| 摘要 |
<p>In a process for the manufacture of graft-copolymers, a monomer containing a vinyl or vinylidene group is graft-polymerized on to a trunk polymer or copolymer comprising units of a monomer containing at least one halogen atom that is activated by an ester or a phenyl group, in the presence of a free radical polymerization catalyst and under the action of ultra-violet light or high energy ionizing radiation. The trunk polymer may be derived from an ester of a -bromoacrylic acid, a vinyl ester of a bromo- or dibrom-butyric acid or bromoacetic acid, p-bromostyrene or diethyl bromomaleate or bromofumarate, optionally together with vinyl, acrylic, methacrylic or maleic esters, vinyl aromatic compounds, acrylonitrile, vinyl chloride, vinylidene chloride or butadiene. The grafted monomer may comprise a styrene derivative, a vinyl aromatic compound, a vinyl ester or ether, or vinylidene chloride; and may comprise a monomer of similar structure to a comonomer of the trunk copolymer. Alternatively the trunk polymer may be obtained by transfer reaction between a halogenated hydrocarbon and the growing chain in a free radical polymerization. The graft monomers may be prepolymerized by bulk, emulsion, suspension or solution polymerization prior to grafting and the graft monomer or prepolymer may be grafted in bulk, emulsion, suspension or solution. The heat distortion of polyvinyl chloride may be improved by grafting methyl methacrylate or cyclohexyl acrylate on a vinyl chloride copolymer, and the impact strength of polystyrene can be improved by grafting styrene on a styrene/vinyl naphthalene/ p-bromostyrene copolymer. Examples describe the grafting of (1) vinyl chloride on a butyl acrylate/butyl a - bromoacrylate / vinylidene chloride copolymer, (2) methyl methacrylate on a vinyl chloride/allyl p-bromobenzoate copolymer, (3) styrene on a styrene/vinyl naphthalene/ p-bromostyrene copolymer, and vinyl chloride on a vinyl chloride/butyl acrylate/allyl a ,b -dibromobutyrate.</p> |
