Abstract: Thermally conductive and electric insulating polypropylene(PP)/T-ZnOw /MgO composites were prepared using a twin-screw extruder with the tetrapod-like zinc oxide whisker (T-ZnOw) and magnesium oxide (MgO) as thermally conductive fillers. The effects of content of the MgO on the thermally conductivity(λ), volume resistivity (ρv), mechanical properties, and processability of the prepared PP/T-ZnOw/MgO composites containing 10 % T-ZnOw were investigated. Results indicate that as the MgO contents increased, the λ of the composites increased and their ρv decreased. Besides, the tensile and flexural strength and the melt flow rate reduced but the impact strength remained stable first and then fall with increasing contents of MgO amounts to or above 30 %. The PP/T-ZnOw/MgO composites filled with 60 % (33 vol %) of MgO possesses the maximum λ and the minimum ρv. The former was 0.7563 W/(m·K), which was 108.0 % and 210.0 % higher than that of the PP/T-ZnOw composite without MgO and that of the unfilled PP, respectively; and the latter was 9.20×1015 Ω·cm, which can meet the requirements for electro insulating materials.

Key words: Polypropene, Tetrapod-like zinc oxide whisker, Magnesium oxide, Thermal conductivity, Volume resistivity