▎ 摘　　要

It is a major challenge to reduce water diffusion through hydrophilic polymers like epoxies without affecting their thermomechanical performance. Herein, both graphene oxide (GO) nanosheets and barium oxide (BaO) microparticles were incorporated together into epoxy to develop water resistant epoxy/BaO/GO nanocomposite. The manuscript signifies the role of these fillers in reducing water diffusion through epoxy matrix without deterioration in its basic thermal and mechanical properties. Morphological studies of epoxy/BaO/GO nanocomposites revealed the presence of uniformly distributed micro/nano-clusters of graphene oxide sheets and BaO. This enhanced the hydrophobicity of the nanocomposite with a water contact angle of 131.7?. The BaO/GO micro/nano-clusters also created a barrier to the diffusion of water molecules which reflected in the lower diffusion coefficient of epoxy/BaO/GO nanocomposite. Dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and thermomechanical (TMA) analysis has been carried out to investigate the viscoelastic, thermal stability, and dimensional stability of the prepared composites. Good viscoelastic performance of epoxy/ BaO/GO nanocomposite with balanced thermal stability and dimensional stability has been confirmed. The developed water resistant epoxy nanocomposite is suitable to be used in areas where moisture attack is a serious concern.