Polystyrene-graft-polyacrylic

Similar grafting experiments by the emulsion technique were described (34) in the system vinyl chloride/copolymer butyl methacrylate-methacrylic acid and in the reverse system, and also in the system styrene/polyvinyl chloride. In this last case again as in homogenous medium, the inverse process failed (vinyl chloride on polystyrene). Grafted acrylonitrile copolymers were also prepared in order to improve their dyeability, by polymerizing acrylonitrile in emulsion in the presence of many different polymers as polyvinyl alcohol, polymethacrylamide and polyvinylpyrrolidone (119, 120, 121), polyvinyl acetate and polyacrylic acid (115), wool (224,225), proteins (136), etc. 

A large variety of polymers has been considered. In the beginning, polystyrene and styrene/ divinylbenzene copolymers (Merrifield resins) were by far the most used.73 Then others were tested such as polyvinyls,47-50,61-64 polyacrylates,72 4,75 and cellulose.76,77 Most commonly, diphenylphos-phane groups were grafted on the polymeric support, either directly or via one CH2 group. 

Barrere and Landfester [184] prepared a hybrid miniemulsion in which isophorone diisocyanate was condensation polymerized with dodecanediol to form polyurethane at the same time that the polystyrene or polyBA was free radical polymerized. Unlike previous work, the polyurethane was not prepared in organic solvent in advance. Therefore, in this one-pot synthesis, polyaddition and free radical polymerization both take place in the same particle. HD was used as the costabihzer. After miniemulsification, the polycondensation was allowed to take place, and then a free radical initiator was added to polymerize the styrenic or acrylic monomer. Molecular weight distributions were bimodal the PU had a substantially lower molecular weight than the polyacrylate. Neither intra- nor interparticle phase separation could be detected by TEM the particles appeared to be homogeneous. No measurements of grafting were made, but since there was no unsaturation in the PU, none was expected. 

The earliest work of this kind appears to have been the grafting of polyacrylic acid to cellophane films [2] although many years earlier ion exchange membranes were prepared by grafting polystyrene to teflon and polyethylene followed by sulfo-nation [3]. Later a number of commercial ion exchange membranes were studied for the removal of sodium chloride and other salts from water by a reverse osmosis... 

The most important example of graft eopolymers having polystyrene sidearms is high-impaet polystyrene (HIPS), in whieh polystyrene is the continuous phase and polybutadiene grafted with polystyrene forms the separated phase. Grafting occurs when some of the radicals react with the double bonds in polybutadiene [182-186], Grafting is also possible onto poly(ethene-co-propene-co-butadiene) [187] and polyacrylic ester [188], High-impact polystyrene is reviewed in detail in Ref. [189]. 

ESR spectroscopy has been applied to studies of unsaturation and other structural features in a wide range of homopolymers including polyethylene [101-110], polypropylene [111-121], polybutenes [115], polystyrene [122-124], PVC [125,126], polyvinylidene chloride [127], polymethylmethacrylate [128-137], polyethylene glycol polycarbonates [137-140], polyacrylic acid [136-139, 141, 142], polyphenylenes [143], polyphenylene oxides [143], polybutadiene [144], conjugated dienes [145,146], polyester resins [146], cellophane [143,147] and also to various copolymers including styrene grafted polypropylene [148], ethylene-acroline [149], butadiene-isobutylene [150], vinyl acetate copolymers [151] and vinyl chloride-propylene. 

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