The effect of environmental conditions on mechanical properties and buckling behavior of nanoparticle reinforced composites

In this study, the effects of Al2O3 and TiO2 nanoparticle additives on the mechanical properties and buckling behavior of e-glass fiber (woven fabric-woven) reinforced composites were experimentally investigated under different environmental conditions. In addition, the heat transmission coefficients of nanoparticle added composites were determined; Mass and density measurements were performed and compared with the nanoparticle-free composite. For this purpose, firstly, three different composite plates (a pure composite plate with e-glass reinforcement without nanoparticle additives, ana d the other being 2% Al2O3 nanoparticle added e-glass fiber reinforced composite plate and the third 2% TiO2 nanoparticle added e-glass fiber reinforced composite plate) were produced by vacuum assisted resin infusion method. To process the produced plates in CNC milling machine according to the standards, the test samples were designed in CAD (Computer Aided Design) program, cutting parameters, tool paths were determined in CAM (Computer Aided Manufacturing) program and CNC codes were created. Afterwards, these composite plates were aged by keeping them in a seawater environment prepared under laboratory conditions and in room environment for 120, 240 and 360-day periods; For the freezing/thawing environmental conditions, it was cycled 9, 18 and 27 times in the freeze/thaw cabinet prepared in the laboratory. Before the samples cut from the plate were exposed to environmental conditions; and after each period and cycle, tensile, compression, bending, impact and buckling tests were applied. Experiment results were evaluated statistically. Buckling test results were compared with the finite element method. In addition, heat transmission coefficient measurements were carried out in these periods. As a result of the findings, it was determined that 2% Al2O3 and 2% TiO2 nanoparticle additives improved the mechanical properties and critical loads in buckling of the composites. According to the results of all the tests made in the unaged state of the composites, the composite type that provided the most improvement was the 2% Al2O3 nanoparticle added composite. In all experiments performed as a result of aging, it was observed that Al2O3 and TiO2 nanoparticle added nanocomposites were more resistant to environmental conditions than purely produced composite plate. As a result of the mass analysis of the samples released into seawater, it was determined that nanoparticle doped composites provided less water absorption than pure composite. In all experiments, it was determined that the highest protection was in TiO2 nanoparticle doped nanocomposites. In addition, it was determined that the heat transmission coefficients of the composites increased with the addition of 2% nanoparticles.