Intercalation structure and highly enhancing tribological performance of monomer casting nylon-6/graphene nano-composites

A series of monomer casting nylon-6 (MC PA6)/graphene (GN) nano-composites were in situ synthesized by incorporation of polyethylene glycol (PEG) as a solid lubricant and compatibilizer. Addition of PEG led to more efficient grafting of PA6 molecules on GN surface, while GN was exfoliated and uniformly distributed in the matrix. Compared with neat MC PA6, addition of only 0.5 wt% GN resulted in a roughly 12% increase in tensile strength and 20.6% increase in impact strength, while over 75% reduction in specific wear rate and 13% reduction in friction coefficient were obtained with 0.7 wt% GN addition. The worn surface displayed smooth and flat features with uniform depth distribution, and the annealing degree due to produced friction heat was much lower for the composites. The mechanical and tribological properties of the composites in presence of PEG were superior to those in absence of PEG, further confirming the synergistic reinforcing/lubrication effect of GN-PEG.