Carbon nanotube yarns (CNTYs) are hierarchical fibers with outstanding electrical properties, and understating the temperature‐dependence of their electrical resistance (thermoresistivity) is essential for sensing applications and development of self‐sensing polymer composites. The cyclic thermoresistive response of individual CNTYs and the effect of embedding the yarn into a polymer are experimentally investigated herein. The effect of confining the CNTY by a thermosetting polymer is addressed by studying the thermoresistive response of CNTY/vinyl ester single‐fiber composites. Heating–cooling cycles ranging from 25 (room temperature [RT]) to 100 °C and 25 to −30 °C are applied to individual CNTYs and to CNTYs embedded into a vinyl ester polymer, while their electrical resistance is simultaneously recorded. Both the CNTY and its single‐fiber composite show a negative dependence of electrical resistance with temperature. For both temperature ranges (above and below RT), the average temperature coefficient of resistance found for individual CNTYs is ≈−9.5 × 10⁻⁴ K⁻¹, and its magnitude decreases about ≈30% when the yarn is embedded into the vinyl ester polymer. The hysteresis rendered by the different heating and cooling pathways is small for individual CNTYs, and largely increases when the CNTY is embedded into the polymer.

中文翻译：

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独立式和聚合物包埋的碳纳米管纱的循环热阻

碳纳米管纱线（CNTYs）是具有出色电性能的分层纤维，低估其电阻的温度依赖性（热敏性）对于传感应用和自感聚合物复合材料的开发至关重要。本文通过实验研究了各个CNTY的循环热阻响应以及将纱线嵌入聚合物中的作用。通过研究CNTY /乙烯基酯单纤维复合材料的热阻响应，可以解决热固性聚合物限制CNTY的作用。将25个（室温[RT]）到100°C和25到-30°C的加热-冷却循环应用于单个的CNTY和嵌入乙烯基酯聚合物的CNTY，同时记录它们的电阻。CNTY及其单纤维复合材料均显示出电阻与温度的负相关性。在两个温度范围内（高于和低于RT），单个CNTY的平均电阻温度系数为≈-9.5×10^-4  K ^-1，并且当纱线嵌入乙烯基酯聚合物中时，其大小降低约≈30％。对于单个的CNTY，通过不同的加热和冷却路径产生的磁滞很小，而当CNTY嵌入到聚合物中时，磁滞会大大增加。