In this study, composite thin films were fabricated by mixing one-dimensional silver nanowires (AgNWs) with graphene, polybenzoxazine (PBZ) and epoxy. Their electrical and thermal properties under different environmental conditions were investigated. The AgNWs were prepared by a polyol reduction method using ethylene glycol as a reducing agent and polyvinylpyrrolidone as a soft template to reduce silver ions. High aspect ratio AgNWs were then mixed into polymer matrices to allow them to form electrical and thermal conductive paths. Next, a trace amount of graphene was added into the nanocomposites in order to enhance their electrical and thermal properties. The results showed that the addition of graphene and AgNWs improved the threshold leakage current, and a 33% increase in thermal diffusivity was observed. The water resistance and gas barrier properties of PBZ and graphene effectively improved the thermal oxidation stability, and a 200% increase in electrical conductivity was achieved after 120h of thermal oxidation treatment. A considerable difference was observed between the moduli of epoxy and PBZ. Hardness and phase analyses using atomic force microscopy showed that material modulus mismatch occurred across the interface between the materials, triggering phonon scattering. However, the increase in thermal conductivity was not significant for either material. (c) 2018 Society of Chemical Industry