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

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

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

UMIDADE DE EQUILÍBRIO DE PAINÉIS OSB EM FUNÇÃO DA UMIDADE RELATIVA E DA TEMPERATURA AMBIENTE

http://dx.doi.org/10.5902/1980509820661The study aimed to obtain statistical models to estimate the equilibrium moisture content of OSB panels as a function of temperature and relative humidity of air, as well as evaluate the effect of some production variables on the equilibrium moisture content of the panels. The experimental design consisted of six processing conditions, three air temperature and six relative humidity of air. In the processing conditions, were evaluated three different thicknesses of the strand particles (0.4, 0.7 and 1.0 mm), two apparent densities of panels (0.65 and 0.90 g/cm³) and three levels of pressure in the pressing of the panels (40, 60 and 80 kgf/cm²). For each treatment four panels were produced with the wood of Pinus taeda and 6% of phenol formaldehyde adhesive. In the evaluation of the experiment was considered a completely randomized design arranged in a factorial triple 6 x 6 x 3, in order words, six production variables (processing conditions), three air temperatures (30, 40 and 50°C) and 6 relative humidity (40, 50, 60, 70, 80, 90%). The means were compared statistically by Scott-Knott test at the 5% level of significance. The modeling the equilibrium moisture content of OSB panels was performed with fit the multiple polynomial models for each treatment. Based on measurements of accuracy and the results can be concluded that: 1) it is recommended to use the model UEQ = β0 + β1UR + β2UR² + β3UR³ + β4Temp + ε for indirect estimation of equilibrium moisture content of OSB panels 2) The temperature shows linear influence on the equilibrium moisture content of the panels, while the relative humidity of air shows behaving of third order polynomial, and the relative humidity of air affects more pronouncedly the equilibrium moisture content of OSB panels than the ambient temperature; 3) In respect of the effect of production variables, the pressing of pressure of 80 kgf/cm² and the increased the thickness of the strand particles to 1.0mm thick promoted trend of reductions in average of the equilibrium moisture content of OSB panels. But the increased density of the panel promoted the trend of increasing of equilibrium moisture content of OSB panels; and 4) The use of multiple polynomial models allows that are produced contours to obtain the values of equilibrium moisture content of OSB as a function of relative humidity and temperature of the place where the panel is exposed, standing out for its convenience of use. http://dx.doi.org/10.5902/1980509820661O trabalho teve como objetivo obter modelos estatísticos para a estimativa da umidade de equilíbrio de painéis OSB em função da temperatura e da umidade relativa do ar, assim como também avaliar o efeito de algumas variáveis de produção sobre a umidade de equilíbrio dos painéis. O delineamento experimental se constituiu de seis condições de processamento, três temperaturas do ar e seis umidades relativas do ar. Nas condições de processamento, foram avaliadas três diferentes espessuras das partículas strand (0,4; 0,7 e 1,0 mm), duas densidades aparentes do painel (0,65 e 0,90 g/cm³) e também três níveis de pressão na prensagem dos painéis (40, 60 e 80 kgf/cm²). Para cada tratamento foram produzidos quatro painéis com a madeira de Pinus taeda e 6% de adesivo fenol-formaldeído. Na avaliação do experimento foi considerado um delineamento inteiramente casualizado disposto em esquema fatorial triplo 6 x 3 x 6, ou seja, 6 variáveis de produção (condições de processamento), 3 temperaturas do ar (30, 40 e 50°C) e 6 umidades relativas (40, 50, 60, 70, 80, 90%). As médias foram comparadas estatisticamente pelo Teste Scott-Knott em nível de 5% de significância. A modelagem da umidade de equilíbrio dos painéis OSB foi realizada mediante o ajuste de modelos polinomiais múltiplos para cada tratamento. Com base nas medidas de precisão e nos resultados obtidos pode-se concluir que: 1) recomenda-se a utilização do modelo  UEQ = β0 + β1UR + β2UR² + β3UR³ + β4Temp + ε  para a estimativa indireta da umidade de equilíbrio dos painéis OSB; 2) A temperatura apresenta influência linear na umidade de equilíbrio dos painéis, enquanto que a umidade relativa do ar apresenta comportamento polinomial de terceira ordem, sendo que a umidade relativa do ar influência de forma mais pronunciada a umidade de equilíbrio dos painéis OSB do que a temperatura ambiente; 3) Quanto ao efeito das variáveis de produção, a pressão de prensagem de 80 kgf/ cm² e o aumento da espessura das partículas strand para 1,0 mm de espessura promoveu tendência de reduções nos valores médios de umidade de equilíbrio dos painéis OSB. Já o aumento da densidade do painel promoveu uma tendência de aumento da umidade de equilíbrio dos painéis OSB; e 4) O uso de modelos polinomiais múltiplos permite que sejam produzidas curvas de nível para a obtenção dos valores de umidade de equilíbrio dos painéis OSB em função da umidade relativa e da temperatura do local onde o painel esta exposto, se destacando pela sua praticidade de utilização

Transferência de calor através de paineis aglomerados de bagaço de cana, pinus e eucalipto : Heat transfer through against panels of sugar cane, pinus and eucaliptus

O objetivo deste trabalho foi determinar a transferência de calor, a temperatura de combustão e o calor específico de painéis de aglomerado feitos de bagaço de cana, pinus e eucalipto. Os painéis foram expostos a uma fonte de calor até a combustão e mantido por 30 minutos o fluxo de calor entre os materiais. Os resultados mostraram que a transferência de energia durante o aquecimento é maior para os painéis feitos de bagaço de cana-de-açúcar em comparação com os demais materiais

Efeito da associação de bagaço de cana, do tipo e do teor de adesivo na produção de painéis aglomerados.

http://dx.doi.org/10.5902/198050985088This study aimed to evaluate the association effect of sugar cane bagasse, type and levels of adhesive in the physical-mechanical properties of particleboards with Pinus spp. wood. The experimental design consisted of a 3x2x3 factorial scheme, with three percentages of substitution pine wood by sugar cane bagasse - 25, 50 and 75%; two types of adhesives – phenol-formaldehyde (PF) and urea-formaldehyde (UF); and three levels of adhesive - 6, 9 and 12%. The cycle of pressing used was 40kgf/cm² pressure, temperature of 160ºC for UF and 180ºC for PF, and for a time of 8 minutes. From the results, it is concluded that: 1) For the percentage of sugar cane bagasse association, in the properties where significant effect was observed, the trend the decrease in panel quality as the association of sugar cane bagasse amount increases; 2) The UF adhesive was statistically equal or greater than PF in all evaluated properties; 3) The levels of adhesive showed significant effects for all properties, being that, except for internal bond property, in all other properties the level of 12% was statistically superior to 6%, and equal or greater than 9%.http://dx.doi.org/10.5902/198050985088Este trabalho teve como objetivo avaliar o efeito da associação de bagaço de cana, tipo e teor de adesivo nas propriedades físico-mecânicas de painéis aglomerados com madeira de Pinus spp. O delineamento experimental se constituiu de um esquema fatorial 3x2x3, sendo três porcentagens de substituição de madeira de pinus por bagaço de cana - 25, 50 e 75%; dois tipos de adesivos - fenol-formaldeído (FF) e ureia-formaldeído (UF); e três teores de adesivo - 6, 9 e 12%. O ciclo de prensagem utilizado foi de pressão de 40 kgf/cm², temperatura de 160ºC para UF e de 180ºC para FF, e por um tempo de 8 minutos. Mediante os resultados pode-se concluir que: 1) Para a porcentagem de associação de bagaço de cana, nas propriedades em que foi observado efeito significativo, a tendência foi de diminuição da qualidade dos painéis à medida que se aumenta a quantidade de associação de bagaço de cana; 2) O adesivo UF se mostrou estatisticamente igual ou superior a FF em todas as propriedades avaliadas; 3) Os teores de adesivo apresentaram efeito significativo para todas as propriedades analisadas, sendo que, com exceção da propriedade ligação interna, em todas as outras propriedades o teor de 12% foi estatisticamente superior a 6%, e ainda igual ou superior a 9%

Compósitos minerais reforçados com madeira e borracha de pneu

Nesta pesquisa, objetivou-se avaliar o potencial da madeira de Eucalyptus grandis e partículas de borracha depneu na produção de painéis cimento-madeira. Foram utilizadas madeiras de Eucalyptus grandis com 8 anosde idade, provenientes da Companhia Mineira de Metais, localizada no município de Paracatu - MG. Para aformação dos painéis foi utilizado cimento Portland CPV-ARI/Plus de alta resistência inicial como aglutinantemineral e cloreto de cálcio (CaCl2) como acelerador de cura do cimento. Os painéis foram produzidos comos seguintes parâmetros: dimensões de 48,0 x 48,0 x 1,5 cm, densidade nominal de 1,2 g/cm³, relação madeira:cimento (1:2,5) e relação água:cimento (1:1,5). Os painéis foram prensados com pressão específica de 4MPa, a temperatura ambiente, tempo de prensagem/grampeamento de 24 horas e tempo de maturação de 28dias. A análise dos resultados obtidos, em relação aos requisitos mínimos de painéis convencionais produzidospelo processo Bison, permite afirmar que: (1) para as propriedades físicas de densidade aparente, absorçãode água e inchamento em espessura todos os tratamentos atenderam as especificações; (2) para as propriedadesmecânicas de ligação interna e módulo de ruptura no ensaio de flexão estática, todos os tratamentosatenderam as especificações; (3) para compressão e módulo de elasticidade no ensaio de flexão estática, nenhumdos tratamentos apresentaram valores compatíveis com o processo bison.Palavras-chave: Painel mineral, resíduo, propriedades físico-mecânicas

Effects of thermal pre-treatment and variables of production on properties of OSB panels of Pinus taeda

The main objective of this study was to compare the effect of thermal pre-treatment in particles of strand type with the effect of variables of production on physical-mechanical properties of OSB panels, aiming to improve their dimensional stability. The experimental design consisted on five treatments with the assessment of two temperatures of thermal treatment on particles (200 and 240°C) during 60 minutes; the increase of adhesive content, the application of paraffin in different treatments and a control treatment. For each treatment three panels with Phenol-Formaldehyde adhesive were produced. The cycle of pressing panels was: pressure of 3.5 MPa and temperature 160°C during 8 minutes. Analyzing the results of tests it was possible to conclude that: the thermal treatment of particles at 200°C promoted a negative effect on physical and mechanical properties, while thermal treatment of particles at 240°C promoted a significant improvement on physical properties and reduction of mechanical properties. The increase on adhesive content resulted in a significant improvement of WA24h, and the application of paraffin improved the WA2h and TS2h of panels, however such treatments were not so efficient on keeping the dimensional stability of OSB panels as a thermal treatment applied on particles at 240°C