添加剂PVB对炭气凝胶制备工艺及结构的影响

EFFECTS OF ADDITIVES PVB ON THE PREPARATION AND STRUCTURE OF CARBON AEROGELS

采用溶胶—凝胶法,以间苯二酚(R)、甲醛(F)为原料、无水碳酸钠(C)作催化剂、聚乙烯醇缩丁醛(PVB)为添加剂、无水乙醇作溶剂,通过常温常压干燥和高温炭化制备炭气凝胶。考察了中间产物有机凝胶的热解行为和催化剂浓度及PVB用量对炭气凝胶孔隙结构的影响。结果表明:PVB的加入不仅加强了有机凝胶的网络结构,使其更利于常温常压干燥,而且能够较好地调控炭气凝胶的孔径分布;在一定的PVB加入量范围内,随着PVB加入量的增加,炭气凝胶的比表面积增加,孔径分布也更加集中;催化剂浓度对炭气凝胶的比表面积及孔径分布有较大的影响,当R/C=300,PVB/R=1/10时比表面积达到最大值(386m^2/g)。

Carbon aerogels were prepared from the sol-gel polymerization of resorcinol with formaldehyde catalyzed by anhydrous sodium carbonate, followed by ambient drying and carbonization. Anhydrous ethanol and PVB （Polyvinyl Butyral）were used as solvent and additives,respectively. The influences of pyrolysis of organic aerogels,catalyst concentration and PVB content on the pore structure of carbon aerogels were investigated. The results show that the additive of PVB not only reinforces the net structure of organic aerogels,but also preferably controls the pore size distribution of carbon aerogels, in the range of PVB content,the specific surface area of carbon aerogels increases with the PVB content,and the pore size distribution gets more concentrative. Furthermore,the catalyst concentration has more efects on the specific surface area and pore size distribution of carbon aerogels. The specific surface area reaches maximum （386m^2/ g） when R/C=300 and PVB/R=1/10.