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. (c) 2007 Wiley Periodicals, Inc.