Thermal, electrical, and mechanical properties of Si₃N₄ filled LLDPE composite

Abstract

Abstract Silicon nitride (Si 3 N 4 ) filled linear low‐density polyethylene (LLDPE) composite was prepared. The effects of Si 3 N 4 filler content, dispersion, and LLDPE particle size on the thermal conductivity, and Si 3 N 4 filled content on the mechanical and electrical properties of Si 3 N 4 reinforced LLDPE composites prepared using powder mixing were investigated. The results indicate that there existed a unique dispersion state of Si 3 N 4 particles in LLDPE, shell‐kernel structure, in which Si 3 N 4 particles surrounded LLDPE matrix particles. With increasing filler content and LLDPE particles size, thermal conductivity increased, and reached 1.42 W/m K at 30 vol% of filler, seven times as that of unfilled LLDPE. Furthermore, the examinations of Agari model demonstrate that larger size LLDPE particles form thermal conductive networks easily compared with smaller ones. The values predicted by theoretical model underestimate the thermal conductivity of Si 3 N 4 /LLDPE composites. In addition, the composites still possessed rather higher electrical resistivity and dielectric properties, but the mechanical properties decreased. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers