Preparation and tribological properties of 3D network polymer-based nanocomposites reinforced by carbon nanofibers

A new robust three-dimensional (3D) network epoxy (EP)-based nanocomposite was fabricated via vacuum assisted resin transfer molding (VARTM) method. Carbon nanofibers (CNFs) and 3D polyimide (PI) fiber felt were utilized to improve the mechanical and tribological properties of the prepared EP nanocomposites. Results indicated that both the friction coefficients and wear rates of CNFs/PI/EP nanocomposites were lower than the other two comparative materials at various loads and velocities. CNFs/PI/EP nanocomposites obtained superior tribological properties, which enhanced the wear resistance by 18 times compared with pure EP under the applied load of 1.2 MPa. The worn surface and wear mechanism of composites were analyzed by a scanning electron microscope (SEM). Additionally, CNFs/PI/EP nanocomposites also exhibited remarkable improvements in the mechanical properties. These improved properties could be attributed to the synergistic effect between PI fiber felt and CNFs. The 3D PI fiber felt was used as structural skeleton reinforcing while the CNFs played its role in enhancing interface bonding strength between EP matrix and PI fiber felt. The CNFs could also act as solid lubrication and anti-friction agent in the composites.