Summary: Various output heaters were extruded with CB‐filled HDPE composites. The effects of crystallinity on the PTC and thermal reproducibility of the quenched, annealed, and E‐beam crosslinked heaters were examined during heating and cooling cycles at an applied voltage of 220 V. Conductor resisitivity and PTC effect of the heaters increased as crystallinity of composites increased. During the thermal cycling test, significant changes in heater‐output and resistivity for annealed and quenched heaters were observed. However, for quenched/E‐beam radiated and annealed/E‐beam radiated heaters no significant difference was found. These results indicate that the annealing process did not affect the thermal and electrical reproducibility of HDPE/CB heaters significantly.
Acetylene black aggregates in polyethylene matrix.
