Preparation and mechanical properties of polylactic acid composites containing hydroxyapatite fibers

Abstract

Ceramic-polymer composite biomaterials were prepared by hot-pressing a mixture consisting of poly- l-lactic acid (PLA) and hydroxyapatite fibers (HAF) with dimensions of 40–150 μm length and 2–10 μm diameter, which were converted from β-Ca(PO 3) 2 fibers. After PLA dissolved with methylene chloride was mixed with the fibers, the mixture was dried completely and subsequently hot-pressed uniaxially under a pressure of 40 MPa at 180°C, resulting in the fabrication of the PLA/HAF composite. The modulus of elasticity was improved effectively even by introducing a small amount of HAF; almost no degradation in the bending strength was observed and the modulus of elasticity showed high values of 5–10 GPa when the fibers of 20–60 wt% were introduced. With increasing HAF content, the maximum strain decreases and the specimen is apt to show a brittle fracture; this result implies that HAF in the composites can share the applied load efficiently due to the formation of a bond between HAF and PLA.