Preparation of thermally rearranged poly(benzoxazole-co-imide) membranes containing heteroaromatic moieties for CO2/CH4 separation
Preparation of thermally rearranged poly(benzoxazole-co-imide) membranes containing heteroaromatic moieties for CO2/CH4 separation
复制标题
用于CO2/CH4分离的含杂芳族部分的热重排聚(苯并恶唑-酰亚胺)膜的制备
DOI：
10.1016/j.polymer.2019.121945
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发表时间：
2019-12-17
期刊：
影响因子：
4.6
通讯作者：
Zhang, Qinghua
中科院分区：
文献类型：
--
作者：
Gan, Feng;Dong, Jie;Zhang, Qinghua
同时获得优异的力学性能和优良的气体分离性能，对于热重排聚合物作为膜材料应用于大规模气体分离应用而言，仍然是一个巨大的挑战。本论文将含有苯并咪唑/苯并恶唑结构的不同杂芳族不可阻燃的可二胺引入到邻羟基功能化的聚酰亚胺骨架中，然后通过热重排反应将其转化为聚苯并恶唑-聚酰亚胺共聚物。在所有情况下，固态tr反应导致聚合物链的优先链段间距(d间距)增加和自由体积分数增加，有利于气体渗透。而苯并咪唑基和苯并恶唑基的TR-PBOI膜的pi-pi堆积距离表现出相反的变化趋势，这对气体选择性有显著的影响。在420℃下热处理1h的TR-PBOI膜具有较高的拉伸性能，其拉伸强度为97-118兆帕，初始弹性模数为2.0-2.4 GPA。此外，掺入杂芳族非TR型辅基二胺可使所制得的TR-PBOI膜对CO2/CH4气体具有良好的气体分离性能，CO2透过率和CO2/CH4理想选择性值超过1991年的上限，接近2008年的上限。我们预计，这种简便的方法将有助于气体分离用TR膜的大规模制备和应用。
Simultaneously achieving excellent mechanical properties and superior gas separation performance remains a great challenge for thermally rearranged polymers when applied as the membrane materials in large scale gas separation applications. Herein, different heteroaromatic non-TR-able codiamines containing benzimidazole/benzoxazole structures were incorporated into ortho-hydroxyl functionalized polyimide backbones, which were subsequently transformed into the poly(benzoxazole-co-polyimide) copolymers by thermal rearrangement (TR). In all cases, the solid-state TR reaction induces the increased preferential intersegmental distances (d-spacing) and fractional free volumes of polymer chains, favorable for the gas permeation. While, the pi-pi stacking distance exhibits opposite variation tendencies for benzimidazole-based and benzoxazole-based TR-PBOI membranes, which is demonstrated to make a significant effect on the gas selectivity. These TR-PBOI membranes thermally treated at 420 degrees C for 1 h exhibit higher tensile properties in relative to most of previously reported TR-PBOI membranes with the tensile strength of 97-118 MPa and initial modulus of 2.0-2.4 GPa. Moreover, incorporating heteroaromatic non-TR-able codiamines endows the resultant TR-PBOI membranes with excellent gas separation properties for the CO2/CH4 gas pairs with the CO2 permeability and CO2/CH4 ideal selectivity values exceeding the 1991 upper bound and close to 2008 upper bound. We anticipate this facile method will facilitate the large-scale preparation and application of TR membranes for gas separation.