Influência da relação estequiométrica resina/endurecedor em propriedades mecânicas de compósitos ternários hierárquicos resina - Epóxi/tecido de fibra de carbono/nanotubos de carbono

Abstract

The production of materials that exhibit high performance in their applications requires scientific and technological advances. The high values of tensile strength and modulus of elasticity, combined with flexibility, low density and high aspect ratio, make carbon nanotubes exceptional candidates for reinforced polymer composites. We prepared by lamination composite systems based on epoxy resin/woven carbon fiber (for binary), plus carbon nanotubes for the ternary systems. The effect of the stoichiometry of the epoxy system (Phr value) and concentration of carbon nanotubes used in the composite systems was evaluated by their morphological (SEM), thermal (TG) and mechanical properties (ASTM D790-10). Although the epoxy system with 10.0 Phr has presented a higher thermal stability, the ternary composite system produced with 26.6 Phr showed values of maximum stress and elastic modulus up to 8 times greater than those produced with the 10 Phr system. The addition of carbon nanotubes to composites with 26.6 Phr resulted in additional increase of approximately 38 and 15% of the maximum stress and elastic modulus, respectively. These results revealed a limitation in the methods of incorporation of the nanostructures in composite systems, where the dispersion is limited by a number of factors, inherent to the chemical and/or physical interactions during fabrication of nanostructured composites.