Effect of zinc oxide nanoparticles on critical buckling load of glass/epoxy composites exposed to sunlight irradiation

Today, advanced materials like fibrous composites are widely used in the industry due to their favorable strength-to-weight ratio, corrosion resistance and many other suitable properties. Buckling phenomenon may occur in a thin composite structure subjected to high compressive loads. Moreover, the buckling strength of polymer based composites such as glass/epoxy decreases due to sunlight radiation. In this research, the effect of adding zinc oxide (ZnO) nanoparticles as a reinforcement to the matrix material of glass/epoxy composite on the critical buckling load of the beam specimens is investigated experimentally. In addition, samples are exposed to simulated sunlight irradiation and the effect of adding nanoparticles is investigated. Rectangular composite beams are made and reinforced with 1 wt. % of ZnO nanoparticles. Beams are clamped under tensile testing machine for buckling test. Compressive load is applied to the beams in the longitudinal direction and force-displacement graphs are plotted. Results indicate that the addition of ZnO nanoparticles into the epoxy resin increases the critical buckling load of these beams. As the results show, the critical buckling load of ZnO reinforced glass/epoxy specimens increases by %39.4 with respect to that of glass/epoxy samples. Moreover, to investigate the effect of adding nanoparticles after sunlight irradiation, some samples were placed in the accelerated weathering system for 24 h. Buckling test results represent a remarkable increase in the amount of critical buckling load for ZnO/glass/epoxy specimens even after the irradiation. SEM images of the break section of ZnO reinforced glass/epoxy specimens illustrate homogeneous dispersion of ZnO nanoparticles in the epoxy resin.