ANIONIC-POLYMERIZATION OF CYCLOSILOXANES IN HETEROGENEOUS MEDIUM

Anionic polymerization of various cyclosiloxanes [octamethylcyclotetra siloxane (D-4), 7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (V- 4), and hexamethylcyclotrisiloxane (D-3)] was performed. As catalysts, IRA-900 and PB-100 type anionites with benzyltrimethylammonium and 3- acrylamidopropylbenzyldimethylammonium groups, respectively, were used . The anionite with higher strongly basic exchange capacity (IRA-900) is more efficient in dimethylcyclosiloxane polymerization. PB-100 anio nite with less strongly basic capacity is more active for polymerizati on of the V-4 monomer with bulky and electronegative substituent. (C) 1996 John Wiley & Sons, Inc.