Novel thermoplastic polyurethane (TPU)/multi walled carbon nanotubes (MWCNTs) conductive nanocomposites were fabricated by direct solution compounding method for volatile organic compounds (VOCs) sensors applications. The results of field emission scanning electron microscopy (FESEM) and electrical conductivity test showed that MWCNTs formed ideal conductive networks in TPU matrix. The volume conductivity of TPU/MWCNTs nanocomposites increased from 10^-12 to 10^-4 S/mm, and the percolation value was 4.76 wt%. The size parameters of MWCNTs did not show obvious effects on the formation of conductive networks based on our comparative investigation. XRD and FTIR tests showed that MWCNTs enhanced the short range ordered structure in amorphous region of TPU due to the physical entanglement. The characteristic stretching of TPU showed no obvious change because of weak chemical interaction between MWCNTs and TPU. Moreover, MWCNTs effectively enhanced the thermal stability of the nanocomposites, as verified by TG analysis. The gas sensing property tests showed that the gas sensing response of TPU/MWCNTs nanocomposites mainly came from the resistance changes due to the disconnection of conductive networks, as a result of VOCs adsorption-swelling effects. The prepared nanocomposites showed superior selectivity, especially to benzene vapor when compared with formaldehyde and other gases. The parameters and contents of MWCNTs have a certain influence on the gas sensing response speed and recovery ability of the nanocomposites. In addition, the prepared TPU/MWCNTs nanocomposites displayed excellent repeatability and fast response to the change of electrical resistance (in seconds) after cyclic exposure to VOCs and pure dry air.

新型热塑性聚氨酯 (TPU)/多壁碳纳米管 (MWCNTs) 导电纳米复合材料是通过直接溶液复合方法制造的，用于挥发性有机化合物 (VOCs) 传感器应用。场发射扫描电子显微镜（FESEM）和电导率测试结果表明，MWCNTs在TPU基体中形成了理想的导电网络。TPU/MWCNTs纳米复合材料的体积电导率从10 ^-12 S提高到10 ^-4 S/mm，渗透值为4.76wt%。根据我们的比较研究，MWCNTs 的尺寸参数对导电网络的形成没有显示出明显的影响。XRD 和 FTIR 测试表明，由于物理纠缠，多壁碳纳米管增强了 TPU 非晶区的短程有序结构。由于多壁碳纳米管与TPU之间的化学相互作用较弱，TPU的拉伸特性没有明显变化。此外，如TG分析所证实的，MWCNT有效地增强了纳米复合材料的热稳定性。气敏性能测试表明，TPU/MWCNTs纳米复合材料的气敏响应主要来自由于VOCs吸附-膨胀效应导致导电网络断开引起的电阻变化。制备的纳米复合材料显示出优异的选择性，与甲醛和其他气体相比，尤其是对苯蒸气。MWCNTs的参数和含量对纳米复合材料的气敏响应速度和恢复能力有一定的影响。此外，制备的 TPU/MWCNTs 纳米复合材料在循环暴露于 VOC 和纯干燥空气后，表现出优异的重复性和对电阻变化（以秒为单位）的快速响应。