| 摘要 |
<p>A polymerisation 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: <MATH> or <MATH> in which R<1> is hydrogen or an optionally substituted hydrocarbon group or in which two R<1> groups bonded to the same N atom may be linked to complete a heterocyclic ring, R<2> 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. Also claimed is a process which comprises mixing siloxanes having silicon-bonded groups R' and cyclic or linear siloxanes having no silicon-bonded groups R' with ionic phosphazene base catalysts and allowing the siloxane having silicon-bonded groups R' to condense and the cyclic and linear siloxanes having no silicon-bonded R' groups to polymerise by equilibration.</p> |
