Liquid, Methoxylated Polysiloxane / Silica Hybrid Resins by a Non-Hydrolytic Route

Abstract

AbstractThe preparation of liquid, methoxylated, polysiloxane hybrid resins containing Me2Si(O-)2 (D) or MeHSi(O-)2 (DH) units cross-linked by Si(O-)4 (Q) units was attempted using the nonhydrolytic condensation reaction between Si-Cl and Si-OMe groups, catalyzed by ZrCI4. The structure of the resins was investigated by 29Si NMR, which showed that redistribution reactions played a prominent role. Thus, Si-OMe/Si-OSi redistributions lead to a highly homogeneous, random structure for the D/Q resin. On the other hand, this route does not apply to the synthesis of DH/Q resins, due to the redistribution of Si-H bonds which leads to the escape of MeSiH3 and to the formation of T and TH units.