Enhanced Thermal Conductivity and Mechanical Toughness of the Epoxy Resin by Incorporation of Mesogens Without Nanofillers

Abstract

Epoxy resin is widely used due to its electrical insulation performances, but low elongation defects at the break, low thermal conductivity, and high brittleness limit its application scenarios. In this paper, the mesogen is utilized to improve the thermal conductivity and mechanical toughness of the traditional epoxy resin. Both the mechanical performances, including the impact strength, tensile strength, the bending strength, and the thermal behaviors, including the thermal conductivity, are investigated. Results show that with the biphenyl liquid crystal epoxy resin(BLCER) content of 10%, the impacting strength, tensile strength, and bending strength are increased by 71%, 21%, and 11%, respectively. The thermal conductivity of the composites increases to 2.26 times that of pure epoxy resin. Both the enhanced mechanical and thermal performance of the epoxy resin by the mesogen incorporation are further investigated. It is indicated that the mesogen in the Biphenyl Liquid Crystal Epoxy Resin significantly improve both the mechanical toughness and thermal conductivity of the epoxy resin by the formation of the micro-crack behavior and the thermal conductive networks, respectively. With the aids of the mesogen, the improved variety of properties in epoxy resin without reducing its original performance is attractive in the industry application with great demand in the balance of the comprehensive performances.INDEX TERMS Mesogen, epoxy resin, toughness, thermal conductivity.

Advances in Liquid Crystal Epoxy: Molecular Structures, Thermal Conductivity, and Promising Applications in Thermal Management

“…This can be achieved via various factors: designing different structural biphenyl LCE, selecting appropriate curing agents, and governing the spatial distribution of these LCE domains. [30] An illustrative study conducted by Tian et al [65] introduced biphenyl mesogenic units into common E-51 epoxy, engendering microscale ordered structures in the random crosslinked network. Comparative analysis with pure E-51 epoxy demonstrated significant improvements in impact strength, tensile strength, and bending strength by 71%, 21%, and 11%, respectively, at 10 wt% of biphenyl LCE.…”

“…An illustrative study conducted by Tian et al. [ 65 ] introduced biphenyl mesogenic units into common E‐51 epoxy, engendering microscale ordered structures in the random crosslinked network. Comparative analysis with pure E‐51 epoxy demonstrated significant improvements in impact strength, tensile strength, and bending strength by 71%, 21%, and 11%, respectively, at 10 wt% of biphenyl LCE.…”

Advancements in The Cross-Linking and Morphology of Liquid Crystals

“…In the recent scientific literature, there are cases of blends comprising liquid crystal epoxy resins and conventional epoxy resins. Combining two components with the same functional groups not only improves the performance of the resin itself but also avoids the negative effects caused sometimes by inorganic fillers [109]. Due to the presence of the rigid segments of mesogenic units in the liquid crystal and their substantial degree of organization, the available space within the hardened composite network diminishes, leading to a heightened cross-linking density in the resultant product.…”

“…Due to the presence of the rigid segments of mesogenic units in the liquid crystal and their substantial degree of organization, the available space within the hardened composite network diminishes, leading to a heightened cross-linking density in the resultant product. Consequently, this density growth substantially enhances the thermal stability of the system along with its thermal conductivity [109]. The liquid crystal phase can be stabilized with epoxy resin particles.…”