Rubber-modified Polystyrene

STYRENE. Styrene, CgH5CH=CH2, is the simplest and by far the most important member of a series of aromatic monomers. Also known commercially as styrene monomer (SM). styrene is produced in large quantities for polymerization. It is a versatile monomer extensively used for the manufacture of plastics, including crystalline polystyrene, rubber-modified impact polystyrene, expandable polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile resins (SAN), styrene-butadiene latex, styrene-butadiene rubber (SBR). and unsaturated polyester resins. See also Acrylonitrile Polymers. 

Year General Purpose Polystyrene Rubber- Modified Polystyrene san ABS = Total... 

Toughened polystyrene rubber modified polystyrene rubber toughened polystyrene. 

Compared to straight polystyrene, rubber-modified polystyrenes have much improved impact strength, but they have reduced clarity, softening point and tensile strength. (See Table 3.1.)... 

ABS/polycarbonate alloy Acrylic Butadiene-styrene Phenykne-oxide based resins Polycarbonate Pblyetherimide Polyethersulfone Polystyrene general purpose) Polystyrene (rubber modified) Poiysulfbne... 

Because of such desirable characteristics as low cost, good mouldability, excellent colour range, transparency, rigidity and low water absorption, polystyrene became rapidly developed. For many purposes, however, it was considered to be unacceptably brittle and this led to the development of the rubber-modified high-impact polystyrene (HIPS) and to the complex ABS, AMBS and... 

In the late 1940s, the demand for styrene homopolymers (PS) and styrene-acrylonitrile copolymers (SAN) was drastically reduced due to their inherent brittleness. Thus, the interest was shifted to multiphase high-impact polystyrene (HIPS) and rubber-modified SAN (ABS). In principle, both HIPS and ABS can be manufactured by either bulk or emulsion techniques. However, in actual practice, HIPS is made only by the bulk process, whereas ABS is produced by both methods [132,133]. 

General Considerations. Continuous mass processes for polystyrene have been in commercial use since the 1930 s, and for rubber-modified polystyrene (HIPS) since the 1950 s. Much of the information on equipment design, process configuration and operating parameters connected with continuous processes is found in the patent literature. There are inherent limitations to such sources. Recognizing this, we will provide... 

For simplicity it will be assumed the plant will be located in the United States. The 1969 American sources of styrene are given in Table 2E-1 The 1969 uses for this styrene are given in Table 2E-2. It should be noted that over 50% of the styrene produced is used to make straight and rubber-modified polystyrene. The capacities and locations of the main polystyrene producers are given in Table 2E-3. With the exception of Midland, Mich. Kobuta, Pa. Torrence, Calif. and Penuelas, Puerto Rico, all the styrene is produced in the Gulf Coast states of Louisiana and Texas. At Midland, Dow Chemical uses nearly all the styrene internally. The same is true of Sinclair-Koppers at Kobuta. The capacity of the Shell plant in California is pres-... 

Transition from liquid behavior to solid behavior has been reported with fine particle suspensions with increased filler content in both Newtonian and non-Newtonian liquids. Industrially important classes are rubber-modified polymer melts (small rubber particles embedded in a polymer melt), e.g. ABS (acrylo-nitrile-butadiene-styrene) or HIPS (high-impact polystyrene) and fiber-reinforced polymers. Another interesting suspension is present in plasticized polyvinylchloride (PVC) at low temperatures, when suspended PVC particles are formed in the melt [96], The transition becomes evident in the following... 

The preferred morphology of these rubber modified amorphous thermoplastics is the distribution of distinct rubber particles unfilled or filled in an isotropic matrix of the basic polymer. This was shown to be the case for rubber modified polystyrene and for ABS-type polymers. 

Figure 1. Morphology of rubber modified high impact polystyrene.

SB for butadiene rubber-modified polystyrene or HIPS (high-impact polystyrene)... 

The absorption of butane into polystyrene proceeds more rapidly than pentane or hexane. Thus, the addition of the required amount (7% ), plus an excess only for air-purging, to polystyrene (or to rubber-modified polystyrene) particles in a sealed container provides useful expandable polystyrene after agitation for 24 hours at room temperature (27). If the butane is mixed with a noncombustible gas of lower density, the explosion hazard is avoided (50). 

Molded Objects Immersed in Liquids. Molded, non-foamed articles, such as drinking cups from rubber-modified polystyrene, are immersed... 

Filled Graft Rubber as the Disperse Phase. Rubber-modified polystyrene is generally obtained by polymerization grafting of a rubber in the presence of styrene monomer. The polymerization is carried out totally or partially in mass with the aid of shearing agitation, as patented by Amos et al. (1). The study on the initial stage of this type of polymerization was first published by Bender (5), and phase inversion similar to that discovered for the two-phase pressure-sensitive adhesives was observed. The mechanism of particle formation has also been reviewed (47). 

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