Abstract: Siloxanes are polymerized by equilibration, condensation and/or ring-opening polymerization using a phosphazene base catalyst. A linear phosphazene base catalyst of the general formula wherein R denotes a C1-10 hydrocarbon or wherein two R groups on one N atom form with the N atom a heterocyclic group, X denotes an anion and n is from 1 to 10 is prepared by reacting a linear phosphonitrile halide compound with a secondary amine or a salt of a secondary amine or a metal amide thereof to form an aminated phosphazene material, followed by an ion exchange reaction replacing the anion with a nucleophile.

Abstract: A polymerization process comprising mixing a siloxane having silicon-bonded groups R′ and a cyclic or linear siloxane having no silicon-bonded groups R′ with a phosphazene base catalyst in the presence of water and allowing the siloxane having silicon-bonded groups R′ to condense and the cyclic or linear siloxane having no silicon-bonded R′ groups to polymerize by equilibration.

Abstract: A polymerization process comprising mixing siloxane polymers with organosilicon compounds having at least one silicon-bonded group RN, which is a substituent comprising at least one amine group, and with a phosphazene base catalyst and allowing the siloxanes and organosilicon compounds to polymerize to form amino-functional polyorganosiloxane polymers is claimed.

Abstract: A polymerization process comprising mixing siloxanes having silicon-bonded groups R′ with ionic phosphazene base catalysts and allowing condensation via reaction of Si—R′ groups with the formation of a Si—O—Si linkage, R′ denoting a hydroxyl group or a hydrocarbonoxy group having up to 8 carbon atoms is claimed. The catalysts may be of the general formulae: {((R12N)3P═N—)x(R12N)3−xP—N(H)R2}+{A−} or {((R12N)3P═N—)y(R12N)4−yP}+{A}− in which R1 is hydrogen or an optionally substituted hydrocarbon group or in which two R1 groups bonded to the same N atom may be linked to complete a heterocyclic ring, R2 is hydrogen or an optionally substituted hydrocarbon group, x is 1, 2 or 3, y is 1, 2, 3 or 4 and A is an anion.