Mechanical Characterization of Thermally Insulated Composites

This research study investigated the flame-smoke-toxicity (FST) behaviors of water-based, nontoxic, and lightweight coating materials as thermal insulation for fiber-reinforced polymer (FRP) composites. Material experiments were conducted to evaluate the thermal and mechanical performances of these materials in two forms, namely as coatings on and matrices in structural composites. The present research evaluated the thermal protection performance of a nontoxic, aqueous coating material (SBS-1607[1]) demonstrated on carbon- and glass fiber-reinforced epoxy composites. The SBS-1607 coating is a ceramic particulate-filled thermoset material. The SBS-1607 coating does not produce toxic gases during a burn event and can be used as novel matrix material. The SBS-1607 material was applied as thin coatings on glass fiber (GF) and carbon fiber (CF) epoxy laminated plates. The dimensions of both laminates were 8 inches by 8 inches by 0.197 inches (203.2 mm by 203.2 mm by 5.00 mm). The thickness of the SBS-1607 coating was 0.025 inches (0.67 mm). The maximum temperatures measured from the thermocouple for the uncoated GF and CF samples were 158.7°F and 431.1°F, respectively; the inclusion of the SBS-1607 coating on the GF and CF samples reduced their maximum temperatures to 144.6°F and 227.2°F, respectively. Residual tensile strengths and elastic moduli were used as indicators of thermal damage in the matrix. Visible damage zones were approximated using surface measurements. The coated GF and CF burned composite specimens respectively had 71.85% and 151.14% higher UTS than their uncoated counterpart; the GF and CF specimens with the SBS-1607 coating therefore sustained less damage after the thermal event test.