EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Many applications of glass fibres reinforced laminates (GFRP) require stable properties along many years of use, thus studies on how they will behave under the influence of weather conditions are necessary. Satisfactory would be no changes or a slight decrease in the microstructure and mechanical properties that may indicate degradation resistance of the composite material.
The aim of the study was to evaluate the effect of aging conditions on the strength and microstructure of fabricated GFRP laminates. The laminates were fabricated by the vacuum bag method using epoxy or epoxy vinyl ester resins reinforced by glass unidirectional fabrics. The epoxy resin has a higher viscosity than the epoxy vinyl ester resin and its curing is conducted at a higher temperature. The aging tests were conducted under the following conditions: temperature 80 °C, 80% humidity with test duration of two weeks.
In order to verify material properties tensile, bending, and impact strength tests, as well as microstructural observations, were carried out before and after aging. The glass transition temperature was determined by DMA analysis. In the end, Tg temperature was assessed whether it changed after aging.
Based on the test results, it can be concluded that the strength properties decrease by no more than 20% as the result of aging tests. Moreover, laminates fabricated using epoxy resin exhibited higher mechanical properties before as well as after aging in comparison to laminate based on epoxy vinyl ester resin. However, few material defects, such as air bubbles, were observed in the SEM images of the laminate microstructure. In addition, from the industrial point of view, the advantage of the application of epoxy resin is the styrene-free fabrication process.
The work was supported by National Center for Research and Development as a grant no. MAZOWSZE/0141/19-00.