Search Results (5)

Modifying the polymer matrix by nanoparticles can be a promising approach to improve the performance of fiber-reinforced polymer (FRP) composites. Organic solvents are usually used for dispersing graphene oxide (GO) well in the polymer matrix. In this study, a green, facile, and efficient approach was developed to prepare epoxy/GO nanocomposites. In situ polymerization is used for synthesizing nanocomposites, eliminating the need for organic solvents and surfactants. By loading just 0.6 wt% of GO into the epoxy resin, Young’s modulus, tensile strength, and toughness improved by 38%, 46%, and 143%, respectively. Fractography analysis indicates smooth fracture surfaces of pure resin that changed to highly toughened fracture surfaces in this nanocomposite. Plastic deformation, crack pinning, and deflection contributed to improving the toughness of the nanocomposites. FTIR investigations show that amide bonding was created by the reaction of the carboxylic acid groups in GO with some amine groups in the curing agent during the dispersion processes. Full article

Fiber-reinforced plastic (FRP) rebar has drawbacks that can limit its scope, such as poor heat resistance, decrease its strength over time, and under the influence of substances with an alkaline medium, as well as the drawback of a low modulus of elasticity and deformation. Thus, the aim of the article is the nano- and micro-modification of building reinforcing bars using FRP rebars made of basalt fibers, which were impregnated with a thermosetting polymer binder with micro- or nanoparticles. The research discusses the major results of the developed composite reinforcement with the addition of micro- and nanosized particles. The microstructure of FRP has been studied using scanning electron microscopy. It was revealed that dispersion-strengthened polymer composites with the inclusion of microsilica (SiO₂) and nanosized aluminum oxide (Al₂O₃) particles have a much higher modulus of elasticity and strength when compared with the original polymer materials. In the course of the experiment, we also studied the retained plastic properties that are characterized by the absence of fragility. However, it was found that the high strength of materials was attained with a particle size of 10–500 nm, evenly distributed in the matrix, with an average distance between particles of 100–500 nm. It was also exhibited that composite reinforcement had improved the adhesion characteristics in comparison with both steel reinforcement (1.5–2 times, depending on the diameter), and with traditional unmodified FRP rebar (about 1.5 times). Thus, the use of micro-/nanosized powders increased the limit of the possible temperature range for the use and application of polymeric materials by almost two times, up to 286–320 °C, which will undoubtedly expand the range of the technological applications of products made of these materials. Full article

The use of fiber reinforced plastics (FRPs) has significant potential to reduce the weight of components. As regards the sustainability of these components, thermoplastic matrices offer more potential for recycling than thermoset ones. A possible manufacturing process for the production of thermoplastic FRPs is thermoplastic resin transfer molding (T-RTM). In this very moisture-sensitive process, ε-caprolactam in addition to an activator and catalyst polymerizes anionically to polyamide 6 (aPA6). The anionic polymerization of aPA6 is slowed down or even completely blocked by the presence of water. This study analyses the sorption behavior of the matrix, fiber, binder and core materials for the production of anionic polyamide 6 composites, which are processed in the thermoplastic RTM process. Water vapor sorption measurements are used to determine the adsorption and desorption behavior of the materials. The maximum moisture loading of the materials provides information about the water adsorption capacity of the material. This knowledge is crucial for correct handling of the materials to achieve a fast process and good properties of the final product. Full article

Glass or carbon fibers have been verified that can enhance the mechanical properties of the polymeric composite injection molding parts due to their orientation distribution. However, the interaction between flow and fiber is still not fully understood yet, especially for the flow–fiber coupling effect. In this study, we have tried to investigate the flow–fiber coupling effect on fiber reinforced plastics (FRP) injection parts utilizing a more complicated geometry system with three ASTM D638 specimens. The study methods include both numerical simulation and experimental observation. Results showed that in the presence of flow–fiber coupling effect, the melt flow front advancement presents some variation, specifically the “convex-flat-flat” pattern will change to a “convex-flat-concave” pattern. Furthermore, through the fiber orientation distribution (FOD) study, the flow–fiber coupling effect is not significant at the near gate region (RG). It might result from the strong shear force to repress the appearance of the flow–fiber interaction. However, at the end of filling region (ER), the flow–fiber coupling effect tries to diminish the flow direction orientation tensor component A₁₁ and enhance the cross-flow orientation tensor component A₂₂ simultaneously. It results in the dominance in the cross-flow direction at the ER. This orientation distribution behavior variation has been verified using a micro-computerized tomography (micro-CT) scan and image analysis technology. Full article

The paper investigates overview of construction process of a 1 MW class floating photovoltaic (PV) generation structural system fabricated with fiber reinforced polymer (FRP) members. The floating PV generation system consists of unit structures linked by a hinge type connection of which the effect of bending moment between the unit structures, induced by the unstable movement of the water surface, was minimized. Moreover, the unit structures were classified into three types of structures by combining the floating PV generation system and pontoon bridges, which are constructed to install the electrical equipment and a route of movement for workers. The structural safety of the connection system among the unit structures and/or the mooring system is confirmed by referring to the relevant design codes. In addition, structural analysis using the finite element method was performed to ensure the safety of the floating PV generation structure, and commercial viability evaluation was performed based on the construction cost. The FRP member shows superior performance in construction and cost effectiveness in a floating PV generation system. Full article