29Si NMR study of base-catalyzed polymerization of dimethyldiethoxysilane

Studies on dialkoxysilane hydrolysis kinetics under alkaline conditions

“…Finally, no cycle trimer (À9 ppm) was found in the NMR spectra of alkaline system, but cycle tetramer (À19 ppm) was found after 40 min of reaction. The results are similar with those obtained by Rankin [18].…”

“…We introduced the hypothesis that hydrolysis is irreversible, which is supported by Rankin [18]. The differential equation of hydrolysis can be written as follows:…”

“…The peak assignment for DMDMS deviations was made according to the previous literature [18]. However, compared with the 29 Si NMR spectra in the literature, the chemical position of monomer is shifted to high field (from À3.6 ppm to À0.275 ppm) [18]. This may be due to the solvent effect of monomer in acetone and ethanol.…”

“…In recent reports, McCormick and coworkers studied the hydrolysis pseudo-equilibrium and equilibrium constants of monofunctional silane by 29 Si NMR [14][15][16][17]. On Di-functional silane, hydrolysis, deprotonation and cyclization were also investigated [18], however, there was no quantitative description to the kinetics.…”

Polycondensation of Diethoxydimethylsilane in Active Medium

“…However, the manufacture of polyorganosiloxanes of cyclic or linear structure based on dialkoxydiorganosilanes is uncommon, including, notably, kinetic studies of monomer polycondensation [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. In that case, either cyclosiloxanes or mixtures of linear and cyclic products are obtained.…”