Effect of heat treatment time on the PTC behavior of wollastonite/CB/CPE composites

Wollastonite (W)/carbon black (CB)/chlorinated polyethylene (CPE) conductive composites were prepared via melt compounding using CB and wollastonite as fillers and CPE as the matrix. To analyze the internal structure of the material and examine how changes in crystallinity affect the positive temperature coefficient (PTC) behavior of the composites, several characterization techniques were employed. These methods included scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry. Each method provided insights into the structural adjustments and their implications for the electrical properties of the material. Special attention was given to the influence of the wollastonite content on the electrical conductivity of the composites. The results demonstrated that the lowest room-temperature resistivity (1.66 Ω·cm) was achieved with 15 wt.% wollastonite doping after 1 h of heat treatment. At the same time, the PTC strength increased to 4.7.