Preparation and characterization of porous polyimide fibers with electromagnetic wave absorption properties

Abstract The porous polyimide (PI) composite fibers, which exhibit high‐efficiency electromagnetic wave adsorption (EMWA) performance, were successfully fabricated by controlling temperature of the coagulation bath during the wet spinning process. The mechanical properties of composite fiber decreased and average radius of micropores increased gradually with the rise of coagulation bath temperature. In addition, carbon nanotubes (CNTs) and nano‐Fe 3 O 4 were introduced into the system by in situ polymerization. CNTs and nano‐Fe 3 O 4 contribute to the attenuation of electromagnetic wave (EMW) through microwave absorption and reflection loss (RL), and the porous structure was able to provide multiple reflection paths for incident EMW and achieved higher attenuation. Particularly, when the temperature of coagulation bath was 50°C, the minimum RL (RL min ) value of the PI/CNTs/nano‐Fe 3 O 4 (PI/C‐Fe) composite fibers was demonstrated to be −54.61 dB with the matching thickness of 2.10 mm. The successful preparation of PI/C‐Fe composite fiber in this study pointed out a new direction for the application of PI‐based fiber materials in structural EMWA materials.