Anionic Polymerization of Vinylsilanes III. Polymerization Behavior of Trimethylvinylsilane

Abstract

Polymerization behavior of trimethylvinylsilane by sec-butyllithium was investigated in the presence or absence of N,N,N′,N′-tetramethylethylenediamine (TMEDA). In the absence of TMEDA, the elimination reaction of lithium hydride which was observed apparently at 40°C was suppressed at −10°C. In the presence of TMEDA, the chain transfer reaction to the monomer occurred even at −10°C. Initial monomer concentration was found to affect the propagation rate considerably. In the absence of TMEDA at −10°C, the apparent propagation rate constant was high at high initial monomer concentration. In the presence of TMEDA, the reverse relation was observed. The former was interpreted by the association state of the active centers and the latter by the combination of two types of propagation reaction. For the isomerization reaction, low monomer concentration and high temperature were advantageous. The content of isomerized units in the polymer increased with an increase in degree of polymerization.