SYNTHESIS AND CHARACTERIZATION OF OLIGO(LACTONE) METHACRYLATES

Oligo(lactone) methacrylates have been synthesized by oligomerization of L-lactide, D,L-lactide, epsilon-caprolactone and glycolide as well as by cooligomerization of the latter two with the former two. The oli gomerization reaction was initiated by bisphenol-A-bis(2-hydroxypropyl methacrylate) and catalysed by a series of coordination-insertion cat alysts of ring-opening polymerizations of lactones. The kinetics of th e oligomerization of lactide at 130 degrees C and the relatively narro w molecular weight distribution of the macromonomers, characterized by M-W/M-n approximate to 1.2, suggest a living mechanism of the reactio n. Optically pure macromonomers were obtained from L-lactide using Sn( II) octoate as a catalyst. Other catalysts, e.g. MgO, CaO, SnO2 etc., caused racemization (17-37%). Relationships between the nature of the lactone units as well as the oligomerization degree of the macromonome rs and the glass transition temperatures, melting points and degrees o f crystallinity of the macromonomers were determined. (C) 1997 Elsevie r Science Ltd.