Controlled ring opening polymerization of e-Caprolactone by complexing with Zinc Chloride. Structure, morphology and kinetics effects

G.A. ABRAHAM; GALLARDO,A.; LOZANO,A.; SAN ROMAN,J

Oxford, UK

Congreso; Gordon Research Conference on Polymers; 1999

Gordon Research Conferences (GRC)

Although halogenides of metals possessing free p- or d-orbitals, such as BF3, AlCl3, ZnCl2 and SnCl4, are strong Lewis acids and good catalysts to initiate the cationic polymerization of lactones, it has been reported that some of these compounds can promote a coordination insertion mechanism instead of a true cationic chain growth.  In this work we present a study of the interactions e-caprolactone/ZnCl2 and it is described the formation of a new crystalline specie ascribed to the stoichiometric complex e-CL/ZnCl2.  New evidences of the insertion coordination mechanism proposed for the ring-opening polymerization are shown. The effect of the monomer-initiator ratio on the molecular weight of polymerized samples is also discussed.