Enhanced thermal conductivity of PE/BN composites through controlling crystallization behavior of PE matrix

In this article, in order to enhance the thermal conductivity of the polyethylene (PE)/boron nitride (BN) composites through controlling the crystallization behavior of the PE matrix, the crystallization and melting behavior of the PE in the PE/BN composites was investigated. When the BN content was more than 10 wt%, an extra weak exothermic peak (Th) at 130°C was observed. Moreover, after the annealing of the PE/BN composites at 130°C, the extra weak melting peaks (Tmh) of the PE in the PE/BN composites were also observed and shifted to the high temperature with increasing annealing time, which proved that the Th was induced by PE crystallization. Meanwhile, the results of temperature‐dependent absorbance IR spectra of the PE/BN composites showed that the crystallization peak (729 cm−1) remarkably appeared at 130.2°C, indicating that the crystallization of the PE in the PE/BN composites can occur at 130.2°C. When the annealing time and temperature were 20 min and 130°C, the thermal conductivity of the PE/BN composite was 16% higher than that of the unannealed PE/BN composites. In addition, the results of the wide angle X‐ray diffraction (WAXD) showed that the BN particles had no influence on the PE crystalline form in the PE/BN composites. POLYM. COMPOS., 38:2806–2813, 2017.