Abstract: LDPE/EVA/CB conductive foam was made with low density polyethlene (LDPE) and ethylene-vinylacetate copolymer (EVA) as matrix, acetylene carbon black (CB) as conductive filler, azobisformamide (AC) as foamer and dicumyl peroxide (DCP) as crosslinker. The bubble structure and resistivity-temperature characteristic were observed. Influences of carbon black content, crosslinker and foamer on conductive properties of LDPE/EVA/CB foaming conductive composites were investigated. The obtained foam has a rather good bubble structure and a switching characteristic. Acetylene CB filled LDPE/EVA system exhibits positive temperature coefficient (PTC) effect during heating process. The proper filler contents of the crosslinker and foamer were confirmed to make the composite have not only good foam performance but also PTC characteristic.

Key words: low density polyethlene, carbon black, foam, positive temperature coefficient characteristic, conductive composite