Preparation of polylactic acid composites containing β–Ca(PO3)2 fibers

Abstract

Novel biomaterials for application to artificial bone with modulus of elasticity close to that of natural bone were prepared using bioresorbable poly-L-lactic acid (PLLA) and high-strength β–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 under a pressure of 40 MPa at 180 °C, resulting in fabrication of a PLLA composite containing β–Ca(PO3)2 fibers. Almost no degradation in the bending strength was observed even when a large amount of the fibers (≈50 wt. %) was introduced, and the modulus of elasticity was increased effectively with increasing the fiber content. The PLLA composite with modulus of elasticity of <5 GPa similar to that of natural bone was found 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 fracture and that the fracture proceeds step by step, even beyond the maximum stress.