Time-dependent effect on wetting and tribological properties of plasma-modified acrylonitrile–butadiene rubber (NBR) surface

Abstract

Different time air plasma treatment was conducted on acrylonitrile–butadiene rubber (NBR) surface, the wettability and friction behavior of the samples surface were measured after two months of storage. The changes in surface composition and microstructure during storage process were observed by X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM), respectively. The results show that the wettability of modified surface has obvious “hydrophobic recovery” phenomenon in the storage process, and the range of contact angle increase is closely related to the plasma treatment time, mainly because the change in surface composition at various time treatment are different during storage; the frictional behavior of plasma-modified NBR surface has not exhibited a “recovery” phenomenon after two months of storage, and the friction coefficient of the surface treated for 4 min and 8 min were even smaller than those before storage, which is due to the smoother and lower roughness of the surface morphology after storage. This study demonstrates that air plasma treatment is a promising technique for improving the wettability and tribological properties of NBR rubber, but the proper treatment time is needed to make the surface have the best wetting and frictional behavior.