Bonding Properties of Liquid Crystalline Epoxy Resins Having Different Phase Structures

ABSTRACT Liquid-crystalline epoxy resin systems, which have different phase structures (isotropic and nematic polydomain), were prepared. The bonding properties of their systems were investigated and related to their phase structure. As a result, the lap shear strength of the nematic system was lower than that of the isotropic system, although the nematic adhesive layer showed larger deformability than the isotropic one. The interfacial bonding properties of both the isotropic and nematic systems were investigated, and, thus, it was clarified that the low bonding strength of the nematic system was due to the low concentration of hydroxyl groups at the adhesive interface. The decrease in the concentration of hydroxyl groups was due to the restriction of the molecular motion derived from the ordered structure of the nematic system. Keywords: Cross-linkingOrientationBonding property ACKNOWLEDGMENT This work was supported in part by the Kansai University High Technology Research Center (HRC).