Thermally conductive PP/AlN composites with a 3-D segregated structure

PP (Polypropylene)/AlN (Aluminum Nitride) composite particles with a structure of PP core and AlN shell were prepared by mechanical grinding a mixture of PP particles and AlN powder in a mortar. Thermally conductive PP/AlN composites with a 3-D segregated structure were fabricated by sintering the composite particles with a core-shell structure. The PP/AlN composites were characterized by optical microscopy and scanning electron microscopy. It was found that the AlN particles were selectively localized at the interface among the PP particles in the composites leading to enhancement in the Thermal Conductivity (TC) of the composites. The composites fabricated by mechanical grinding show higher TC values than those fabricated by solution mixing and melt mixing methods. In addition, the TC data of the composites were correlated with Agari's model. Both SEM observations at a high magnification and TC measurements of the PP/AlN composites revealed that only a small amount of the fine AlN particles form continuous thermal conductive paths at the interfaces due to the intermixing between the PP and AlN particles.