Continuous cationic polymerization of siloxanes

A continuous polymerization process for producing liquid hydride-functional and/or organofunctional siloxane polymer products, comprising the steps of:

• (a). providing a substantially homogeneous liquid mixture of siloxane reactants;
• (b). continuously introducing the siloxane reactants to a tubular reactor packed with a solid, acidic polymerization catalyst which is substantially insoluble in and substantially immobile to the siloxane reactants and the polymer products;
• (c). driving the reactant mixture through the tubular reactor under substantially plug flow conditions;
• (d). carrying out cationic polymerization of the siloxane reactants in the tubular reactor until reaching a substantially thermodynamic equilibrium composition of siloxane reactants and siloxane polymer products;
• (e). continuously removing the substantially thermodynamic equilibrium composition from the tubular reactor;
• and
• (f). volatilizing the siloxane reactants and any low boiling by-products from the equilibrium composition;
• wherein the composition contains substantially no catalyst or by-products, such that neutralization of the catalyst or filtering of the composition is unnecessary.