Boron nitride nanoflakes (BNNF) are rendered as ideal thermal conductivity fillers for thermal interface materials (TIMs) due to their ultrahigh thermal conductivity (TC) and superior electronic insulation. However, it is difficult to guarantee the high yield of well dispersed BNNF in the polymer matrix for industrial production. Herein, we propose a novel “in-situ exfoliation” strategy to fabricate the thin BNNF via chemical bonding engineering. By enhancing the π–π stacking between the inclusion and matrix, the average thickness of the BN is efficiently reduced during the three-roll mixing process. The as-prepared BNNF composite presents ultrahigh in-plane TC (10.58 W·m⁻¹·K⁻¹) with 49.5% (in mass) BN loading at 100 parts per hundreds of rubber (phr) with simultaneously enhanced flexibility. Notably, the tensile strength, the initial thermal decomposition temperatures (T_5%) and elongation at break of the composite can reach 4.94 MPa, 470.6 °C and 98%, respectively. Our LED chip cooling tests validate the outstanding heat dissipation ability of the composites for TIM applications. Furthermore, this strategy also proves effective in exfoliating the graphite flakes, demonstrating excellent generalization capability. This work opens up a new avenue for developing the high-performance TIMs, showing huge potential in large-scale production.

中文翻译：

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π-π 相互作用可实现 BN 纳米薄片的原位剥离，用于高性能热界面材料


氮化硼纳米薄片 （BNNF） 具有超高导热性 （TC） 和卓越的电子绝缘性，因此成为热界面材料 （TIM） 的理想导热填料。然而，很难保证工业生产中聚合物基体中分散良好的 BNNF 的高产率。在此，我们提出了一种新颖的“原位剥离”策略，通过化学键合工程制造薄 BNNF。通过增强夹杂物和基体之间的π-π堆叠，在三辊混合过程中有效地减小了 BN 的平均厚度。所制备的 BNNF 复合材料表现出超高的面内 TC （10.58 W·m⁻¹·K⁻¹） 中具有 49.5%（质量）BN 负载量，每百个橡胶 （phr） 中 100 份，同时增强了柔韧性。值得注意的是，复合材料的拉伸强度、初始热分解温度 （T_5%） 和断裂伸长率分别达到 4.94 MPa、470.6 °C 和 98%。我们的 LED 芯片冷却测试验证了复合材料在 TIM 应用中的出色散热能力。此外，这种策略还被证明可以有效地去除石墨片，表现出出色的泛化能力。这项工作为开发高性能 TIM 开辟了一条新途径，在大规模生产中显示出巨大的潜力。