Effects of Thermal Cross-Linking on the Structure and Property of Asymmetric Membrane Prepared from the Polyacrylonitrile
Effects of Thermal Cross-Linking on the Structure and Property of Asymmetric Membrane Prepared from the Polyacrylonitrile
复制标题
热交联对聚丙烯腈非对称膜结构与性能的影响
DOI：
10.3390/polym10050539
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发表时间：
2018-05-01
期刊：
影响因子：
5
通讯作者：
Wang, Tonghua
中科院分区：
文献类型：
--
作者：
Jin, Xin;Li, Lin;Wang, Tonghua
提高传统聚合物膜的热稳定性和化学稳定性将有利于其在高温或腐蚀性环境中的应用。以聚丙烯腈（PAN）为原料，采用热交联法制备了交联型非对称（CLA）PAN超滤膜，以提高其热稳定性和化学稳定性。采用傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）、正电子湮没寿命谱（帕尔斯）、扫描电子显微镜（SEM）、热重分析（TGA）和气体渗透试验等手段，研究了热交联工艺参数（温度和保温时间）对PAN膜结构、气体分离性能、热稳定性和化学稳定性的影响。热交联对PAN膜的化学结构、微观结构和孔结构有重要影响。在热交联过程中，膜的收缩、孔结构的合并或坍塌，使大孔缩小，小孔消失，孔体积减小。随着交联温度的升高和保温时间的延长，CLA-PAN膜的气体透过率增加，这是由于小分子的挥发所致。CLA-PAN膜表现出优异的热稳定性和化学稳定性，并在水处理的超滤和用作具有侵蚀性和苛刻环境的纳滤或气体分离的基底方面具有良好的应用前景。
Improving the thermal and chemical stabilities of classical polymer membranes will be beneficial to extend their applications in the high temperature or aggressive environment. In this work, the asymmetric ultrafiltration membranes prepared from the polyacrylonitrile (PAN) were used to fabricate the cross-linking asymmetric (CLA) PAN membranes via thermal cross-linking in air to improve their thermal and chemical stabilities. The effects of thermal cross-linking parameters such as temperature and holding time on the structure, gas separation performance, thermal and chemical stabilities of PAN membranes were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), positron annihilation lifetime spectroscopy (PALS), scanning electron microscopy (SEM), thermogravimetic analysis (TGA) and gas permeation test. The thermal cross-linking significantly influences the chemical structure, microstructure and pore structure of PAN membrane. During the thermal cross-linking, the shrinkage of membrane and coalescence or collapse of pore and microstructure make large pores diminish, small pores disappear and pore volumes reduce. The gas permeances of CLA-PAN membranes increase as the increasing of cross-linking temperature and holding time due to the volatilization of small molecules. The CLA-PAN membranes demonstrate excellent thermal and chemical stabilities and present good prospects for application in ultrafiltration for water treatment and for use as a substrate for nanofiltration or gas separation with an aggressive and demanding environment.