Optimization of Boron Nitride Sphere Loading in Epoxy: Enhanced Thermal Conductivity and Excellent Electrical Insulation

Key Laboratory of Optoelectronic Devices and System of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China

Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China

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Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

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Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, School of Materials Science & Engineering, Beijing institute of Technology, Beijing 100081, China

Authors to whom correspondence should be addressed.

Polymers 2019, 11(8), 1335; https://doi.org/10.3390/polym11081335

Received: 23 June 2019 / Revised: 8 July 2019 / Accepted: 12 July 2019 / Published: 12 August 2019

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Abstract

Thermally conductive but electrically insulating materials are highly desirable for thermal management applications in electrical encapsulation and future energy fields, for instance, superconducting magnet insulation in nuclear fusion systems. However, the traditional approaches usually suffer from inefficient and anisotropic enhancement of thermal conductivity or deterioration of electrical insulating property. In this study, using boron nitride sphere (BNS) agglomerated by boron nitride (BN) sheets as fillers, we fabricate a series of epoxy/BNS composites by a new approach, namely gravity-mix, and realize the controllable BNS loading fractions in the wide range of 5–40 wt%. The composites exhibited thermal conductivity of about 765% and enhancement at BNS loading of 40 wt%. The thermal conductivity up to 0.84 W·m⁻¹·K⁻¹ at 77 K and 1.66 W·m⁻¹·K⁻¹ at 298 K was observed in preservation of a higher dielectric constant and a lower dielectric loss, as expected, because boron nitride is a naturally dielectric material. It is worth noting that the thermal property was almost isotropous on account of the spherical structure of BNS in epoxy. Meanwhile, the reduction of the coefficient of thermal expansion (CTE) was largely reduced, by up to 42.5% at a temperature range of 77–298 K. View Full-Text

Keywords: boron nitride; isotropous thermal conductivity; epoxy; electrical insulation

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MDPI and ACS Style

Zhang, H.; Huang, R.; Li, Y.; Li, H.; Wu, Z.; Huang, J.; Yu, B.; Gao, X.; Li, J.; Li, L. Optimization of Boron Nitride Sphere Loading in Epoxy: Enhanced Thermal Conductivity and Excellent Electrical Insulation. Polymers 2019, 11, 1335. https://doi.org/10.3390/polym11081335

AMA Style

Zhang H, Huang R, Li Y, Li H, Wu Z, Huang J, Yu B, Gao X, Li J, Li L. Optimization of Boron Nitride Sphere Loading in Epoxy: Enhanced Thermal Conductivity and Excellent Electrical Insulation. Polymers. 2019; 11(8):1335. https://doi.org/10.3390/polym11081335

Chicago/Turabian Style

Zhang, Hua, Rongjin Huang, Yong Li, Hongbo Li, Zhixiong Wu, Jianjun Huang, Bin Yu, Xiang Gao, Jiangang Li, and Laifeng Li. 2019. "Optimization of Boron Nitride Sphere Loading in Epoxy: Enhanced Thermal Conductivity and Excellent Electrical Insulation" Polymers 11, no. 8: 1335. https://doi.org/10.3390/polym11081335

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Optimization of Boron Nitride Sphere Loading in Epoxy: Enhanced Thermal Conductivity and Excellent Electrical Insulation

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