Mechanical characterization of polymeric composites reinforced with para-aramid after thermal exposure

In this study, heat treatments were applied to samples of para-aramid fiber-reinforced epoxy at two different temperatures (250 and 500 ℃) for five (5) min. The effects on mass and mechanical properties were investigated by tensile tests according to ASTM-D3039-00 and compared with untreated samples. In addition, the fiber/matrix interface was verified by scanning electron microscopy (SEM). At both exposure temperatures, a mass loss of 2.7% and 8.9% was observed for samples submitted to 250 ℃ and 500 ℃, respectively. However, the mechanical tensile strength in both cases was improved, being more significant in samples exposed to a temperature of 500 ℃, with an increase of more than 30% in tensile strength. Although the presence of delamination in the samples was not verified in the visual analysis, in the micrographs studied, it was observed that the decomposition of the fibers and the matrix causes localized delamination between the weft, the warp, and the matrix of the composites after the test.