Free-radical synthesis of new phosphorus-containing silane monomers and polysiloxanes

This paper deals with the synthesis of silane monomers and polysiloxanes be aring phosphorus compounds. Two reactive schemes were used. The first one w as a direct hydrosilylation of unsaturated phosphonate on triethoxy silane. This reaction was too low and conversion rate was weak. Inversely, hydrosu lfidation was very effective either with mercapto silane or mercapto polysi loxane. Thus. allyl and vinyl phosphonates were immobilized quantitatively on triethoxy mercaptopropyl silane monomer and on poly (dimethyl-co-mercapt o propyl) siloxane. All the compounds were characterized by FTIR, H-1 and P -31 NMR. Thermogravimetric analysis of modified compounds shows clearly tha t the presence of phosphonic acid functions onto polysiloxane backbone decr eases drastically the thermal stability. (C) 1998 Elsevier Science Ltd. All rights reserved.