低温保冷用SiO_2气凝胶复合材料的制备和性能

Preparation and properties of silica aerogel composites for cold insulation

以玄武岩纤维为增强相,与SiO_2溶胶复合,经超临界干燥制备疏水SiO_2气凝胶复合材料。采用N_2吸附法、接触角分析仪、傅里叶红外光谱仪、激光法导热仪、万能试验机对玄武岩纤维增强SiO_2气凝胶复合材料的结构和性能进行表征。结果表明:玄武岩纤维增强SiO_2气凝胶复合材料的比表面积为398.31 m^2/g、孔体积为1.076 9cm^3/g、接触角为152°、吸水率为1.7%,材料具有良好的隔热性能和耐低温性能,其常温热导率为0.032 W/(m·K),在深冷条件下体积没有发生明显的收缩。玄武岩纤维的加入提供了力学支撑,使材料具有良好的力学性能,其抗压强度为0.37 MPa(10%应变)、0.85 MPa(25%应变)和1.65 MPa(50%应变)。

Hydrophobic silica aerogel composites were prepared by using basalt fibers as reinforcement via supercritical drying process. Its structure and properties were characterized by pore size distribution,contact angle analyzer,Fourier transform infrared spectroscopy,laser flash apparatus,and universal testing machine. Results showed that the specific surface area,the pore volume,contact angel,and the bibulous rate were 398. 31 m^2/ g,1. 076 9 cm^3/ g,152°,and 1. 7%,respectively. SiO_2 aerogel composites showed excellent thermal insulation properties and low temperature resistance. The thermal conductivity was0. 032 W /（ m·K）. Volume did not shrink obviously under cryogenic conditions. With the reinforcement of fibers,the materials had good mechanical property. The compressive strengths were 0. 37 MPa（ 10%strain）,0. 85 MPa（ 25% strain） and 1. 65 MPa（ 50% strain）.