以甲基三甲氧基硅烷(MTMS)和N-氨乙基-γ-氨丙基-三甲氧基硅烷(ATAPTES)为硅源,间苯二酚和甲醛为有机增强体,采用溶胶-凝胶法通过常压干燥制备了有机韧性SiO 2气凝胶。研究了MTMS与ATAPTES、甲醛与间苯二酚摩尔比对复合气凝胶结构和性能的影响。采用N 2吸附脱附等温线、SEM、FT-IR及压缩测试等方法对韧性气凝胶进行了表征。结果表明,甲醛与间苯二酚摩尔比为4时,气凝胶孔径分布范围较宽,总孔容积0.15~0.40 cm ^3/g,比表面积5~70 m ^2/g,最大形变率可达50%,对有机溶剂的吸附量可达自身质量的7~11倍。甲醛与间苯二酚摩尔比为2时,气凝胶孔径主要分布范围3~10 nm,总孔容积0.52~0.53 cm^ 3/g,比表面积110~120 m 2/g,有机复合硅气凝胶柔韧性较小,最大形变率为10%。
Cesium tungsten bronze(Cs_xWO_3) powders were synthesized by hydrothermal reaction at 190 ℃ by using sodium tungstate and cesium carbonate as raw materials,and the effects of N_2 annealing on the microstructure and near-infrared(NIR) shielding as well as heat insulation properties of Cs_xWO_3 were investigated.The results indicated that the synthesized Cs_xWO_3 powders exhibited hexagonal Cs_(0.32)WO_3crystal structure,and subsequent N_2 annealing could further improve the crystallinity of CsxW03 particles.Moreover,the NIR shielding and heat insulation properties of Cs_xWO_3 could be further improved after N_2annealing at appropriate temperature for a period of time.Particularly,the 500 ℃-annealed Cs_xWO_3 products in the N_2 atmosphere showed the best NIR shielding and heat insulation properties.When the N_2 annealing temperature was higher than 700 ℃,the NIR shielding properties decreased again.The 800 ℃-annealed samples in the N_2 atmosphere showed higher visible light transmittance,however,the NIR shielding properties were lower than that of the non-annealed samples.
Fei ShiJingxiao LiuXiaoli DongQiang XuJiayu LuoHongchao Ma
