Reinforcement mechanism of KH550-modified cellulose nanofibers in continuous carbon fiber/polyamide 12 composites: a molecular dynamics simulation study

Abstract

The mechanical properties of continuous carbon fiber (CCF) reinforced polyamide 12 (PA12) composites are typically governed by the weak polymer matrix and poor fiber-matrix interface. Both limitations can be alleviated by incorporating the KH550-modified cellulose nanofibers (CNF), yet, the underlying mechanisms require further clarification. Here, we utilized the molecular dynamics (MD) method to investigate the reinforcement mechanisms of KH550-modified CNF on PA12 matrix and the CCF-PA12 interface. Amorphous cell simulation results indicated that the PA12 matrix containing 10 wt% KH550-modified CNF exhibits superior mechanical properties, attributed to the improved nanofiber dispersion. Moreover, the pull-out simulations of the interfacial shear strength (IFSS) of the CCF-PA12 interface based on a threelayer sandwich model revealed that, compared with the pristine interface, the modified one increases it by 10.5%, owing to the formation of a rigid molecular region near the interface and more efficient stress transfer enabled by uniform nanofiber dispersion. This study offers some insights into the mechanism of KH550-modified CNF reinforcing CCF/PA12 composites from the perspective of MD.