SiO_2气凝胶常压干燥制备及性能分析

PREPARATION OF SILICA AEROGELS IN AMBIENT PRESSURE DRYING AND ANALYSIS OF PROPERTIES

采用溶胶-凝胶法制备SiO2气凝胶,通过酸、碱催化两步法调控正硅酸乙酯(TEOS)的水解-缩聚速率,用乙醇和正硅酸乙酯溶液浸泡和老化醇凝胶,并以乙醇、三甲基氯硅烷(TMCS)和正己烷为表面改性剂,采用逐级改性方法对气凝胶进行改性,再在常压下干燥改性后的醇凝胶,制备出了憎水性和良好的热稳定性的SiO2气凝胶。采用XRD、傅立叶红外吸收光谱(FTIR)、DT-DSC曲线等测试方法对SiO2气凝胶进行性能表征。

Silica aerogels were prepared with Sol-Gel. Rate of hydrolysis and polycondensation were adjusted by catalyst, such as acid and base. Alcosol were aging by mixed solvent of ethanol and ethylorthosilicate. Surface of aerogels were modified gradually with ethanol, trimethylchlorosilane and n-hexane. Then the modified alcosol were dried in ambient pressure. Properties of silica aerogels were characterized with XRD, IR spectrum and DT-DSC methods.