α-Tricalcium phosphate hydrolysis to hydroxyapatite at and near physiological temperature
α-Tricalcium phosphate hydrolysis to hydroxyapatite at and near physiological temperature
复制标题
DOI：
10.1023/a:1008934024440
复制
发表时间：
2000-06-01
影响因子：
3.7
通讯作者：
Brown, PW
中科院分区：
文献类型：
--
作者：
Durucan, C;Brown, PW
研究了α-磷酸三钙（α-TCP）[α-Ca-3（PO_4）（2）]直接水解生成羟基磷灰石（HAp）的动力学。通过等温量热分析检查了37摄氏度、45摄氏度和56摄氏度下反应的转化动力学。凝固时间和所得HAp的形态被发现是强烈依赖于反应温度。XRD分析和FTIR分析证实，合成了纯相的缺钙羟基磷灰石（CDHAp）[Ca 10-x（HPO 4）（x）（PO 4）（6-x）（OH）（2-x）]。完全反应分别在37、45和56 ℃下在18、11、6.5 h内发生。HAp形成的程度对于颗粒浆料和预成形形式的反应物α-TCP是不同的。由于水的渗透有限，预成型颗粒中羟基磷灰石的形成受到阻碍，但随着NaCl作为造孔剂的存在而增强。无论前体特性和温度如何，HAp形成的特征在于α-TCP前体的润湿的初始期、诱导期和生长期，在生长期期间发生向HAp的本体转化。所得HAp在所有温度下的微观结构大体相似，其特征在于形成多孔片状形态。在生理温度以上形成的CDHAp观察到显微结构粗化。使用径向压缩试验证明了水解反应产生的硬化。在37 ℃下水解成CDHAp后，56%致密的α-TCP的原始拉伸强度从0.70 +/-0.1MPa增加到9.36 +/-0.4MPa，对应于70%的密度。(C)2000 Kluwer Academic Publishers.
The kinetics of hydroxyapatite (HAp) formation by direct hydrolysis of alpha-tricalcium phosphate (alpha-TCP) [alpha-Ca-3(PO4)(2)] have been investigated. Transformation kinetics were examined for reactions at 37 degrees C, 45 degrees C and 56 degrees C by isothermal calorimetric analysis. Setting times and morphologies of the resultant HAp were found to be strongly dependent on reaction temperature. XRD analysis accompanied by FTIR confirmed that phase pure calcium-deficient hydroxyapatite (CDHAp) [Ca10-x(HPO4)(x)(PO4)(6-x)(OH)(2-x)] was formed. Complete reaction occurs within 18, 11, 6.5 h at 37, 45 and 56 degrees C, respectively. The extent of HAp formation differs for particulate slurries and pre-shaped forms of reactant alpha-TCP. Formation of hydroxyapatite in pre-formed pellets was hindered due to limited water penetration, but enhanced with the presence of NaCl as a pore generator. Regardless of the precursor characteristics and temperature, HAp formation is characterized by an initial period of wetting of the alpha-TCP precursor, an induction period and a growth period during which the bulk transformation to HAp occurs. The microstructures of the resultant HAp at all temperatures were generally similar and are characterized by the formation porous flake-like morphology. Microstructural coarsening was observed for the CDHAp formed above the physiological temperature. The hardening generated by the hydrolysis reaction was demonstrated using diametrical compression tests. The original tensile strength of 56% dense alpha-TCP increased from 0.70 +/- 0.1 MPa to 9.36 +/- 0.4 MPa after hydrolysis to CDHAp at 37 degrees C, corresponding to a density of 70%. (C) 2000 Kluwer Academic Publishers.