块体溶胶-凝胶生物活性玻璃的制备与表征

由于溶胶-凝胶工艺和玻璃组分的限制,从凝胶制备块体生物玻璃有一定难度.获得块体凝胶的关键步骤是干燥工艺,其中毛细管压力起决定作用.用一种简便可靠的方法,制备了均匀、透明、无裂纹的块体溶胶-凝胶生物玻璃585.选用合适的干燥添加剂(DCCA),结合准平衡干燥可以有效防止干燥过程中的凝胶开裂.体外浸泡试验表明,该样品具有优良的生物活性,但是机械强度不高.在玻璃组分中引入TiO₂后,选择合适的DCCA制得的块体材料保持一定的生物活性,同时抗压强度明显提高.讨论了不同的DCCA对干燥过程的不同作用机理和对材料的介孔结构特征的影响,以及TiO₂对提高凝胶骨架和材料整体强度的贡献,还有对体外生物活性的影响.

Preparation and Characterization of Monolithic Sol-gel Bioactive Glass

The synthesis of bioglass from gels is difficult due to its composition and the character of sol-gel route. The drying process is the decisive step in obtaining monolithic gels, in which an essential role is played by capillary forces. This work presented an easy and reliable method to get homogeneous, transparent and crack-free monolithic 58S sol-gel bioglass. Using suitable drying control chemical additives (DCCA) and high relative humidity drying is effective to prevent crack. The obtained bioglass samples have excellent bioactivity in vitro test, but poor mechanical properties. The compressive strength of 58S can be improved greatly by introducing TiO 2 and appropriate DCCA to the glass composition. In this work, the drying mechanism of different DCCA and the effects on the mesoporous structures were discussed, and the contribution of TiO 2 to the improvement of the gel skeleton, the final mechanical intensity and the in vitro bioactivity was also discussed.