Confined Pyrolysis-Driven One-Dimensional Carbon Structure Evolution from Polyacrylonitrile Fiber and its Microwave Absorption Performance

Abstract

The evolution of one-dimensional carbon structures from polyacrylonitrile (PAN) fiber precursors is investigated based on confined pyrolysis strategy, which is employed to convert electrospun PAN fibers into carbon in a closed system. Carbon tube with ultra-large diameter derived from silica-coated organic PAN precursor fiber is observed and its low-performance of microwave absorption is revealed. To enhance microwave absorption, cobalt acetylacetonate is introduced as a magnetic resource into PAN, facilitating one-dimensional carbon structure evolution and yielding magnetic/carbon nanofibers. The mechanism resulting in such one-dimensional carbon structure evolution is discussed. The microwave absorption performances of the prepared magnetic carbon nanofibers are analyzed based on their complex permittivity and permeability. Remarkably, the magnetic carbon nanofibers exhibit strong microwave absorption intensity of -42 dB at only 20 wt% filler content. Further simulations are conducted based on radar-absorbing structure with prepared magnetic carbon nanofibers-coated laminate and wing models by using CST software. The laminated composite structure appears the maximum RCS reduction value of 18.70 dBsm at 6 GHz with 3.0 mm thickness in the frequency range of 2-18 GHz. In the corresponding wing structure, highly efficient electromagnetic wave absorption is observed and the RCS reduction can achieve -14.12 dBsm at 10 GHz with 3.5 mm thickness.

Keywords: confined pyrolysis, one-dimensional carbon, structure evolution, microwave absorption