Hao Jiang, Yuhui Xie, Mukun He, Jindao Li, Feng Wu, Hua Guo, Yongqiang Guo, Delong Xie*, Yi Mei and Junwei Gu*. Highly Thermally Conductive and Flame-Retardant Waterborne Polyurethane Composites with 3D BNNS Bridging Structures via Magnetic Field Assistance. Nano-Micro Letters, 2025, 17: 138. 2023IF=31.6.（1區材料科學Top期刊）
https://doi.org/10.1007/s40820-025-01651-1
Abstract
The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices. Hence, a composite with three-dimensional network (Ho/U-BNNS/WPU) is developed by simultaneously incorporating magnetically modified boron nitride nanosheets (M@BNNS) and non-magnetic organo-grafted BNNS (U-BNNS) into waterborne polyurethane (WPU) to synchronous molding under a horizontal magnetic field. The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction, combined with the bridging structure established by U-BNNS, enable Ho/U-BNNS/WPU to exhibit exceptional in-plane (λ//) and through-plane thermal conductivities (λ⊥). In particular, with the addition of 30 wt% M@BNNS and 5 wt% U-BNNS, the λ// and λ⊥ of composites reach 11.47 and 2.88 W/(m·K) respectively, which representing a 194.2% improvement in λ⊥ compared to the composites with a single orientation of M@BNNS. Meanwhile, Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips. The composites also demonstrate excellent flame retardancy, with a peak heat release and total heat release reduced by 58.9% and 36.9% respectively, compared to WPU. Thus, this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites, presenting broad application potential in electronic packaging fields.
在聚合物電氣封裝材料中，優化熱傳導通路的微觀結構設計對于滿足現代電子設備對高效散熱管理和熱失控安全至關重要。因此，本研究開發了一種具有三維導熱網絡的復合材料（Ho/U-BNNS/WPU），通過同時引入磁性改性氮化硼納米片（M@BNNS）和非磁性有機接枝氮化硼納米片（U-BNNS）至水性聚氨酯（WPU）中，并在水平磁場下同步成型。研究結果表明，由M@BNNS沿磁場方向排列形成的連續面內導熱通路，以及U-BNNS所構建的橋接結構，使Ho/U-BNNS/WPU復合材料表現出優異的面內（λ//）和面間（λ⊥）導熱性能。尤其是當M@BNNS和U-BNNS的添加量分別為30 wt%和5 wt%時，復合材料的λ//和λ⊥分別達到11.47 W/(m·K)和2.88 W/(m·K)，其中λ⊥較單一取向M@BNNS復合材料提升了194.2%。此外，Ho/U-BNNS/WPU作為LED和芯片的熱界面材料展現出卓越的熱管理能力。同時，該復合材料還表現出優異的阻燃性能，其峰值熱釋放速率和總熱釋放量相較于純WPU分別降低了58.9%和36.9%。因此，本研究為聚合物復合材料的導熱結構設計及高效阻燃體系提供了新思路，并在電子封裝領域展現出廣闊的應用前景。
論文亮點
1. 通過在聚合物基體中同時引入磁性填料改性的氮化硼納米片（M@BNNS）和非磁性填料U-BNNS，并在水平磁場下同步成型，成功制備出具有三維熱傳導通路的復合材料。
2. 得益于三維橋接結構的微觀設計，僅添加5 wt%的U-BNNS，復合材料的面間導熱系數（λ⊥）便達到2.88 W/(m·K)，相較于單一取向的復合材料提升了194.2%。
3. 三維橋接結構的復合材料還表現出優異的阻燃性能，這主要歸因于凝聚相和氣相的協同阻燃機制，有效降低了電子設備發生熱失控的風險。
第一作者：姜豪
郵件地址：jianghao0820@mail.nwpu.edu.cn
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