Tougher biodegradable polylactide system for bone fracture fixations: Miscibility study, phase morphology and mechanical properties

Abstract

Choosing materials for orthopedic implants often imposes strict requirements for the mechanical properties. Poly-L-lactide (PLLA) is widely employed for this purpose, however toughnening schemes are necessary for its suitable application. Blending of PLLA and biodegradable poly(L-lactide-co-ɛ-caprolactone) copolymer (PLCL) showing a thermoplastic-elastomeric behavior has been performed in an effort to toughen the PLLA without compromising its biodegradability and biocompatibility. The miscibility state of PLLA/PLCL blend system is studied by means of Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). The mechanical properties will be also discussed, as well as, phase morphology observed by Scanning Electron Microscopy (SEM). Blends of PLLA/PLCL show different miscibility degrees depending on the blending process and the copolymer content. Blends prepared by melt-quenching show a miscibility window for compositions ≤30 wt% of PLCL, while a phase separation occurred in the rest of compositions. The toughness of PLLA was considerably improved by the addition of PLCL. The elongation at break was significantly increased.