Investigation of liquid crystal epoxy resin composites for application in cryogenic environments

Abstract

It is well accepted that the intrinsic thermal conductivity is extremely important in achieving excellent thermal conductivity composite and can be improved via incorporation of mesogens. In this work, an azomethine type liquid crystal epoxy (LCE) with aliphatic ether was designed and synthesized with expected structure, and the liquid crystal epoxy resin (LCER), together with KH‐550‐modified boron nitride (K‐BN)/LCER composites, has been obtained. Results show an increase of 31.6% in the thermal conductivity of the matrix, which could result in an enhancement of 57.7% for the composites when compared with E‐51. Additionally, the coefficient of thermal expansion (CTE), dielectric properties, and shear strength of LCER and K‐BN/LCER composites were assessed across a broad temperature range. Remarkably, the 30 wt% K‐BN/LCER composites showed a maximum decrease of 37.8% in CTE, while maintaining adequate shear strength to fulfill the bonding requirement and high thermal conductivity at both RT and −196°C.