Análise de degradação do compósito de resina epóxi e fibra de vidro via envelhecimento natural

Abstract

This work analyzes the influence of climatic conditions on the degradation of composites manufactured from epoxy and fiberglass prepregs, focusing on the climatic context of Northeast Brazil. Moisture and ultraviolet (UV) radiation are known degrading agents for polymer matrix composites. Prolonged exposure to both agents enhances the degradation of polymeric composite materials through mechanisms involving the formation of cracks, a reduction in adhesion between matrix and reinforcement, and the modification of thermal, and mechanical properties, as well as chemical alterations of the material. In order to assess the degree of degradation of the materials in question under direct and natural exposure to sunlight, atmosphere, and rain, this study applied an aging process over 744 hours. Three unaged samples and three aged samples were investigated to compare physical, chemical, and morphological changes through dynamic mechanical analysis (DMA), Fourier- transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results of the analyses on the aged samples revealed visual changes, such as yellowing, indicating degradation. SEM images showed microcracks in the matrix and detachment at the interface, caused by exposure to moisture and UV radiation. FTIR spectroscopy suggests chemical signatures of degradation, with indication of functional groups such as amide. DMA results suggest a slight increase in the glass transition temperature (Tg) and the tan δ peak of the aged samples, possibly due to increased epoxy resin crosslinking