General purpose polystyrene plastic

Laboratory tests indicated that gamma radiation treatment and cross-linking using triaHylcyanurate or acetylene produced a flexible recycled plastic from mixtures of polyethylene, polypropylene, general-purpose polystyrene, and high impact grade PS (62). 

Intermediate. Most of the scattered light in intermediate systems has been scattered many times, but some unscattered fight emerges from the sample [6]. A typical application would be a plastics operation that works with pigments and general-purpose polystyrene. Most systems that are typically assumed to fall into the optically thin and optically thick areas are actually intermediate media. Classically, offset... 

High impact polystyrene plastics with a higher impact strength than general purpose polystyrene due to the presence of a modifier, such as rubber. 

Toughened or rubber modified polystyrene blends are prepared by incorporating up to 10 percent by weight of poly butadiene or styrene-butadiene copolymer rubbers into the resin. The dispersed rubber particles decrease the plastic s brittleness by interrupting the crack propagation process. Unlike the unblended polymer, rubber modified polystyrene is translucent. The volume of rubber modified polystyrene made is roughly the same as that of general purpose polystyrene. 

The nylons have found steadily increasing application as plastics materials for speciality purposes where their toughness, rigidity, abrasion resistance, good hydrocarbon resistance and reasonable heat resistance are important. Because of their high cost they have not become general purpose materials such as polyethylene and polystyrene, which are about a third of the price of the nylons. 

In Japan, the production of polystyrene (PS) is fairly high for example, 115 00001 were produced in 1999, involving one of the four major general-purpose type resins. It has been reported that some kinds of styrene oligomers, which are by-products of polymerization, remained in PS products [1]. In the Wingspread statement announced by Colborn et al. in 1996, it was reported that certain synthetic chemicals have endocrine-disrupting effects on humans or animals. Most of these chemicals are pesticides, but styrene dimers (SDs) and trimers (STs) are listed in this statement along with plasticizers and antioxidants [2]. 

Styrene is produced by the alkylation of benzene with ethylene followed by catalytic dehydrogenation. It is used in the manufacture of general-purpose and high-impact polystyrene plastics ( 50%), expanded polystyrene ( 7%), copolymer resins with acrylonitrile and butadiene ( 7%) or acrylonitrile only ( 1%), styrene-butadiene latex ( 6%) and synthetic rubber ( 5%), unsaturated polyester resins ( 6%), and as a chemical intermediate. 

The general purpose thermoplastics introduced in the 1930 s and 1940 s were readily fabricated by extrusion and injection molding techniques. Thermoplastics, such as polyvinyl chloride, polystyrene and polyethylene were resistant to mineral acids at temperatures up to 60OC but they could not be used at higher temperatures, such as that of boiling water. These large volume plastics had other characteristic deficiencies which were overcome by the use of additives. 

The brittleness of polyvinyl chloride and polystyrene was decreased by blending with plasticizers or impact modifying polymers. The flammability of polystyrene and polyolefins was decreased by the addition of flame retardants and the Instability of polyvinyl chloride and polypropylene was reduced by the addition of stabilizers. — The strength and heat resistance of all of the general purpose plastics were Improved by reinforcing with fiberglass or graphite fibers. 

The heat resistance of polyvinyl chloride was also improved by post chlorination, the ductility of polyethylene was Improved by increasing the molecular weight and the usefulness of polystyrene was Increased by copolymerization with acrylonitrile. Nevertheless, in spite of improvement in performance, resulting from these modifications, most general purpose plastics were under engineered for many applications. 

Had these and other basic relationships of composition and chain configuration to polymer properties been well understood fifty years ago, we could visualize a polymer chemist of that day—a day when Bakelite was well known but polystyrene and poly(vinyl chloride) (PVC) were novelties—setting out deliberately to design and synthesize a new high-utility, general-purpose, low-cost plastic with the aid of these principles. 

Styron. [Dow Plastics] Polystyrene general-purpose, impact, and structural foam resins. 

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