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In this study, various amounts of clay nanoparticles and titan nanoparticles (1, 3 and 5% wt.) were introduced into a vinyl ester resin matrix by high shear mixer. The influence of these nanoparticles on the mechanical properties (tensile strength, tensile modulus, flexural strength, flexural strength and fracture toughness) is investigated. To investigate the structure of nanocomposites, X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests are done. The XRD test shows that the structure of clay-vinyl ester nanocomposites is exfoliated. The results of tensile, flexural and fracture toughness experiments show that clay is better than titan in the improvement of the mechanical properties. Clay- vinyl ester nanocomposite with 1% wt. of clay has the better mechanical properties than others samples.

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In this research, vinyl ester matrix composite coatings reinforced by E-glass fibers, Nano TiO_2, and Carbon Nanofiber were prepared by hand lay-up method and their mechanical properties were investigated. The mechanical properties of fiber-reinforced composites were investigated by the tensile, impact, hardness, shear test, and wear tests. Scanning electron microscopy was employed in order to study the fracture surface of the prepared samples. The results of the tensile test showed that the presence of the E-glass fibers in the vinyl ester matrix increases the strength about 4 times and the elongation about 8 times. There was no change in the fiber-reinforced composite strength by reinforcing the composite with nanoparticles of TiO₂ and carbon Nanofiber, but the elongation of the fiber-reinforced composite increased by 1.6 times. Impact resistance of fiber-reinforced composite and fiber-reinforced nanocomposite relative to vinyl ester resin increased about 20 and 29 times. The presence of glass fiber and Nanoparticles in the vinyl ester matrix increases the hardness of the samples about 1.5 to 2 times. The results of the adhesion test demonstrated that the presence of nanoparticles in fiber-reinforced nanocomposite improves adhesion to concrete surfaces. Also, the results of the wear test showed that the presence of glass fiber in the matrix of vinyl ester reduces wear resistance and the presence of Nanoparticles in fiber-reinforced nanocomposite improves wear resistance of the fiber-reinforced composite.