明胶溶液中沉淀法制备纯相β-磷酸三钙(英文)

Synthesis of Pure β-Ca_3(PO_4)_2 Bioceramicswith Gelatin by Precipitation Method

本文以明胶、硝酸钙Ca(NO3)2和磷酸氢二铵(NH4)2HPO4为前驱体,初始Ca/P为1.5,制备了纯相的β-磷酸三钙.红外谱图和X射线晶体衍射结果表明,溶液中直接沉淀得到的产物为缺钙磷灰石,该产物在明胶浓度≥0.22%(质量分数)时热转化为纯相的β-磷酸三钙.通过晶体尺寸计算和比表面积测定,缺钙磷灰石的晶体大小随着明胶用量的增加而变小.透射电镜结果显示溶液中直接沉淀的缺钙磷灰石呈针状形貌,经过高温煅烧后,针状的缺钙磷灰石将相互融合形成葡萄状的β-磷酸三钙.差热/热重结果表明,明胶与生成的缺钙磷灰石形成了化学键合,这将有助于吸附较多的水分子,随后水分子与缺钙磷灰石发生化学反应生成羟基磷灰石,羟基磷灰石继续与沉淀中的偏磷酸钙反应生成β-磷酸三钙.本文还研究了明胶对纯相β-磷酸三钙的生成机理.

Pure β-tricalcium phosphate （β-TCP） was synthesized using the precipitation method, starting from the gelatin, Ca （NO3）2 and （NH4）2 HPO4 precursors by adopting the initial Ca/P ratio of 1.5. FT-IR spectroscopy and X-ray diffractometry indicated the solution derived precipitate was calcium deficient phosphate （Ca-dHAP） and it would thermally transform into pure β-TCP as the amount of gelatin exceeds 0. 22% （mass concentration）. The Ca-dHAP crystal dimensions decreased with increasing gelatin amount as shown by crystallite calculation and SSA measurement. TEM results showed that the as prepared Ca- dHAP powders were needle-like and formed a botryoidal shape characteristic of β- TCP when being calcined at high temperatures. The DTA/TG results showed that gelatin chemically bonded with the Ca-dHAP crystals which could be beneficial for the absorption of water molecules and the absorbed water molecules, then subsequently reacted with Ca-dHAP to form HA which would react with a second phase calcium pyrophosphate （Ca2P2OT） （CPP） to prepare pure 13-TCP. In this paper, we also studied the mechanism of gelatin on the formation of β-TCP