Evolution of interfacial bonding performance and molecular dynamics simulation of modified resin matrix/glass fiber interface

The interfacial bonding performance between glass fiber and epoxy resin directly affects the stress transfer and durability of glass fiber reinforced polymer (GFRP) composites. By hybridizing nanomaterials and synergistically enhancing with siloxane-active oligomers, a modified epoxy resin matrix with superior interfacial bonding and corrosion resistance properties was developed. The evolution of the interfacial bonding performance between the modified resin and fiber was investigated using single-filament tensile tests and digital image correlation microscopy. The underlying mechanism of interfacial degradation in an alkaline environment was elucidated through molecular dynamics simulations from an atomic perspective. The results indicate that, compared to the unmodified system, the modified resin/fiber interface exhibits an approximately 33.3% increase in interfacial bonding strength and an approximately 53.84% increase in maximum interfacial strain. After 30 days of corrosion, the interfacial bonding strength of the modified system shows an approximately 130.7% improvement relative to the corroded unmodified system. Molecular dynamics simulations reveal that the modified resin matrix strengthens the O_epoxy-H_s bonding interaction, delays interfacial bond failure, mitigates the reduction in both epoxy resin concentration and hydrogen bond density at the interface under corrosive conditions, and improves interfacial adhesion properties.