Three-in-one polyimide-based blended membrane for Upgrading helium separation performance and physical aging resistance
Bingbing Gao, Yiran Peng, Ming Wu, Hua Ma, Jianchao Sun, Peng Zhang, Xingzhong Cao, Like Ouyang, Xiaobin Fu, Chunfang Zhang, Yunxiang Bai, Lijun Liang, Yang Liu, Liangliang Dong
Abstract
Polyimide membranes have attracted considerable attention for gas separation applications; however, achieving efficient helium (He) separation remains a significant challenge due to the low fractional free volume ( FFV ) and poorly controlled pore size distribution. Here, we report a novel three-in-one polyimide-based blended membrane constructed from a polymer (6FDA-TFMB) and alkynyl-based polyimide (EBPA-TB) matrix via thermal crosslinking. By carefully designing membrane synthesis and structure, the resulting membrane achieves the “1 + 1>2” effect: (i) high He selectivity derived from reinforced interphase adhesion and size-sieving ability due to the hydrogen bonding and similar structure between 6FDA-TFMB and EBPA-TB; (ii) high He permeability derived from the rigid cross-linked network distorting the EBPA-TB chain packing and generating additional free volume; (iii) high anti-aging performance derived from the thermal crosslinking preventing microstructural rearrangements. The optimal membrane an unprecedented combination of high He permeability (51.24 Barrer), excellent He/N 2 selectivity (146.40) and remarkable aging resistance (less than 3.97 % of permeability decrease over 50 days), outperforming the performance of state-of-the-art polyimide-based blended membranes for He purification. This three-in-one blended membrane construction strategy provides a general toolbox for the development of next-generation, high-performance blended membranes with desirable performance for diverse industrial applications. A three-in-one polyimide-based blended membrane consisting of a new organic polymer filler (6FDA-TFMB) and an alkynyl-based polyimide (EBPA-TB) matrix were prepared by thermal crosslinking. The optimal membrane exhibited an unprecedented combination of high He permeability (51.24 Barrer), excellent He/N 2 selectivity (146.40), and remarkable aging resistance.