Direct functionalizing of acrylonitrile-butadiene rubber surfaces through different peroxide curing

This study focuses on the influence of peroxide type on the chemical composition, curing properties, and free-radical reactions of peroxide cured acrylonitrile-butadiene rubber (NBR). A novel perspective regarding peroxide curing as a surface modification method to control the formation of functional groups on cured rubber surfaces via the primary curing process is provided. During curing, the peroxide acts as a useful curing agent and as an efficient controller of functional group formation on rubber surfaces. Surface functionalization of NBR cured using peroxides containing structures such as alkyl, phenyl, and both groups was examined by X-ray photoelectron spectroscopy (XPS). The effects of different curing temperatures were also studied. Oxygen-containing functional groups were obtained on the cured NBR surfaces. Notably, NBR surfaces cured by the peroxide containing phenyl groups showed an increased abundance of oxygen-containing functional groups compared to those cured by the peroxide containing alkyl groups. The functional group formation mechanism on rubber surfaces is also discussed herein. This strategy offers opportunities for large-scale fabrication of versatile functional surfaces and thin films on rubber for various applications.