Preparation of polylactic acid composites containing beta-Ca(PO3)(2) fibers

Novel biomaterials for application to artificial bone with modulus of elast icity close to that of natural bone were prepared using bioresorbable poly- L-lactic acid (PLLA) and high-strength beta-Ca(PO3)(2) fibers treated with dilute NaOH solution. PLLA dissolved by using methylene chloride was mixed with the fibers. After drying the mixture, it was hot-pressed uniaxially un der a pressure of 40 MPa at 180 degrees C, resulting in fabrication of a PL LA composite containing beta-Ca(PO3)(2) fibers. Almost no degradation in th e bending strength was observed even when a large amount of the fibers (app roximate to 50 wt. %) was introduced, and the modulus of elasticity was inc reased effectively with increasing the fiber content. The PLLA composite wi th modulus of elasticity of >5 GPa similar to that of natural bone was foun d to be prepared when the fiber content was over 35 wt. %, The bending test of the composites showed that very high energy is consumed for their fract ure and that the fracture proceeds step by step, even beyond the maximum st ress.