyrene is a colorless, transparent thermoplastic that softens slightly above 100°C; (212°F;) and becomes a viscous liquid at around 185°C; (365°F;). It is resistant to acids, alkalies, oils, and alcohols. It is produced either as a solid or as a foamed plastic marketed under the trade name Styrofoam. Its many uses include electrical and thermal insulation, translucent window panels, storage-battery cases, and toilet articles.

polystyrene

A hard, tough, stable thermoplastic that is easily colored, molded, expanded, or rolled into sheeting. See also: Plexiglas

Polystyrene

 

a linear polymer of styrene, [—CH2— CH(C6H5) —]n; a clear vitreous substance. Moleculer weight, 30,000–500,000; density, 1.06 g/cm3 (20°C); glass transition point, 93°C.

Polystyrene is an inexpensive, large-tonnage thermoplastic resin. It has high hardness and good dielectric properties; it is weatherproof and readily dyeable and moldable. It is chemically stable and soluble in aromatic and chlorinated aliphatic hydrocarbons, and it is physiologically harmless. However, it has relatively low heat resistance (Vicat softening point, about 100°C) and high brittleness; various styrene copolymers have better use properties. For example, copolymerization of styrene with acrylonitrile or α-methylstyrene increases heat resistance and tensile strength by about 60 percent; an increase in strength and impact strength from 5–10 to 50–100 kilojoules per sq m, or kilograms = force · cm per sq cm, is achieved by production of graft styrene copolymers with 5–10 percent rubber—for example, butadiene (impact-resistant polystyrene)—or triple copolymers of acrylonitrile, butadiene, and styrene (ABS polymers). Transparent triple copolymers are synthesized upon substitution of methyl methacrylate for acrylonitrile.

Polystyrene and styrene copolymers are produced in industry by radical polymerization in bulk or in aqueous emulsions; they are processed by injection molding, extrusion, compression molding, and vacuum forming.

Polystyrene is used in the manufacture of household appliances and domestic items, packing material, toys, accessories, and films, as well as in the preparation of polystyrene foam. In addition, impact-resistant polystyrene and ABS polymers are used in the manufacture of radio and television housings, motor vehicle and refrigerator parts, furniture, and pipes. Polystyrene is also mixed with rubber and with other plastics.

World production of polystyrene and styrene copolymers in 1973 was about 5 million tons.

REFERENCES

Houwink, R., and A. Staverman [compilers]. Khimiia i tekhnologiia polimerov, vols. 1–2 (parts 1–2). Moscow-Leningrad, 1965–66. (Translated from German.)
See also references under .

S. A. VOL’FSON

polystyrene

[¦päl·i′stī‚rēn]
(organic chemistry)
(C6H5CHCH2)x A water-white, tough synthetic resin made by polymerization of styrene; soluble in aromatic and chlorinated hydrocarbon solvents; used for injection molding, extrusion or casting for electrical insulation, fabric lamination, and molding of plastic objects.

polystyrene

a synthetic thermoplastic material obtained by polymerizing styrene; used as a white rigid foam (expanded polystyrene) for insulating and packing and as a glasslike material in light fittings and water tanks
References in periodicals archive ?
Surprisingly, as the amount of high impact polystyrene in the blends was increased above 30 pph, the temperature at which the blends began to soften and flow fell from 120[degrees]C to about 80[degrees]C.
ABS and high impact polystyrene samples exhibited a whitening effect due to craze formation through the whole fracture surface, indicating that stable crack propagation was occurring.
a national leader in the manufacturing and distribution of cups, foodservice containers, lids and straws today announces the launch of Vio[TM] -- the first expandable polystyrene (EPS) foam cup and high impact polystyrene (HIPS) lid with EcoPure[R] technology.
Compatibility of the impact grade with high impact polystyrene facilitates cost-effective tailoring for specific temperature performance.
When completed, the polystyrene plant will produce 40,000 metric tons per year of high impact polystyrene and 90,000 metric tons per year of general purpose polystyrene.
These included PP - with Phase One production unable to meet demand - polyvinyl chloride (PVC), LDPE, HDPE, high impact polystyrene and general purpose polystyrene.