聚酰亚胺低温热解炭膜的制备及气体分离性能

摘要

Low temperature pyrolytic membranes were prepared from Kapton-Type Polyimide. TG-MS, FTIR, EA, XRD and gas permeability were used to character the change of chemical structure and microstructure, the gas separation performance during the low temperature pyrolysis at different temperatures and atmosphere. Results show that pyrolytic temperature and atmosphere have a great impact on chemical and carbon structure and the gas separation performance of low temperature carbon membrane. There is no evident variation of gas permeability before 450 ℃ and the gradual enlargement in gas permeability and decrease in gas selectivity with the increase of temperature after 450 ℃. The carbon membranes prepared in air have a larger gas permeability and lower selectivity than those prepared in nitrogen.%以商业化的Kapton型聚酰胺酸为前驱体制备了低温热解炭膜,采用热重质谱(TGMS)、红外光谱(FTIR)、元素分析(EA)、X射线衍射(XRD)和气体渗透等手段对不同温度、不同气体氛围下制备出的膜的化学结构、微结构和气体分离性能变化规律进行了研究,结果表明,低温热解温度和气体氛围对炭膜的化学结构、微结构存在着显著的影响,进而影响到炭膜的气体分离性能,表现为450℃之前气体渗透系数变化很小,450℃以后气体渗透系数逐渐增大,分离系数逐渐下降,同时空气促进了热分解和热交联反应的进行,炭膜具有较大的气体渗透系数和较小的气体分离系数.