The invention relates to the technical field of
gas separation membranes, in particular to a cross-linked
BPDA-based
polyimide separation membrane for extracting
helium from
natural gas, which is prepared by copolymerizing
diamine with TPEQ and
BPDA, carrying out thermal crosslinking to synthesize a plurality of cross-linked polyimides, carrying out imidization treatment to prepare a membrane
casting solution, and carrying out
vacuum drying on the membrane
casting solution to obtain the cross-linked
BPDA-based
polyimide separation membrane for extracting
helium from
natural gas. The crosslinking type
polyimide separation membrane for extracting
helium from
natural gas is prepared through the prepared membrane
casting solution, adopted
diamine comprises DABA, ppd and ODA, and three polyimide materials with different polarities and crosslinking densities are synthesized by precisely regulating and controlling the
chemical structure and network form of crosslinking type polyimide. Preferential
permeation of He is promoted by optimizing the structural advantages of
diamine; in this way, the technical problems that in the prior art, a separation membrane material is difficult to meet the requirements of high
permeation flux and
high selectivity at the same time, and the stability is insufficient under complex working conditions are solved.