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Synergetic improvements of intrinsic thermal conductivity and breakdown strength in liquid crystal epoxy resin for high voltage applications

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Abstract

Heat conductive epoxy composites as electronic packaging materials present wider applications. However, the high loading of fillers required for a high thermal conductivity (k) inevitably degrades the electrical resistivity and breakdown strength (Eb) of epoxy composites, significantly limiting their urgent applications in high voltage fields. The key to tackling this dilemma is to improve the intrinsic k of pristine epoxy with inherently disordered structure. Liquid crystal epoxy (LCE) containing rod-shaped mesogenic units and flexible segments, emerges as a unique epoxy resin presenting inherently high-k realized via self-assembling the mesogens into ordered domains, represents a promising solution to this critical issue. In this work, two types of LCEs, i.e., BE and LCM6, were designed and synthesized, and their LC behaviors were investigated. Further, the thermal and electric properties of the 4,4-methylenedianiline cured BE/LCM6 were explored as a function of the LCM6 loading. The results reveal that the cured BE/LCM6 at an optimal ratio showcases the obviously elevated k and Eb along with low dielectric permittivity and loss, when compared with traditional epoxy and a single LCE component. The concurrent enhancement in both k and Eb is ascribed to the introduced ordered domains resulting from the self-assembled mesogens into the cured epoxy network, which pave the highway for phonon transport and impede the migration of charge carries. The prepared LCEs with high k and Eb show appealing application prospects in electrical power systems.

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Acknowledgements

The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (Nos. 52277028, 22205180), the Special Project for Local Service of Education Department of Shaanxi Provincial Government (22JC052), Priority Research and Development Foundations of Xianyang City Government (2021ZDYF-GY-0026), and the Analytic Instrumentation Center of XUST.

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Authors and Affiliations

  1. School of Chemistry and Chemical Engineering, Xi’an University of Science & Technology, Xi’an, 710054, China

    Jingyu Di-wu, Wenying Zhou, Yun Wang, Yanqing Zhang & Nan Zhang

  2. School of Materials Science and Engineering, Xi’an University of Science & Technology, Xi’an, 710054, China

    Ying Li

  3. Library, Xi’an University of Science & Technology, Xi’an, 710054, China

    Yajuan Lv

  4. Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China

    Qingguo Chen

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  1. Jingyu Di-wu
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Contributions

Jingyu Di-wu: Data curation, Formal analysis, Methodology, Writing – original draft. Wenying Zhou: Conceptualization, Funding acquisition, Supervision, Writing – review and editing. Yun Wang: Data curation. Ying Li: Conceptualization. Yajuan Lv: Visualization. Yanqing Zhang: Methodology, Visualization. Nan Zhang: Data curation. Qingguo Chen: Funding acquisition, Supervision.

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Correspondence to Wenying Zhou or Qingguo Chen.

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Di-wu, J., Zhou, W., Wang, Y. et al. Synergetic improvements of intrinsic thermal conductivity and breakdown strength in liquid crystal epoxy resin for high voltage applications. J Polym Res 31, 72 (2024). https://doi.org/10.1007/s10965-024-03919-3

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