Effects of carbonisation atmosphere on the structural characteristics and transport properties of carbon membranes prepared from Kapton® polyimide
Effects of carbonisation atmosphere on the structural characteristics and transport properties of carbon membranes prepared from Kapton® polyimide
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DOI：
10.1016/j.memsci.2007.08.010
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发表时间：
2007-11
影响因子：
9.5
通讯作者：
J. Su;A. Lua
中科院分区：
文献类型：
--
作者：
J. Su;A. Lua
以Kapton®100HN聚酰亚胺为前驱体，制备了碳膜。碳化反应在873和1073K下，分别在Ar、He、氮气或真空气氛下进行。研究了碳化气氛对膜结构和传输性能的影响。得到了不同惰性吹扫气体在热降解过程中的失重。在1073K的终温下，Ar、N和He的热解表观活化能分别为212.83、175.72和117.51kJ/m ol。在每个大气压下873和1073K的碳化降低了所得碳膜的d间距和拉曼D峰与G峰的强度比。在这两种温度下，氦的热解比表面积、总孔容和微孔体积最大。在真空气氛下，873和1073K下的碳化得到最低的气体渗透率，但对O2/N2的理想选择系数最高，分别为9.37K和17.76K，而在Ar气氛下碳化，对CO2/CH4的理想选择系数最高，分别为93.35K和476.74。
Carbon membranes were prepared using Kapton®100HN polyimide as the precursor. Carbonisations were carried out at 873 and 1073K under argon, helium, nitrogen flow or vacuum atmosphere. The effects of carbonisation atmosphere on the membrane structure and transport properties were studied. Weight losses during thermal degradation were obtained for different inert purging gases. The values of apparent activation energy for the pyrolysis carried out under argon, nitrogen and helium at a final temperature of 1073K were 212.83, 175.72 and 117.51kJ/mol, respectively. Carbonisation at 873 and 1073K under each atmosphere decreased the d-spacing and the intensity ratio of the Raman D-peak to the G-peak for the resulting carbon membranes. At these two temperatures, helium pyrolysis produced the highest BET pore surface area, total pore volume and micropore volume. Carbonisation under vacuum atmosphere at 873 and 1073K yielded the lowest gas permeances but the highest ideal selectivities of 9.37 and 17.76 for O2/N2, respectively, whilst carbonisation under argon atmosphere produced the highest selectivities of 93.35 and 476.74 for CO2/CH4for 873 and 1073K, respectively.