Consumption of polystyrene

Expanded polystyrene accounts for over 20% of the weight consumption of polystyrene and high-impact polystyrene. The volume of expanded material produced annually exceeds even the volume production of the aliphatic polyolefins. 

Thermoplastics. The highest consumption of color concentrates is in thermoplastic resins, such as low and high density polyethylene, polypropylene, PVC, and polystyrene. Processing techniques for thermoplastics are usually based on dry color dispersion in a compatible resin (36). 

The oxidative coupling of 2,6-dimethylphenol to yield poly(phenylene oxide) represents 90—95% of the consumption of 2,6-dimethylphenol (68). The oxidation with air is catalyzed by a copper—amine complex. The poly(phenylene oxide) derived from 2,6-dimethylphenol is blended with other polymers, primarily high impact polystyrene, and the resulting alloy is widely used in housings for business machines, electronic equipment and in the manufacture of automobiles (see Polyethers, aromatic). A minor use of 2,6-dimethylphenol involves its oxidative coupling to... 

In 1990, the annual U.S. capacity to manufacture styrene monomer was 4,273,000 t/yr, and production was 3,636,000 t/yr (11). Polystyrene resin is the dominant user of styrene monomer. SBR use is about 7% of U.S. domestic styrene monomer production. Woddwide production in 1995 was projected to be 77% of capacity as demand increased just under 5% per year, from 1990 consumption of 13,771,000 to 17,000,000 metric tons in 1995. 

Styrene—butadiene elastomers, emulsion and solution types combined, are reported to be the largest-volume synthetic mbber, with 28.7% of the world consumption of all synthetic mbber in 1994 (38). This percentage has decreased steadily since 1973 when SBR s market share was 57% (39). The decline has been attributed to the switch to radial tires (longer milage) and the growth of other synthetic polymers, such as polyethylene, polypropylene, polyester, and polystyrene. Since 1985, production of SBR has been flat (Table 3). 

Benzene is alkylated with ethylene to produce ethylbenzene, which is then dehydrogenated to styrene, the most important chemical iatermediate derived from benzene. Styrene is a raw material for the production of polystyrene and styrene copolymers such as ABS and SAN. Ethylbenzene accounted for nearly 52% of benzene consumption ia 1988. 

CE has been used for the analysis of anionic surfactants [946,947] and can be considered as complementary to HPLC for the analysis of cationic surfactants with advantages of minimal solvent consumption, higher efficiency, easy cleaning and inexpensive replacement of columns and the ability of fast method development by changing the electrolyte composition. Also the separation of polystyrene sulfonates with polymeric additives by CE has been reported [948]. Moreover, CE has also been used for the analysis of polymeric water treatment additives, such as acrylic acid copolymer flocculants, phosphonates, low-MW acids and inorganic anions. The technique provides for analyst time-savings and has lower detection limits and improved quantification for determination of anionic polymers, compared to HPLC. 

Polystyrene will in the coming years have to show that it can master this situation by further process rationalization and the development of even more sophisticated products. In spite of unfavorable cost trends, polystyrene has up to now continued its march. Production and sales have risen steadily - except for a brief decline in 1975 - and for 1980 we are expecting, in spite of the second price explosion in 1979, a doubling of 1970 sales in the western world to 4.2 million tons. If the estimated 1980 consumption of ABS/SAN polymers and EPS is added to this figure, an amount of 6.1 million tons of styrene polymers is obtained. 

Depending on the region, the consumption of expandable polystyrene is 15-30% of the polystyrene total. 

The polydispersity of polymers prepared in this way is usually very low for example, a value MJM of 1.05 was found for a sample of poly(a-methylsty-rene). Living polymers can also be used for the preparation of block copolymers after the consumption of the first monomer, a second anionically polymerizable monomer is added which then grows onto both ends of the initially formed block. By termination of the living polymer with electrophilic compounds the polymer chains can be provided with specific end groups for example, living polystyrene reacts with carbon dioxide to give polystyrene with carboxylic end groups. 

The demethanative coupling appears to be a step polymerization, as initial consumption of the germane monomer produces oligogermanes within the first few minutes, followed by further condensation to high polymer within hours at 25°C. Molecular weights of the permethylpolyger-mane (GPC, polystyrene calibration) range from Mn 1-4 X 104 and... 

This work was motivated by the need to quantify the pentane vapor diffusion through closed-cell polystyrene foam (Salejova et al., 2005). Once the polystyrene foam is formed, the pentane as the blowing agent has to diffuse out from the cellular microstructure and is replaced by air. Freshly foamed polystyrene is not dimensionally stable and it shrinks as it relaxes on the timescale of days to weeks. Environmental concerns call for the reduced consumption of pentane as the blowing agent. 

K7. Kvarstein, N., Oxygen consumption during the initial stage of human leucocyte phagocytosis of polystyrene latex particles, Scand. J. Clin. Lab. Invest. 25, 337-348 (1970). 

Plastics and rubber are essential materials in today s industrialized societies. The consumption of plastics has grown by a factor of about 60 in the past 30 years, which has led to a corresponding increase in the generation of plastic wastes. One of the most valuable properties of plastics, their low density, is one of the major limitations in the recycling of plastic wastes. Thus, to recover one tonne of plastics it is necessary to collect about 20 000 plastic bottles. Plastic wastes are mainly found in municipal solid wastes (MSW). As a consequence of their low density, plastics account for just 8 wt% of the MSW, but this value increases to over 20% in volume terms. In spite of the great diversity of plastic materials, plastic wastes are made up of a relatively small number of polymers polyethylene, polypropylene, polystyrene, polyvinyl chloride and polyethylene terephthalate. These resins account for more than 90% of total plastic wastes. 

The discovery of living cationic polymerization has provided methods and technology for the synthesis of useful block copolymers, especially those based on elastomeric polyisobutylene (Kennedy and Puskas, 2004). It is noteworthy that isobutylene can only be polymerized by a cationic mechanism. One of the most useful thermoplastic elastomers prepared by cationic polymerization is the polystyrene-f -polyisobutylene-(>-polystyrene (SIBS) triblock copolymer. This polymer imbibed with anti-inflammatory dmgs was one of the first polymers used to coat metal stents as a treatment for blocked arteries (Sipos et al., 2005). The SIBS polymers possess an oxidatively stable, elastomeric polyisobutylene center block and exhibit the critical enabling properties for this application including processing, vascular compatibility, and biostability (Faust, 2012). As illustrated below, SIBS polymers can be prepared by sequential monomer addition using a difunctional initiator with titanium tetrachloride in a mixed solvent (methylene chloride/methylcyclohexane) at low temperature (-70 to -90°C) in the presence of a proton trap (2,6-dt-f-butylpyridine). To prevent formation of coupled products formed by intermolecular alkylation, the polymerization is terminated prior to complete consumption of styrene. These SIBS polymers exhibit tensile properties essentially the same as those of... 

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