The reactivity of TiO2 and ZrO2 in organically modified silicates

The objective of this investigation was to compare the influence of titania, zirconia and silica on synthesis and properties of epoxide group containing organically modified silicates. These materials were prepared from the epoxysilane (MeO)sub 3 SiC sub 3 H sub 6 OCH sub 2 CHCH sub 2O and titanium, zirconium and silicon alkoxides by the sol-gel process. The results show that titanium and zirconium, beside their role as network formers, act as efficient catalysts for epoxide polymerization. Zirconium promotes thermically the polymerization of epoxides to polyethylene oxide crosslinking chains, whereas titanium promotes this reaction photochemically. The incorporation of crosslinking polyethylene oxide decreases the scratch resistance of the silicate condensates. The activity of silicon in both reactions is very poor.