固相拉伸对CNTs/PP复合材料力学及电磁屏蔽性能的影响

Effects of solid-phase drawing on mechanical and electromagnetic shielding properties of CNTs/PP composites

以聚丙烯(PP)为基体,以碳纳米管(CNTs)为改性材料,利用熔融共混法制备CNTs/PP复合材料,并进行固相拉伸处理,分析固相拉伸和加入CNTs对PP性能的影响。通过广角X射线衍射仪、2D-广角X射线衍射仪、小角X射线散射仪、差示扫描量热仪、偏光显微镜、扫描电子显微镜、万能试验机和矢量网络分析仪对复合材料的结晶、力学与电磁屏蔽性能进行了研究并给出了相应的电磁屏蔽增强机理。结果表明:经固相拉伸处理和加入CNTs均会提高复合材料的拉伸强度,降低断裂伸长率;CNTs的加入起到了明显的异相成核作用,细化晶粒并提高了结晶度;同时,固相拉伸前后的CNTs/PP复合材料的晶型未发生改变,但固相拉伸显著促使了α晶的生长。随着固相拉伸速率的增加,复合材料的结晶度出现轻微降低;固相拉伸处理和CNTs加入均会提升电磁屏蔽性能,且拉伸速率过高反而使电磁屏蔽性能降低。

Using polypropylene(PP)as a matrix and carbon nanotube(CNTs)as a modified material to prepare CNTs/PP composites,the effects of solid-phase drawing and CNTs on properties of PP-based composites after solid-phase drawing were analyzed.Crystallization,mechanical and electromagnetic shielding properties of the composites were studied by wide angle X-ray diffraction,2D wide angle X-ray diffraction,small angle X-ray scattering,differential scanning calorimetry,polarizing microscope,scanning electron microscope,universal test machine,and vector analyzer.The results show that the solidphase drawing and CNTs increase the tensile strength of the composite and reduce its elongation at break;the addition of CNTs plays a clear heterogeneous nucleation,refines the grain and improve the crystallinity,and the crystal formation of the CNTs/PP composite before and after the solid-phase drawing does not change,but theα-crystal for PP is improved significantly.The crystallinity of the composites is slightly decreased with increasing solid-phase drawing rate.The solid-phase drawing treatment and CNTs can improve the electromagnetic shielding performance,but make the electromagnetic shielding performances reduce after high drawing rate treatment.