BULK-POLYMERIZATION OF 1,3,5,7-TETRAVINYLTETRAMETHYLCYCLOTETRASILOXANE INDUCED BY GAMMA-RADIATION

Gamma ray-induced bulk polymerization of 1,3,5,7-tetravinyltetramethyl cyclotetrasiloxane at ambient temperature has been investigated. It wa s found that the polymerization proceeds via a free radical mechanism through the reaction of vinyl groups, and the resulting polymer had a three-dimensional network structure. Kinetic features of the reaction were also studied, strong postpolymerization effects were observed at doses between 8 and 80 kGy. The composition of the sol fractions was d etermined by high pressure liquid chromatography, and the chemical str ucture of both the sol and gel fractions was analyzed by FTIR spectros copy. Thermal stability of the gel fractions, determined by thermograv imetric analysis, and the thermomechanical behavior of unextracted sam ples were found to depend on the irradiation dose. (C) 1998 Elsevier S cience Ltd. All rights reserved.