Morphology and properties of PE-RT antistatic composites modified by conductive carbon black

Using heat-resistant polyethylene (PE-RT) pipe materials as matrix, conductive carbon black master batch (remarked as CBE) carried by ethylene-vinyl acetate copolymer (EVA) as conductive medium, with 3.86wt% of polyethylene-octene copolymer elastomer (POE), via twin-screw extrusion process, PE-RT antistatic pipe material with conductive mesh structure was prepared, reducing the percolation threshold of composite system, and comparing it to system with addition of conductive carbon black (remarked as CB) to study the electrical properties, morphology structure, rheological properties, mechanical properties and thermal stability in CB/PE-RT and CBE/POE/PE-RT composite system. The results show that it produces a synergistic effect between POE and EVA, the addition of POE changes the differences of viscoelastic between PE-RT and EVA, so that EVA reaches percolation to form a continuous network structure in matrix, and CB disperses preferentially in EVA phase with low viscosity, higher polar, POE plays an inhibitory effect on migration of CB from EVA phase to PE-RT phase, then CB reaches percolation in EVA phase easily. Finally it forms a conductive network structure because of dual role of percolation. CB improves the crystallization property of PE-RT and thermal stability of CBE/POE/PE-RT composite system, and CB has little effects on the mechanical properties of CBE/POE/PE-RT composite system, to a certain extent, it solves the contradiction between conductivity and mechanical properties of filled-type conductivity systems. POE has a plasticizing effect on composite system, maintaining the advantages of PE-RT pipes that can be bent, expanding the application scope of plastic pipe.