Processing, structure, and electrical properties of metal-filled polymers

Polymer-metal composites (PMCs) based on polyethylene (PE) and polyoxymethy lene (POM) and on the blend PE/POM filled with dispersed iron or copper wer e prepared. Composites were produced by several methods: (1) extrusion of h omopolymer (PE or POM) filled with iron, (2) extrusion of the blend PE/POM filled with iron, (3) compression molding of PE filled with dispersed coppe r, and (4) extrusion of PE filled with copper. The method of processing was found to influence the percolation behavior of electrical conductivity. Po lymer-metal composites obtained by extrusion were characterized by low valu es of conductivity and high values of percolation threshold phi (c), wherea s composites based on the polymer blend showed low values of phi (c). These differences are caused by the specific structure of composites based on th e polymer blend. The metal filler was involved only in the POM phase and fo rms an ordered structure in the volume of the polymer matrix. PE-Cu composi tes produced by compression molding showed the best electrical parameters. A structure model explaining these results is proposed.