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二氧化硅气凝胶的性能受热过程的影响
引用本文:刘光武.二氧化硅气凝胶的性能受热过程的影响[J].同济大学学报(自然科学版),2013,41(7):1078-1083.
作者姓名:刘光武
作者单位:同济大学物理科学与工程学院,上海200092;上海市特殊人工微结构材料与技术重点实验室,上海200092
基金项目:国家自然科学基金,"十一五"国家科技支撑计划
摘    要:成功地以水玻璃为硅源,经乙醇溶剂替换及六甲基二硅醚和盐酸的混合液对SiO2湿凝胶表面基团改性后,常压干燥制备出低密度、高比表面积、超疏水、低热导率的高性能SiO2气凝胶块体.SiO2气凝胶在室温至400℃附近具有稳定的疏水性能,460℃附近气凝胶由疏水型完全转变成亲水型.重点研究了室温至400℃之间,SiO2气凝胶的微观结构和物理性能受热处理过程的影响.SiO2气凝胶即使经过400℃高温热处理后,仍能保持优异的疏水性能、较高的比表面积和较低的热导率等.

关 键 词:二氧化硅气凝胶  水玻璃  疏水性  热导率  高保温
收稿时间:8/2/2012 12:00:00 AM
修稿时间:2013/4/19 0:00:00

Effect of Thermal Process on Microstructure and physical properties of silica aerogels
liuguangwu.Effect of Thermal Process on Microstructure and physical properties of silica aerogels[J].Journal of Tongji University(Natural Science),2013,41(7):1078-1083.
Authors:liuguangwu
Institution:Institute of Physical Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Shanghai 200092, China;Institute of Physical Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Shanghai 200092, China;Institute of Physical Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Shanghai 200092, China;Institute of Physical Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Shanghai 200092, China
Abstract:Prepared with sodium silicate precursor, ethanol (EtOH)/ hexamethyldisiloxane (HMDSO) /hydrochloric acid (HCL) as solvent exchange and surface modification agent, the crack free and high hydrophobic silica aerogel monoliths were obtained. Silica aerogels possessed the superior properties, such as low density, high surface area, high hydrophobicity and low thermal conductivity. Silica aerogel monoliths maintained hydrophobic behavior up to a maximum temperature of 460 °C above which they become hydrophilic. After a thermal process changing from room temperature to 400 °C, the final product still remained hydrophobic and presented good performance with the surface area of 530 m2?g-1. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.025 to 0.049 W?(m?K)-1 as temperature increased from 25 °C to 400 °C, an excellent heat insulation effect during thermal process remained.
Keywords:silica aerogels  sodium silicate  hydrophobicity  thermal conductivity  high temperature thermal insulation
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