Hydrolysis and condensation behavior of tetraethoxysilane, hexaethoxydisiloxane, and octaethoxytrisiloxane

Abstract

In the initial stage of the hydrolysis–condensation of tetraethoxysilane (TEOS), hexaethoxydisiloxane (HEDS) and octaethoxytrisiloxane (OETS) are formed. However, little is known about the hydrolysis–condensation of HEDS and OETS. In this study, the hydrolysis–condensation of TEOS, HEDS, and OETS was investigated. HEDS and OETS were synthesized from diethoxy(diisocyanato)silane, a raw material with controllable functionality. The hydrolysis of TEOS, HEDS, and OETS was analyzed by mass spectroscopy, gel permeation chromatography, and nuclear magnetic resonance. The hydrolysis–condensation product of TEOS was a three-dimensional network-type polysiloxane. The hydrolysis–condensation product of HEDS consisted mainly of four-membered cyclic siloxane. The hydrolysis–condensation product of OETS consisted mainly of various membered cyclic siloxanes. Graphical Abstract

Preparation and properties of PDMS elastomer cross-linked with hydrolyzate of tetraethoxysilane, hexaethoxydisiloxane, and octaethoxytrisiloxane: influence of cross-linker structure

“…Recently, we discussed the hydrolysis-condensation reaction of ethoxysilanes, known to form during the early stages of the sol-gel reaction of tetraethoxysilane (TEOS) [9]. Our findings indicate that TEOS, hexaethoxydisiloxane (HEDS), and octaethoxytrisiloxane (OETS) produce polymers with distinct characteristics: network-type polymers containing cyclic siloxanes, polymers containing cyclic siloxanes with four silicon atoms, and polymers containing various cyclic siloxanes, respectively.…”