| 摘要 |
Homo- or co-polymers of olefinic compounds are prepared by conducting the polymerization in a redox-type aqueous emulsion system at a temperature between 0 and 35 DEG C. employing diisopropylbenzene dihydroperoxide in quantity sufficient to act both as an oxidizing agent and as the sole chain terminating agent, thereby producing polymers containing terminal hydroperoxy groups. Olefinic compounds specified are butadiene, 2,3-dimethyl butadiene, isoprene, piperylene, 2-chlorobutadiene, 2-bromobutadiene, vinyl acetate, methyl vinyl and isopropenyl ketones, methyl vinyl ether, styrene, chlorostyrene, alpha-methyl styrene, alkyl styrenes, vinyl naphthalene, methyl and ethyl acrylates, methyl methacrylate, acrylonitrile, methacrylonitrile, methacrylamide, vinyl and vinylidene chlorides and vinyl pyridine and mixtures thereof, e.g. mixtures of butadiene and styrene, chlorostyrene, alpha-methyl styrene, methyl methacrylate, acrylonitrile, acrylamide and vinyl pyridine, and a mixture of isoprene and styrene. As reducing component for the redox catalyst system there is specified ferrous sulphate. The aqueous medium may also contain potassium fatty acid soap or dodecylamine hydrochloride as an emulsifier and potassium pyrophosphate as a sequestering agent. The catalyst components may be added portionwise during the course of the reaction. The polymers containing terminal hydroperoxy groups may be used to initiate the polymerization of unsaturated monomers of the types specified above, thereby producing block copolymers. Such second stage polymerizations are preferably carried out in solution in a solvent such as benzene. The preparation of block copolymers is described in Examples XXIV to XXX. Specification 785,169 is referred to.
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