BN填充PA6基导热绝缘复合材料导热性能研究

以聚酰胺6（PA6）为基体, 氮化硼（BN）作为导热填料,经双螺杆挤出机熔融共混,模压成型制得导热绝缘复合材料。研究了BN含量、粒径、形状和不同BN粒径复配对复合材料导热性能的影响，并研究了BN含量和粒径对复合材料绝缘性能的影响。结果表明，在各种粒径下，复合材料热导率均随BN填充量的增加而增大；在BN粒径为5 μm、填充量为25 %（体积分数，下同）时，复合材料热导率达到1.2187 W/(m·K)；在BN填充量相同时，填料粒径对复合材料热导率的影响不是简单的单调规律，呈现50、100 μm时较小，1、5、15 μm时较大，150 μm时最大的规律；片状BN填料比球状BN填料更有利于提高复合材料的热导率；2种不同粒径填料复配所填充的复合材料的热导率大于单一粒径填充的复合材料；5 μm与150 μm粒径BN复配，在填充量为20 %，配比为1:3时，复合材料的热导率最大，达到1.3753 W/(m·K)，为纯PA6的4.9倍；在不同BN含量和粒径下，复合材料体积电阻率均能达到10000000000000 Ω·cm以上，满足绝缘性能。

Study on Thermal Conductivity of Thermal Insulative Composites of PA6 Filled with BN Particles

Thermal insulative composites were prepared with PA6 as a matrix and BN as thermal conductive filler through a twin screw extruder. The effect of BN content and particle size on the insulation property was studied. For various particle size, the thermal conductivity of the composites increased with increasing content of the filler. When the particle size of BN was 5 μm, filling content was 25 vol %, the thermal conductivity reached 1.2187 W/(m·K). For improving the thermal conductivity, flaky BN filler was more effective than spherical filler, and bimodal particles were more effective than mono modal ones. Using a binary filler mixture at a content of 20 vol % in which the size of the two fillers were 5 and 150 μm, and the volume ratio was 1:3, the thermal conductivity reached 1.3573 W/(m·K).