Evaluating the Mechanical Characteristics of Graphene Nanoparticle-Infused Polyurethane Coating on Low-Density Polylactic Acid Part

Recent advancements in additive manufacturing have sparked interest in low-density materials such as LW-PLA, which can be presented as alternatives to foam and balsa, which are the main components of the structural marine components. The lightweight properties of LW-PLA provide advantages, particularly for underwater components like propeller shrouds and hydrodynamic surfaces, due to reduced drag and increased fuel efficiency. However, the durability of LW-PLA in a corrosive environment necessitates protective coatings. This study investigates the effectiveness of graphene nanoparticles (GNPs)-infused polyurethane (PU) coating on LW-PLA specimens. Integrating GNPs into PU enhances mechanical strength and stability through van der Waals forces and π–π stacking interactions. A 100-hour accelerated salt spray test demonstrated that the coated specimens experienced only a 15.33% reduction in maximum stress compared to a 41.65% reduction in uncoated specimens. Additionally, a case study was conducted to evaluate the efficacy of the GNP-infused PU coating on the 3D-printed scale-down model of the propeller under the simulated salt spray condition, with further SEM analysis performed to examine the surface. Overall, GNP-infused PU coatings enhance the durability and reliability of LW-PLA in marine environments.