Thermal aging and strain endurance experiments on a filled rubber were performed at several temperatures. The rubber was polyurethane (PU) made from hydroxyl-terminated polybutadiene (HTPB) with 4,4′-diphenyl methane disocyanate (MDI). The filler was sodium chloride. The mechanical properties, glass transition temperature, dynamic viscoelasticity, and chemical structures were investigated for filled and unfilled PU under an aging period at 60 and 80°C and 50% relative humidity. We found that at 60°C the chemical structures of the filled and unfilled rubbers had no changes in 30 days during aging. But moisture had some effects on the filled PU and changed its mechanical properties. At 80°C, the chemical structures of the filled and unfilled PU had changed due to the thermal oxidation of polybutadiene in aging. The deterioration was more apparent for the filled rubber than for the unfilled. The prestraining would dewet the filler from the samples and it increased the voids.
Relation:
Journal of applied polymer science 43(12), pp.2193-2199
