Copolymers of <scp>L</scp>‐ and <scp>D</scp>,<scp>L</scp>‐lactide with 6‐caprolactone: synthesis and characterization

Abstract

Abstract L ‐ and D , L ‐lactide copolymers with 6‐caprolactone were synthesized and characterized in a wide range of compositions. The polymerizations were carried out in batch at 130°C, with Sn(II) octoate as a catalyst, a monomers/initiator mole ratio of 5000/1 and a reaction time of 48 h. The copolymers having from 5 to 40 wt.‐% of 6‐caprolactone are characterized by higher values of non‐reacted monomers and deviations of the polymer composition from the feed ratio. In the same interval of compositions, L ‐lactide copolymers showed progressive hardening with time at room temperature, attributable to the tendency to crystallization of homopolymeric sequences. This behaviour was more deeply studied in the case of poly( L ‐lactide‐ co ‐6‐caprolactone) with 30 wt.‐% of 6‐caprolactone. 1 H NMR at 300 MHz appeared to be a suitable method for the determination of the monomer sequence.