| The preparation and characterization of composites with poly (D,L) lactic acid (PDLLA) and synthesized nano-hydroxyapatite have been studied in this paper.Firstly, the process to synthesize nano-hydroxyapatite (HA) with calcium-nitrate and ammonium-dihydrogen-phosphate was studied. The main effect factors such as reaction temperature, the pH value of solution etc. on the performance of HA were studied.Secondly, n-butyl alcohol was used as surface treatment agent to prepare nano-hydroxyapatite (HA)(L/D ratio is about 2.5/1) by azeotropic distillation based on solution reaction method. Compared with the untreated HA, after treated by n-butyl-alcohol, the crystalline temperature of HA was decreased by two hundred centigrade, the crystallite dimension of HA was reduced by two thirds, moreover, the particle aggregation phenomena was decreased obviously. The synthesis of the compound HA with a mesostructured framework was achieved by use of CTAB. Nanoparticle HA and mesoporous HA with high surface areas were characterized by XRD, FT-IR, DSC, SEM, TEM and BET.Thirdly, composites with PDLLA and HA were prepared by SUD. The degradation experiment in vitro has also been carried out to test the degradation behavior of the composites. Composites were characterized and analyzed by DSC, SEM and IR. The results show: thermal stability of composite is better than PDLLA. There are two stages in vitro degradation of composites, one is degradation of the organic material, the other is calcification of the inorganic material. Compared with PDLLA, the degradation of composites can be effectively buffered by HA.
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