Adição de poli(etileno-co-ácido-metacrílico) (EMAA) como agente de auto-reparo em compósitos carbono-epóxi

Abstract

Self-healing techniques in epoxy resins have been developed to improve the durability and reduce costs associated with repairs of these materials during service. The addition of thermoplastics into the thermoset matrix producing mendable resins appears as a promising self-healing technique. In this study, poly(ethylene-co-methacrylic acid) (EMAA) was added in the mid-plane of carbon fiber-epoxy composites laminates to produce a self-healing system. Plates were manufactured with addition of 5%, 10% and 15% of EMAA as related to the resin weight of prepreg. Interlaminar shear strength test (ILSS), dynamic mechanical analysis (DMA), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and field-emission gun scanning electron microcopy (FEG-SEM) were employed in order to evaluate the effect of the addition of the thermoplastic to the composite and its behavior before and after a healing cycle. The healed samples did not show an increase in interlaminar shear strength (ILSS) after healing. However, for higher percentages of EMAA there was a reduction of this property, besides a reduction of Young’s modulus and glass transition temperature (Tg), in relation to the values presented by the unmodified composite. SEM images confirmed the strong adhesion between EMAA and epoxy resin, which produced an adhesive layer that prevented delamination in the mid-plane of the laminate.