PP/滑石粉导热绝缘复合材料的制备与性能研究

Preparation and Properties of Thermally Conductive and Electroinsulating PP/Talc Composites

采用聚丙烯（PP）为基体，不同粒径滑石粉为填料，通过双螺杆挤出机挤出制备导热绝缘的PP／滑石粉复合材料。在滑石粉用量为30％的条件下，探讨了粒径分别为3．6、6、12、30、50μm的滑石粉对PP脂石粉复合材料的热导率、体积电阻率、力学性能和结晶性能的影响。结果表明，随着滑石粉粒径的减小，复合材料的拉伸强度和弯曲强度呈先增大后减小的变化趋势，而其热导率则呈先减小后增大的变化趋势。填充粒径为12μm的滑石粉时，复合材料的拉伸强度和弯曲强度达到最大值，分别为29．92MPa和52．58MPa，比纯PP分别提高了5．5％和12．8％。填充粒径为50μm的滑石粉时，复合材料的热导率最大，达到0．3237W／（m·K），比纯PP提高了32．7％。填充1：1的粒径为12μm和30μm滑石粉混合物时，PP复合材料的热导率为0．3184W／（m·K），高于相应的填充单一粒径滑石粉的PP复合材料。此外，所制备的PP脂石粉复合材料的体积电阻率均大于10^8Ω·cm。

Thermally conductive and electroinsulating polypropylene （PP） composites were prepared with a twin-screw extruder using different mesh of talc as filler. The effect of particle size, which varied between 3.6μm and 50μm, on the thermal conductivity, volume resistivity, mechanical properties, and crystallization behavior of the PP/talc （70/30） composites was investigated. As the talc particle size became smaller, the tensile and flexural strength of the composites increased firstly and then decreased, while the thermal conductivity decreased firstly and then increased. The composite containing 12μm talc exhibited the maximum tensile and flexural strengths, 29.92 MPa and 52.58 MPa, which are 5.5 % and 12.8 % higher than those of neat PP, respectively. The composite filled with 50μm talc gave rise to the maximum thermal conductivity, 0.3237 W/（m·K）, which is 32.7 % higher than that of neat PP. When a mixture of 12μm and 30μm talc （1/1） was used, the thermal conductivity of the composite was 0.3184W/（m· K）, which is higher than that of the composites when either single talc was used. In addition, all the volume resistivities of the PP/talc composites were higher than 10^8Ω·cm.