IONIC POLYMERIZATION IN AQUEOUS EMULSION

A kinetic study of the anionic polymerization of octamethylcyclotetras iloxane (D-4) in aqueous emulsion has been carried out in the presence of ionic additives. The rate of polymerization of several cyclosiloxa nes has been compared, leading to additional evidence for an interfaci al mechanism of polymerization. The emulsion process has been applied to the cationic polymerization of D-4 and of tetramethylcyclotetrasilo xane (D-4(H)) initiated by dodecylbenzenesulfonic acid. Very efficient for the synthesis of linear polymethylhydrogenosiloxanes (PMHS), thes e conditions did not seem suitable for the polymerization of D-4. The extension of the process to other heterocyclic monomers is discussed t hrough the anionic polymerization of phenylglycidylether.