Polystyrenes , polymer

Other apphcations of sodium bromide iaclude use ia the photographic iadustry both to make light-sensitive silver bromide [7785-23-1] emulsions and to lower the solubiUty of silver bromides during the developing process use as a wood (qv) preservative in conjunction with hydrogen peroxide (14) as a cocatalyst along with cobalt acetate [917-69-1] for the partial oxidation of alkyl side chains on polystyrene polymers (15) and as a sedative, hypnotic, and anticonvulsant. The FDA has, however, indicated that sodium bromide is ineffective as an over-the-counter sleeping aid for which it has been utilized (16). 

In these mbber-modified polystyrene polymers, the mbbers should have low T, large particle sizes (0.5—5 J.m), graftable and cross-linkable sites, and should be compatible with styrene monomer (93). Polybutadiene, with a T of —SS C, meets all of these requirements and is used most frequently. These mbber-modified systems exhibit excellent low temperature impact strength, a required attribute for use in refrigerators. 

Requirements for heat- and cold-curing denture-base resins prepared from powder—liquids, gels, preopolymerized blanks, and fluid resins composed of acryflc, vinyl, and polystyrene polymers are given in ANSI/ADA specification no. 12 for denture-base polymers. 

The use of an acidic solution of p-anisaldehyde in ethanol to detect aldehyde functionalities on polystyrene polymer supports has been reported (beads are treated with a freshly made solution of p-anisaldehyde (2.55 mL), ethanol (88 mL), sulfuric acid (9 mL), acetic acid (1 mL) and heated at 110°C for 4 min). The colour of the beads depends on the percentage of CHO content such that at 0% of CHO groups, the beads are colourless, -50% CHO content, the beads appear red and at 98% CHO the beads appear burgundy [Vdzquez and Albericio Tetrahedron Lett 42 6691 200]]. A different approach utilises 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (Purpald) as the visualizing agent for CHO groups. Resins containing aldehyde functionalities turn dark brown to purple after a 5 min reaction followed by a 10 minute air oxidation [Coumoyer et al. J Comb Chem 4 120 2002]. 

Transparent toughened polystyrene polymers are produced by blending polystyrene with SBS block copolymers (see Section 11.8). During the 1970s and 1980s most development was with block copolymers with a radial (or star) shape. Two types were developed block copolymers with a central butadiene block, and block copolymers with a central polystyrene block. 

Another important and growing market for plastics is the automotive field. Many automobile parts are now made of plastics. Among the most used polymers are polystyrene polymers and copolymers, polypropylene, polycarbonates, and polyvinyl chloride. These materials reduce the cost and the weight of the cars. As a result, gasoline consumption is also reduced. 

World polystyrene production in 1997 was approximately 10 million tons. The demand is forecasted to reach 13 million tons by 2002. The 1997 U.S. production of polystyrene polymers and copolymers was approximately 6.6 billion pounds. ABS, SAN, and other styrene copolymers were approximately 3 billion pounds for the same year. 

Q A Boc-protected amino acid is covalently linked to the polystyrene polymer by formation of an ester bond (Sn2 reaction). 

Dinitropolystyrene. An expl weaker than DNT (Ref 2). Prepd from the polystyrene polymer by nitration. It is not possible to prepare the expl by nitration of styrene followed by polymerization (Ref 4)... 

Mallikarjun, R. and Nauman, E. B., A staged multitubular process for crystal polystyrene, Polym. Process Eng., 4, 31-51 (1986). 

Puskas, J.E. Biomacromolecular engineering Design, S3mthesis and characterization. One-pot synthesis of block copolymers of arborescent polyisobutylene and polystyrene, Polym. Adv. TechnoL, 7, 1, 2006. 

The molecular weight distribution (MWD) of the linear polyurethanes were determined by GPC. The solvent used was THF and the instrument calibrated by narrow MWD polystyrenes. Polymer BPUla... 

We can divide commodity plastics into two classes excellent and moderate insulators. Polymers that have negligible polar character, typically those containing only carbon-carbon and carbon-hydrogen bonds, fall into the first class. This group includes polyethylene, polypropylene, and polystyrene. Polymers made from polar monomers are typically modest insulators, due to the interaction of their dipoles with electrical fields. We can further divide moderate insulators into those that have dipoles that involve backbone atoms, such as polyvinyl chloride and polyamides, and those with polar bonds remote from the backbone, such as poly(methyl methacrylate) and poly(vinyl acetate). Dipoles involving backbone atoms are less susceptible to alignment with an electrical field than those remote from the backbone. 

Figure 3.2. Chiral phosphine-phosphite ligands on a highly cross-linked polystyrene polymer...

Guerra, G. Mensitieri, G. Venditto, V., Method for the detection of organic pollutants using syndiotactic polystyrene polymers as sensing elements, US Patent 20020073764 2002... 

The absolute number of monomer units of the polystyrene (m) and polybutadiene (n) blocks were determined by combined H-NMR and GPC measurements. The triblock copolymer is a commercially available polystyrene-b-polybutadiene-i-polystyrene polymer and was purchased from Aldrich (M = 100,000 28 wt% polystyrene). 

As polymerization proceeds, the total volume of polystyrene polymer particles increases rapidly at the expense of the styrene monomer from the solution. What happens next depends on several factors, mainly composition and stirring. It was found that for SIN formulations having an elastomer content greater than about 15%, no further changes occur and elastomer material will remain the continuous phase, regardless of the extent of agitation. 

However, for SIN s having up to 10-15% elastomer content, it was found that stirring induces significant changes in the morphology of the mixture. If stirring is not provided, the polystyrene polymer particles will sink and coalesce giving rise to a twolayered system. 

V. Bojinov and T. Konstantinova, On the possibility of one-step colouration and stabilization of polystyrene. Polym. Degr. Stab., 68 (2000) 295-298. 

Fig. 15. Comparison of the measured and predicted exit concentrations obtained by Todd for a polystyrene polymer containing ethylbenzene as the volatile component. Data were obtained in a twin-screw extruder. From Todd (1974).

A study of methods for controlling the grafting sites of polystyrene polymers may serve as an example for the quantitative and structural analysis of the site of lithiation. Trimethylsilyl chloride serves as the quenching agent owing to the low incidence of side reactions besides metal replacement. Thus, on varying the conditions of metallation of low molecular weight polystyrene (409) and poly(4-methylstyrene) (410), aromatic and... 

Mainz, Germany, 4th-5th Nov.1997, p.87-115. 6124 NEW POLYETHYLENE AND POLYSTYRENE POLYMERS FOR FOAM APPLICATIONS Kelusky E C Nova Chemicals Ltd. 

It was indicated earlier that swelling limits resolution in solvent-developed negative resists. It was also intimated that swelling effects could be minimized if there were a sufficient polarity change between the exposed and non-exposed areas of the type mentioned in the previous discussion of the PBOCST system. A similar principle was utilized by Hofer et al., (145-146) at IBM, based on ion pair formation. The resist consists of a polystyrene polymer to which tetrathiofulvalene (TTF) units have been attached. When spun down with an acceptor such as CBr4, a complex is formed which, on irradiation, undergoes an electron transfer reaction to form an ion pair ... 

Nemoto,N. Viscoelastic properties of narrow-distribution polymers. II. Tensile creep studies of polystyrene. Polymer J. (Japan) 1,485-492 (1970). 

T., 1. Xue and C. A Wilkie, Graft copolymerization of acrylonitrile onto polystyrene,./. Polym. Sci. Part... 

Bhattacharyya, D. N., C. L. Lee, J. Smid, and M. Szwarc The absolute rate constants of anionic propagation by free ions and ion pairs of living polystyrene. Polymer 5, 54 (1964). 

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