Tengbo Ma, Kunpeng Ruan, Yongqiang Guo*, Yixin Han and Junwei Gu*. Controlled length and number of thermally conductive pathways for copper wire/poly(lactic acid) composites via 3D printing. SCIENCE CHINA Materials, 2023, doi.org/10.1007/s40843-023-2540-9. 2022IF=8.1.
https://www.sciengine.com/SCMs/doi/10.1007/s40843-023-2540-9
Abstract
Thermal conduction pathways play a crucial role in understanding the thermal behavior of thermally conductive polymer composites, yet there is a lack of in-depth research on the mechanism of how the properties of thermal conduction pathways (length, number) affect the thermal conductivity of polymer composites. In this study, one-dimensional copper wire/poly(lactic acid) (1D Cw/PLA) thermally conductive composites with controllable length and quantity of copper wire (Cw) thermal conduction pathways were fabricated using 3D printing technology. A thermal conduction model for polymer composites with one-dimensional thermal conduction pathways was established, elucidating the quantitative relationship between the properties of thermal conduction pathways and their thermal performance. With the same Cw content, the in-plane thermal conductivity (λ//) of 1D Cw/PLA thermally conductive composites is positively correlated with the number and length of thermal conduction pathways. When the Cw volume fraction is 25.1 vol%, the λ// of the 1D Cw/PLA thermally conductive composites containing 20 Cw intact thermal conduction pathways can reach up to 4.23 W/(m·K), which is 87.2% higher than the λ// of the 1D Cw/PLA thermally conductive composites without Cw intact thermal conduction pathways (2.26 W/(m·K)), 72.0% higher than the λ// of the 1D Cw/PLA thermally conductive composites containing short Cw (2 intact Cw, 18 broken at 1/2 point Cw) (2.46 W/(m·K)), and 1527% higher than the λ// of the pure PLA matrix (0.26 W/(m·K)). Using the thermal conduction model and empirical equations constructed in this study, the thermal conductivity of 1D Cw/PLA composites was predicted, and it was found that there was no significant difference between the predicted values and the measured values at a 95% confidence level.
導熱通路對理解導熱高分子復合材料的導熱行為至關(guān)重要，但目前有關(guān)導熱通路屬性（長度、數(shù)量）對高分子復合材料導熱系數(shù)的影響機制缺乏深入的研究。本文采用3D打印技術(shù)制備了銅線（Cw）導熱通路長度和數(shù)量可控的一維銅線/聚乳酸（1D Cw/PLA）導熱復合材料，建立了針對一維導熱通路的高分子復合材料的導熱模型，明晰了其導熱通路屬性與其導熱性能的定量關(guān)系。相同Cw用量下，1D Cw/PLA導熱復合材料的面內(nèi)導熱系數(shù)（λ//）與導熱通路的數(shù)量和長度成正相關(guān)。當Cw體積分數(shù)為25.1 vol%時，含20根Cw貫穿導熱通路的1D Cw/PLA導熱復合材料的λ//最高可達4.23 W/(m·K)，比相同Cw用量下不含Cw貫穿導熱通路的1D Cw/PLA導熱復合材料λ//（2.26 W/(m·K)）高87.2%，比相同Cw用量下含短Cw（2根貫穿的Cw，18根在1/2處被打斷的Cw）的1D Cw/PLA導熱復合材料的λ//（2.46 W/(m·K)）高72.0%，較純PLA基體的λ//（0.26 W/(m·K)）提高了1527%。采用本文構(gòu)建的導熱模型和經(jīng)驗方程對1D Cw/PLA復合材料的導熱系數(shù)進行預測，95%的置信度認為預測值與實測值無顯著差異。
論文亮點
1. 采用3D打印技術(shù)制備了導熱通路長度和數(shù)量可控的一維銅線/聚乳酸（1D Cw/PLA）導熱復合材料，明晰了導熱通路長度和數(shù)量與導熱系數(shù)的定量關(guān)系。
2. 相同Cw用量下，1D Cw/PLA導熱復合材料的λ//與導熱通路的數(shù)量和長度成正相關(guān)。當Cw體積分數(shù)為25.1 vol%時，含貫穿導熱通路的1D Cw/PLA導熱復合材料的λ//最高可達4.23 W/(m·K)，較純PLA基體的λ//（0.26 W/(m·K)）提高了1527%。
3. 95%的置信度認為采用本文建立的導熱模型和經(jīng)驗方程預測的導熱系數(shù)與實測值無顯著差異。
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