添加环氧丙烷法常压干燥制备ZrO2气凝胶

以无机锆盐硝酸氧锆(ZrO(NO3)2·5H2O)为前驱体,1,2-环氧丙烷(PO)为凝胶促进剂,甲酰胺(FA)为干燥控制化学添加剂(DCCA),采用溶胶-凝胶法并通过常压干燥制备了轻质二氧化锆(ZrO2)气凝胶,利用差热分析(DTA)、扫描电镜(SEM)、N2吸附/脱附等测试技术对所制得的ZrO2气凝胶进行了表征.结果表明:添加环氧丙烷常压干燥制得的ZrO2气凝胶具有纳米尺寸的多孔网络结构,表观密度可低至202.08 kg·m-3,比表面积可高达645.0 m2·g-1,与超临界干燥效果相当.环氧丙烷因其环氧原子的强亲核性和不可逆的开环反应,可促进凝胶化,并通过环氧丙烷的量控制反应过程和凝胶状态.

Synthesis of Zirconia Aerogels by Ambient Pressure Drying with Propylene Oxide Addition

ZrO₂ aerogels were successfully synthesized by the sol-gel process and ambient pressure drying using ZrO(NO₃)₂·5H₂O as a precursor, 1,2-propylene oxide (PO) as a gelation agent, and formamide (FA) as a drying control chemical additive (DCCA). The prepared zirconia aerogel samples were characterized using differential thermal analysis (DTA), scanning electron microscopy (SEM), and nitrogen adsorption/desorption analysis. The results showed that the zirconia aerogels prepared by the propylene oxide addition method had a nanoscale porous network structure, as well as supercritical dried ones, with a low bulk density (202.08 kg·m^-3) and a high surface area (645.0 m²·g^-1). Propylene oxide can induce gelation through its nucleophilic property and its irreversible ring-opening reaction, and thus the sol-gel process and the state of gel can be controlled.