中文摘要：

基于碳纳米管（CNT）优异的导电能力和聚氨酯（Pu）弹性体的大变形特性，原位聚合制备CNT／PU复合材料，并研究其在拉伸变形过程中CNT网络结构的演变，及其电学性能对拉伸应变的响应敏感性。结果表明，CNT／PU复合材料具有显著的电阻一应变响应敏感性，其在大应变范围（0～200％）内电阻率变化高达6个数量级以上，这与CNT导电网络在拉伸过程中的结构演变密切相关。复合材料在拉伸过程中的体积膨胀使得CNT体积分数随应变的增加而逐渐降低，当CNT含量低于渗流阈值时，CNT网络呈断开状态并导致复合材料电阻的急剧增加；此外，CNT含量对复合材料电阻-应变响应敏感性也有显著影响。CNT／PU复合材料电阻对拉伸应变的响应敏感性使得该材料可望应用于结构诊断、应变传感、安全监控、智能材料与结构系统等领域。

英文摘要：

Carbon nanotube/polyurethane （CNT/PU） composites were prepared by using an in-situ polymerization method, and their electrical sensitivity to tensile strain was investigated. The addition of CNTs can remarkably enhance both the mechanical strength and electrical conductivity of the composite. The CNT/PU composite exhibits a high sensitivity of electrical resistance to changes in tensile strain. The electrical resistance of the CNT/PU composite increases by six orders of magnitude in the enlongation range 0-200%, which can be attributed to the decrease of CNT volume fraction, expansion of total volume, and changes in the CNT-network structure under the high strain. The dependence of electrical resistivity of the composites on tensile strain can be well explained by a percolation threshold theory. The high electrical sensitivity of the CNT/PU composites to tensile strain can be used as an intelligent material and strain sensors in the field of construction safety.