Effect of hydroxyapatite with different morphology on the crystallization behavior, mechanical property and in vitro degradation of hydroxyapatite/poly(lactic-co-glycolic) composite

This work describes the effect of hydroxyapatite with different morphology of nano-particle (n-HA) and whisker (w-HA) on the properties of hydroxyapatite/poly-lactic-co-glycolic acid (HA/PLGA) composite. The crystallization behavior, mechanical property and in vitro degradation of HA/PLGA composite were studied by scanning electron microscope, differential scanning calorimeter, polarized optical microscopy, electromechanical universal tester and soaking in simulated body fluid (SBF) at 37 degrees C for 2, 4, 8, 12 and 16 weeks, comparing with pure PLGA. The results showed that n-HA had better mechanical increment effect for PLGA than w-HA, because of the more uniformly dispersion in PLGA matrix without any cavities and the better promotion crystallization effectiveness in HA/PLGA composite than w-HA. However, the in vitro degradation showed that w-HA could keep denser microstructure so that the w-HA/PLGA composite had lower bending strength reduction percent than the n-HA/PLGA composite, owing to the higher crystallinity of w-HA and the more perfectly microcrystalline of PLGA (PLGA/w-HA) than n-HA. The study would be of guidance to select the suitable filler for poly(lactic acid) (PLA) or PLGA polymers in manufacturing bone fracture internal fixation material in future. (C) 2014 Elsevier Ltd. All rights reserved.