含部分碳酸根的针状羟基磷灰石晶体的均相合成

The Preparation of Needle-like Carbonate-containing Hydroxyapatite Crystals by Homogeneous Precipitation Method

选用可溶性的硝酸钙和磷酸氢二铵 ,在尿素用作添加剂的条件下用均相沉淀法合成了含部分碳酸根的针状羟基磷灰石晶体。同时给出了碳酸根对羟基磷灰石晶体阴离子的置换及反应条件对碳酸根含量的影响的定性分析。还讨论了体系温度、营养料浓度、添加剂种类对晶体长度及长径比等性能的影响。实验结果表明 ,用尿素作添加剂合成羟基磷灰石时 ,晶体中含有部分碳酸根 ,碳酸根对羟基和磷酸根均存在部分替代 ,其含量仅与体系温度有关 ,而营养料的浓度、添加剂的水解速度和体系温度对晶体的长度和长径比有直接影响。在钙磷离子浓度积为 4～ 5 0 (m mol/L ) 2 ,温度为 82～ 95℃时 ,用均相沉淀法可以获得长度为 5 0～ 15 0 μm,长径比为 40～ 10

Calcium nitrate 4-hydrate and diammonium hydrogen orthophosphate are selected as initial materials; needle-like carbonate-containing hydroxyapatite crystals are synthesized by homogeneous precipitation method with urea is used as additive. The paper discussed the substitution of carbonate to anions of the crystal together with qualitative analysis about effect of reaction conditions on carbonate content. Effects on length and length/diameter ratio of crystal are also analyzed in the paper. It is mainly temperature of the system, concentration of nutrients and additives that affects length and length/diameter ratio. Experimental results reveals that carbonate exist in crystal lattice when urea is used as additive. Carbonate partly substitutes both hydroxyl and phosphate, and content of carbonate is decided only by temperature of the system. Needle-like hydroxyapatite crystals, which is 50-150 μm long with length/diameter ratio ranges from 40 to 100, could be obtained by homogeneous precipitation method under condition of that ions product of calcium and phosphate ranges from 4 to 50 (mmol/L)2 in 82°C to 95°C environment.