Preparation and radar wave absorbing characterization of bicomponent fibers with infrared camouflage

Sheath‐core bicomponent fibers were prepared by a general melt‐spinning method with polypropylene chips and various particles. The melt‐spun fibers were characterized by DSC and mass specific electrical resistance (MSER) apparatus. The electromagnetic constant was measured using a network analyzer and the absorbing wave effect was evaluated by an arch method. The results of the DSC thermogram indicated that the crystallinity of polypropylene containing particles in the core‐part slightly increased first and then kept steadily with the particles content increase. Nanoparticles in the sheath‐part did not make the crystallinity of fibers change markedly. The MSER of fibers rapidly decreased with the metal particles input. The complex permeability of fibers with Ba/Mn‐Zn ferrite was improved compared with that of fiber with single Mn‐Zn ferrite and the complex permittivity of fiber containing the 20 wt % Ba/Mn‐Zn ferrite increased with the increasing bronze content. The fibers filled with the Ba/Mn‐Zn ferrite and bronze particles had good radar absorbing effect. The input of Al particles in the sheath‐part of the fibers showed a limited effect on the radar wave absorbing properties of the fibers. The lowest infrared emissivity of the fibers including 15 wt % Al particles in sheath‐part reached 0.62.