Polystyrene derivs homopolymer

The homopolymers of styrene and acrylonitrile were not soluble In the acetonitrile mobile phase. Calibration factors thus had to be derived from a combination of literature data and experimental measurements. To calibrate the UV detector for polystyrene, 254 nm absorbance of both monomer and polymer was measured with a conventional spectrophotometer, using chloroform... 

Based on this approach Schouten et al. [254] attached a silane-functionalized styrene derivative (4-trichlorosilylstyrene) on colloidal silica as well as on flat glass substrates and silicon wafers and added a five-fold excess BuLi to create the active surface sites for LASIP in toluene as the solvent. With THF as the reaction medium, the BuLi was found to react not only with the vinyl groups of the styrene derivative but also with the siloxane groups of the substrate. It was found that even under optimized reaction conditions, LASIP from silica and especially from flat surfaces could not be performed in a reproducible manner. Free silanol groups at the surface as well as the ever-present impurities adsorbed on silica, impaired the anionic polymerization. However, living anionic polymerization behavior was found and the polymer load increased linearly with the polymerization time. Polystyrene homopolymer brushes as well as block copolymers of poly(styrene-f)lock-MMA) and poly(styrene-block-isoprene) could be prepared. 

It is particularly important for certain mechanical vulcanizate properties, as stress relaxation, creep and compression set, that all the polymer molec in the vulcanizate should become bound into molecular networks of inc nite size during the vulcanization process. The results of Shundo et al. [ shown in Figure 15.7, demonstrate clearly that much more polymeric n" rial can be extracted by suitable oiganic solvents from vulcanizates der from polystyrene-polybutadiene blends than from vulcanizates derived from copolymers. These results indicate clearly the presence of non-network-bo polymer in the vulcanizates derived from the homopolymer blends. 

Most thermoplastics begin with poly and then this term, which means many is followed by the old fashioned name for the monomer from which the plastic is derived i.e the name is source-based. Because of this practice we get names such as polystyrene and polyethylene for homopolymers. When the plastics material has more than one word in the name, parentheses, or brackets, may be put around the words so that we get poly (vinyl chloride). However this practice is not universal and so we also meet the same term without the brackets i.e. polyvinyl chloride. Source-based nomenclature is not however, universally used and so names such as acetals and cellulosics are also encountered. Other, more logical systems of nomenclature have been proposed but as yet, they have not been adopted,... 

As for the other methods mentioned above, NMP and ATRP living polymerizations of NIPAM have also been reported very recently. NMP has been carried out with initiator 6 (Fig. 3), cK-hydrogen alkoxyamine derivatives, instead of the TEMPO-based systems [53-55]. Although the living polymerization behavior has not been reported in detail, the synthesis of homopolymer of NIPAM with a narrow MWD, its block copolymers with polystyrene (PS) [53], and well-controlled star block copolymers having PNIPAM and PS segments was achieved by Hawker and Fr6chet et al. [54]. On the other hand, the successful ATRP of NIPAM has been reported by Masci et al. [56] and StOver et al. [57]. In each case, alkyl 2-chloropropionate (7), copper(I)... 

Polybutadiene Derivatives. Copolymers of butadiene are economically more important than the homopolymer. Polybutadiene is used to prepare high-impact polystyrene (HIPS) and ABS. These materials are described in Section 15.4.2, which is devoted to styrene copolymers. 

Polystyrene is one of the most common commercial polymers. Its basic properties can be modulated by copolymerization and by the varied presentations of its semi-finished products. The level of its annual world production and that of its derivatives exceeds 18 million tons, and its growth rate remains high. From a scientific point of view, polystyrene homopolymer is regarded as the reference polymer by physicists as well as by chemists and physical chemists. Thus it was comprehensively studied, and its properties are particularly well known. 

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