Blends of Poly(d,l-lactide) with Polyhedral Oligomeric Silsesquioxanes-Based Biodegradable Polyester: Synthesis, Morphology, Miscibility, and Mechanical Property

A highly branched hybrid copolymer based on polyhedral oligomeric silsesquioxane (POSS) was designed to improve the brittleness of poly(d,l-lactide) (PDLLA). The toughening material was synthesized using POSS-OH as the core, which initiated the ring-opening polymerization of e-caprolactone and d, l-lactide sequentially to form the highly branched POSS-g-poly (e-caprolactone)-b-poly(d, l-lactide) (POSS-g-PCL-b-PLA) copolymer with eight PCL-b-PLA arms. The POSS-g-PCL-b-PLA copolymer had a very good dispersion in the PDLLA matrix with the size of microdomains smaller than 1 mm when added at a low content below 10 wt %. In related to the nano-scale size of microdomains in the blends, the crystallinity of PCL blocks was significantly suppressed. Thus, the addition of POSS-g-PCL-b-PLA is very effective to improve the roughness of the matrix polymer when added at a low content. (C) 2014 Wiley Periodicals, Inc.