本征导热液晶环氧及其复合材料的研究进展

Progress in intrinsically thermal conductive liquid crystalline epoxy and composites

  • 摘要: 散热困难已成为制约微电子器件和电气绝缘设备日趋微型化的关键问题和技术瓶颈。传统导热环氧复合材料因热导率 (k) 与介电强度 (Eb) 之间难以协同提升及联调的矛盾而无法适应大功率、超高频微电子器件及高电压电力设备的绝缘封装的散热需求,而基于液晶 (LCE) 基元调控交联网络的结构有序性来提高k值而制备的本征导热环氧 (ITCE) 则同时具备高kEb性能。本论文分析了液晶环氧的微结构及本征导热机制,综述和归纳了基于不同结构液晶基元的ITCE的研究进展,系统分析了本征k的影响因素,探讨了液晶环氧及固化剂结构、温度、液晶基元含量及晶粒尺寸、外场辅助加工等因素对固化环氧的本征k的影响机制,阐述了提高液晶环氧的有序结构及本征k的途径和方法。最后,探讨了当前ITCE研究中存在的问题及展望了ITCE的未来发展方向。相比常规环氧,综合性能优异的ITCE代表了导热环氧的未来发展方向,基于ITCE的导热环氧复合材料在高频、高密度、微电子、高电压及大功率电力设备等领域具有潜在的重要用途。

     

    Abstract: Difficulty in prompting heat dissipation has emerged as a critical issue and technical bottleneck restricting further miniaturization of microelectronic devices and electrical insulation equipment. Traditional heat conductive epoxy composites are not qualified for meeting the heat dissipation requirements of high-power, ultra-high-frequency and high-voltage insulating packaging because the thermal conductivity (k) and dielectric strength (Eb) cannot be regulated and improved synergistically. Intrinsically thermal conductive epoxy (ITCE), whose k can be enhanced by regulating ordered structure of cross-linked network containing liquid crystal epoxy (LCE) units, simultaneously exhibits high k and Eb. This paper analyzes the microstructure and intrinsic heat conduction mecha-nism of LCE, and summarizes the latest research progress in ITCE based on different LCE structures. The present work systematically analyzes the influencing factors on k of ITCE, such as structures of LCE and curing agent, temperature, LCE content, grain size, and external field-assisted processing, and expounds the way to improve the ordered structure of LCE and the intrinsic k. Finally, it summarizes the existing problems in current ITCE research and points to the future development direction. ITCE with excellent comprehensive performances represents the future development direction of ITCE, and the ITCE based composites has significant potential applications in high-density packaging microelectronics, high-voltage and high-power power equipment.

     

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