Molecular design of double crosslinked sulfonated polyphenylsulfone /polybenzimidazole blend membranes for an efficient hydrogen purification
Molecular design of double crosslinked sulfonated polyphenylsulfone /polybenzimidazole blend membranes for an efficient hydrogen purification
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DOI：
10.1016/j.memsci.2018.06.033
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发表时间：
2018-10
影响因子：
9.5
通讯作者：
A. Naderi;Akbar Asadi Tashvigh;T. Chung;Martin Weber;C. Maletzko
中科院分区：
文献类型：
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作者：
A. Naderi;Akbar Asadi Tashvigh;T. Chung;Martin Weber;C. Maletzko
该研究首次展示了一种新的双交联方法来操纵PBI膜的微观结构和气体分离性能，用于在150 °C下分离H2/CO2。首先以磺化聚苯砜（sPPSU）为离子交联剂，然后以α，α′-二溴对二甲苯（DBX）为共价交联剂，通过热处理制备了PBI膜。实验表明PBI和sPPSU在分子水平上相互作用。与常规共混物不同，PBI/sPPSU共混物膜在高温下退火后由于链运动和离子交联而显示出增强的耐化学性和更大的自由体积分数（FFV）。结果，共混膜在退火后保持其高渗透性。DBX的添加进一步提高了耐化学性，并收紧了链间间距，导致膜具有小的FFV和孔径。因此，DBX交联共混物膜在高温下保持其高的气体对选择性。在300 °C下用0.7wt%DBX交联的50/50 PBI/sPPSU共混膜具有最好的分离性能，超过了Robeson的上限。它具有令人印象深刻的46.2 Barrer的H2渗透率和在150 °C下9.9的高H2/CO2选择性。
This study, for the first time, demonstrates a new double-crosslinking approach to manipulate the microstructure and gas separation performance of PBI membranes for H2/CO2separation at 150 °C. The PBI membranes were firstly blended with sulfonated polyphenylsulfone (sPPSU) as an ionic-crosslinker and then α,α′-dibromo-p-xylene (DBX) as a covalent crosslinker with the aid of thermal annealing. Experiments show that PBI and sPPSU interact on the molecular level. Different from conventional blends, the PBI/sPPSU blend membranes show both enhanced chemical resistance and greater fractional free volume (FFV) after annealing at elevated temperatures because of chain motion and ionic crosslinking. As a result, the blend membranes maintain their high permeability after annealing. The DBX addition further improves the chemical resistance and tightens the inter-chain spacing that results in membranes with a small FFV and pore size. Consequently, the DBX cross-linked blend membranes retain their high gas pair selectivity at high temperatures. The 50/50 PBI/sPPSU blend membrane crosslinked by 0.7 wt% DBX at 300 °C possesses the best separation performance surpassing the Robeson's upper bound. It has an impressively H2permeability of 46.2 Barrer and a high H2/CO2selectivity of 9.9 at 150 °C.