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

Calcium hydroxyapatite (HAp) and poly-L-lactide (PLLA) were synthesized che mically. The obtained HAp was of high purity and, after special thermal tre atment, of high crystallinity as well. Synthesis of PLLA was performed usin g L-lactide as a monomer and nontoxic initiator. In this way a polymer of l arge molar weight (about 400 000) was obtained. The HAp and PLLA obtained w ere used as constituents of the HAp/PLLA composite biomaterial, a potential material for implants. The composite was obtained by mixing completely dis solved PLLA with granules of HAp. The composite was compacted by cold and h ot pressing at pressures of 49.0-490.5 MPa and temperatures of 20-184 degre es C. The material obtained at optimum process parameters had a density of 99.6% and compressive strength of 93.2 MPa. (C) 1999 Elsevier Science Ltd. All rights reserved.