Improving the Intrinsic Thermal Conductivity of Epoxy Resin by Synergistic Effect between Rigid Groups and Hydrogen Bonds

Abstract

Although introducing liquid crystal phase into epoxy resin for liquid crystal epoxy fabrication is one of the most conventional methods for improving the intrinsic thermal conductivity of epoxy resin, the complex molecular structure design and sophisticated synthesis process seriously limit its rapid expansion and further industrial application. Herein, the rigid groups of 4’4‐dihydroxybiphenyl were introduced into the main chain of epoxy resin by ring‐opening polymerization (ROP) to change the molecular structure of epoxy resin. The introduction of biphenyl groups enhances the “orderliness” of molecular structure and forms hydrogen bonds between molecules, which facilitates the transmission of phonons within the molecule. The intrinsic thermal conductivity of modified epoxy resin (MEP) reaches 0.29 W m−1 K−1. After adding the expanded graphite (EG) into the MEP matrix, the thermal conductivity of MEP/EG reaches 2.59 W m−1 K−1, which is 1133 % higher than that of EP. In addition, the MEP also has certain advantages in harsh environment, the |Z|0.01 Hz of MEP coating is higher than 1.4 times the value of EP coating after immersing in 3.5 wt% NaCl solution for ten days, which identified the excellent anticorrosion of MEP. The MEP prepared by this method can find great applications as heat conduction materials in harsh environment.