原位增强羟基磷灰石/壳聚糖复合棒材

In-situ reinforced hydroxyapatite/chitosan composite rods

利用低温水溶液均相沉积法制备了磷酸钙盐微纤维;应用原位沉析法制备了壳聚糖（CS）三维棒材及羟基磷灰石（HA＊）/CS复合棒材。XRD证实应用原位沉析法制备HA＊/CS复合棒材过程中,磷酸钙盐转化为羟基磷灰石结构,尺寸为10~60μm,并用SEM对晶体形貌进行了表征,分析了转化机制。HA＊/CS复合材料的微观形貌表明,HA＊晶体在CS凝胶棒原位沉析的过程中析出而与CS基体形成镶嵌、相互咬合结构,且在基体中分散均匀,有效地提高了HA＊与CS基体的界面连接作用,使力学性能显著提高。所制备的HA＊/CS棒材随HA＊含量的增大（在其饱和溶解度3.3 wt%范围内）,复合材料的弯曲性能逐渐提高,当羟基磷灰石质量分数为3.3%时,复合材料的弯曲强度达到159.6 MPa,弯曲模量达到5.1 GPa,比CS基体分别提高85.6%和54.5%。HA＊/CS复合棒材的弯曲强度和弯曲模量远高于松质骨,弯曲强度也比密质骨高。

Calcium phosphate microfibrils were fabricated by a homogeneous low-temperature deposition method in an aqueous solution.Chitosan（CS） rods were prepared via an in-situ precipitation processing,and hydroxyapatite（HA＊）/CS composite rods were prepared on the base of the in-situ precipitation processing.The calcium phosphate microfibrils were transformed to hydroxyapatite style through the in-situ precipitation method.X-ray diffractometer（XRD） and scanning electron microscope（SEM） were performed to characterize structure and morphology of the calcium phosphate microfibrils and the hydroxyapatite crystals.Moreover,the transformation mechanism from calcium phosphate to hydroxyapatite was also discussed.XRD results show that the calcium phosphate transforms to hudroxyapatite through the in-situ precipitation processing.SEM results exhibit that the hydroxyapatite crystals are dispersed uniformly in the composites and formed an inlayed and occlusive structure with the CS matrix,which led to significant improvement in mechanical properties of the HA＊/CS composite rods.Results indicate that the HA＊/CS composites show much better mechanical properties than a commercial HA reinforced CS matrix composites.Flexural properties of the HA＊/CS composites are increased with increasing HA＊ concentration within its saturated solubility,mass fraction 3.3%.Flexural strength and flexural modulus of the HA＊/CS composites with 3.3% hydroxyapatite are 159.6 MPa and 5.1 GPa,respectively,which are 85.6% and 54.5% higher than the neat CS rod.The mechanical properties of the HA＊/CS composites are much higher than cancellous bone,and close to compact bone.