Synthesis and properties of hydroxyapatite/poly-L-lactide composite biomaterials

Calcium hydroxyapatite (HAp) and poly-L-lactide (PLLA) were synthesized chemically. The obtained HAp was of high purity and, after special thermal treatment, of high crystallinity as well. Synthesis of PLLA was performed using L-lactide as a monomer and nontoxic initiator. In this way a polymer of large molar weight (about 400,000) was obtained. The HAp and PLLA obtained were used as constituents of the HAp/PLLA composite biomaterial, a potential material for implants. The composite was obtained by mixing completely dissolved PLLA with granules of HAp. The composite was compacted by cold and hot pressing at pressures of 49.0-490.5 MPa and temperatures of 20-184 degrees C. The material obtained at optimum process parameters had a density of 99.6% and compressive strength of 93.2 MPa.