Polylactic acid composites containing hydroxyapatite fibers

摘要

Ceramic-polymer composite biomaterials were prepared by hot-pressing a mixture consisting of poly-L-lactic acid (PLA) and hydroxyapatite fibers (HAF). HAF can be prepared successfully by heating a compact consisting of beta -calcium metaphosphate fibers (CPF) with Ca(OH)_2 particles in air at 1000 deg C and subsequently treating the resultant compact with dilute aqueous HCl solution. HAF was 40 approx 150 mu m in length and 2 approx 10 mu m in diameter, HAF has almost the same dimensions as those of CPF. After PLA dissolved with methylene chloride was mixed with the fibers, the mixture was dried completely and subsequently it was hot-pressed uniaxially under a pressure of 40 MPa at 180 deg C, resulting in 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 approx 10 GPa when the fibers of 20 approx 60 wt.percent were introduced. The stress-strain curves in the bending test of the PLA/HAF composites showed that very high energy is consumed for their fracture.