Characterization of poly L-Lactide/Hydroxyapatite composite: Chemical, thermal and thermomechanical properties

The chemical, thermal, thermo-mechanical and morphology properties of poly (L-lactide) (PLLA) composite with 30% hydroxyapatite (HA) were evaluated. The composite was prepared employing the solvent casting technique. Hydroxyapatite was synthesized by chemical precipitation method. The degradation kinetic parameters were calculated using the Coats - Redfern integral method to obtain the reaction order and the E2 function methodology to calculate the activation energy (Eα). The addition of HA to PLLA matrix increased its glass transition temperature. This was confirmed by DSC and DMTA analysis. Also, the presence of HA increased the crystallization temperature of PLLA, implying a nucleation effect. The PLLA-HA composite exhibited better thermal stability than the neat polymer; additionally higher decomposition temperature and activation energy for the decomposition process were obtained. HA nanoparticles have a rod shape morphology that might improve the interfacial interactions, increasing the thermal stability of the composite. The storage modulus (E’) of this composite was enhanced mainly at temperatures above the glass transition.