Preparation and mechanical properties of polylactic acid composites containing hydroxyapatite fibers

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 mum length and 2-10 mum diameter, which were converted from beta -Ca(PO3)(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 degreesC, 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. (C) 2000 Elsevier Science Ltd. All rights reserved.