硅酸钠为前驱体的SiO_(2)气凝胶制备及性能研究  

Preparation and properties of SiO_(2)aerogel with sodium metasilicate as precursor

作　　者：徐长伟[1] 孙沈涵 张忠伦 王明铭 XU Changwei;SUN Shenhan;ZHANG Zhonglun;WANG Mingming(School of Materials Science and Engineering,Shenyang Jianzhu University,Shenyang 110168,China;CNBM Technology Innovation Academy(Shandong)Co.,Ltd.,Zaozhuang 277100,China;China Building Materials Academy Co.,Ltd.,Beijing 100024,China)

机构地区：[1]沈阳建筑大学材料科学与工程学院,沈阳110168 [2]中建材科创新技术研究院(山东)有限公司,枣庄277100 [3]中国建筑材料科学研究总院有限公司,北京100024

出　　处：《复合材料科学与工程》2024年第11期14-21,共8页Composites Science and Engineering

基　　金：山东省“十四五”重点研发计划项目(2021SFGC0903)。

摘　　要：本实验以硅酸钠为硅源,采用常压干燥的方式来制备SiO_(2)气凝胶。主要探究不同硅酸钠质量分数、化学干燥剂掺入量对SiO_(2)气凝胶振实密度、比表面积、孔容孔径、微观结构等指标的影响。通过水洗法去除其中的Na^(+),确定了最佳的水洗效率,并分析Na^(+)对气凝胶性能产生的影响。结果表明:当硅酸钠质量分数为7wt%时,制备出的气凝胶性能较为优异,具体表现为凝胶时间较短(3 min),振实密度可低至0.209 g/cm^(3),孔隙率较高(90.5%)。当n(DCCA)∶n(Si)=2∶1时,气凝胶有着较大的比表面积(531.69 m^(2)/g)与较高的总孔体积(2.51 ml/g),且孔结构也最为均匀。水洗去除Na^(+)时,应将水洗温度控制在50℃左右,用水量控制在15倍体积水左右,洗四次即可去除97.24%的Na^(+)。最后发现残留的Na^(+)会对SiO_(2)气凝胶的密度和导热系数产生负面影响,因此除Na^(+)工艺非常重要。In this experiment,sodium silicate was used as the silicon source to prepare SiO_(2)aerogel by drying under normal pressure.The influence of different sodium silicate mass fraction and chemical desiccant content on the vibrating density,specific surface area,pore volume and pore diameter,microstructure and other indicators of SiO_(2)aerogel was mainly explored.The best washing efficiency was determined and the effect of Na^(+)on the performance of aerogels was analyzed.The results show that when the mass fraction of sodium silicate is 7wt%,the prepared aerogel has excellent performance,specifically,the gel time is 3 min;the compaction density can be as low as 0.209 g/cm^(3);the higher porosity is 90.5%.When n(DCCA)∶n(Si)=2∶1,the aerogel has a larger specific surface area of 531.69 m^(2)/g and a higher total pore volume of 2.51 ml/g,and the pore structure is the most uniform.When remo ving Na^(+)through water washing,the washing temperature should be controlled at around 50℃,and the water con sumption should be controlled at around 15 times the amount of accumulated water.Four washes can remove 97.24%of the original Na^(+).Finally,it is found that the residual Na^(+)will have a negative impact on the density and thermal conductivity of SiO_(2)aerogels,so the process of removing Na^(+)is very important.

关 键 词：SiO_(2)气凝胶 化学干燥剂 水洗工艺 复合材料 

分 类 号：TB332[一般工业技术—材料科学与工程]