| The dispersion and interface adhesion of the of both hydroxyapatite(HA)/ Polyactic acid (PLA) and nano-hydroxyaptite (n-HA)/Polyactic acid (PLA)composites have been studied in this paper by applying different surface modifiers via special processing method.Different polymers-polyethylene glycol (PEG),polyvinyl alcohol (PVA) and polyacrylic acid (PAA), were selected to coat Hydroxyapatite (HA) particles in an effort to improve the interface compatibility through the enhancement of the dispersion of the filler particles in polymer matrix and the promotion of the interfacial adhesion between these two phases of HA /PLLA composite.Nano-HA has been successfully prepared to attempt 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. Freeze-drying, solvent replacement and surface modification methods were combined in an effort to obtain the deagglomerative n-HA crystallites.The Polyethylene glycol (PEG), Pluronic F-127 and poly(d, l-lactide)-co-poly(ethylene glycol) (PELA) were selected to modify n-HA crystallites.The results indicate that: (1) PEG, PVA, PAA are effective to improve the dispersion of hydroxyapatite in the matrix .But PEG is more eminent than PAA, PVA as to the modification of hydroxyaptite, which is mainly due to the conformation and the dipole of the polymer surface modifier. (2) Interface adhesion is the important factor to the mechanical property of composite. Significant improvements in the fracture strength were achieved when HA was coated by PEG.(3) Surface modification is effective method to obtain the deagglomerative n-HA crystallites.But the effect of modification is influenced by solvent and experimental condition. Excellent dispersion of n-HA in the N,N-dimethylformamide solvent or acetone was achieved. (4) Based on such dispersion, we successfully prepared biodegradable nano-composites with...
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