HDPE/CB/PA6复合材料的导电与力学性能研究

Study on Electrical Conductivity and Mechanical Properties of HDPE/CB/PA6 Composites

为了改善尼龙6低温与干态存在着冲击强度低、纤维状易于电荷富集的缺陷,制备了高密度聚乙烯(HDPE)/导电炭黑(CB)/尼龙6(PA6)复合材料。首先制备了HDPE/CB共混物作为功能改性剂,再以马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)为增容剂,通过双螺杆挤出机熔融共混制备了HDPE/CB/PA6复合材料。通过扫描电子显微镜(SEM)、万能试验机、高阻计等方法,研究了添加增容剂和HDPE与PA6配比以及导电炭黑粒子含量对复合材料力学性能和导电性能的影响。结果表明,加入5 phr的增容剂POE-g-MAH,明显提高了HDPE与PA6的界面黏附力,复合材料相容性较好;当HDPE与PA6的质量比为35/65时,复合材料的断裂伸长率从纯PA6的88%增加到251%,缺口冲击强度从12.5 kJ/m^2增加到53.7 kJ/m^2;当导电炭黑的含量增加到2.5 phr时,复合材料的室温体积电阻率降低了7~10个数量级,约为10~8Ω·cm。

High-density polyethylene （ HDPE ） /conductive carbon black （ CB ） /nylon 6 （ PA6 ） composites were prepared in order to improve the impact strength of nylon 6 at low temperature and dry state and the defect of fiber-like charge-enrichment. Firstly the HDPE/CB blend was prepared as functional modifier, and with maleic anhydride grafted ethylene-octene copolymer （ POE-g-MAH ） used as compatibilizer, HDPE/CB/PA6 composites were prepared by melt blending in twin screw extruder. The effects of the compatibilizer addition and the ratio of HDPE to PA6 and the content of conductive carbon black on the mechanical properties and electrical conductivity of the composites were studied by scanning electron microscopy （SEM）, universal testing machine and high resistance meter. The results show that the addition of 5wt% POE-g-MAH significantly improves the interracial adhesion of HDPE and PA6, and the compatibility of the composites is better. Compared witn pure PA6, when the ratio of HDPE to PA6 is 35/65, the elongation at break of composites increases from 88% to 251% and the impact strength increases from 12.5 kJ/ m2 to 53.7 kJ/m2. The volume resistivity of composites decreases by 7 - 10 orders of magnitude, about 10^8 Ω·cm when the content of conductive carbon black particles increases to 2. 5 phr.