Preparation of Stereocomplex Polylactide/Poly(Butylene Succinate) Blends by Melt Blending

Abstract

Biodegradable polymer blends based on stereocomplex polylactide (scPLA) and poly(butylene succinate) (PBS) were successfully formed by continuous two-step melt blending. An epoxy-based, multifunctional chain extender was chosen to enhance phase compatibility of the blends. Effects of PBS and chain extender on thermal, phase morphology, thermo-mechanical and tensile properties of the scPLA/PBS blends were determined. The PBS blending enhanced plasticizing effect and cold-crystallization of scPLA matrix in an amorphous region. The chain-extension reaction inhibited crystallization of PBS, PLA homo-crystallites and PLA stereocomplex-crystallites as well as reduced thermal stability of the scPLA/PBS blends because of formation of long-chain branched structures. It has been shown that the poor phase compatibility between continuous scPLA and dispersed PBS phases of the blends may be solved through melt blending with a chain extender. The chain extension of scPLA/PBS blends also improved thermo-mechanical properties and flexibility of the scPLA/PBS blend films.