No abstract

The mechanical properties of a water-activated polyurethane–glass fiber composite reinforced using amino-functionalized carbon nanofibers are evaluated for ultimate tensile strength, Young’s modulus, ductility and fatigue life at 60℃. The amino-functionalized carbon nanofibers are dispersed in the water-activated polyurethane matrix at 0.4 weight percent (wt%) with respect to the glass fabric for comparison with the neat (or 0.0 wt% amino-functionalized carbon nanofibers) water-activated polyurethane–glass fiber composite material. Fatigue tests were performed at a stress-ratio (R-ratio) = +0.9. This cyclic loading level and temperature conditions would simulate a vibro-creep-fatigue type loading and response condition. The results showed that the water-activated polyurethane–glass fiber composite when reinforced with amino-functionalized carbon nanofibers (amino-functionalized carbon nanofibers water-activated polyurethane–glass fiber nanocomposite) had improved tensile strength, ductility and fatigue life properties in comparison to the neat composite, but there was a reduction in Young’s modulus in this nanocomposite material at high applied load levels. This amino-functionalized carbon nanofibers water-activated polyurethane–glass fiber nanocomposite could have worldwide applications for external surface repair or rehabilitation on existing civil-mechanical structures such as concrete or metal pilings, vessels and piping, to achieve an extended operational life under elevated temperatures and fatigue-type loading conditions.