Surface modification of vulcanized rubber by radiation grafting, 1; Improvement in friction behavior

Mizote, Norihito*; Katakai, Akio; Tamada, Masao; Matsuoka, Hiroshige*

Hydrophilic monomer, 2-hydroxyethyl methacrylate (HEMA), and hydrophobic monomer, 3-(methacryloyloxy)propyltris(trimethylsiloxy)silane (MPTS), were grafted on vulcanized rubber surface by simultaneous electron beam irradiation. We studied the characteristics of graft polymerization, the relationship between the contact angle of water on the modified surface and friction behavior at the moment of semi-dry. Grafted rubbers were investigated with composition ratio and contact angle. As a result of graft polymerization of HEMA and MPTS, the composition ratio increased as the monomer concentration and the irradiation dose increased. By the graft polymerization of HEMA, the contact angle decreased to approximately 70. By the graft polymerization of MPTS, the contact angle increased approximately to 108. Friction behavior at the moment of semi-dry was evaluated by which is difference with the coefficient of dry friction and maximum friction. The increase in the contact angle owing to hydrophobic properties by graft polymerization of MPTS led to the decrease of . The decrease in the contact angle owing to hydrophilic properties by graft polymerization of HEMA resulted in the increase of .