Chemical structure of poly(vinyl alcohol)/methyl methacrylate graft copolymers prepared by various methods

Abstract

AbstractPoly(vinyl alcohol) (PVA)/methyl methacrylate (MMA) graft copolymers were prepared by mutual irradiation, pre‐irradiation, and by a catalytic method with potassium persulfate (KPS); a technique to prepare graft copolymer using no initiator was also adopted. After pure graft copolymers were isolated from the graft films by vigorous alternate extraction unreacted PVA and homo‐PMMA, hydroxyl groups in the copolymers were completely acetylated to carry out osmotic pressure measurements and determine the chemical composition by hydrolysis. Graft branches were separated by cleaving CC bonds of 1.2‐glycol structure in backbone PVA with periodic acid. The chemical structure of the graft copolymers was made clear on the basis of the measured number‐average molecular weights of the pure graft copolymer, separated branch and mother PVA molecule, and the chemical composition of the graft copolymer. It was shown that the graft copolymer has only one branch and one mother PVA molecule, irrespective of the grafting methods employed.