GB821000A - Block and graft copolymerisation - Google Patents

Abstract

Grafts or block copolymers are made by polymerizing an ethylenically unsaturated monomer in the presence of a polymer containing mercapto groups but free of groups inhibiting radical type polymerization, graft polymers being formed when the mercapto groups are distributed along the polymer chain and block polymers when the polymer contains mercapto end groups. Monomers specified are methyl, ethyl, butyl, isobutyl, octyl, dodecyl, ethoxymethyl and chlorethyl acrylates, methacrylates and chloracrylates, acrylonitrile, methacrylonitrile, vinyl and vinylidene fluorides and chlorides, vinyl acetate, chloroacetate and propionate, styrene and vinyl naphthalene. Polymerization is assisted by catalysts such as acetyl, benzoyl, benzoyl acetyl, dibutyryl, di-(tert.-butyl) and succinyl peroxides, tert.-butyl hydroperoxide, potassium persulphate and listed azo compounds. In Examples (1) a styreneglycidyl methacrylate copolymer is reacted with mercaptopropionic acid and ethyl acrylate is then graft polymerized on to the resulting polymer with the aid of azodiisobutyronitrile, (2) methyl methacrylate is graft polymerized as in (1), (3) styrene is bulk polymerized in the presence of mercaptopropionic acid, the resulting carboxyl end groups are reacted with thionyl chloride and then with mercaptoethanol to produce a polymer containing mercapto end groups which is block copolymerized with ethyl acrylate in the presence of azo diisobutyronitrile, (4) the acid groups of a methyl methacrylateacrylic acid copolymer are converted to acid chloride groups which are reacted with mercaptoethanol, methyl methacrylate is graft polymerized on to the resulting polymer with the aid of azodiisobutyronitrile.