Continuous polymerization of polycaprolactone in a modular co-rotating twin screw extruder

Bulk polymerization of epsilon -caprolactone (CL) has been carried out in a modular intermeshing co-rotating twin screw extruder using aluminum isopropoxide as a "coordination-insertion" initiator under a range of processing condition including temperature profiles, throughput, and screw speed. This homo-polymerization was investigated for various ratios of monomer to initiator. GPC analysis demonstrated that significant quantities of oligomers were produced together with high molecular weight polymer under different reaction temperatures. For continuous polymerization at 130 degreesC using a modular corotating twin screw extruder, high molecular weight up to 200,000 were produced without substantial oligomers by increasing the ratio of monomer to initiator.