Studies on the synthesis and thermal properties of alkoxysilane-terminated oirganosilicone dendrimers

Silicone core dendrimers bearing terminal dialkoxy and trialkoxy silane groups were prepared in a three-step synthesis. Initially, the Si-H terminated multifunctional silicone dendrimer, i.e. tetrakis(dimethylsiloxy)silane, was prepared by the reaction of tetraethoxysilane and dimethylethoxysilane. Tetra kis(dimethylsiloxy)silane on reaction with allylglycidylether in the presence of Speier's catalyst under pressure (100 psi) yielded epoxy-terminated dendrimer in very high yield (95%). The epoxy-terminated dendrimer was reacted with aminopropylalkoxysilanes to yield the next-generation dendrimer bearing dialkoxy and trialkoxy silane groups. The dendrimers were characterized by the usual physico-chemical techniques, i.e. elemental analysis, FT-IR, H-1, C-13 and Si-29 NMR. Thermal studies (Thermogravimetric analysis and Thermomechanical analysis) of the alkoxy terminated dendrimers and its cured products were also carried out. Copyright (C) 2010 John Wiley & Sons, Ltd.