Poly(amidoamine)-grafted Graphene Oxide/Epoxy Nanocomposite: Thermal/Mechanical Characteristics and Viscoelastic Properties

As the most crucial choice in the heavy-duty protective coating industry, epoxy-based coatings suffer from insufficient toughness and impermeableness. So in this study, a reliable method that is, in turn, easy to be scaled up is designed and proposed. Through this method, a significantly toughened and mechanically improved epoxy nanocomposite film is suggested. This film is based on poly(amidoamine)-grafted (PAMAM) graphene oxide (GO). GO is synthesized and then modified through two consecutive steps; first, silane-grafted GO producing SiGO and second polyamidoamine (PAMAM)-grafted SiGO leading to HbpSiGO. FT-IR, TGA, and XRD results confirm a successful functionalization of the GO flakes. Dynamic mechanical thermal analysis (DMTA) results reveal that the nanocomposite film based on HbpSiGO possesses higher storage modulus (50%), elevated glass transition temperature (18%), and higher cross-linking density (237%) compared to unfilled epoxy. According to tensile testing, HbpSiGO nanocomposite shows an increment in work of fracture (148%), elongation at break (52%), and maximum stress (68%) in comparison with neat epoxy.