二胺改性BPDA－ODA型聚酰亚胺的H_2／N_2分离性能

AROMATIC COPOLYIMIDE MEMBRANES BASED ON 3.3',4,4'-BIPHENYLTETRACAROXYLIC DIANHYDRIDE FOR H_2/N_2 SEPARATION

本文合成了一系列二胺改性的ＢＰＤＡ－ＯＤＡ型共聚酰亚胺膜，改性聚酰亚胺与未改性的ＢＰＤＡ－ＯＤＡ相比，透气性得到了明显的改善，改善的程度与第二种二胺单体的结构和用量有关。３０℃时，在ＢＰＤＡ－ＯＤＡ中加入２０ｍｏｌ％三甲基间苯二胺（３ＭＰＤＡ）或四甲基对苯二胺（４ＭＰＤＡ）时，共聚酰亚胺ＢＰＤＡ－ＯＤＡ／３ＭＰＤＡ（８０／２０）或ＢＰＤＡ－ＯＤＡ／４ＭＰＤＡ（８０／２０）的透Ｈ２系数和Ｈ２／Ｎ２分离系数分别大于６．５ｂａｒｒｅｒ和１６０，是比较好的气体分离膜材料。

H2 permeability and permselectivity for gas pair H2/N2 through a series of aromatic copolyimide membranes based on 3,3'4,4'- biphenyltetracarboxylic dianhydride(BPDA)have been investigated at 7 atm and at temperatures from ambient up to 150℃. Replacement partly of 4,4'-oxydianiliane(ODA)with rigid diamine (e.g.m-PDA,NDA,DAB,TDA,3MPDA, and 4WDA) results in increase in H2 permeability and decreased in permselectivity for gas pair H2/N2. BPDA-ODA/3MPDA(80/20)and BPDA-ODA/4MPDA (80/20) have higher permeability and permselectivity for gas pair H2/N2 than those of Ube's BPDA-based polyimide membrane material.