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Anionic polymerization of siloxanes, 2. Internal multifunctional assistance of siloxane system to the siloxane bond cleavage by alcali metal silanolates

1977; Wiley; Volume: 178; Issue: 4 Linguagem: Inglês

10.1002/macp.1977.021780406

0025-116X

M. Mazurek, Julian Chojnowski,

Synthesis and properties of polymers

Abstract The kinetics of the reaction of potassium phenyldimethylsilanolate (1) with the series of linear trimethylsilyl‐end‐blocked dimethylsiloxane oligomers and with the series of cyclic dimethylsiloxane oligomers was studied to clear some mechanistic problems of anionic polymerization of siloxanes. The results indicate that the high reactivity of the siloxane bond in linear and higher cyclic oligomers—responsible for the large scope of chain redistribution and cyclization processes in the siloxane anionic polymerization system—is due to a mechanism involving multifunctional interaction of siloxane with silanolate, which gives assistance to the siloxane bond cleavage. This mechanism is impeded when strong cation solvating agents are present in the system.