Molecular structure influence of porous intrinsic polyimide nanofiber for high temperature flue gas filtration: Bisphenol AF, sulfone, ether bonds and hydroxyl groups

Good atmospheric environment is the prerequisite for green development of technology. Industrial waste gas emission is one of the major causes of air pollution. To investigate the influence of Polyimide (PI) molecular structure on properties (especially thermal performance) and macroscopic porosity, 6FAP, HFBAPP, and BAPS were used to aggregate with 6FDA, respectively. The obtained Polyamide acid (PAA) solution was used to prepare PAA nanofiber (NFs) membranes by electrospinning technology, and PI nanofiber membranes were obtained by high-temperature dehydration condensation. ODPA copolymerization is the intrinsic modification method in this work. The differences in thermal properties, mechanical properties, surface morphology, and air filtration performance of PI nanofiber membranes were examined with six different formulations. The results showed that the PI-ODPA copolymerization nanofibers had high pore structure, and the particle filtration performance increased accordingly. The particle filtration performances of 6FAP-6FDA, HFBAPP-6FDA, and BAPS-6FDA were all exceed 81 %. After ODPA copolymerized modification, HFBAPP-6FDA-ODPA nanofiber membranes can reach a maximum of 95.42 %. In addition, the Tg and T d5 of all NFs reached 250 °C and 455 °C, indicating good thermal performance. Based on the above studies, the performance of PI NFs membrane can be improved by molecular structure designed and copolymerization, with a broader application prospect in the field of high-temperature filtration. • The prepared PI NF membranes could be applied under high temperature environment. • Compared bisphenol AF, sulfone, ether bond and hydroxyl influence on PI NFs pore formation. • ODPA copolymer increased filtration efficiency of PI NFs membranes to 95.42 %. • ODPA copolymer decreased filter resistance of PI NFs membranes to 107Pa. • The above performance are all from intrinsic PI NFs without any additives added.