Micromechanical properties of a hydroxyapatite/poly-l-lactide biocomposite using nanoindentation and modulus mapping

Biocomposites with ceramic fillers and polymer matrix are becoming attractive materials for bone tissue replacements. Nanoindentation has been used to locally characterize the surface mechanical properties of the hydroxyapatite/poly-l-lactide (HAp/PLLA) biocomposite. Additionally, differences in the mechanical properties of HAp phase were successfully characterized as a function of surface morphology by using a high-resolution modulus mapping technique. HAp granules consist of agglomerates of grainy clusters. Mechanical properties of ceramic grains and PLLA are in fair agreement with literature data. High-resolution methods were able to measure the properties of boundary phases between grains and the pore regions between particles in the agglomerate. After short-time immersion in distilled water, material surface showed a large decrease in storage modulus.