Synthesis of microsequential methylvinylsiloxane–dimethylsiloxane copolymers by nonequilibrium copolymerization

✍ Scribed by Lucyna Herczynska; Julian Chojnowski; Liliane Lacombe; Laurence Lestel; Stefan Polowinski; Sylvie Boileau

• Book ID: 101272079
• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 205 KB
• Volume: 36
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19980115)36:1<137::aid-pola18>3.0.co;2-k

✦ Synopsis

Nonequilibrium anionic ring-opening copolymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (V 4 ) with hexamethylcyclotrisiloxane (D 3 ) was examined as a route to methylvinyl-dimethylsiloxane microsequential copolymers. The copolymerization was carried out in toluene and was initiated with Me 3 SiCH 2 Li using DMSO as the promoter. Distribution of siloxane units obtained from kinetic analysis based on first-order Markovian statistics was compared with that found from analysis by 29 Si NMR spectroscopy. Results showed that although chain transfer and back-biting play some role in this system, the kinetics of copolymerization may be described to a reasonable approximation by the first-order Markov model.