Conductive behavior of composites composed of carbon black-filled ethylene-tetrafluoroethylene copolymer

A study was conducted to investigate the effect of positive temperature coefficient (PTC) on composites composed of carbon black- filled (CB) ethylene-tetrafluroethylene (ETFE) copolymers. The study also examined the percolation behavior and the effect of CB concentration on the PTC intensity. The electrical reproducibility of ETFE and CB composites during heating-cooling cycles to adapt for PTC products was also evaluated. The composites were prepared by mixing ETFE and CB on a two-roll mill at 280 °C and 60 rpm for 10 minutes and compression-molded at 280°C under 14.7 MPa for 10 minutes to form sheet specimens. Two pieces of copper nets were mounted onto the opposite wide surfaces of the sheet to ensure better electric contact with the copper electrodes. A two-probe resistance measurement was carried out for determining the resistivity at room temperature, using a M890 B digital multimeter to find the effect of PTC on the ETFE-CB composite copolymers.