Pinus spp. na produção de painéis de partículas orientadas (OSB)

Este trabalho teve como objetivo estudar algumas variáveis de processamento na produção de painéis OSB (oriented strand board). O plano experimental foi dividido em três etapas distintas: 1) construção e avaliação do orientador de partículas; 2) estudo dos efeitos da densidade dos painéis, composição dos painéis e do teor de resina nas propriedades dos painéis; 3) estudo dos efeitos das espécies e adição de parafina nas propriedades dos painéis. Foi concluído na etapa 1 que a largura das partículas de 25, 20 e 15 mm não afetam a qualidade dos painéis; as diferenças entre os painéis de camada única (homogêneos) e de três camadas (heterogêneos), bem como as diferenças de MOR e MOE entre os sentidos perpendicular e paralelo, indicaram a eficiência do orientador de partículas construído para manufatura de painéis OSB em laboratório. Na etapa 2 foi concluído que os painéis OSB apresentam melhores qualidades quando manufaturados com densidade de 0,80g/cm3 , relação face/miolo de 1:3:1 e teor de resina de 6%. Na etapa 3 deste trabalho foi concluído que as espécies estudadas são homogêneas entre si e produzem painéis de qualidade .semelhante; a adição de parafina melhora substancialmente a estabilidade dimensional dos painéis. Os painéis produzidos em todas as fases deste trabalho atenderam às especificações mínimas da norma canadense CSA 0437.0

NEAR INFRARED SPECTROSCOPY TO EVALUATE COMPOSITION OF AGRO-BASED PARTICLEBOARDS

Particleboards can be manufactured from particles of any lignin-cellulosic material that can be combined with an adhesive and consolidated under the action of temperature and pressure. Because the raw materials in the industrial process are continually changing, the particleboard industry requires methods for monitoring the quality of their products. Hence, the aim of this paper was to evaluate the composition of the agro-based particleboards by near infrared spectroscopy. In this study, agro-based particleboards produced with different compositions of Eucalyptus and Pinus wood particles and sugar cane bagasse were evaluated by NIR spectroscopy and partial least square (PLS) regression. The PLS models to estimate the Eucalyptus and Pinus particles and sugar cane bagasse contents presented a strong coefficient of determination (0.90, 0.88 and 0.84, respectively), but also high magnitudes of standard errors of cross-validation were observed (ranging from 8.84 to 11.27%). Development work would be required in order to reduce the standard errors and improve predictive model performance to build robust models that could be applied as quality control tool

Estimation of physical and mechanical properties of agro-based particleboards by near infrared spectroscopy

International audiencePartial least square regression (PLS-R) calibrations based on near infrared (NIR) spectroscopic data were developed in order to predict mechanical and physical properties of agro-based particleboards. The panels were manufactured using and wood particles and sugar cane bagasse. The following panel properties were evaluated according to standard methods: modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) strength, water absorption (WA24H), and thickness swelling (TS24H) after 24 hours of immersion. NIR spectra information was measured on samples cut from each particleboard and correlated with their physical and mechanical properties by PLS-R to build predictive NIR models. The NIR models for IB, WA24H and TS24H presented satisfactory coefficient of determination (0.73; 0.72 and 0.75, respectively.) The key role of resins (adhesives), cellulose, and lignin for NIRS calibrations of mechanical and physical properties of the particleboards is shown. These models can be useful to quickly verify such properties in unknown agro-based particleboards

PRODUÇÃO DE CHAPAS DE PARTÍCULAS ORIENTADAS “OSB” DE Eucalyptus grandis COM DIFERENTES TEORES DE RESINA, PARAFINA E COMPOSIÇÃO EM CAMADAS

Este trabalho foi desenvolvido com o objetivo de avaliar a influência dos seguintes parâmetros de processo de produção sobre as propriedades das chapas “OSB”: composição das chapas em camadas cruzadas com proporções face-miolo-face de 30-40-30 e 20-60-20 em relação à composição homogênea; e, quantidades de 3, 4,5 e 6,0% de resina fenol-formaldeído, com incorporação de 0,5 e 1,0% de emulsão de parafina. Os resultados demonstraram que a composição das chapas, com a relação 20-60-20, apresentou melhor balanço das propriedades de flexão estática entre os sentidos de ensaios paralelo e perpendicular ao plano da chapa. A quantidade de 6,0% de resina foi a que resultou em melhores propriedades físico-mecânicas das chapas “OSB”. A produção de chapas “OSB” de Eucalyptus grandis, com 4,5 e 6,0% de resina fenol-formaldeído, superou as exigências mínimas de propriedades mecânicas das chapas “OSB” referendadas pela norma canadense CSA 0437-0 (1993)

Produção de chapas de partículas orientadas “OSB” de Eucalyptus grandis com diferentes teores de resina, parafina e composição em camadas.

This paper was carried out aiming to evaluate the influence of the following processing variables on the properties of OSB: face to core layer ratios of 30-40-30 and 20-60-20 in relation to a single layer; phenol-formaldehyde resin content of 3, 4.5 and 6.0% and addition of 0.5 or 1.0% of wax sizing. The results showed that the boards composed of face to core layer ratios of 20-60-20, presented the better balance in static bending tests, both in the machine and cross-machine directions. The application of  4.5 and 6.0% of resin resulted in better physical and mechanical properties of the OSB. The OSB produced with Eucalyptus grandis, and 4.5 and 6.0% of phenol-formaldehyde resin were in compliance with values of the mechanical properties of the Canadian Standards CSA 0437-0 (1993).Este trabalho foi desenvolvido com o objetivo de avaliar a influência dos seguintes parâmetros de processo de produção sobre as propriedades das chapas "OSB": composição das chapas em camadas cruzadas com proporções face-miolo-face de 30-40-30 e 20-60-20 em relação à composição homogênea; e, quantidades de 3, 4,5 e 6,0% de resina fenol-formaldeído, com incorporação de 0,5 e 1,0% de emulsão de parafina. Os resultados demonstraram que a composição das chapas, com a relação 20-60-20, apresentou melhor balanço das propriedades de flexão estática entre os sentidos de ensaios paralelo e perpendicular ao plano da chapa. A quantidade de 6,0% de resina foi a que resultou em melhores propriedades físico-mecânicas das chapas "OSB". A produção de chapas "OSB" de Eucalyptus grandis, com 4,5 e 6,0% de resina fenol-formaldeído, superou as exigências mínimas de propriedades mecânicas das chapas "OSB" referendadas pela norma canadense CSA 0437-0 (1993)

Fibers dimensions characteristics and microfibril angle analisys of Toona ciliata cultivated at different places

O presente trabalho teve como objetivos determinar as dimensões das fibras e avaliar o ângulo microfibrilar da madeira de cedro australiano aos 4 anos de idade, no sentido axial base–topo, proveniente dos municípios de Cana Verde, Campo Belo e Santo Antônio do Amparo, localizados na região do sul de Minas Gerais. A partir da altura comercial de cada árvore, foi retirada uma tábua com 5 m de comprimento, da qual foram retiradas amostras em três posições: base, 50 e 100%. Os elementos anatômicos foram mensurados por meio de análise de imagens. Conclui-se que a correlação do AMF com a parede e lume das fibras foi positiva, sendo negativa apenas a interação AMF com o comprimento das fibras em Cana Verde. Em Santo Antônio do Amparo a correlação foi baixa. Não houve um padrão definido da variação no ângulo microfibrilar com as dimensões das fibras no sentido axial por município. As dimensões das fibras apresentaram características semelhantes às do eucalipto. Estudos complementares são necessários para um melhor direcionamento do uso da espécie.Palavras-chave: Dimensões das fibras; ângulo microfibrilar; Toona ciliata. AbstractFibers dimensions characteristics and microfibril angle analisys of Toona ciliata cultivated at different places. The objective of this work was to determine the fibers dimensions and to evaluate the microfibril angle of the wood of Australian cedar with 4 years of age, in the axial direction base–top, proceeding from the municipal districts of the Cana Verde, Campo Belo and Santo Antonio do Amparo, located in the region of the South of Minas Gerais. From the commercial height of each tree, a board with 5 m of length was removed, from this board it was taken samples in three positions: base, 50 and 100%. The anatomical elements were measured through image analysis. Concluded that: the correlation of the AMF with the wall and fire of fibers dimensions was positive and negative only interaction AMF with the fiber length in municipal districts of Cana Verde and in Santo Antonio do Amparo, was low. Top for municipal district did not have a definite standard of variation in the microfibril angle with the fibers dimensions in the axial direction from municipal district. The fibers dimensions presented similar characteristics of the eucalipto. Complementary studies are necessary for one better aiming of the use of the species.Keywords: Fiber dimensions; microfibril angle; Toona ciliata. The objective of this work was to determine the fibers dimensions and to evaluate the microfibril angle of the wood of Australian cedar with 4 years of age, in the axial direction base–top, proceeding from the municipal districts of the Cana Verde, Campo Belo and Santo Antonio do Amparo, located in the region of the South of Minas Gerais. From the commercial height of each tree, a board with 5 m of length was removed, from this board it was taken samples in three positions: base, 50 and 100%. The anatomical elements were measured through image analysis. Concluded that: the correlation of the AMF with the wall and fire of fibers dimensions was positive and negative only interaction AMF with the fiber length in municipal districts of Cana Verde and in Santo Antonio do Amparo, was low. Top for municipal district did not have a definite standard of variation in the microfibril angle with the fibers dimensions in the axial direction from municipal district. The fibers dimensions presented similar characteristics of the eucalipto. Complementary studies are necessary for one better aiming of the use of the species

INFLU\ucaNCIA DAS CARACTER\ucdSTICAS ANAT 4MICAS E DO TEOR DE EXTRATIVOS TOTAIS DA MADEIRA DE Eucalyptus grandis W. Hill ex Maiden NA QUALIDADE DA COLAGEM

The study aimed to anatomically characterize and to quantify the total extractives in different positions of the log of Eucalyptus grandis W. Hill ex Maiden with 18 years of age and to assess their influence on the shear strength and percentage of wood failure in adhesive bonded joints with thermosetting resorcinolformaldehyde. Histological slides were prepared for an anatomical study and determined the total extractive content. The preparation of bonded joints was made according to ASTM D 2339-98(2000). It was used the correlation coefficient of Pearson, 1 % probability by t test to evaluate the correlation between the anatomical and extractives content with the quality of the glued joints. It was found that there was a correlation between the shear strength with the following characteristics: vessel diameter, wall width, length and width of the fiber, the width of the radius and total extractives content. For the percentage of wood failure, there was a correlation between this with the following characteristics: the frequency of vessels, thickness of the heat of fiber, and high frequency of lightning. Both the radial direction as in the longitudinal direction of the logs there was change in the values found for the measurement of the anatomical elements, the total amount of extractives, the shear test strength and the percentage of wood failure.O trabalho teve como objetivo caracterizar anatomicamente e quantificar os extrativos totais em diferentes posi\ue7\uf5es de toras de Eucalyptus grandis W. Hill ex Maiden com 18 anos de idade e avaliar a influ\ueancia dessas caracter\uedsticas sobre a resist\ueancia ao cisalhamento e percentagem de falhas na madeira de juntas coladas com adesivo termoendurecedor resorcinol-formalde\ueddo. Foram preparadas l\ue2minas histol\uf3gicas para o estudo anat\uf4mico e determinou-se o teor de extrativos totais. A prepara\ue7\ue3o das juntas coladas foi feita de acordo com a norma ASTM D 2339-98(2000). Utilizou-se o coeficiente de correla\ue7\ue3o de Pearson, a 1 % de probabilidade pelo teste t de Student, para avaliar as correla\ue7\uf5es existentes entre as caracter\uedsticas anat\uf4micas e teor de extrativos com a qualidade das juntas coladas. Verificou-se que houve correla\ue7\ue3o entre resist\ueancia ao cisalhamento com as seguintes caracter\uedsticas: di\ue2metro do vaso, espessura da parede, largura e comprimento da fibra, largura do raio e teor de extrativos totais. E, em rela\ue7\ue3o \ue0 percentagem de falhas na madeira, houve correla\ue7\ue3o entre esta com as seguintes caracter\uedsticas: frequ\ueancia de vasos, espessura do lume da fibra, frequ\ueancia e altura do raio. Tanto no sentido radial quanto no sentido longitudinal das toras, houve varia\ue7\ue3o dos valores encontrados para a mensura\ue7\ue3o dos elementos anat\uf4micos, quantidade de extrativos totais, resist\ueancia ao cisalhamento e percentagem de falhas na madeira

Valorization of wood shavings waste for the production of wood particulate composites

The aim of this work was to evaluate the physical and mechanical properties of particleboards using particles from wood shaving at three urea-formaldehyde adhesive contents: 6, 9 and 12% (dry mass basis). The particleboards were produced with nominal density of 0.70 g.cm-3, pressing cycle with temperature of 160 °C, pressure of 3.92 MPa and time of 8 minutes. The properties of water absorption (WA), thickness swelling (TS), both after 2 and 24 hours, apparent density, compression ratio, perpendicular traction, modulus of elasticity (MOE) and modulus of rupture (MOR) in static bending, Janka hardness and screw withdrawal resistance were evaluated. The results of the tests indicated that with the increase of the adhesive content from 6 to 12%, there was no significant statistical difference for the average values of apparent density and compression ratio, being 0.621 g.cm-3 and 1.234, respectively, and the WA and the TS are decreased after 2 and 24 hours. There was a gain of 93% for the MOR property and 64% for the MOE property with the increase of the adhesive content. For perpendicular traction, the highest mean value was 0.67 MPa, referring to the panels with 12% of adhesive. For Janka hardness, the treatments with contents of 9 and 12% of adhesive presented the highest average values being of 21.60 and 25.26 MPa, respectively. In general, the use of wood shavings is feasible for the production of particleboards with a 12% adhesive content.Keywords: Mechanical resistance; Dimensional stability; Particleboards

Properties of osb panels with veneer inclusion

This work aimed to evaluate the effect of veneer inclusion with different wood species, and also different levels of pressing pressure applied in the moment of the veneer inclusion over physicalmechanical properties of already consolidated OSB (Oriented Strand Board) panels. Treatments were arranged in factorial scheme 4 x 2 (four wood types for veneer inclusion – Pinus oocarpa, Eucalyptus urophylla, Parkia gigantocarpa and Brosimum parinariodes; and two pressing pressures – 1 and 2MPa) and also a control (without veneer inclusion). Veneer inclusion was made with 180 g.cm-2 phenol formaldehyde adhesive, in a simple glue line, perpendicular to the external layer of panels. The pressingcycle used was 150ºC for 4 minutes under pressure 1 or 2 MPa pressure depending on the pre-established treatment. It was possible to conclude that: 1) Veneer inclusion with pines, eucalypt and amapá promotedsignificant improvements for physical-mechanical properties of OSB panels, highlighting eucalypt and amapá; 2) There was not a significant effect of the level of pressing pressure over mechanical propertiesof OSB with veneer inclusion; and 3) Regarding physical properties, the highest pressure level (2 MPa) promoted a negative effect in some properties, while veneer inclusion the pressure of 1 MPa generallypromoted significant improvement of all physical properties