Effect of direct fluorination on the mechanical and scratch performance of nitrile butadiene rubber

To explore the possibility of direct fluorination to enhance the scratch performance of rubber materials, the effect of direct fluorination on the mechanical and surface properties and scratch performance of nitrile butadiene rubber (NBR) was studied. The bulk mechanical performance of NBR showed no apparent change after fluorination except the fair alteration of the type B tear strength, while the surface properties experienced substantial variations. The surface of the fluorinated samples appears to be cleaner, accompanied with the decreased surface roughness. The friction coefficient decreased substantially with fluorination treatment for only 30 minutes. Obvious changes were observed for the surface modulus and surface energy of the fluorinated NBR. The onset of the scratch groove was significantly delayed under certain fluorination conditions. However, the surface whitening did not show significant improvement. The correlations between the scratch resistance and the bulk mechanical and surface properties were analyzed systematically. The findings demonstrated the surface fluorination can be an efficient method to enhance the rubber's resistance to scratch groove.