[Angewandte Chemie International Edition] Thermally Conductive Naphthalene Epoxy Resin by Tailoring Flexible Chain Length and Liquid Crystal Structure
writer：Shuangshuang Wang, Kunpeng Ruan, Yongqiang Guo*, Jie Kong, Junwei Gu*
keywords：Epoxy resin, Naphthalene liquid crystal, Thermal conduction mechanism, Thermal conductivity
source：期刊
Issue time：2025年
Shuangshuang Wang, Kunpeng Ruan, Yongqiang Guo*, Jie Kong, Junwei Gu*. Thermally Conductive Naphthalene Epoxy Resin by Tailoring Flexible Chain Length and Liquid Crystal Structure. Angewandte Chemie International Edition, 2025, 64(21): e202501459. 2024IF=16.9. （1区化学Top期刊）
https://onlinelibrary.wiley.com/doi/10.1002/anie.202501459
Abstract
Epoxy resins with high thermal conductivity (λ) are widely used in electronic packaging, bonding, and coating. However, those with high intrinsic λ, typically synthesized using biphenyl or aromatic rings extended by ester linkages as the mesogenic unit, often exhibit high liquid crystal transition temperatures and poor processability. In this study, a series of naphthalene-based liquid crystal epoxy monomers (LCEs) were synthesized, using naphthalene as the mesogenic unit and modifying the flexible chain length on both sides. The resulting LCEs were cured within its liquid crystal phase to form naphthalene liquid crystal epoxy resin (LCER). The results show that the network order, radius of gyration, and low-frequency vibrational density of states all initially increase and then decrease with increasing flexible chain length. For LCER2, with a three-carbon flexible chain, these parameters reach their maximum values, facilitating phonon diffusion and enhancing λ. The liquid crystal transition temperature, λ, heat resistance index, and storage modulus of LCER2 were 67–78 °C, 0.40 W.m-1.K-1, 158.8 °C, and 2059 MPa, respectively, approximately 2.2 times higher than that of E-51 resin (0.18 W.m-1.K-1). This work offers insights into designing epoxy resins with low liquid crystal transition temperature, high intrinsic λ, and excellent mechanical properties for thermal management.
高导热环氧树脂在电子设备的封装、粘接和涂覆保护等方面具有广泛的应用，但目前以联苯或酯键连接的苯环作为液晶基元制备的本征高导热液晶环氧的液晶区间温度普遍较高，加工性较差。本文以萘环为液晶基元，通过调控萘环两侧柔性链长度合成一系列萘环液晶环氧单体（LCE），在其液晶温度区间内固化制备本征高导热萘环液晶环氧树脂（LCER）。结果表明，LCER固化网络的有序性、回旋半径和低频振动区域内的分子链振动态密度峰值，均随其分子链中萘环两侧柔性链长度的增加呈先增加后降低的趋势，当柔性链中的碳原子数为3时（即LCER2），其上述指标均达到最大值，有利于分子链中声子的扩散与迁移，进而提高导热性能。LCER2的液晶温度区间为67-78oC，本征λ、耐热指数和储能模量分别为0.40 W/(m·K)、158.8oC和2059 MPa，约为通用环氧树脂E-51的λ（0.18 W/(m·K)）的2.2倍。本工作对设计合成兼具低液晶温度区间的本征高λ、优异热/力学性能的环氧树脂具有一定的指导借鉴意义，有望拓宽其在电子封装和热管理等领域的应用。