反应物结构对酚醛凝胶及其气凝胶的影响

Influence of Reactants Structure on Phenolic Resins Gel and Aerogel

为研究反应物酚与醛的结构对酚醛凝胶过程及其气凝胶结构的影响,采用不同的酚与醛制备出了多种气凝胶。研究了反应物结构对凝胶过程的影响,并通过扫描电镜和孔径分析仪等仪器详细研究了气凝胶的结构。结果表明,酚醛反应的凝胶时间受反应物的活性及位阻效应共同影响,反应体系选择不当可能导致无法凝胶。采用不同的酚-醛体系,所得气凝胶结构也不同。5-甲基间苯二酚-糠醛(MR-F)气凝胶较间苯二酚-糠醛(RF)气凝胶的比表面积增加25%,而微孔比表面积和体积分别增加了3.6倍和9.6倍。

To investigate the influence of reactant structure on gel process and aerogel structure,aerogels were prepared with different reaction systems.The influence of reactant structure on gel process was investigated,and the structure of aerogels was also investigated by means of scanning electron microscope（SEM） and surface area and pore size analyzer.The results show that reactivity and steric effect of reactants affect the gelation time together.Gel can not be formed if reactants were chosen wrongly.Aerogel structure is different with the change of reaction system.The surface area of 5-methyl furfural resorcinol（MR-F） aerogel is 25% bigger than that of resorcinol furfural（RF） aerogel,and the micropore surface area and pore volume of MR-F aerogel are 3.6 times and 9.6 times bigger than those of RF aerogel respectively.