Continuous polymerization of lactam-lactone block copolymers in a twin-screw extruder

Continuous copolymerizations of epsilon-caprolactone with epsilon-caprolactam and omega-lauryl lactam were carried out in a modular intermeshing corotating twin-screw extruder. Sodium hydride (initiator) and N-acetyl caprolactam (coinitiator) were used to synthesize lactam-lactone copolymers in a twin-screw extruder. We consider the variables of feeding order and feed rate of comonomers on the reactive extrusion of lactam-lactone copolymers. It was observed that simultaneous feeding of both monomers with initiator and coinitiator in the first hopper produced a mixture of homopolymers. When we fed the lactam into the first hopper and caprolactone sequentially into the second hopper, we obtained the lactam-caprolactone block copolymers. However, when we fed caprolactone first into the first hopper and the lactam into the second hopper, the extruded product was a mixture of poly(epsilon-caprolactone) and lactam monomer. We synthesized high molecular weight copolymers of poly(caprolactam-b-caprolactone) and poly(lauryl lactam-b-caprolactone) with different block lengths by sequential feeding of monomers. The block length of the block copolymer could be adjusted by controlling the feed rate of each monomer during reactive extrusion. (C) 2003 Wiley Periodicals, Inc.