Preparation and Biocompatibility of .BETA.-Tricalcium-Phosphate/Copolymerized-Poly-L-Lactide Composite

Thermoplastic composites of beta -tricalcium phosphate (TCP) /copolymerized poly-L-lactide (CPLA) were prepared by a heat kneading method and evaluated by XRD, FT-IR, three-point bending strength test and SEM. The composites were white and no structural changes were detected in TCP powder mixed with CPLA by XRD. Their compacts had a three-point bending strength of 51.26plus/minus6.34 MPa, a fracture strength of 52.64plus/minus2.975 MPa and a Young's modulus of 5.18plus/minus1.11 GPa. From SEM observation, TCP and CPLA adhered well, and mechanical fracture took place in both CPLA transgranular and TCP-CPLA intergranular regions. The IR absorption band of the polyester C=O double bond gradually shifted to lower wave numbers with increasing TCP content in the composites. This result suggested the formation of a Ca-O(=C) bond between TCP and CPLA which preserved the mechanical strength of the composite, almost independent of that of CPLA.