In this article, multiwalled carbon nanotube/natural rubber composites with resistance-strain sensitivity were prepared by solution method, when the electrical percolation threshold of multiwalled carbon nanotube is only ∼3.5 wt%. The mechanical properties and resistance-strain response sensitivity were studied and analyzed systematically. The dispersion of multiwalled carbon nanotubes in the natural rubber matrix was characterized by field-emission scanning electron microscope and X-ray diffractometer. The composite exhibits good deformation sensitivity (gauge factor >27), large strain sensing range (>200%), and high signal stability when multiwalled carbon nanotube content was appropriate. The composite is suited to application in strain monitoring of large deformation structures since the resistance-strain response is more stable when strain exceeds 100%. To understand the mechanism of the resistance-strain response, the ‘shoulder peak’ of resistance-strain curve was researched and explained by the digital image correlation method, and an analytical model was developed when considering the effects of electronic tunneling and hopping in multiwalled carbon nanotube networks. Both experiment and analytical results confirm the break-restructure process of multiwalled carbon nanotube networks under applied strain cause the resistance-strain response. Finally, the practical application of the composite to monitoring strain load of rubber isolation bearing was realized.

本文通过溶液法制备了具有电阻应变敏感性的多壁碳纳米管/天然橡胶复合材料，当多壁碳纳米管的电渗阈仅为〜3.5 wt％时。对机械性能和电阻应变响应灵敏度进行了系统的研究和分析。用场发射扫描电子显微镜和X射线衍射仪表征了多壁碳纳米管在天然橡胶基质中的分散性。当多壁碳纳米管的含量合适时，该复合材料表现出良好的变形敏感性（应变系数> 27），大的应变感应范围（> 200％）和较高的信号稳定性。该复合材料适用于大型变形结构的应变监测，因为当应变超过100％时，电阻应变响应更加稳定。为了理解电阻-应变响应的机理，通过数字图像相关方法研究和解释了电阻-应变曲线的“肩峰”，并考虑了电子隧穿和多壁碳中的跳跃效应，建立了解析模型。纳米管网络。实验和分析结果均证实了多壁碳纳米管网络在施加应变下的断裂-重组过程会引起电阻-应变响应。最后，实现了该复合材料在橡胶隔震轴承应变载荷监测中的实际应用。为了理解电阻-应变响应的机理，通过数字图像相关方法研究和解释了电阻-应变曲线的“肩峰”，并考虑了电子隧穿和多壁碳中的跳跃效应，建立了解析模型。纳米管网络。实验和分析结果均证实了多壁碳纳米管网络在施加应变下的断裂-重组过程会引起电阻-应变响应。最后，实现了该复合材料在橡胶隔震轴承应变载荷监测中的实际应用。为了理解电阻-应变响应的机理，通过数字图像相关方法研究和解释了电阻-应变曲线的“肩峰”，并考虑了电子隧穿和多壁碳中的跳跃效应，建立了解析模型。纳米管网络。实验和分析结果均证实了多壁碳纳米管网络在施加应变下的断裂-重组过程会引起电阻-应变响应。最后，实现了该复合材料在橡胶隔震轴承应变载荷监测中的实际应用。考虑多壁碳纳米管网络中电子隧穿和跃迁的影响，建立了一个解析模型。实验和分析结果均证实了多壁碳纳米管网络在施加应变下的断裂-重组过程会引起电阻-应变响应。最后，实现了该复合材料在橡胶隔震轴承应变载荷监测中的实际应用。考虑多壁碳纳米管网络中电子隧穿和跃迁的影响，建立了一个解析模型。实验和分析结果均证实了多壁碳纳米管网络在施加应变下的断裂-重组过程会引起电阻-应变响应。最后，实现了该复合材料在橡胶隔震轴承应变载荷监测中的实际应用。