Estudo da influência de resíduos gerados pela indústria de mineração nas propriedades de compósitos de matriz poliéster reforçados com fibras naturais

Abstract

In this work, it was produced pure isophthalic unsaturated polyester matrix boards, composites with vegetable fibers (sisal, mauve and jute), composites with industrial waste (red mud, kaolin and ash) and hybrid composites with fibers and waste. The residues were used with a particle size less than 100 mesh and in fiber lengths of 15 mm arranged randomly within the matrix. The fibers were characterized considering their physical, mechanical and morphological properties. The composites were manufactured by a manual process called (hand lay-up) in the form of rectangular plates in metal and pressed mold. The proportions of the mass fractions of waste have varied by 10 % until saturation within the matrix, the mass fraction of fibers was fixed at 5 %. The composites were characterized physically (porosity, water absorption and bulk density), mechanically (tensile, bending and impact), thermally (thermogravimetry - TGA), mineralogically (diffraction of rays-X - DRX), flame retardance and morphologically (scanning electron microscopy - SEM). It was found with the insertion of waste and fibers in the composites, an increase of its physical, mechanical, thermal properties and flame resistance. The physical properties of porosity, water absorption and bulk density has increased significantly (6,7 % to 33 %) with the addition of constituents (residues and fibers). There was an increase (15 % to 95 %) in mechanical strength (tensile, bending and impact) of fiber composites and waste (10 %) composites with fibers. It was evident an improvement in thermal stability (10 % to 50 %) of composites with inclusion of waste. Only the red mud composites have presented a flame retardant ability, obtaining V-2 classification according to UL-94 standard. Morphological analysis of fracture surfaces was efficient in identifying the failure mechanisms and features present in the material. The composites manufactured in this study have resulted in materials with good properties, which makes them feasible candidates for certain types of applications such as panels, liners, partitions and internal doors, an inner lining of automobiles, residential rails and other applications of this nature, respecting the characteristics of these materials.