聚丙烯/四针状氧化锌晶须/氧化镁导热绝缘复合材料的制备与性能研究

以聚丙烯(PP)为基体，四针状氧化锌晶须(T-ZnOw)和氧化镁(MgO)为导热填料，通过双螺杆挤出机制备了PP/T-ZnOw /MgO导热绝缘复合材料。在T-ZnOw用量为10 %（质量百分含量，下同），MgO用量在0～60 %的范围内，考察了MgO用量对复合材料的热导率( )、体积电阻率(ρv)、力学性能和加工性能的影响。结果表明，随着MgO用量的增加，PP/T-ZnOw /MgO复合材料的 增大，ρv减小；材料的拉伸强度和弯曲强度以及熔体流动速率均随着MgO用量的增加而下降，而冲击强度则呈先保持稳定，然后减小的趋势。这一变化趋势在MgO用量 30 %时较为显著。当MgO用量为60 %（33 %，体积分数）时，PP/T-ZnOw /MgO复合材料的 最大，达到0.7563 W/(m·K)，比未加MgO时的PP/T-ZnOw复合材料和纯PP的热导率分别提高了108.0 %和210.0 %；此时材料的ρv最小，为9.20×1015 Ω·cm，仍可满足绝缘材料的要求。

Preparation and Properties of Thermally Conductive and Electro-insulating PP/T-ZnOw/MgO Composites

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.