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°C. The material obtained at optimum process parameters had a density of 99.6% and compressive strength of 93.2 MPa.