Comparative Study Between Theoretical and Experimental Values of Dimensional Quantities for Tropical Brazilian Wood

Brazil presents many wood species that are very useful in several sectors such as civil construction and furniture industry. Rational use of wood resources depends on the wood characterizations process, that can become easier using equations involving properties of interest. Some theoretical equations found in the literature were developed for primarily softwood from the northern hemisphere, but not checked regarding of their accuracy for tropical Brazilian wood species. This paper aims to confront four theoretical equations with the dimensional stability quantities of fifteen tropical Brazilian woods and test the accuracy of them for these wood species. Results showed that experimental values present greater variability than the ones provided by the theoretical equations. Kruskal-Wallis ANOVA performed showed that one of the four equations cannot be accurately used for tropical Brazilian wood species at 5% significance level. Keywords: Accuracy. Material. Physical properties. Wood.

Addition of Impregnated Paper Residue to Produce MDP Wood Panel: Example of Solid Waste Recycling

Abstract Brazilian market for wood panels is expanding. Among the types of produced panels, particleboards deserve, being MDP panel the main product. MDP means Medium Density Part icleboard that is a lignocellulosic co mposite made with matrix of synthetic adhesive (urea formaldehyde resin) and reinforcement phase of particles of wood, and composed of three layers. This product can be marketed coated, being the Low Pressure (LP) coating the most widely used. The LP coating is defined as a special imp regnated paper with melamine resin, fused to the wood panel by the action of heat and pressure. During production activities of the MDP with LP coating, impregnated paper waste are generated, which are commonly disposed in landfills, generating costs of transport and disposal of waste. Ho wever, this residue can be better applied. In o rder to pro mote better use of that waste, this study aims to evaluate the technical feasibility of incorporating the impregnated paper waste as an aggregate in the inner layer of the M DP. Other expected benefit fro m this proposal is the decrease of costs production because of optimizat ion for wood consumption. For the new composite suggested a technical feasibility has been conducted by tests performed according to Brazilian standard NBR 14810/2006. To this end, physical tests were performed to determine the density of the panel, swelling in thickness, and water absorption. Also, mechanical tests were conducted of perpendicular tensile (internal adhesion) and static bending of specimens. To prepare the studied panel, were collected impregnated paper waste, and mixed them with the wood particles with resin, in proportions of 0% (condition 1), 4% (condition 2), 8% (condition 3) and 12% (condition 4), based on wood particles weight. It was checked that insertion of impregnated paper waste in the inner layer of MDP panel hasn't affected the physical and mechanical properties in co mparison with the conventional product. All the results were in line with the NBR 14810 for conditions 1, 2 and 3. So me problems were noted to condition 4, where part of the results were not in consonance with the Brazilian standard for particleboards. These conclusions were also engaged in the results of statistical variance analysis performed. However, the recycling proposal of utilizat ion the impregnated paper waste is technically feasible, contributing favorably to the rational use of raw materials, reducing operational costs with waste treatment and a greater level of environ mental sustainability within the industry