Investigation of mechanical properties of carbon/cotton fabric reinforced hybrid biocomposites

Today, concepts such as sustainability and recycling come to the fore due to increasing environmental problems. With the developments in material sciences, natural fibers in composite materials have many properties such as being environmentally friendly, light, biodegradable and potentially alternative sources, making them attractive to be used as reinforcement materials. In order to create some solution to environmental problems, to reduce costs and to obtain high-performance materials, it has become attractive to use natural fiber reinforced materials by hybridizing with different fibers, and research and development studies on this subject have increased. In this thesis, hybrid biocomposite materials were produced by using carbon fabric/cotton fabric in the same structure, taking into account the high strength of carbon fiber and the lightness of cotton fiber. In order to avoid any wetting problem during production, the fabrics were wetted by hand laying method and then the excess epoxy was evacuated by vacuum bagging method. 6 different materials were produced, namely carbon fabric, cotton fabric and four hybrid (carbon fabric + cotton fabric) biocomposite with different layup sequence. In order to determine the mechanical properties of these materials, the specimens for tensile test, Charpy test and low speed impact test were cut from the plates according to ASTM standards and then the tests were performed. As a result of the tests; tensile stresses, impact strengths were determined, and energy conversion graphs were created for low-speed impact. In addition, the fracture surfaces of the tensile test specimens were examined by scanning electron microscopy (SEM). As a result, the properties of newly produced hybrid composite materials were compared with reference samples of pure carbon fabric and pure cotton fabric composites. According to the results obtained from the mechanical tests, the impact strength of the hybrid biocomposite samples increased due to the rigidity and impact resistance properties of carbon fiber reinforced with pure cotton fiber. It was determined that the materials behaved more rigidly and showed a higher reaction force against the incoming impact with the increase of the reinforced cotton layer ratio. In addition, fiber pull out, delamination and debonding damage mechanisms were observed in the samples after the tensile test.