GB814393A - Improvements in and relating to thermoplastic graft polymers - Google Patents

Abstract

Graft polymers of polyethylene are made by forming and reacting together in the liquid state under polymerizing conditions a mixture of an ethylene homopolymer and a polymerizable monoethylenically unsaturated monomer of molecular weight above 28 in the presence of a polymerization catalyst. The polymerization may be effected in bulk or both the monomer and polymer may be dissolved in an inert organic volatile solvent such as benzene, toluene, or xylene. The monomer may be added portionwise. The crude reaction product is generally a mixture of polyethylene, the homopolymer of the monomer, and the graft polymer. If desired, the graft polymer can be isolated by dissolving from the product the two homopolymers. Suitable monomers are vinyl formate, acetate, propionate, butyrate, octoate, stearate, benzoate, or chloroacetate, methyl, ethyl, butyl, octyl acrylate or methacrylate, acrylamide, Nmethyl acrylamide, N-tert.-butyl acrylamide, N,N-dimethyl acrylamide, methacrylamide, Nmethyl methacrylamide, vinyl chloride, bromide, or fluoride, vinylidene chloride, bromide, fluoride, or cyanide, styrene, methyl, ethyl, methoxy or chlorostyrene, 2,5-dichlorostyrene, acrylonitrile, methacrylonitrile, vinyl carbazole, or vinylene carbonate. Catalysts mentioned are benzoyl, acetyl, and lauryl peroxides, cyclohexyl hydroperoxide, di-tert.-butyl peroxide, and alpha, alpha-azobis-isobutyronitrile. The graft copolymers may be plasticised and stabilized against heat and light by incorporating in the polymer small amounts of stabilizers and/or plasticizers such as phosphoric acid, dioctyl or tri-butyl phosphate, para-toluene sulphonic acid, dioctyl tin maleate, monochlorofumaric acid, tetrachlorophthalic anhydride, phosphorous pentoxide, phthalimide, dodecyl mercaptan or triphenyl methane. The graft polymer may be heat-formed into films, threads, tubes, rods, sheets, tapes, ribbons, or used as waterproofing and electrical insulating agents. Laminates can be made by uniting aluminium foil or sheets of regenerated cellulose with films made of the graft copolymer.