Study of Sol–gel reaction of organically modified alkoxysilanes. Part I: Investigation of hydrolysis and polycondensation of phenylaminomethyl triethoxysilane and tetraethoxysilane

Hydrolysis and polycondensation of phenylaminomethyl triethoxysilane (PAMS) and tetraethoxysilane (TEOS) with different molar ratios were investigated by Fourier transform infrared spectrometry (FTIR). Viscosity-time change investigations were also utilized to aid the FTIR measurements. The results show that for a such a reaction system, an increase in the PAMS component can quicken the polycondensation reaction and reduce the cyclic products at first, however, a further increase in PAMS concentration will hinder the formation of the linear silica network and delay the gelation time. When the molar ratio of PAMS to TEOS increases to 1:2 or higher, precipitation instead of uniform gelation is formed, mainly due to the formation of large amounts of cyclic silica structures.