Polymerisation of cyclosiloxanes

摘要

A process for the ring-opening polymerisation of cyclosiloxanes, which comprises contacting a cyclosiloxane with 1-500 ppm by weight of a phosphazene base, based on the weight of cyclosiloxane, in the presence of water, preferably 0.5-10 mols per mol of phospazene base. Also claimed is a process in which the cyclosiloxane is present together with an agent which inhibits catalyst activity of the phosphazene base, e.g. carbon dioxide or water, in which the polymerisation is initiated by reducing the effect of the inhibiting agent e.g. by heating.