José Guilherme Prata

Utilização de madeiras de Eucalyptus grandis e Eucalyptus dunnii para produção de painéis de partículas orientadas – OSB.

This study was developed to evaluate the feasibility of OSB manufacturing using woods of Eucalyptus grandis and Eucalyptus dunnii. Boards with nominal density of 0,70 g/cm³ and 1,0 g/cm³ were manufactured in laboratory, using 100% of wood particles from Pinus taeda, Eucalyptus grandis and Eucalyptus dunnii, and mixtures of 50% of Pinus taeda in the internal layer of the board, with 50% of Eucalyptus grandis and 50% of Eucalyptus dunnii . The boards of Eucalyptus grandis with density of 0,70 g/cm³, as standard board density, showed the values of properties compatible with the requirements of the Canadian and European Standards and also in relation of boards manufactured from Pinus taeda. The results of the mechanical properties showed an increase in the MOE and MOR in static bending with the increase in the board density, opening the possibility to use the high density OSB for applications requiring higher strength. The results of this research indicate that wood of Eucalyptus grandis can be used as alternative specie to OSB manufacturing in the Brazil.

Produção de painéis aglomerados homogêneos e multicamadas de Melia azedarach (Cinamomo) e Pinus taeda com diferentes teores de resina

This research was developed to evaluate the quality of homogeneous and multilayer particleboards manufactured from Melia azedarach wood and Pinus taeda with different resin contents. The experimental boards were manufactured with the nominal density of 0,75 g/cm³, using the urea-formaldehyde resin in the proportion of 6% and 8% (solid content based on oven dried wood particles) in the internal layer and 8% and 10% in the external layers. The boards were pressed at the specific pressure of 40 kgf/cm², temperature of 160oC and press time of 8 minutes. The evaluations of the physical and mechanical properties of the boards showed the high potentiality of Melia azedarach for particleboard manufacture. The increase of resin content in the internal and external layers improved the properties of water absorption and thickness swelling. However, the mechanical properties were not affected.

Evaluation of the use potential of nine species of genus Eucalyptus for production of veneers and plywood panels

The objective of this study was to evaluate the use potential of nine species of Eucalyptus for production of veneer sheets and multilaminated plywood panels. Veneers were cut using a pilot laminating lathe to a nominal thickness of 2.0 mm. Analysis included finding values of overall yield and yield according to three quality classes for the nine relevant species. Plywood panels were manufactured in a laboratory, consisting of five 2.0 mm veneer sheets which were bonded together with phenol-formaldehyde resin at a weight of 360 g/m² (double line). The panels were compressed using a specific pressure of 10 kgf/cm², a temperature of 140°C and a pressing time of 10 minutes. Results indicated that, with the exception of E. phaeotricha and E. pellita, all other Eucalyptus species had above 50% average veneer yield after lamination. Results of glue line shear testing and static bending parallel and perpendicular demonstrated that species Eucalyptus grandis, Eucalyptus saligna, Eucalyptus dunnii, Eucalyptus globulus, Eucalyptus viminalis, Eucalyptus robusta and Eucalyptus pellita have great potential within the parameters of this study for use in the production of veneer sheets and plywood panels intended for outdoor use.

Comparison of Methods for Estimating Mechanical Properties of Wood by NIR Spectroscopy

Near-infrared (NIR) spectroscopy provides a rapid alternative to traditional methods of wood property assessment. For organizations who assess wood properties on a large scale, multisite, multispecies calibrations are of practical interest. We examined NIR spectroscopy for the estimation of density (at 12% moisture content), modulus of elasticity (MOE), and modulus of rupture (MOR) using clear wood samples obtained from several pine species (Pinus caribaea var. bahamensis, var. hondurensis, and var. caribaea, P. chiapensis, P. maximinoi, P. oocarpa, P. taeda, and P. tecunumanii). We compared different methodologies for collecting spectra, that is, benchtop instrument versus benchtop fiber-optic probe and field portable fiber-optic probe, and different wood surfaces (radial and transverse). Calibrations based on the benchtop instrument were superior to those obtained using the fiber-optic probe systems. Difficulty with adequately representing the sample when collecting spectra using a fiber-optic probe and lower quality spectra explain the differences among the data sets. Spectra collected from radial and transverse surfaces provided similar calibration statistics. The calibrations obtained for density (R2 = 0.81, SECV = 38.5 kg/m3) and MOE (R2 = 0.81, SECV = 1124 GPa) using benchtop instrument spectra demonstrate that it is possible to obtain general calibrations for estimating the wood properties of a number of tropical, subtropical, and temperate pine species.

Propriedades físicas e mecânicas de painéis de madeira aglomerada de Acrocarpus fraxinifolius , compostos com diferentes percentuais de casca

The particleboard industries have used a large volume of wood mainly from planted forest of Pinus, being necessary to diversify the wood species and optimize...

Relação entre a deformação residual longitudinal com crescimento e propriedades da madeira de espécies de Eucalyptus

This study aimed to assess the relationship of longitudinal residual strain due to growth stresses with tree growth variables and the physical and mechanical properties of wood. The species studied were E. dunnii and E. grandis, both with 40, 52 and 64 months of age and E. saligna with ages 28, 40, 52 months of age for solid wood production. The growth stress levels were measured indirectly through the CIRAD-Forêt method. The physical and mechanical properties of wood were obtained in accordance with the standards of COPANT (1972a). Correlations among longitudinal residual strain with tree growth variables and physical and mechanical properties showed a high dispersion; wood at 52 months of age exhibited a more obvious correlation among investigated variables. Thus, forest breeding programs, associated with increments of new silvicultural practices should be directed to the production of wood with desirable characteristics for obtaining the solid wood with low propensity for growth stress.

Propriedades tecnológicas de painéis cimento-madeira produzidos com partículas de eucalipto

The study aimed to determine the technological properties of cement-wood panels produced with the particle Eucalyptus benthamii Maiden et Cambage. The experiment plan consisted of four compositions with different treatments of the particles (cold water, hot water, sodium hidroxyde (NaOH) and calcium hidroxyde (Ca(OH) 2 ), and a control composition. The panels were produced with nominal specific gravity of 1.20 g cm-³, with the ratios wood:concrete 1:2.75 and water:cement 0.40. The panels were evaluated for their physical and mechanical properties through the European standard EN. Analyses were performed to verify the occurrence of outliers, data normality and homogeneity of variances, and subsequently submitted to analysis of variance and Tukey test. The results of physical and mechanical properties of the panels indicated that the best method of treating particles is through the use of Ca(OH) 2 . With the exception of the modulus of rupture, the thickness swelling, modulus of elasticity and tensile perpendicular, they met the specifications of commercial panels produced by the BISON process. Therefore, the feasibility of use of Eucalyptus benthamii for wood-cement panels production was discovered.

MONITORAMENTO GEODÉSICO TRIDIMENSIONAL EM ENSAIOS ESTRUTURAIS DE MADEIRA

Uma parceria entre o Laboratorio de Instrumentacao Geodesica e o Laboratorio de Tecnologia da Madeira, ambos da Universidade Federal do Parana, possibilitou o desenvolvimento deste projeto. Optou-se em inserir metodos geodesicos, aplicaveis ao monitoramento de estruturas, em ensaios estruturais de madeira. Realizaram-se ensaios de flexao estatica em paineis compensados de madeira, com uso de uma Maquina Universal de Ensaios, aplicando-se juntamente o monitoramento de deslocamentos de pontos de interesse atraves do metodo de irradiacao tridimensional. Ao final do ensaio estrutural foram analisadas e comparadas as flechas de deslocamento (deformacao na componente vertical) dos corpos de prova obtidas pela maquina de ensaios e pelo monitoramento geodesico. Como tambem, observou-se o comportamento tridimensional dos corpos de prova no decorrer dos ensaios. Desta forma, testando tecnicas e metodo geodesico como uma nova proposta de verificacao de deslocamentos em ensaios estruturais de madeira. Estatisticamente comprovou-se que os valores dos deslocamentos centrais dos paineis – flechas maximas – obtidos pelo monitoramento geodesico foram iguais aos resultados da maquina universal de ensaios. Confirmando assim, que o metodo proposto e as tecnicas geodesicas testadas, podem tambem, ser aplicadas em laboratorio em ensaios estruturais de madeira.

Avaliação da qualidade de painéis compensados de Pinus maximinoi , Pinus oocarpa e Pinus tecunumannii com diferentes composições estruturais

This study was developed to evaluate the effects of different compositions of plywood of Pinus maximinoi, Pinus oocarpa e Pinus tecunumannii. Were manufactured in laboratory plywood composed by seven veneer with 3,0 mm thickness, with standard composition, longitudinal reinforced composition and transversal reinforced composition. Were used for veneer gluing the phenol- formaldehyde resin with the following formulation in parts of weight: resin = 100, extender = 10 and water = 10. The amount of glue spread was 160 g/m² (one side layer). The boards were pressed at temperature of 150oC, specific pressure of 15 kgf/ cm² and press time of 15 minutes. Were realized static bending tests in the parallel and cross direction. The boards of Pinus maximinoi showed better results in MOE and MOR, parallel and cross direction in comparison to boards of Pinus oocarpa and Pinus tecunumannii. The boards made from three species showed satisfactory results of MOE and MOR, parallel and cross direction, in comparison to commercial plywood of Pinus taeda. The veneer reinforced in to parallel and cross direction not influenced significantly in the results of MOE and MOR parallel direction. The longitudinal veneer reinforced plywood affects poorly the results of MOE and MOR in the cross direction.