硅藻土/SiO2气凝胶复合材料的制备

关键字：硅藻土；常压干燥；SiO2气凝胶；抗压强度

（天津城建大学 材料科学与工程学院，天津  300384）

    摘要：采用溶胶-凝胶法，以正硅酸乙酯为硅源，硅藻土为增强相，通过常压干燥法制备硅藻土/SiO2气凝胶复合材料。研究了硅藻土用量对复合材料导热系数、孔隙率及抗压强度的影响，并通过SEM对其微观形貌进行分析。结果表明，硅藻土与SiO2气凝胶实现了一定程度的复合；随着硅藻土含量由5%逐渐增加至25%时，复合材料的导热系数由0.0312 W/（m·K）增大到0.0447 W/（m·K）；平均孔径和比表面积则分别由16.98 nm、817.2142 m2/g减小到了9.87 nm和594.8543 m2/g；此外，硅藻土的加入可以极大提高复合材料基体的耐压性能，鉴于材料本身仍需具备一定的保温隔热性能，硅藻土的最佳含量为15%。

    关键词：硅藻土；常压干燥；SiO2气凝胶；抗压强度

    中图分类号：TU55+1.3        文献标识码：A        文章编号：1001-702X（2018）05-0121-04

 

Preparation of diatomite/SiO2 aerogel composites

LIU Hongli，AN Guoqing，HE Xiang，CHU Peng

（School of Materials Science and Engineering，Tianjin Chengjian University，Tianjin 300384，China）

    Abstract：SiO2/diatomite composites was prepared with tetraethoxysilane as silicon source，diatomite as raw material by sol-gel method combining an atmospheric pressure drying method. Effects of different dosage of diatomite on the thermal conductivity，porosity and compressive strength of composite materials were investigated，and the microstructure was analyzed through the SEM. The results show that the diatomite and SiO2 aerogel achieve a certain degree of recombination；with the gradual increase of diatomite content（from 5% to 25%），the thermal conductivity of composite increased from 0.0312 W/（m·K） to 0.0447 W/（m·K），the average pore size and surface area were decreased from 16.98 nm，817.2142 m2/g to 9.87 nm，594.8543 m2/g respectively，in addition，the addition of diatomite can greatly improve the compression performance of composite matrix. Considering the material itself still needs a certain thermal insulation performance，the best addition amount of diatomite should be 15%.

    Key words：diatomite，ambient pressure drying，SiO2 aerogels，compressive strength