LDPE/EVA/CB导电泡沫复合材料的压阻行为

Piezoresistance Behavior of LDPE/EVA/CB Foam Conductive Composites

研究了导电炭黑(CB)填充低密度聚乙烯(LDPE)/乙烯-醋酸乙烯酯(EVA)泡沫复合材料的压阻行为(PRB)。结果表明,LDPE/EVA/CB导电泡沫复合材料的电阻在低压力作用下就发生显著变化,呈现出电阻负压力系数(NPC)效应。复合材料的NPC效应依赖于CB填充质量分数,质量分数较低时,材料的NPC效应随质量分数的增加而增强;质量分数为23%时,材料达到较强的NPC效应。复合材料在加载-卸载压力过程中,R/R0-F曲线具有明显的电阻滞后行为,滞后性与循环次数和CB质量分数密切相关,增加循环次数或CB质量分数,都可有效提高材料的PRB稳定性。在恒定压力作用下,复合材料的电阻随时间呈非线性下降,表现为典型的电阻弛豫现象。

The piezoresistive behavior（PRB） of low-density polyethylene/ethylene-vinyl acetate-matrix foaming composites filled with conductive carbon black（CB） is investigated.The results reveal that the foaming composites exhibite a sharp negative pressure coefficient（NPC） effect of the resistance under very low pressure.The NPC phenomenon of the composites depends on the CB mass fraction.In the scope of low CB mass fraction,the NPC phenomenon becomes more apparent with the increase of the CB mass fraction.When the CB mass fraction is 23%,the composites display almost the most strong NPC effect.There exists a clear hysteresis loop on the R/R0-F curve during the cycle of pressure loading-unloading process,which is closely related to the CB mass fraction or the number of cycles.The PRB stability of composites can be significantly improved by increasing the CB mass fraction or the number of cycles.It can also be found that the resistance of the composites decreases non-linearly at a given constant pressure,and presents a typical relaxation behavior.