摘要
一种独特的电性能形变敏感行为-镍/聚氨酯复合材料的电阻率在20%拉伸应变下呈现近6个数量级的降低,导致该行为的填料网络演变机理仍不清晰.针对该现象,本文通过交流阻抗分析考察了2种具有不同拉伸敏感特性的镍/聚氨酯复合材料体系在不同应变下各种微观参数对频率的依赖性.采用尼奎斯特曲线拟合得到的数据及参数计算了团聚体电阻、团聚体之间电阻在拉伸下的变化,以此推测了2种复合材料体系在拉伸时导电网络不同的变化模式.结果表明,对于27.5 vol%填料含量的复合材料,在拉伸时由于团聚体维度发生变化使得逾渗在拉伸下发生,即拉伸逾渗现象.而25 vol%填料含量的复合材料由于填料含量远低于逾渗区域,即使团聚体维度发生变化也没有连续的导电网络产生.本工作为导电高分子复合材料在拉伸时导电网络的变化提供了新的理解,并为拉伸敏感导电高分子复合材料的网络研究提供新的思路.
An unconventional resistivity-strain behavior - the resistivity of nickel/polyurethane composites decreases by more than six orders of magnitude under 20% tensile strain was observed for the first time, while the conductive network evolution mechanism responsible for such unusual behavior is still unclear. In this work, the frequency dependence of various parameters of two nickel/polyurethane composite systems with contrary strain sensing behaviors was investigated by means of impedance spectra(IS) to achieve better understanding. Through further analysis using fitting parameters of Nyquist plot, the changes in the resistance of aggregates and the resistance between aggregates under tension were calculated and two different evolution modes of conductive network for both composite systems were proposed. It is illustrated that the percolation behavior occurred under tension for the composite with 27.5 vol% filler concentration due to the dimensional change of these aggregates,which is named as stretch-induced percolation. However, no continuous conductive network is constructed in the matrix within the whole strain range for composite with 25 vol% filler loading, because such content is much lower than that in the percolation region. This study provides a new understanding for the variation in conductive network of conductive polymer composites(CPCs) during stretching, and offers a new strategy to investigate the evolution of conductive network in CPCs.
作者
田可
邓华
傅强
Ke Tian;Hua Deng;Qiang Fu(College of Polymer Science and Engineering,State Key Laboratory of Polymer Material Engineering,Sichuan University,Chengdu 610065)
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2020年第5期559-568,共10页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号51773139,51922071)资助.
关键词
导电网络
阻抗分析
团聚体电阻
团聚体之间电阻
拉伸逾渗
Conductive network
Impedance spectra
Resistance in aggregate
Resistance between aggregates
Stretch-induced percolation
