Water absorption and hydrothermal ageing of epoxy adhesives reinforced with amino-functionalized graphene oxide nanoparticles

The study is focused on quantitative characterization of water absorption and hydrothermal ageing effects in a room-temperature amine cured epoxy adhesive widely used in automotive, aerospace, construction, and marine industries. Amino-functionalized graphene oxide (mGO) nanoparticles were incorporated into the epoxy (up to 1.72 wt.%) enabled cross-linking reactions and providing high interfacial adhesion, superior reinforcement efficiency and enhanced resistance to hydrothermal ageing of nanocomposites. Anomalous water absorption accompanied by progressive weight loss of samples (down to 7%) is fitted by two-stage models considering additive and coupled contribution from water diffusion and leaching of low molecular weight epoxy species. Nanocomposites are characterized by lower water diffusivity (40%) and decreased leaching effects (70%). High reinforcing efficiency of epoxy/mGO appeared in the increased glassy and rubbery storage moduli (60%), glass transition temperature (10 degrees C) and activation energy of glass transition (70%) compared to the neat epoxy. Hydrothermal ageing resulted in noticeable properties degradation of samples, although to a much lower extent in the case of nanocomposites. The results will contribute to the enhancement of global durability of common epoxy-based adhesives and extension of their lifetime. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study demonstrates that the amino-functionalized graphene oxide nanoparticles can significantly improve the performance of epoxy adhesive by enhancing its resistance to hydrothermal ageing, reducing water diffusivity, and leaching effects. The nanocomposites exhibit high reinforcing efficiency, and are able to mitigate the degradation of sample properties under hydrothermal ageing conditions.