The development of electronic devices towards miniaturization and integration has put forward higher requirements for polymer-based composites with high thermal conductivity (TC). Aluminum nitride (AlN) is one of the most promising fillers thanks to its high TC (∼320 W m K) and outstanding physicochemical properties. However, the traditional composites filled with randomly dispersed AlN particles generally require extremely high filling fraction to enhance the TC, leading to increased production cost and degraded mechanical performance. To address this issue, an innovative strategy combining freezing casting and in-situ reaction process was proposed to directly construct vertically aligned AlN skeletons, which was further used as reinforcements to enhance the TC of epoxy (EP) composites. The close arrangement of AlN particles along the vertical direction was not only beneficial for enhancing the TC, but also improving the mechanical strength. The AlN/EP composites achieved an extremely high TC of ∼8.25 W m K at the AlN filling fraction of 56.2 vol%, which was 45.83 times higher than that of pure EP. The actual thermal management applications and finite element simulations also demonstrated the oriented AlN skeletons exhibited a more significant TC enhancement than that of randomly arranged AlN. Furthermore, the as-prepared AlN/EP composites also exhibited superior thermal stability and dielectric properties, presenting a broad application prospect as thermal management materials for the next-generation electronic devices.

中文翻译：

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原位反应策略构建AlN取向骨架及其对环氧复合材料导热性能的增强作用

电子器件向小型化、集成化方向发展，对高导热率聚合物基复合材料提出了更高的要求。氮化铝 (AlN) 因其高 TC (∼320 W m K) 和出色的物理化学性能而成为最有前途的填料之一。然而，随机分散的AlN颗粒填充的传统复合材料通常需要极高的填充率来提高TC，导致生产成本增加和机械性能下降。为了解决这个问题，提出了一种结合冷冻铸造和原位反应工艺的创新策略，直接构建垂直排列的AlN骨架，并进一步用作增强体，以提高环氧（EP）复合材料的TC。 AlN颗粒沿垂直方向的紧密排列不仅有利于提高TC，而且有利于提高机械强度。 AlN/EP 复合材料在 AlN 填充分数为 56.2 vol% 时实现了~8.25 W m K 的极高 TC，是纯 EP 的 45.83 倍。实际的热管理应用和有限元模拟也表明，定向AlN骨架比随机排列的AlN骨架表现出更显着的TC增强效果。此外，所制备的AlN/EP复合材料还表现出优异的热稳定性和介电性能，作为下一代电子设备的热管理材料具有广阔的应用前景。