Molecular Dynamics Simulation of Polymer Concrete Enhanced by Carbon Nanoparticles: Effect of Surface Functional Groups

Polymer concrete (PC) has attracted considerable interest for its excellent deformation resistance and durability. However, the mechanical drawbacks of polymers, particularly their limited compressive strength, constrain the wider application and design flexibility of PC. While experimental techniques such as X-ray diffraction and scanning electron microscopy provide insights into nanoparticle interactions within the polymer matrix, they lack the resolution to fully elucidate nanoscale mechanisms. To bridge this gap, this study utilizes molecular dynamics (MD) simulations to analyze the shearing behavior of carbon nanoparticle (CNP)-reinforced PC composites. MD simulations allow for atomic-level insights into the interactions between CNPs and the polymer matrix, providing a more detailed understanding of how surface-modified CNPs enhance mechanical properties. Our results show that surface-modified CNPs influence the distribution and conformation of epoxy within the PC system. Amino-functionalized CNPs strengthen the epoxy and calcium silicate hydrate (C–S–H) interface by facilitating calcium–oxygen bond formation. These interactions play a crucial role in improving the mechanical properties of PC. This study provides a fundamental understanding of how surface-modified CNPs reinforce PC and offers valuable insights for optimizing the performance of CNP-reinforced cementitious composites.