Thermal Conducting Thermosets Driven by Molecular Structurally Enhanced Mesogen Interactions

Thermally conductive thermosets are greatly relevant for improving heat dissipation in advanced electronics. Although the thermal conductivities of organic materials, which are largely heat insulators, cannot be readily improved, a liquid crystal moiety can efficiently improve these properties via its selfassembling nature. Here, we report the syntheses of a series of bifunctional liquid crystal epoxy resins (LCERs) containing double mesogenic structures that are connected by aliphatic spacers to enhance their self-assembling properties. Phenyl benzoate derivatives are utilized as mesogens, and the series is chemically well-characterized. Although all the monomers exhibit clear mesomorphic properties in a wide temperature range (115-210 degrees C), as revealed by differential scanning calorimetry and polarized optical microscopy investigations, a slight difference is observed based on the length of the spacer. Cured LCERs are prepared by hot compression molding utilizing 4,4'-diaminodiphenylmethane, which is a suitable curing agent for the liquid crystal (LC) phases. They exhibit a glass transition temperature (T-g) of similar to 100 degrees C with a high decomposition temperature of similar to 350 degrees C. Interestingly, owing to the enhanced LC interaction, the maximum thermal conductivity attained is 0.45 W/m.K, which is remarkably high.

Automated summary

A new type of liquid crystal epoxy resin was synthesized with double mesogenic structures connected by aliphatic spacers, enhancing its self-assembling properties and achieving remarkably high thermal conductivity.