Tribological Behavior of Three-Dimensional Carbon Felt-Supported Polyamide Nanocomposites

Nanomaterials are widely used as interface reinforcing materials because of their unique structure, nano-size and excellent performances, which are always used to improve the interface bonding force. Graphene, as a two-dimensional nanomaterial, has excellent mechanical strength, thermal conductivity, significant self-lubricating property and high bearing capacity, which has great potential in improving the tribological properties of polymers, and have been extensively applied in aero-space, automobile manufacturing, building engineering and other fields due to their excellent mechanical properties. Graphene oxide (GO) is a derivative with many oxygen-containing groups on its surface. It is thus characteristic of excellent solubility in both aqueous and organic solvents (amphiphilic). So Graphene oxide (GO) shows infinite prospects of application in composite materials, nanomaterials and friction materials. However, due to high filling and poor dispersion, the mechanical properties of the composites may deteriorate. Therefore, the 3D supported graphene can be constructed by using the supporting material as the reinforcement framework which can not only overcome the problems of graphene agglomeration and filler dispersion in the matrix, but also improve the mechanical properties of the material. In order to improve the tribological and mechanical properties of monomer cast nylon 6 (MCPA6) composites, carbon felt (CF) was used as supporting materials, and graphene oxide (GO) and paraffin (PW) were used as fillers. We prepared the 3D lubrication reinforcement modified MCPA6 composites of CF/GO/PW. The mechanical and tribological properties of MCPA6 composites modified by corresponding 3D supported graphene lubrication reinforcers were investigated. The specific research contents and conclusions were as follows. In this paper, using CF as the 3D support material, the CF/GO/PW 3D lubricating reinforcement was prepared by one-step hydrothermal method to load GO and PW on the CF, and then MCPA6/CF/GO/PW composites were prepared by in-situ polymerization. After that, the microstructure of CF/GO/PW 3D lubrication reinforcement and the structure of the composites were characterized and tested. Moreover, the tribological and mechanical properties of pure MCPA6 and its composites were studied, and the effect of the ratio of GO to PW on the tribological properties of the composites was also studied. Surprisingly, it was found that the presence of a small quantity of GO in the MCPA6 composites could significantly enhance the tribological properties of the composites. The study found that when the mass ratio of GO to PW was 1:3, the tribological performance of the composites reached the best level. Compared with pure MCPA6, the friction coefficient and specific wear rate of the composites were reduced by 87% and 73%, respectively. This was due to the improvement of the interfacial properties between CF and matrix and the synergistic enhancement of lubrication by GO/PW and CF. The tensile modulus and flexural modulus of the composites were increased by 37%, 155%, respectively, indicating that CF/GO/PW 3D lubrication reinforcement can toughen and strengthen the composites. To sum up, in this work, MCPA6/CF/GO/PW composites were synthesized using in-situ polymerization. The discussion of the friction reduction and wear resistance of MCPA6 composites illustrated the synergistic effect. This work can be useful for the development of MCPA6 composites with outgoing tribological properties of GO and PW for various applications.