Reinforcement Effects of Polyethylene Glycol on Pyro-Resistive Properties of Carbon Black/SiO2/LLDPE Composites

Carbon black/SiO 2 /LLDPE (CB/SiO 2 /LLDPE) is a commonly used polymer material with a positive temperature coefficient (PTC). However, the inferior reproducibility of PTC significantly restricts its service life. The objective of this study is to enhance the PTC reproducibility of CB/SiO 2 /LLDPE material. Polyethylene glycol (PEG) was chosen as the additive, and its effects on SiO 2 dispersion, PTC reproducibility, and electrothermal performance were studied in detail. A more stable SiO 2 /CB synergistic filler network was formed after the incorporation of PEG, which results in a significant improvement in PTC reproducibility. The variation of PTC intensity change rate after 10 heating–cooling cycles decreased by 19.4% after the incorporation of 5 wt% PEG. Additionally, the electrothermal performance of the PEG modified CB/SiO 2 /LLDPE composites was also enhanced with a 15.3°C increase in equilibrium temperature under a DC voltage of 140 V. This study offers an effective strategy for developing high-performance PTC materials.