Desenvolvimento de compósitos utilizando resina éster vinílica reforçada por fibra de aramida para aplicação em bindagem de veículos militares

Abstract

The resin transfer molding (RTM) consists of a molding technique widely used in the automotive industry to obtain composites with high specific properties. This work aims to obtain high performance composites made with vinyl ester resin reinforced by 4, 5 and 6 aramid fabric (Kevlar 29) and characterize them by tests of flexural strength, impact resistance, tensile strength and interlaminar shear strength, density, fiber volume and voids, dynamic-mechanical thermal analysis (DMTA), dynamic compression at high shear rates using the Hopkinson Bi-Splice Bar and Ballistic Impact. Aramid tissue was characterized by moisture content, TGA, FTIR and FEG-SEM. During the molding step it was observed that the increase of fiber content increased the resistance to the resin flow through reinforcement, making it difficult to wet the fibers more distant to the injection point, confirmed by the voids content, that was up to 7%, in the edges of the evaluated composites. In general, the increase in the reinforcement content increased the mechanical properties of composite. The composite with 6 aramid fabrics (AD6) had impact strength of 327 kJ / m², tensile strength of 503 MPa, and flexural strength of 197 MPa. The increase in the reinforcement content resulted in better mechanical dynamics properties, confirmed by the increase of the modulus of loss and storage and reduction of the height of the delta peak. In the Hopkinson impact test the AD6 composite presented higher tenacity and maximum stress. Due to the best mechanical properties, the AD6 composite was subjected to ballistic impact, presenting a V50 of 302 m/s and a level I of ballistic protection. These results show that RTM can be a promising technique to produce composites to be incorporated into multicomponent shields.