Desenvolvimento e caracterização física e mecânica de painéis de poliuretano com fibras de curauá e resíduos madeireiros

Abstract

The development of sustainable materials obtained by renewable resources and residues has been the main objective of various researches. Amazon region presents high temperatures and relative humidity, which causes thermal discomfort in conventional buildings. Furthermore, high volume of wood waste, due to the low exploitation of sawmills, generates a great environmental impact. Because of this, composites that use renewable sources such as lignocellulosic fibers and by-products of other materials, such as wood sawing, are alternatives for a more sustainable construction market. The purpose of this research was to produce composites with curauá fibers and wood residues agglutinated with polyurethane resin of castor oil, varying ratio of its components and evaluating its physical, mechanical and thermal properties. Particleboard were produced in different proportions, with fibers treated with 5 % NaOH concentration and wood residues sieved in a range of 0.425 mm and 0.250 mm and had their properties of humidity, density, swelling, absorption, flexural strength, elastic modulus, thermal conductivity and scanning electron microscopy evaluated. From the results, it is inferred that the alkaline treatment in the fibers was effective in the removal of hemicellulose and lignin and that the hydrophilic characteristic of the fiber increases the swelling and absorption of the composite. However, this treatment has reduced the mechanical properties of the panels, implying that a greater amount of resin is needed for the improvement of physical and mechanical properties. Nevertheless, the values of MOR and MOE from 7.8 to 14 MPa and from 1441 to 2256 MPa, respectively, together with the low thermal conductivity between 0.26 and 0.38 W / mK suggest the potential of using these composites as material alternative for the construction of buildings, including as an improvement of thermal comfort, considering its proximity to conventional materials used in civil construction, such as gypsum board.