聚合物改性SiO_2气凝胶的常压干燥制备及表征

以TEOS（四乙氧基硅烷）和APTES（3-氨丙基三乙氧基硅烷）共缩聚制备SiO2凝胶后采用N3200（1,6-环己烷二异氰酸酯低聚物）对其改性,经常压干燥制备了聚合物改性SiO2气凝胶。采用TGA、N2吸附-脱附、SEM和单轴抗压实验等测试方法对所制备的气凝胶进行了表征。结果表明：随气凝胶中聚合物含量的增加,气凝胶制...

Preparation and characterization of polymer modified silica aerogels dried under ambient pressure

Silica gels, which were prepared by copolymerization of TEOS with APTES, were modified with N3200 (a 1,6-hexamethylene diisocyanate oligomer). Polymer modified silica aerogels were obtained via drying of the silica gels under ambient pressure. The resulting materials were characterized by TGA, nitrogen adsorption-desorption, SEM, uniaxial compression tests, etc. It is found that with the increase of polymer incorporated in silica aerogels, the shrinkage and the compressive strength of this material decrease, the bulk density and the elastic modulus firstly decrease and then increase slightly, the cracking limit strain and breaking limit strain during compression test increase dramatically. SEM observation indicates that the structure of polymer modified silica aerogels is porous network. The porosity decreases and then increases with the increase of polymer incorporated in silica aerogels, The thermal conductivity for a sample with density of 434kg/m 3 is 0.052 W/(m·K).