Synthesis of graft polymers and block-copolymers of acrylic and methacrylic monomers by a “living” radical polymerization

Abstract

It was shown that in the presence of a complex-forming agent— o-phosphoric acid radical graft polymerization of methyl metahacrylate or methyl- α-chloracrylate on a γ-irradiated cellophane film takes place by a mechanism of “living” chains. At the initial stage of the reaction with a practically constant number of graft chains under given conditions graft polymer yield and the molecular weight of graft chains increases in direct proportion to the time of contact of a γ-irradiated film with the reaction system. A study was made of the dependence of graft polymer yield, molecular weight and the number of PMMA graft chains, on the composition of the H 3PO 4-MMA system. The rate constant of chain propagation was evaluated when carrying out graft post-polymerization of MMA on a γ-irradiated cellophane film. It was shown that the existence of “live” chains in the grafting of methyl methacrylate and methyl- α-chloracrylate in the presence of H 3PO 4 on to γ-irradiated cellophane film enables graft block-copolymers and graft tri-block copolymers of these monomers to be obtained with control of the molecular composition and the length of each unit. The block structure of individual graft chains was confirmed by turbidimetric titration. Block-copolymers of methyl methacrylate and methyl- α-chloracrylate practically free from homopolymers were obtained by hydrolysis of this modified cellophane film.