Secagem da madeira de louro preto (Nectandra cuspidata) em estufa de micro-ondas

Microwave drying will play an important role in the industrialization of timber in the near future, because improved dimensional stability and increased mechanical strength of wood are dependent on its drying. The objective of this study was to evaluate the drying of Louro preto wood using the microwave process and its influence on drying time, final moisture content, and formation of checks. A program originally developed for Mahogany wood was used due to the similarity between the basic density values of the two wood species. To this end, three (3) drying processes were conducted: drying S1, with initial average moisture content above the fiber saturation point (FSP), reached 13.99% of the final average moisture content after 2h 25min; whereas drying S2 and S3, with initial average moisture contents below the FSP, showed 14.00 and 14.62% of the final average moisture content after 2h 8min and 2h 2min, respectively. The drying processes were considered fast, and the difference in the initial moisture contents of the samples showed the influence of the treatments in the formation of end and surface checks. Drying S2 was more prone to present surface checks than end checks, whereas internal checks were not found in any of the drying processes performed

Avaliação do potencial de utilização da madeira de Schizolobium amazonicum "Paricá" e Cecropia hololeuca "Embaúba" para produção de painéis aglomerados Evaluation of potential use of the wood of Schizolobium amazonicum "Paricá" and Cecropia hololeuca "Embaúba" to particleboard manufacture

Esta pesquisa teve por objetivo avaliar o potencial de utilização de madeira de Schizolobium amazonicum (Paricá) e Cecropia hololeuca (Embaúba) para produção de painéis aglomerados. Foram produzidos painéis experimentais com densidade nominal de 0,70 g/cm³, utilizando a resina uréia-formaldeído e partículas de madeira de Paricá e Embaúba, e mistura destas, em proporções de 75, 50 e 25%. A madeira de Pinus taeda foi utilizada como testemunha. Os painéis foram prensados com pressão específica de 40 kgf/cm², temperatura de 160ºC e tempo de prensagem de 8 minutos. Os resultados das avaliações de propriedades de absorção de água, inchamento em espessura, ligação interna, módulo de elasticidade e módulo de ruptura, indicaram que as madeiras de Schizolobium amazonicum (Paricá) e Cecropia hololeuca (Embaúba) são tecnicamente viáveis para produção de painéis aglomerados.<br>This research was developed to evaluate the potential use of the woods Schizolobium amazonicum (Paricá) and Cecropia hololeuca (Embaúba) for manufacturing particleboard. Were made panels with the densities of 0.70 g/cm³, using mixtures of urea-formaldehyde resin and wood particles of Paricá and Embaúba, in proportions of 75, 50 and 25%. The Pinus taeda wood was used as the reference. The panels were pressed at the temperature of 160ºC, pressure of 40 kgf/cm², for 8 minutes. The evaluations of the properties of water absorption, thickness swelling, internal bond, modulus of elasticity and modulus of ruptures, showed that the woods of Schizolobium amazonicum (Paricá) e Cecropia hololeuca (Embaúba) are technically feasible for particleboard manufacture