Popcorn Polymerization of Vinyl Acetate

Abstract

The popcorn polymerization of vinyl acetate (VAc) has been studied. In the following experiments, popcorn polymerizations were carried out under nitrogen at 55°C. Popcorn polymers of VAc–ethylene glycol diacrylate (EGDA) and VAc–ethylene glycol dimethacrylate (EGDMA) were prepared (Table 1). The polymerizability of VAc in this system was investigated by using various popcorn seeds (Table 2). The rate of popcorn growth of n–butyl methacrylate (n–BMA) (using VAc–EGDMA popcorn seeds treated with heating in n–hexane—CCl4 or benzene—CCl4) was measured dilatometrically (Fig. 1). Popcorn polymers of VAc–, vinyl propionate–, vinyl butylate–, vinyl valeriate–EGDA, VAc–EGDMA, VAc(using n–BMA—EGDMA popcorn seed) and n–BMA (using VAc–EGDA popcorn seed) were hydrolyzed in aqueous 10% NaOH–acetone solution, and the water–acetone–insoluble part (S1) was measured (Table 3~6). The above experiments indicated that: (1) the popcorn polymerization is initiated with the small amount of radicals contained in the popcorn seed, (2) the net–works in the popcorn seed or formed during polymerization play an important part in the popcorn polymerization, and (3) popcorn polymerization of VAc, the chain–transfer of radicals to main– and side–chains of polymers occurs to give new bridges therefrom. © 1973, The Chemical Society of Japan. All rights reserved.