Estudo da incorporação de resíduos industriais, lama vermelha e caulim, nas propriedades de compósitos de matriz poliéster reforçados com fibras de juta e malva

Abstract

The Amazon region of Brazil is a major producer of bauxite and kaolin, with the state of Pará accounting for a large national share of the production of these materials. The processing of these raw materials generates considerable amounts of waste that is then stored in sedimentation ponds which can cause serious environmental damage, therefore it is very important to explore reasonable methods of utilizing the red mud and kaolin waste, and thus reduce their landfill volumes. Many recent studies have been conducted and presented various ways of comprehensive utilization of these wastes. Natural fiber reinforced composites with insertion of these industrial wastes have received increasing attention in recent decades, as good specific mechanical properties can be achieved and industrial wastes can be reduced and used in a useful form. In this work, polyester matrix composite materials reinforced by jute and mallow fibers in continuous configuration and aligned at 0° and 90° in the loading direction, and composite materials with insertion of industrial waste were manufactured. The polyester matrix used was a pre-accelerated orthophytalic and cured at room temperature with methyl ethyl ketone peroxide 1.0% by mass. The Jute and mallow fibers were manually cut in length of 300 mm and manually arranged in a continuous manner and aligned and without surface treatment. Fiber composites were produced by vacuum-assisted hand lay-up/vaccum-bagging procedure. The proportions of the fiber volume fraction have varied by 5, 15 e 25 %. The composites with kaolin and red mud residues were manufactured by a manual process in the form of silicone and pressed mold. The proportions of the mass fractions of waste have varied by 5, 10, 15, 20, 25 e 30 %. The residues were characterized in terms of their physical, morphological and chemical aspects and the fibers in terms of their physical and mechanical aspects and the experimental values are similar to that presented from old newspaper. Just as the composites manufactured had their specific mass determined, which resulted in an increase in the average value of the specific mass of the composites with insertion of red mud and kaolin residues. In the case of composites reinforced with fibers of jute and mallow, there was a reduction in the average value when compared to the matrix. Tensile and shear properties were observed for the composites with industrial waste, red mud and kaolin. The composite 5RC exhibited tensile strength value closer to the matrix, as well as for 5RLV, 10RLV and 15 RLV which exhibited the same behavior. For shear strength the composites 10RLV and 15 RLV were closer to the matrix. As well as the composites reinforced with jute fibers 0° presented the highest tensile strength were 0J5, 0J15 and 0J25, exceeding in 2%, 150% and 166% the tensile strength of polyester. For the composites reinforced with mallow fibers 0° showed the highest tensile strength were 0M15 and 0M25, exceeding in 67% and 96% the tensile strength of polyester. For shear strength the composites reinforced with jute (0J15 and 0J25) and mallow (0M15 and 0M25) fibers exceeded the matrix in 201%, 206%, 71% and 144%, respectively. The tensile strength of the three-phase composites (0JRLV, 0JRC, 0MRLV and 0MRC) exceeded the matrix by 129|%, 100%, 54% and 21%, respectively. For shear strength they exceeded the matrix by 49%, 47%, 63% and 52%. Composites with 0-aligned fibers showed satisfactory mechanical behavior for application in composite materials presenting reinforcement characteristics.