Hybrid enhancements by polydopamine and nanosilica on carbon fibre reinforced polymer laminates under marine environment

In this study, two enhancement methods, i.e., toughen the epoxy matrix by commercially available nanosilica and enhance the interfaces of fibres and matrix by autoxidation of dopamine were applied together in carbon fibre reinforced polymer laminates with potential large-scale applicability. Significant enhancements were found for Mode I interlaminar fracture toughness and interlaminar shear strength with the combined addition of nanosilica and polydopamine in the laminates. The enhancement mechanism is proposed as well. Salt spray tests were applied in this study to simulate a marine environment for the laminates. Model I interlaminar fracture toughness and interlaminar shear strength both decreased under the simulated marine environment with an increase in immersion time, but the deterioration was significantly mitigated when nanosilica and polydopamine were added together with still much higher mechanical properties measured after 3 weeks of salt spray immersion than in neat laminate without salt spray immersion, providing promising evidence for maritime engineering applications of such laminates.