Oligoethylene-End-Capped Polylactides

ABSTRACT: Oligoethylene-end-capped polylactides were synthesized through the ring-opening polymerization of L-lactide with alcohol-terminated oligoethylenes as macro-initiators. The polymerization of L-lactide was carried out in bulk at 130 8C in the presence of stannous octoate and primary alcohols with four different molecular weights: 350, 425, 550, and 700 g/mol. The end-capped copolymers that formed had a number-average molecular weight of approximately 40,000 (weight-average molecular weight/number-average molecular weight 1.7) according to gel permeation chroma-tography and were highly crystalline in comparison with the similarly formed homo-polymer of L-lactide. The copolymer structure was characterized by Fourier transform infrared, NMR, matrix-assisted laser desorption/ionization time-of-flight mass spec-trometry, and differential scanning calorimetry analysis. This work focused on devel-oping more crystallizable and hydrolytically stable polylactide derivatives that could potentially be used as compatibilizers in polylactide–polyolefin blends or as nucleat-ing agents for poly(L-lactide) or other polyesters. VC 2005 Wiley Periodicals, Inc. J Poly