Follow-up of the course of the anionic ring-opening polymerization of lactams onto an isocyanate-bearing polymer backbone in the melt

摘要

In this study, a batch mixer was used as a rheoreactor to carry out and follow up in real time the rate of the anionic polymerization of s-caprolactam onto a 3-isopropenyl-alpha,alpha-dimethylbenzene isocyanate bearing polypropylene (PP-g-TMI) in the presence of sodium s-caprolactam as a catalyst. The isocyanate group in the PP-g-TMI was capable of activating the anionic polymerization, leading to the formation of a graft copolymer with polypropylene as the backbone and polyamide 6 as the grafts. The polymerization rate was related to the viscosity increase of the polymerization system. The latter then resulted in a concomitant torque increase. It was shown that torque was a rapid, convenient, and approximate measure of the polymerization rate. The use of the torque allowed for rapid and approximate evaluation of the effects of chemical and operating conditions on the polymerization rate without the need to determine the monomer conversions. Torque profiles were also a very useful piece of information for the design of a reactive extrusion process for the same type of polymerization system. (c) 2006 Wiley Periodicals, Inc.