Thermal conductivity of polypropylene composites filled with silane-modified hexagonal BN

The aim of this study is to increase thermal conductivity of polypropylene (PP) composites filled with hexagonal boron nitride particles. Two types of BN with different types of surface treatment were used – pristine and covered with 3-amino-propyl-3-ethoxy-silane (APTES), which was bonded to hydroxyl groups, formed on the h-BN surface by annealing at 1100 °C. The presence of covalently bonded silane functional groups on the surface of h-BN particles was proved by Fourier transform infrared spectroscopy (FTIR) method. Surface treatment of h-BN particles allowed to introduce 3-times increased amount of the filler in the composite produced by extrusion casting technique as compared with non-treated h-BN filler. The thermal conductivity of PP composites filled with surface-modified h-BN was effectively enhanced – up to 2 times as compared with the composite filled with pristine h-BN and more than 2.5–4 times as compared with pure PP.