Some properties of polypropylene filled with metal fibers

Abstract Polypropylene/steel fiber composites were prepared and tested for mechanical, electrical, and permeability performance. To enhance adhesion of polypropylene to steel fibers, two kinds of coupling agents, maleated polypropylene wax and maleated polypropylene, were used. It was found that maleated polypropylene wax was more effective. However, as indicated by permeability measurements and scanning electron microscopy (SEM), adhesion was rather poor. Oxygen and water vapor permeabilities of the polypropylene/steel fiber composites increased with the steel fiber concentration. The lack of adhesion at the fiber‐polymer interface created diffusive paths for the gas to penetrate the composite. Addition of polyamide to polypropylene caused a decrease in the permeability of the system, due to a reduction of the permeability of the matrix. The polypropylene/steel fiber composites become conductive at a volume loading of about 10 percent. At this concentration the volume resistivity of the composite is 10.8 ohm cm.