A novel polymer composite with double positive‐temperature‐coefficient transitions: effect of filler–matrix interface on the resistivity–temperature behavior

BACKGROUND: Sn–Pb alloy‐filled high‐density polyethylene (HDPE) composites exhibit double positive‐temperature‐coefficient (PTC) behavior, with the first transition at the melting point of HDPE and the second at that of Sn–Pb alloy. The objective of this study is to improve the reversibility and reproducibility of double‐PTC transitions of these composite materials by enhancing the filler–matrix interface. RESULTS: Fourier transform infrared spectroscopy, surface wettability and dynamic mechanical and rheological measurements confirm that surface‐treating Sn–Pb with titanate concentration ≤1 wt% enhances the interface adhesion between Sn–Pb alloy and HDPE matrix. Surface‐treating Sn–Pb with titanate concentration ≤1 wt% increases the PTC transition temperature, reduces the PTC intensity and improves the reversibility and reproducibility of the double‐PTC behavior of Sn–Pb/HDPE composites. CONCLUSION: It is demonstrated that adjusting the filler–matrix interface is an effective means to modify the double‐PTC behavior of Sn–Pb alloy‐filled HDPE composites.