Preparation of poly(lactic acid) composites containing calcium carbonate (vaterite)

A new type of ceramic-polymer biomaterial having excellent apatite-forming ability in simulated body fluid was prepared by hot-pressing a mixture of poly(- -lactic acid) (PLA) and calcium carbonate (vaterite). After PLA dissolved in methylene chloride was mixed with calcium carbonate consisting of vaterite, the mixture was dried completely and subsequently hot-pressed uniaxially under a pressure of 40 MPa at 180°C. When 30 wt% vaterite was introduced, the modulus of elasticity was effectively improved by 3.5–6 GPa, which was about twice higher than the modulus of PLA. The composite showed no brittle fracture behavior and a comparably high bending strength of 50 MPa. The composite containing 30 wt% vaterite formed a 5–15-μm-thick bonelike apatite layer on its surface after soaking in SBF at 37°C even for 1–3 d.