块状纳米孔超级绝热材料的制备与表征

Preparation and characterization of monolithic super thermal insulation with nanoporous structures

以正硅酸乙酯为硅源,采用两步溶胶-凝胶法结合超临界干燥技术制备出了块状无裂纹SiO_2气凝胶,体积密度在50kg·m^(-3)和300kg·m^(-3)之间,样品尺寸约为300mm×300mm×50mm。热学测试表明,常温常压下体积密度大约为100kg·m^(-3)的样品导热系数为0．020 W/m·K,并采用XRD、SAXS、BJH和SEM等其他方法对典型样品(100kh·m^(-3))进行了测试。测试结果表明,SiO_2气凝胶是非晶态的,并且具有纳米多孔结构(骨架颗粒平均粒径为6．8nm,孔径主要集中在10～20nm范围内,而且所有孔径都在70nm以内)。因而可作为具有一定潜在应用价值的块状纳米孔超级绝热材料。

Monolithic silica aerogels of crackfree which were from tetraethoxysilane were prepared by two-step sol-gel process and supercritical drying technique.their densities are in the range of 50～300kg·m^(-3)and their sizes are about 300×300×50mm^3.The thermal conductivity measurement of the material(100 kg·m^(-3))is 0.020 W/m·K at normal temperature and pressure,and is also tested by using XRD,SAXS,BJH,SEM and some other experimental tech- niques.The test results showed that the silica aerogel was non-crystallin...