Abstract The role of carbon nanotube (CNT) coating on the carbon fiber (CF) surfaces in the effective thermal conductivities of the unidirectional polymer hybrid nanocomposites is investigated by a newly presented multi-stage micromechanical method. The constructional feature of the hybrid nanocomposite is that randomly oriented CNTs grown on the CF surfaces. For simulating, a new version of the semi-empirical Halpin-Tsai (H-T) model is appropriately coupled with an analytical unit cell micromechanical model developed in the present research. The model captures the influences of the CNTs random dispersion, waviness, length, diameter, volume fraction and the CNT/polymer interfacial thermal resistance and also the CF cross-section shape parameters. The predicted results for the thermal conductivities of fibrous composites and polymer nanocomposites containing CNTs are verified with the available experimental data and a very good agreement is found. The results show that the longitudinal thermal conductivity of CF-reinforced hybrid nanocomposites is not affected by the CNTs coating. However, the nanocomposites transverse thermal conductivities are significantly enhanced over those of the conventional fibrous composites without the CNTs coating. An improvement in the nanocomposites transverse thermal conducting behavior can be observed with (i) increasing the CNTs volume fraction and length (ii) using straight CNTs and (iii) forming a perfect bonding interface.

中文翻译：

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CNT涂层对单向聚合物杂化纳米复合材料整体热导率的影响

摘要 通过新提出的多级微机械方法研究了碳纳米管 (CNT) 涂层在碳纤维 (CF) 表面上对单向聚合物杂化纳米复合材料有效热导率的作用。混合纳米复合材料的结构特征是随机取向的碳纳米管生长在 CF 表面。为了进行模拟，新版本的半经验 Halpin-Tsai (HT) 模型与本研究中开发的分析晶胞微机械模型适当结合。该模型捕获了 CNT 随机分散、波纹度、长度、直径、体积分数和 CNT/聚合物界面热阻以及 CF 横截面形状参数的影响。纤维复合材料和含有碳纳米管的聚合物纳米复合材料的热导率的预测结果用可用的实验数据进行了验证，并且发现了非常好的一致性。结果表明，碳纤维增强杂化纳米复合材料的纵向热导率不受碳纳米管涂层的影响。然而，与没有碳纳米管涂层的传统纤维复合材料相比，纳米复合材料的横向热导率显着提高。纳米复合材料横向导热行为的改进可以通过 (i) 增加 CNT 的体积分数和长度 (ii) 使用直 CNT 和 (iii) 形成完美的结合界面来观察。结果表明，碳纤维增强杂化纳米复合材料的纵向热导率不受碳纳米管涂层的影响。然而，与没有碳纳米管涂层的传统纤维复合材料相比，纳米复合材料的横向热导率显着提高。纳米复合材料横向导热行为的改进可以通过 (i) 增加 CNT 的体积分数和长度 (ii) 使用直 CNT 和 (iii) 形成完美的键合界面来观察。结果表明，碳纤维增强杂化纳米复合材料的纵向热导率不受碳纳米管涂层的影响。然而，与没有碳纳米管涂层的传统纤维复合材料相比，纳米复合材料的横向热导率显着提高。纳米复合材料横向导热行为的改进可以通过 (i) 增加 CNT 的体积分数和长度 (ii) 使用直 CNT 和 (iii) 形成完美的结合界面来观察。