OLIGOMERIZATION AND COPOLYMERIZATION OF GAMMA-BUTYROLACTONE - A MONOMER KNOWN AS UNABLE TO HOMOPOLYMERIZE .1. COPOLYMERIZATION WITH EPSILON-CAPROLACTONE

Copolymerization of gamma-butyrolactone (gamma BL) with epsilon-caprol actone (epsilon CL) initiated with aluminium isopropoxide trimer ([Al( (OPr)-Pr-i)(3)](3), (A(3))) is described. Copolymers with molecular we ights (<(M)over bar (n)>) up to 3 . 10(4) and containing up to 43 mol- % repeating units derived from gamma BL are prepared. Their molecular weight is controlled by the concentrations of the consumed comonomers and the starting concentration of initiator (<(M)over bar (n)> = (86.0 9 . [gamma BL](c) + 114.14 . [epsilon CL](c))/3 [Al((OPr)-Pr-i)(3)] 60.10). C-13 NMR and DSC data are indicative of a pseudoperiodic or ra ndom copolymer structure.