Studies on the mechanism of radiation polymerization—II. Mechanism of the carbonium polymerization of styrene and methylmethacrylate initiated by gamma rays : M. K. Yakovleva, A. P. Sheinker and A. D. Abkin, Vysokomol. soedin. 3: No. 6, 828–832, 1961

Abstract

The gamma-ray induced copolymerizatron of styrene and methyl methacrylate in ethyl chloride solution was studied at monomer concentratron 2.0 mole/l. and temperatures ranging from +25 to --78 deg . The dose rate was 110 rad/sec. The relative amount of the styrene component of the copolymer increased wrth lowering of the temperature from +25 to --78 deg . The styrene-methyl methacrylate copolymers are sharply enriched in styrene at --78 deg for all monomer mixtures; r/sub 1/ (styrene) = 20; r/sub 2/ = 0.005. A sharp inhibition of styrene polymerization ps observed when small amounts (ca. 0.1 mole) of methyl methacrylate are added to the former. In radical polymerization, styrene retards polymerization of methyl methacrylate. Data on the copolymer composition and kinetic data lead to the conclusion that copolymerization of styrene and methyl methacrylate at low temperatures initiated by gamma rays proceeds by means of a carbonium mechanism. (tr-auth)