Radical copolymerization of ethylene with unsaturated organosilicon monomers under pressure

Abstract

The rate of copolymerization of ethylene with the organosilicon monomers CH 2 = =CHSiR 3 (m), where R represents the alkoxy or the OSi(CH 3) 3 group, is about the same as the rate of homopolymerization of ethylene over a wide range of composition of the monomer mixture. With a low concentration of m in the reaction mixture, the conversion of m is approximately the same as that of ethylene when R is an alkyl, alkoxyl or (OSi (CH 3) 3 group; the conversion is considerably greater than that of ethylene when R is a phenyl or phenoxy group or Cl. As the concentration of m increases, the density of the copolymers increases when R is a phenyl or alkoxy group, and decreases when R is an alkyl or a OSi (CH 3) 3 group. The capacity of the copolymers to crosslink with vinylalkoxysilanes decreases as the length of the alkyl group is increased. Thermooxidative degredation of the high molecular crosslinked copolymers occurs at a slower rate, as compared with polyethylene.