The structure of crystallisable copolymers of L-lactide, epsilon-caprolactone and glycolide

Channuan, W., Siripitayananon, J., Molloy, R., Sriyai, M., Davis, F. J. ORCID: https://orcid.org/0000-0003-0462-872X and Mitchell, G. R. (2005) The structure of crystallisable copolymers of L-lactide, epsilon-caprolactone and glycolide. Polymer, 46 (17). pp. 6411-6428. ISSN 0032-3861 doi: 10.1016/j.polymer.2005.04.097

Abstract/Summary

We apply a new X-ray scattering approach to the study of melt-spun filaments of tri-block and random terpolymers prepared from lactide, caprolactone and glycolide. Both terpolymers contain random sequences, in both cases the overall fraction of lactide units is similar to 0.7 and C-13 and H-1 NMR shows the lactide sequence length to be similar to 9-10. A novel representation of the X-ray fibre pattern as series of spherical harmonic functions considerably facilitates the comparison of the scattering from the minority crystalline phase with hot drawn fibres prepared from the poly(L-lactide) homopolymer. Although the fibres exhibit rather disordered structures we show that the crystal structure is equivalent to that displayed by poly(L-lactide) for both the block and random terpolymers. There are variations in the development of a two-phase structure which reflect the differences in the chain architectures. There is evidence that the random terpolymer includes non-lactide units in to the crystal interfaces to achieve a well defined two-phase structure. (c) 2005 Published by Elsevier Ltd.