Insights Into Nanoparticle Geometry Effects on the Degradation Resistance of Polymeric Composites Through Experimental and Numerical Evaluation

This study investigates the development of high‐performance polymer nanocomposites with enhanced environmental durability through combined experimental and numerical approaches. Three carbon‐based nanoparticles with distinct dimensionalities, carbon nanotubes (CNT, 1D), graphene nanoplatelets (GNP, 2D), and nanodiamonds (ND, 0D), were incorporated into epoxy coatings at concentrations of 0.5, 1.0, and 2.0 wt.%. Durability was evaluated through mechanical, tribological, and surface‐topography characterization following 1000 h of ASTM B117 salt spray exposure. The results demonstrate that nanoparticle geometry is one of the key factors, alongside the dispersion state, that significantly influence reinforcement efficiency and degradation resistance. Neat epoxy exhibited a 31% reduction in tensile strength after exposure, whereas ND‐reinforced coatings showed the highest stability. CNT‐ and GNP‐reinforced coatings also improved durability, reducing abrasion mass loss by up to 52% and 60%, respectively. To understand the underlying mechanisms, a three‐dimensional representative volume element (RVE) finite element model with randomly distributed nanoparticles was developed. The simulations revealed the effects of nanoparticle geometry and dispersion on stress transfer and local stress distribution. The combined findings establish that long‐term durability is governed by a combination of nanoparticle dimensionality and microstructural dispersion state, providing guidance for designing advanced protective coatings for metallic infrastructure.