Silicone Rubbers. Ix. Contributions to Polydimethylsiloxane-α,ω-Diols Synthesis by Heterogeneous Catalysis

The cationic polymerization of a cyclosiloxane mixture (hexamethyl-cyclotrisiloxane-D3, octamethylcyclotetrasiloxane-D4, decamethylcyclopentasiloxane-D5, dodecamethylcyclohexasiloxane-D6 and tetradecamethylcycloheptasiloxane-D7) in the presence of water as adjusting-control agent for molecular weight is studied in heterogeneous catalyst system using an ion-exchange VIONIT CS-34C with sulphonic groups. Thus poly(dimethylsiloxane)-α,ω-diols for room temperature vulcanization (RTV) silicone rubbers, were obtained.