Preceramic polysiloxane networks obtained by hydrosilylation of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane.

Abstract Precreamic polysiloxane networks were prepared by hydrosilylation of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D 4 Vi ) with a series of linear hydrogensiloxanes as well as with a cyclic hydrogensiloxane, namely 2,4,6,8-tetramethylcyclotetrasiloxane (D 4 H ) at various hydrogensiloxane/D 4 Vi molar ratios in the starting reaction mixture. FTIR spectroscopic measurements conducted during the processes as well as for the reaction products allowed to reveal that the rate of D 4 Vi hydrosilylation as well as its efficiency are influenced by the type of hydrogensiloxane used and by the reactants molar ratio. Ceramic yields determined at 1000 °C by thermogravimetric analyses were higher for D 4 Vi –D 4 H than for D 4 Vi – linear hydrogensiloxane networks (86–89% vs 65–76%, respectively). Preceramic polysiloxanes prepared as well as the products of their pyrolysis obtained after thermal investigations were monolithic, pore-less materials.