The Effects of Some Antioxidants on a Polyurethane Fuel Binder

The antioxidation effect of N,N′-diphenyl-p-phenylene diamine and N,N′-di-(2-naphthyl)-p-phenylene diamine was studied with polyol-cured polyurethane containing an organo-ferric compound as a curing catalyst. These antioxidants, after weathering for one year, were found to be very effective. The same polymer without the antioxidants was degraded and flowed after only three weeks exposure (during the month of May). Although most of the inhibited polymers showed no depression in tensile properties after being exposed for one year, it was noted that the reddish transparent polymers turned dark brown and became opaque. Polyurethane is, in general, strong and resistant to weathering and aging. The degradation mentioned in this study, however, should be attributed to the degradative action of sunlight and the atmospheric conditions. The characteristics of the specimens for tensile strength and elongation at the breaking point have generally been improved without any remarkable change in the tensile modulus, the...