聚丙烯腈基炭膜的制备及气体分离性能的研究

Preparation and gas separation performance of polyacrylonitrile-based carbon membranes

以聚丙烯腈(PAN)作为前驱体,经过溶解、成膜、预氧化及炭化等步骤得到无缺陷炭膜。通过热质量损失、红外光谱、x射线衍射和电子显微镜等技术分析了前驱体的热稳定性与微结构演变,研究了PAN交联结构及预氧化温度与炭化温度对炭膜微观结构与气体分离性的影响。由结果可知:PAN膜最佳预氧化温度为230℃。较低的炭化温度或渗透压力有利于获得较高的气体渗透性。在预氧化温度230℃及炭化温度650℃所制备炭膜对O2/N2选择性达2.7。

Defect-free carbon membranes were prepared using polyacrylonitrile( PAN) as precursor via the processes of dissolution,membrane-forming,preoxidation and pyrolysis. The thermal stability of precursor and the structural evolution were analyzed by thermogravimetric analysis,infrared spectroscopy,x-ray diffraction and electron microscopy. Simultaneously,the crosslinking structure of PAN and the effects of preoxidation temperature and pyrolysis temperature on the microstructure and gas permeation of carbon membranes were also studied. Results show that the optimum preoxidation temperature is 230 ℃. Low pyrolysis temperature is favorable for the improvement of gas permeability of carbon membranes. In addition,permeation at low pressure is benefit to the separation performance of carbon membranes. The selectivity of present carbon membranes for O2/ N2 can reach to2. 7 when the preparation condition is preoxidation temperature of 230 ℃ and pyrolysis temperature of 650 ℃.