Polymerization of hexamethylcyclotrisiloxane by α,ω-bis-(tetramethylammonium) oligodimethylsiloxanolate in the presence of trimethylsilanol

Abstract

A study was made of the role of trimethylsilanol (TMS) in polymerization of hexamethylcyclotrisiloxane (D 3) by the action of α,ω-bis-(tetramethylammonium) oligodimethylsiloxanolate. In the presence of TMS as a result of solvation of silanolate groups by silanol groups complexes are formed which are characterized by a lower activation energy E a of polymerization D 3 than α,ω-bis-(tetramethylammonium) oligodimethylsiloxanolate. In addition to copolymerization with D 3 TMS takes part in homocondensation and co-condensation with the siloxanols formed, which take place at a much lower rate than copolymerization. Homo- and co-condensation are only observed in those cases when [TMS] 0>[D 3] 0, co-condensation predominating with high conversions of D 3. When [TMS] 0⩽[D 3] 0 initial rates of consumption of TMS and D 3 are the same.