One type of aerogels is carbon aerogel, which has been used in polymer composites due to their unique physical an‎d chemical properties. Despite extensive research in improving the surface properties of carbon aerogels, the modification of carbon aerogels with silane materials as a coating for basalt fibers has not yet been investigated. The main objective of this research is synthesis an‎d surface modification of carbon aerogel particles with silane coating, followed by their use as reinforcement in epoxy/basalt fiber composites. This research investigates the effects of various structural variables, including the size an‎d distribution of pores, specific surface area, an‎d surface functional groups, on mechanical properties of two-component blankets an‎d fiber reinforced composites. Two main variables were considered: the first factor was the change in the physical, chemical, an‎d structural properties of the aerogel, an‎d the second factor was the change in the concentration of carbon aerogel particles. At the first step, chemical modification of the aerogel surface was employed using a silane coupling agent. The silane material enhances the adhesion between the aerogel an‎d the polymeric matrix (epoxy resin) by forming a chemical bond an‎d molecular penetration. Therefore, three types of particle reinforcements were prepared regarding the modification condition: raw carbon aerogel, carbon aerogel modified with silane, an‎d carbon aerogel modified with silane under vacuum condition. Different particle contents, including 0.1, 0.3, an‎d 0.5%wt., were coated on basalt fibers. The composites were then prepared using a vacuum-assisted injection (VIP) process. Nitrogen gas absorption an‎d desorption tests, Fourier transform spectroscopy (FTIR), an‎d scanning electron microscopy (FESEM) were employed to investigate the physical, chemical, an‎d morphological characteristics of the aerogel particles. The results showed that all aerogels had a porosity above 90%. The densities of raw carbon aerogel, particles modified with silane, an‎d particles modified with silane in a vacuum environment were 0.18, 0.2, an‎d 0.19 g/cm3 an‎d their specific surface areas were about 632.38, 416.4, an‎d 603.77 m2/g, respectively. The cross-sectional morphology of blankets an‎d the fractured surface area of fibrous composites were studied using FESEM an‎d roughness analysis. The mechanical properties of the samples were also investigated using tensile, bending, an‎d punch shear tests. The results of mechanical tests demonstrated that the presence of all three types of aerogels on the surface of basalt fibers improved the properties of composite samples. Specifically, tensile tests showed improvements in tensile strength of fiber reinforced composites up to 39% an‎d an increase of tensile modulus up to 12%. The results were attributed to the increase in adhesion an‎d the contact surface between the fiber reinforcement an‎d the polymer due to the increase of surface roughness, which led to an effective increase in load transfer from the matrix to the fiber. Additionally, the penetration of polymer chains into the three-dimensional porous structure of the aerogel causes a further increase in adhesion an‎d absorption of the applied energy. However, increasing aerogel content led to a decrease in properties due to the agglomeration effects between particles. Furthermore, the nonuniform distribution of particles on the fibers is another reason for the loss of properties. The improvement of composite properties in this research was attributed to the physical an‎d mechanical interaction between the reinforcement an‎d the base polymer, as well as chemical interaction with creation of functional groups on the surface of carbon aerogels during the surface modification operation.

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مهدي حجازي , اكبر خدامي