Preparation And Characterization Of Hydroxyapatite Microspheres

Hydroxyapatite(HAp) is a new type of biological material developed from 1980 year and is similar with the inorganic components of the organism's teeth and bones, which has good biocompatibility and bioactivity, and can be used to repaird the organisms. Furthermore, HAp also can be used as catalyst, cosmetics, paints, adsorbents, and fluorescent materials etc., so it has developed very quickly. And the preparation, doped material and application of HAp have gradually become a hotspot with the gradually deepening.In this study, a simple environmentally friendly way was used to prepare good morphology HAp microspheres by calcium carbonate microspheres as template, which as-prepared by laboratory ourselves. Any organic reagents of harmful organisms have not been adopted throughout the entire preparation. Depending the different morphology of calcium carbonate as-prepared on experimental research process, hollow HAp microspheres, rods and blocks HAp topography were prepared, and carrying silver HAp(Ag-HAp) also preliminary is prepared out. The experiment explored the optimal route prepared ideal sample by changing the test factors of the process of prepared calcium carbonate and HAp microsphere. Specific conclusions are as follows:(1) Calcium carbonate microspheres with uniform morphology and good dispersion were prepared by liquid precipitation and use citric acid as morphology control agents what is harmless for organism. The concentration of reactant concentration and citric acid have great effect on the reaction product, but the stirring speed, air and settling time have little effect on the overall appearance of the product. Finally, ideal Ca CO3 microspheres with homogeneous and has good crystallinity were prepared when the concentration of reactants concentration carbonate and calcium ions is 0.3~0.5mol/L, the concentration of citric acid is consistent with the reactants, the settlement time is 24 h.(2) By hydrothermal method, HAp microspheres were prepared which have similar morphology with raw materials of calcium carbonate microspheres as-prepared previously. Hydrothermal temperature and time directly affects the degree of reaction product and the integrity of morphology, but the p H value at reaction has little effect on the degree of reaction. The best reaction condition prepared good morphology of HAp microspheres by hydrothermal method is the concentration of the reactant(NH4)2HPO4 is 0.06 mol/L, and the molar ratio of calcium and phosphate is 1.67, p H is 12.0, hydrothermal temperature is 140? and hydrothermal time is 24 h.(3) Experiment preliminary discussed prepared rods and blocks HAp with similar morphology of calcium carbonate as templates, but the degree of different morphology of calcium carbonate to similar HAp maybe different. Block HAps prepared from blocks calcium carbonate have more calcium carbonate than which HAps prepared from calcium carbonate rods in the same conditions.(4) Moreover, Laboratory preliminary prepared carrying silver HAp(Ag-HAp) which has certain amount of Ag+. It was found that high concentrations(0.05mol/L) of Ag+ at the reaction can be prepared HAp contains more elemental silver, and at the preparing process, high concentrations of Ag+ is not conducive to prepared Ag-HAp microspheres, and also reduce the crystallinity of Ag-HAp microspheres.