Surface modification of vulcanized rubber by radiation grafting, part 2: Improvement in performance of wiper rubber

Abstract Surface of natural rubber was modified by radiation‐induced grafting of hydrophilic monomer, 2‐hydroxyethyl methacrylate (HEMA), to improve the properties of surface hardness, dry friction, wiping performance, and wear duration. The ratio of grafted‐HEMA to the rubber near the surface layer of HEMA‐grafted rubber was analyzed by FT‐IR and expressed as composition ratio. The composition ratio was controlled from 0.29 to 0.93 by changing HEMA concentration and dose in graft polymerization. When this composition ratio was higher than 0.8, the surface hardness was higher than 70 and the coefficient of dry friction lower than 0.65. Those values became better than those of commercially available chlorinated‐rubber in terms of wear and friction against glass. The surface hardness in wet state became very close to natural rubber since grafted‐HEMA was softened by contacting with water. As a result, the grafted‐HEMA rubber realized 95% and higher wiping performance of water on glass. Additionally, the wear resistance was eight times higher than chlorinated rubber. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012