Abstract
Aliphatic polyesters have received much attention because of their biodegradability and biocompatibility. In this study, we describe the ring-opening copolymerization of lactones with oxetanes having hydroxyl group by cationic initiator. The copolymerization of ε-caprolactone (1) with 3-ethyl-3- (hydroxymethyl) oxetane (2b) (equimolar feed ratio) by scandium trifluoromethanesulfonate was carried out in bulk at 60-120 °C for 6 h. In the polymerization at 60 °C, it was found that the resulting polymer was the corresponding copolymer with hydroxyl groups from NMR measurements and was soluble in DMSO and DMF. At 120 °C, the obtained networked copolymer was insoluble in solvents, although respective homopolymerization gave soluble polymers. In addition, it was found that the thermal stability was drastically improved by copolymerization with only addition ca. 6% of 2b to 1. These results might suggest that 2b served as a crosslinkable monomer for ring-opening copolymerization.
