硝化棉气凝胶的制备与表征

Preparation and Characterization of Nitrocellulose Aerogel

以硝化棉为原料,分别以六亚甲基二异氰酸酯三聚体、异佛尔酮二异氰酸酯、甲苯二异氰酸酯为交联剂,二月桂酸二丁基锡为催化剂,丙酮为溶剂制备了硝化棉湿凝胶,采用超临界干燥制得硝化棉气凝胶。用FTIR、SEM以及BET比表面积分析对气凝胶进行了表征。结果表明,凝胶骨架由50nm左右的粒子堆积而成。凝胶孔隙集中在10～40nm,为介孔材料;硝化棉气凝胶的比表面积受NC交联密度控制;当硝化棉浓度为75g/L、交联剂为TDI时,硝化棉气凝胶的比表面积为133.3625m2/g,初始分解温度及最大分解温度分别提前12℃及6℃。

Using nitrocellulose as raw material , poly-hexamethylene diisocyanate,isophorone diisocyanate and tolu ene diisoeyanate as cross linker respectively, dibutyltin dilaurate as catalyst, acetone as solvent, nitrocellulose wet gel was prepared successfully, and nitrocellulose aerogel was prepared by supercritical fluid drying. The structure of nitrocellulose aerogel was characterized by FTIR, SEM and BET specific surface area analysis. The results show that the gelskeleton is accumulated by nano-particles with the size of about 50 nm. The size of aerogel pores ranges from 10nm to 40nm, which confirms that the aerogel belongs to mesoporous material. The BET surface area of the aerogel is controlled by the cross linking density. When NC concentration is 75g/L and TDI as cross linker, the BET surface area of the aerogel is 133. 3625 m^2/g,and its onset and maximum decomposition temperature decreases about 12℃ and 6 ℃, respectively.