The Method of Increasing the Mechanical Characteristics of Sea Transport Vehicles due to Environmentally Friendly Nanomodification of Epoxy Composites

Protective polymer composite coatings are widely used in marine transport owing to their improved adhesion and cohesion properties. Modifiers are introduced to enhance the performance characteristics of polymer coatings based on epoxy binders. This study investigates the impact of the eco-friendly nano modifying additive d-ascorbic acid on the structure and properties of an epoxy matrix. Based on the test results, a modified epoxy matrix with improved adhesion and physicomechanical properties was developed. The nature of the chemical bonds in the structure of the synthesized modifier and its molar mass were investigated by gas chromatography. A significant number of hydroxyl groups in the structure of the d-ascorbic acid molecule is one of the main criteria that determine the activity of this nano modifying additive in terms of homogeneous interactions during the cross-linking of the epoxy binder-based compound. It has been established that modifying epoxy compositions with d-ascorbic acid in the amount of 0.75 to 1 mass % per 100 mass % of ED-20 epoxy resin ensures an increase in adhesion strength while reducing residual stresses. The positive impact of the modifier on improving the adhesive properties of the modified epoxy matrix to the metal substrate is due to the chemical structure of the nano modifying additive, which determines the intermolecular interaction in the homogeneous polymer system. It has been proven that the epoxy composite's cohesive property indicators (elastic modulus, destructive stresses, impact toughness) significantly increase at the optimal d-ascorbic acid content. This is due to the additional formation of physical and chemical bonds in the structural network of the compound during its cross-linking in the presence of the modifying additive, which affects the indicators of the material's cohesive strength and impact resistance.