Thermal crosslinking polymerization of aromatic alkynyl monomers to microporous polyimides in diphenyl sulfone

In recent years, building microporous polyimides (MPIs) via choosing simple commercial aromatic monomers or concise experimental methods is still an issue worthy to explore. Herein, two cross-linkable aromatic alkynyl monomers (TAPM-PEPA and TAPA-PEPA) were prepared from a commercial alkynyl anhydride PEPA and two aromatic multi-amine TAPM (3D-tetrahedron) and TAPA (near 2D-planar) monomers with different topological structures. The crosslinked polyimides were prepared and endowed microporous features via one-pot thermal crosslinking polymerization in the diphenyl sulfone. The TAPM-PEPA-CL has higher BET surface area and total pore volume (736 m2 g-1 and 0.497 cm3 g-1) than those of the TAPA-PEPA-CL (351 m2 g-1 and 0.358 cm3 g-1). As the topological structure becomes more stereoscopic, CO2 adsorption capacity has been significantly improved from 9.6 wt% to 13.5 wt%. Furthermore, the TAPM-PEPA-CL and TAPA-PEPA-CL have excellent selectivity for CO 2 /CH 4 (12.0–23.6) and CO 2 /N 2 selectivity (54.4–57.6) at 273 K and 1 bar. These results reveal that the introduction of crosslinked structures and control of topological structures have potential application significance for preparing microporous polyimides based on cross-linkable aromatic alkynyl monomers, which is beneficial for the development of the field of gas adsorption and selectivity.