PE-UHMW/GNPs导电复合材料的制备和表征

Preparation and Characterization of PE-UHMW/Graphene Nanoplatelets Conductive Composites

采用超声溶液分散法制备出超高分子量聚乙烯/石墨烯(PE-UHMW/GNPs)导电复合材料,研究了该材料的导电渗流行为和阻-温特性。研究发现,PE-UHMW/GNPs导电复合材料的导电渗流阈值为3.8%,即当导电填料在体系中的质量分数达到3.8%时,材料内部逐渐形成较为完善的导电网络,从而实现其导电特性。研究和探讨了PE-UHMW/GNPs导电复合材料的正温度系数(PTC)效应和负温度系数(NTC)效应。研究发现,PE-UHMW/GNPs导电复合材料的PTC效应会随着GNPs含量的增加逐渐增强,当导电填料GNPs的添加量达到3.8%时,通过阻-温曲线可以观察到,PE-UHMW/GNPs导电复合材料具有最大的PTC强度和相对较低的室温体积电阻率。场发射扫描电子显微镜分析结果表明,GNPs和PE-UHMW之间的相互作用会随着热循环次数的不同而发生变化,最终会影响到材料的PTC效应。

Ultra-high molecular weight polyethylene （PE-UHMW） / graphene nanoplatelets （GNPs） conductive composites with a segregated structure was fabricated using ethanol-assisted dispersion. A percolation threshold of 3.8% was achieved because the conductive network was formed to realise electrical conductivity. The positive temperature coefficient （PTC） and negative temperature coefficient （NTC） effects of PE-UHMW / GNPs conductive composites was investigated. The results show that PTC behavior enhance with increasing GNPs content but this is not always the case. The maximum PTC effect is observed in PE-UHMW /GNPs conductive composites （GNPs is 3.8%） with relatively low room temperature resistivity and relatively high PTC intensity. The structure characteristic of PE-UHMW/GNPs conductive composites examined by field emission scanning electron microscopy reveal that the slight interaction between GNPs and PE-UHMW matrix may be changed by thermal cycles, and this can explain why thermal cycles could increase PTC and NTC intensity.