| The preparation and characterization of both dense and porous bioactive composites have been studied in this paper by applying different surface modifiers via special processing method \vith PLA and synthesized nano-HA. Higher content of nano-HA has been attempted to achieve so as to modulate the mechanical biocompatibility. The dispersion of nano-HA and the interface between inorganic and organic phase have been investigated. In vitro experiment has also been carried out to test the bioactivity and the degradation behavior of the composites. The results show:(l)PAA is more eminent than PVA as to the modification, which is mainly due to the conformation and the dipole of the polymer surface modifier.(2) Mechanical properties of all composites are improved and change the same as the content of nano-HA. The compromise properties reach to the highest value when the composite contains about 50\vt% nano-HA. (3) Unmodified nano-HA still adheres to PLA to some extent, which results in the reinforcing. Surface modification attributes much to the dispersion of nano particles but little to the interfacial adhesion. The dispersion of nano-HA in the matrix is influenced by the surface modification and processing method. (4)The pore distribution and the porosity of the porous composite are determined by the processing method. And when the content of HA increases beyond about 50wt%, the porous composite fails to be prepared. (5) Bioactive HA endows the composite with bioactivity, which changes the same as the contents of inorganic phase, while varies little to the PH value. The degradation of PLA can be effectively buffered by HA.
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