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利用正硅酸乙酯做先躯体,盐酸与氨水做催化剂,通过二步法制备了二氧化硅气凝胶,并利用三甲基氯硅烷和正己烷做表面改性剂采用共沸法逐级对湿凝胶进行表面改性。测试分析了气凝胶的密度、表观、疏水性、比表面积、孔径分布和热稳定性。结果表明:气凝胶的物理特性及其疏水性受到三甲基氯硅烷与正己烷的体积比()的影响,其密度随着的增大而减小,当=3%时,气凝胶的疏水性最好;所制得的SiO2在350℃仍具有良好的热稳定性,并且具有高比表面积(838.6m2/g)和孔体积(2.10cm3/g)。
Using tetraethyl orthosilicate as a precursor, hydrochloric acid and ammonia as a catalyst, a two-step method was used to prepare a silica airgel, and the use of trimethylchlorosilane and n-hexane as a surface modifier by azeotropic distillation Wet gel surface modification. The aerogels were tested for their density, apparent, hydrophobicity, specific surface area, pore size distribution and thermal stability. The results show that the physical properties and hydrophobicity of the aerogels are affected by the volume ratio () of trimethylchlorosilane to n-hexane, and their densities decrease with increasing. When = 3% The airgel has the best hydrophobicity; the prepared SiO2 still has good thermal stability at 350 ° C and has high specific surface area (838.6m2 / g) and pore volume (2.10cm3 / g).