螯合剂用量对Al2O3-SiO2气凝胶复合材料性能的影响研究

Effect of Chelating Agent Dosageon Properties of Al2O3-SiO2 Aerogel Composites

针对Al2O3-SiO2溶胶稳定性差、复合材料结构不稳定等问题,通过溶胶-凝胶和超临界干燥工艺制备出Al2O3-SiO2气凝胶复合材料。采用平板导热仪、SEM、BET等对Al2O3-SiO2气凝胶复合材料在不同工艺参数下的结构和性能进行分析与表征,完成了Al2O3-SiO2溶胶制备工艺参数研究,确定了较佳的Al2O3-SiO2气凝胶复合材料优化工艺参数。结果表明:随着螯合剂与仲丁醇铝物质的量的比增加,气凝胶的孔径分布(30~50nm)变化不大,复合材料的密度均匀性提高,在微观结构中,气凝胶与纤维的结合程度先增加后减小,其中螯合剂与仲丁醇铝物质的量的比为0.09时结合较好。

Aiming at the problems of poor stability of Al2O3-SiO2 sol and unstable structure of composite materials, Al2O3-SiO2 aerogel composites are prepared by sol-gel and supercritical drying technology. The structure and properties of Al2O3-SiO2 aerogel composites under different technological parameters are analyzed and characterized by means of plate thermal conductivity tester, SEM, BET and so on. The technological parameters of Al2O3-SiO2 sol preparation process are completed, and the better Al2O3-SiO2 aerogel composites are optimized. The results show that the pore size distribution (30-50 nm) of aerogel changes little with the increase of the ratio of chelatingagent to aluminum tri-sec-butoxide, and the density uniformity of the composites increases. In the microstructure, the binding degree of aerogels and fibers increases first and then decreases, and a better one comes when the quantity relativeratio of chelating agent to aluminum tri-sec-butoxide reaches 0.09.