PAN预氧丝复合RF气凝胶的性能研究

Performance of the RF aerogels composited PAN pre-oxidized fibers

摘要:

本文以间苯二酚(C6H4(OH)2)和甲醛(HCHO)为前驱体,碳酸钠(Na2CO3)为催化剂,采用溶胶-凝胶技术、超临界干燥工艺制备了间苯二酚-甲醛(RF)气凝胶。另外,通过添加聚丙烯腈(PAN)预氧丝改善了RF气凝胶的力学性能,制备了PAN预氧丝复合RF气凝胶。文中通过调节质量分数ω、间苯二酚与催化剂摩尔比(R/C值)这两个参数对微结构进行调控,其中选取质量分数ω为15%, R/C值为100和500的气凝胶进行比较,经过分析可知R/C值为100的气凝胶性能优良,复合后样品的比表面积变为618.6 m₂/g,孔体积为2.423 cm₃/g,平均孔径为15.1nm。PAN预氧丝复合后的气凝胶依然具有优异的热学性能,在常温下热导率为0.032W/(m.K)。力学性能有了很好的改善,压缩模量为1.499MPa,比纯RF气凝胶提高了0.6倍。

Abstract:

The resorcinol–formaldehyde (RF) aerogels composited polyacrylonitrile (PAN) pre-oxidized fibers were prepared by a sol-gel method combined with the CO₂ supercritical drying technique using resorcinol (C₆H₄(OH)₂) and formaldehyde (HCHO) as the precursors andSsodium carbonate as catalyzer respectively, enhanced frame support by PAN pre-oxidized fibers in the solvent. The sample composition is characterized by using Fourier transform infrared spectrometer. Field emission scanning electron microscopy (FESEM), surface area and pore size analyzer were used to investigate the microtopography and the microstructure of the RF aerogels composited PAN pre-oxidized fibers with the nanoporous structure. Compared with the pure RF aerogel, the excellent thermal conductivity of the RF aerogels composited PAN pre-oxidized fibers is 0.032W/mK at 25°C and Young"s modulus of 1.499MPa has increased 0.6 time.