Tengbo Ma, Kunpeng Ruan, Yongqiang Guo*, Yixin Han, Junwei Gu*. Controlled length and number of thermal conduction pathways for copper wire/poly(lactic acid) composites via 3D printing. SCIENCE CHINA Materials. 2023. Doi: 10.1007/s40843-023-2540-9.
https://www.sciengine.com/SCMs/doi/10.1007/s40843-023-2540-9

Thermal conduction pathways play crucial roles in comprehending thermal transport in thermally conductive polymer composites. However, there is a lack of in-depth investigation on how the thermal conduction pathways (length and number) influence the thermal conductivity coefficients (λ) of the composites. In this work, three-dimensional (3D) printing is performed to fabricate the thermally conductive 1D copper wire/poly(lactic acid) (1D-Cw/PLA) composites, allowing for controlling the length and number of Cw thermal conduction pathways. And one thermal conduction model is also proposed and established for polymer composites with 1D thermal conduction pathways, elucidating the quantitative relationship between thermal conduction pathways and thermal conductivity. For composites with the same amount of Cw, the in-plane λ (λ//) of thermally conductive 1D-Cw/PLA composites is positively correlated with the number and length of Cw thermal conduction pathways. Specifically, when the volume fraction of Cw is 25.1 vol%, the λ// of 1D-Cw/PLA composites, containing 20 intact Cw thermal conduction pathways, can reach up to 4.23 W m−1 K−1, which is 87.2% higher than that of 1D-Cw/PLA composites without intact Cw thermal conduction pathways (2.26 W m−1 K−1), 72.0% higher than that of 1D-Cw/PLA composites with short Cw (2 intact Cw and 18 Cw broken at the half, 2.46 W m−1 K−1), and 1527% higher than that of the pure PLA matrix (0.26 W m−1 K−1). Furthermore, the predicted λ values from our established thermal conduction model and empirical equation show no significant difference from the measured λ at a 95% confidence level.
导热通路对理解导热高分子复合材料的导热行为至关重要，但目前有关导热通路属性（长度、数量）对高分子复合材料导热系数的影响机制缺乏深入的研究。本文采用3D打印技术制备了铜线（Cw）导热通路长度和数量可控的一维铜线/聚乳酸（1D Cw/PLA）导热复合材料，建立了针对一维导热通路的高分子复合材料的导热模型，明晰了其导热通路属性与其导热性能的定量关系。相同Cw用量下，1D Cw/PLA导热复合材料的面内导热系数（λ_//）与导热通路的数量和长度成正相关。当Cw体积分数为25.1 vol%时，含20根Cw贯穿导热通路的1D Cw/PLA导热复合材料的λ//最高可达4.23 W/(m·K)，比相同Cw用量下不含Cw贯穿导热通路的1D Cw/PLA导热复合材料λ_//（2.26 W/(m·K)）高87.2%，比相同Cw用量下含短Cw（2根贯穿的Cw，18根在1/2处被打断的Cw）的1D Cw/PLA导热复合材料的λ_//（2.46 W/(m·K)）高72.0%，较纯PLA基体的λ_//（0.26 W/(m·K)）提高了1527%。采用本文构建的导热模型和经验方程对1D Cw/PLA复合材料的导热系数进行预测，95%的置信度认为预测值与实测值无显著差异。

论文下载：Controlled length and number of thermal conduction pathways for copper wirepoly(.pdf

论文链接：https://www.sciengine.com/SCMs/doi/10.1007/s40843-023-2540-9