Thermal properties and relaxation transitions in copolymers of dimethylsiloxane with methyltrifluoropropylsiloxane

Autor: V.N. Kirillov, V.G. Nikol'skii, Ya.A. Abeliov, B.F. Alekseyev
Rok vydání: 1978
Předmět:
Zdroj: Polymer Science U.S.S.R.. 20:2590-2599
ISSN: 0032-3950
DOI: 10.1016/0032-3950(78)90196-x
Popis: The linear thermal expansion coefficient, heat conductivity and dynamic and mechanical characteristics have been investigated for a number of copolymers of dimethylsiloxane with methyltrifluoropropyl in relation to the ratio of copolymer components over a wide range of temperatures. Relaxation transitions in these polymers have been examined by means of the radiothermoluminescence method. No effects related to processes of crystallization and melting were detected for the copolymers under study. The main β relaxation transition is displaced towards positive temperatures as the content of methyltrifluoropropyl units in the copolymer rises, besides which there is also a secondary γ transition that makes a major contribution to the glass transition process in the region of 150–160°K. A modified Simha-Boyer equation is presented to describe the multiple character of the glass transition process.
Databáze: OpenAIRE