Preparation of chemically bonded anatite for biomaterials

通过添加聚丙烯酰胺、聚甲基丙烯酸甲酯、丙烯酰胺单体，制备了磷酸钙液压硬化体。在室温条件下，上述添加剂能显著延缓磷酸钙的水解，并能加速80℃的水解。采用羟基磷灰石、α - ca_3 (PO_4)_2、β - ca_3 (PO_4)_2和无定形磷酸钙的热分解产物作为磷酸钙胶结剂。首先将磷灰石热分解产物中的丙烯酰胺单体进行聚合，然后将磷酸钙胶结物在水中加热。由此获得的磷酸钙硬化体的体积密度约为1.7，弯曲强度约为11-12 mpa，与未添加聚合物的硬化体相比增加了一倍。除上述水化条件外，还采用丙烯酰胺单体桥接剂制备了水力磷酸钙。含桥接剂的磷酸钙体的容重约为1.8，抗弯强度约为20 MPa。在磷酸钙水泥中加入二氧化硅改善了水泥浆的和易性。

Preparation of hydraulic hardened bodies of calcium phosphates was carried out adding polyacrylamide, polymethylmetacrylate, monomer of acrylamide. Hydrolysis of calcium phosphates were remarkably retarded by the above additives at room temparature and accelerated 80ﾟC.Thermal decomposition products of hydroxyapatite, alpha-Ca_3 (PO_4)_2, beta-Ca_3 (PO_4)_2 and amorphous calcium phosphate were used as calcium phosphate cements.Acrylamide monomer in the thermal decomposition products of apatite was polimerized at first and then the calcium phosphate cements were heated in water. The calcium phosphate hardened bodies thus obtained were found to be about 1.7 in bulkdensity and 11-12 MP a in bending strength, which was doubled compared with that obtained on no addition of polymers. In addition to the above hydration conditions, bridging agents for acrylamide monomer was used on the preparation of hydraulic calcium phosphates. The calcium phosphate bodies containing the bridging agent were found to be about 1.8 in bulk density and about 20 MPa in bending strength. Silica addition into calcium phosphate cements improved the workability of the cement slurries.