Polystyrene/halogenated polybutadiene

For (b), a block copolymer, in which one side of the block has affinity to the solvent and the other block to the polymer particle, is the most reasonable stabilizer. Block copolymers of polystyrene/halogenated polybutadiene, polystyrene/ polyethyleneglycol, and polystyrene/PDMS are examples of this type of stabilizer (12). When using a block copolymer, it is possible to provide appropriate amphiphilic and other surface properties by changing the block ratio. For example, when using a block copolymer of polystyrene/PDMS for polymerization of methyl methacrylate in hexane, the ratio of polystyrene/polydimehtylsiloxane should be below 4.4 (13). If the ratio is above 4.4, the block copolymer forms a stable micelle and will not function properly as a stabilizer. 

Berlin and coworkers (5,56) desired to obtain a material with an increased mechanical strength. They carried out a plasticization of bulk ami emulsion polystyrene molecular weight 80000 and 200000 respectively at 150-160° C, with polyisobutylene, butyl rubber, polychloroprene, polybutadiene, styrene rubber (SKS-30) and nitrile rubber (SKN 18 and SKN 40). The best results were obtained with the blends polystyrene-styrene rubber and polystyrene-nitrile rubber. An increase of rubber content above 20-25% was not useful, as the strength properties were lowered. An increase in the content of the polar comonomer, acrylonitrile, prevents the reaction with polystyrene and decreases the probability of macroradical combination. This feature lowers the strength, see Fig. 14. It was also observed that certain dyes acts as macroradical acceptors, due to the mobile atoms of hydrogen of halogens in the dye, AX ... 

These results indicate that if polydienes and similar polymers can be prepared quantitatively with tertiary amine terminal groups, then they can be combined with other halogen functional polymers using established techniques to create interesting new block copolymer systems. For example, consider the reaction between telechelic pyridine terminated polybutadiene and monofunctional bromine terminated polystyrene (equation 4) -the latter has been prepared in 95% yield. >it The product would be an ABA... 

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