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

A study was made of the role of trimethylsilanol (TMS) in polymerization of hexamethylcyclotrisiloxane (D3) 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 Ea of polymerization D3 than α,ω-bis-(tetramethylammonium) oligodimethylsiloxanolate. In addition to copolymerization with D3 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>[D3]0, co-condensation predominating with high conversions of D3. When [TMS]0⩽[D3]0 initial rates of consumption of TMS and D3 are the same.