ABSTRACT The attempt to face the limitations of wood-based materials, especially concerning the relationship with water, is still a considerable gap in research on this subject. The present work proposes the accomplishment of thermal treatment in fiberboard-type hardboard, using different temperatures and times, to evaluate the effect on the physical-mechanical properties. The parameters of the heat treatment were temperatures of 120 and 160 °C and times of 20 and 40 min. The hardboards were individually heat treated in a kiln. The characterization was performed from physical tests such as bulk density, moisture content, water absorption (2 and 24 h), thickness swelling (2 and 24 h); and mechanical properties of flexural strength. The treatment with a temperature of 160 °C for 40 min showed the lowest values of water absorption in 24 h (34%). Thickness swelling was lower compared to control, for all the treatments applied. Regarding flexural strength, the treatment that adopted the 160 °C for 20 min showed the highest MOR value (26.3 MPa). In general, the performance of heat treatments positively influenced the physical and mechanical properties of the hardboards, being an interesting alternative in the development of products for applications in internal environments.

ABSTRACT Background: Determining the basic density of the wood is usually defined as a simple process, but it requires caution and the operator’s skill to avoid errors in the analysis. In addition, it involves sample preparation and time to saturate the wood until obtaining the dry sample mass. The development of alternative measurement techniques could reduce the time to obtain the results and provide reliable values. Therefore, this study aimed to develop multivariate models to estimate the basic density of native woods using near-infrared spectra (NIR). Basic densities were determined by the water immersion method, and the values were associated with NIR signatures. Spectra were directly collected on the wood transversal and radial faces with an integrating sphere. Partial least squares regression (PLS-R) was calibrated and validated to estimate basic density based on spectral signatures. Results: In the cross-validation and prediction of the models, the results were promising. The coefficients of determination varied from 0.87 to 0.93 with a standard error of 0.01 %. The partial least squares discriminant analysis (PLS-DA) efficiently classified the wood species. The ratio of performance to deviation obtained satisfactory values, a minimum of 2.81 and a maximum of 4.20. Conclusion: The statistical parameters of the models based on NIR spectra showed potential for density measurements in floors, furniture, and solid wood products.

ABSTRACT Economic development based on cleaner industrial technologies has been increasingly studied in recent years. Cementitious composites reinforced with lignocellulosic fibers can be a sustainable alternative for use in engineering. The study aimed to evaluate the technological properties of cementitious composites produced from natural and industrial coconut fiber to compare the reinforcement with wood particles. Physical tests (density, water absorption, and thickness swelling) and mechanical tests (static bending) were carried out in four treatments, which varied the fiber and cement contents. It was found that treatment with natural coconut fiber had the lowest density value, 0.59 g/cm3, and treatment with industrial coconut fiber had the lowest water absorption value for the times and times of 2 and 24 h, 0.19, and 0.38%, respectively, and the treatment with wood particles, the highest values of modulus of elasticity and rupture, 1,897 MPa and 2.44 MPa. The study of the use of lignocellulosic materials as protection in cementitious composites is essential for applications in building constructions to reduce the environmental impacts generated by the generation of waste and use of non-renewable materials and to promote sustainable development.

ABSTRACT Were characterized microstructurally and mechanically the Ti-6Aℓ-4V alloy obtained through powder metallurgy in an uncontrolled atmosphere, varying the sintering parameters, arose. The samples were compacted in a uniaxial press at 874 MPa, 999 MPa, and 1124 MPa, and sintered without a protective atmosphere or vacuum, at 675 °C, 750 °C, and 850 °C. When sintering the material, the oxides influenced the results due to titanium’s high affinity for interstitial elements, promoting increased density and high hardness values. Based on the results, the treatment carried out at a pressure of 1124 MPa and a temperature of 750 °C showed the highest hardness in the beta phase (β), with a value of 1165.1 HV. In the alpha phase (α), the highest value was 1321.3 HV, presented by the treatment performed at a pressure of 999 MPa and a temperature of 850 °C. The high hardness values observed in the alloy are associated with the reinforcement promoted by the dissolution of Fe atoms. Materials with high hardness values use in the aerospace and biomedical industries, which always look for better mechanical resistance results, thus increasing their products’ useful life and applicability.

RESUMO Foram caracterizadas micro estruturalmente e mecanicamente a liga Ti-6Aℓ-4V obtida através da metalurgia do pó em atmosfera não controlada variando os parâmetros de sinterização. As amostras foram compactadas em uma prensa uniaxial à 874 MPa, 999 MPa e 1124 MPa, e sinterizadas sem atmosfera protetora ou vácuo, nas temperaturas de 675 °C, 750 °C e 850 °C. Ao sinterizar o material, houve influência dos óxidos nos resultados devido à alta afinidade que o titânio tem por elementos intersticiais, promovendo um aumento na densidade e elevados valores de dureza. A partir dos resultados verificou-se que o tratamento realizado na pressão de 1124 MPa e temperatura de 750 °C foi o que apontou a maior dureza na fase beta (β), sendo o valor de 1165,1 HV. Na fase alfa (α), o maior valor foi de 1321,3 HV, apresentado pelo tratamento realizado na pressão de 999 MPa e temperatura de 850 °C. Os elevados valores na dureza observados na liga estão associados ao reforço promovido pela dissolução átomos de Fe. Materiais com elevada dureza possuem uma vasta aplicação nas indústrias aeroespaciais e biomédicas, que buscam sempre por melhores resultados de resistência mecânica, aumentando assim a vida útil e a aplicabilidades de seus produtos.

ABSTRACT Efforts have been done in order to decrease the human dependence on petroleum materials. This idea can be applied for wood adhesives and wood products. This study proposes to evaluate laminated veneer lumber (LVL) panels of Hevea brasiliensis produced with castor oil-based polyurethane and resorcinol formaldehyde in different grammages. Six rubber tree (12 years old) with diameters at breast height (DBH) > 25 cm were harvested to generate veneers (500 x 500 x 2 mm; length, width, and thickness, respectively) for the panels production. The veneers were pre classified by a non-destructive impulse excitation method (Sonelastic system). Seven veneers were arranged in the same grain direction to produce each LVL. The following grammages were used for each adhesive type: 240, 280 and 320 g.m-². The volumetric swelling of the panels, glue line strength under dry, wet and post-boiling conditions, and stiffness and strength in static bending tests in flatwise and edgewise positions were evaluated. The glue line was evaluated by optical microscopy. The panels with grammages of 240 g.m-² had the highest volumetric swelling for both adhesives. As the grammage increased from 240 to 280 g.m-², the panel volumetric swelling decreased 32.53% for the resorcinol formaldehyde adhesive and 21.42% for the castor oil-based polyurethane adhesive. The panels glued with the vegetal polyurethane adhesive presented the best results for shear strength in the glue line. No significant statistical differences were found between the compositions for static bending. The results indicate that rubber wood glued with vegetal polyurethane has the potential to be used for production of LVL panels and consequently replace the petroleum based adhesives.

ABSTRACT The aim of this study was to evaluate the properties of Hevea brasiliensis wood wastes for production structural pieces of glued laminated (glulam) timber. Three trees with age close to 25 years and diameter at breast height (DBH) higher than 500 mm were obtained. The basic density of the wood were quantified, as well as the stiffness and the strength in static bending, shear strength and parallel compression to grain and hygroscopic equilibrium moisture. The beams of glulam were evaluated according to the modulus of elasticity (MOE), modulus of rupture (MOR) and delamination. Due to the bending properties MOR (75.14 MPa) and MOE (8166.79 MPa), as well as the shear strength (12.29 MPa) obtained, was concluded by the suitability of the rubber wood for the production of glulam beams. The composite beams presented values of MOR (75.14 MPa) and MOE (8166.79 MPa) compatible with species traditionally used in the production of glulam beams. The adhesive bond quality was verified by the delamination test, presenting delamination of 4.95 %, indicating its use for internal and external environments.

ABSTRACT A wide range of materials for the development of new products can be obtained from natural resources. Good examples of these materials are lignocellulosic wastes, which are a good alternative for the production of particleboards. This study aimed to evaluate the feasibility of using cotton wastes in association to eucalyptus particles in the production of particleboards. Cotton waste proportions used were 0, 10, 20 and 30%. Urea formaldehyde (UF) adhesive was applied at 12%, based on dry the weight of particles. Physical and mechanical tests were performed in order to evaluate panels. Water Absorption (2 and 24 h) and Internal Bond (IB) showed not significant effect with increased percentage of cotton waste. Thickness Swelling (2 and 24 h) of particleboards increased with increased percentage of waste material. The Modulus of Elasticity for cotton waste particleboards ranged from 726.47 ± 99.98 to 205.12 ± 66.24 MPa, while the Modulus of Rupture ranged from 8.63 ± 1.39 to 3.87 ± 0.75 MPa. According to results, cotton wastes could be added to particleboards up to the percentage of 9%, being indicated for the manufacture of some types of furniture such as doors and sides.

ABSTRACT The aim of this study was to evaluate the effect of different radial regions of Pinus oocarpa wood on the physical and mechanical properties of particleboard panels. Three different radial regions (internal, intermediate and external) and the mixture (integral log) were assessed. Experimental panels were produced with a nominal density of 0.70 g/cm3 using 8% urea-formaldehyde adhesive; they were compressed at a specific pressure of 40 kgf/cm2 and temperature of 160 °C, for 8 minutes. Wood radial position affected particleboard quality and a direct influence of the chemical composition and density of the material used was observed. Only the panels produced the mixture (integral log) and with the internal region met all the requirements stipulated by the marketing standard.

RESUMO A indústria de painéis de madeira vem em constante crescimento, sendo necessária a inovação em tecnologias e matéria-prima para melhorar a qualidade do produto final. Considerando a escassez e pressão na diminuição da dependência por madeira, existe um interesse em outros materiais renováveis, como os resíduos agrícolas. Entre esses resíduos, o pergaminho de café merece destaque. Uma alternativa para utilização do pergaminho de café poderia ser na produção de particulados, em associação com partículas de madeira. O objetivo deste trabalho foi avaliar a viabilidade de utilização do pergaminho de café para produção de aglomerados. As porcentagens de resíduo utilizadas foram: 0, 10, 20, 30, 40 e 50% em associação com madeira de eucalipto. Os painéis foram produzidos com 8% de uréia-formaldeído (base massa seca de partículas). O ciclo de prensagem consistiu de: pré-prensagem de 0,5 MPa por 10 minutos, seguido por prensagem de 4,0 MPa e temperatura de 160° C por 15 minutos. A razão de compactação dos painéis produzidos com maiores quantidades de pergaminho melhorou as propriedades físicas. As propriedades de absorção de água (2 e 24 h) e inchamento em espessura (2 h) diminuíram com o aumento da porcentagem de pergaminho de café. O inchamento em espessura (24 h) não apresentou diferenças significativas com o aumento de resíduo de café. O Módulo de Elasticidade dos painéis variou de 646,49 ± 112,65 até 402,03 ± 66,24 MPa, enquanto o Módulo de Ruptura variou de 8,18 ± 1,39 até 4,45 ± 0,75 MPa. Os resultados mostraram que até 10% de pergaminho de café poderia ser adicionados para a produção de painéis aglomerados.

ABSTRACT The wood panel industry is constantly growing, being necessary the innovation in technologies and raw materials to improve the quality of the final product. Considering the shortage and pressure to decrease the dependence of wood, there is an interest in other renewable materials such as agricultural wastes. Among these wastes, coffee parchment is one which deserves notoriety. An alternative use for coffee parchment could be for production of particleboard in association with wood particles. This study aimed to evaluate the feasibility of using coffee parchment for production of particleboard. The following percentages of wastes were used: 0, 10, 20, 30, 40 and 50% in association to eucalyptus wood. The panels were produced with 8% of urea formaldehyde (based on dry weight of particles). The pressing cycle consisted by: pre-pressing of 0.5 MPa for 10 minutes followed by pressing of 4.0 MPa, and temperature of 160° C for 15 minutes. The compaction ratio of particleboards produced using higher quantities of parchment improved the physical properties. The properties of Water Absorption (2 and 24 h) and Thickness Swelling (2 h) decreased with increasing percentage of coffee parchment. The Thickness Swelling (24 h) showed not significant effect with an increase of coffee waste. The Modulus of Elasticity for coffee parchment particleboards was in the range 646.49 ± 112.65 to 402.03 ± 66.24 MPa, while the Modulus of Rupture ranged from 8.18 ± 1.39 to 4.45 ± 0.75 MPa. The results showed that 10% of coffee parchment could be added for production of particleboards.

Os resíduos agrícolas são materiais gerados em grande quantidade no Brasil, que podem se acumular, gerando problemas ambientais. Um dos resíduos mais gerados nas culturas agrícolas do Brasil é o sabugo de milho. Sendo um material lignocelulósico, o sabugo poderia ser utilizado como matéria-prima na produção de painéis aglomerados, cuja principal utilização é no setor moveleiro. Portanto, estudos sobre sua estabilidade térmica e resistência ao fogo seriam de interesse relevante. Objetivou-se, neste trabalho, avaliar a combustibilidade e estabilidade térmica de painéis aglomerados produzidos com sabugo de milho e madeira de Pinus oocarpa. As porcentagens de sabugo de milho utilizadas foram de 0%, 25%, 50%, 75% e 100% associadas com partículas de madeira de Pinus oocarpa. Os painéis foram produzidos com 8% de ureia-formaldeído e 1% de parafina. Os parâmetros do ciclo de prensagem foram: temperatura de 150 ºC, pressão de 3,92 MPa e tempo de 10 min. A análise das curvas de combustibilidade mostrou que os painéis, contendo 25% de sabugo, foram mais resistentes à combustão. Em geral, a estabilidade térmica decaiu à medida que foi aumentada a substituição de madeira por sabugo de milho.

Agricultural waste materials are generated in large quantities in Brazil. These can accumulate and cause serious environmental problems. One of the most commonly generated wastes in the brazilian agricultural culture is the maize cob. Being lignocellulosic in nature, the maize cob can find use as the raw material in the production of particleboards mainly concerned with furniture making. Therefore, studies regarding its thermal stability and fire resistance would be interesting. The aim of this study was to evaluate the combustibility and thermal stability of the particleboards produced from maize cob and Pinus oocarpa wood. The percentages in which maize cob was associated with Pinus oocarpa were 0%, 25%, 50%, 75% and 100%. The panels were produced using 8% urea-formaldehyde and 1% paraffin. The pressing cycle parameters included: temperature 150 °C, pressure of 3.92 MPa during 10 min. The combustibility curve analysis showed that the panels containing 25% content of maize cob had higher resistance to combustion. In general, the thermal stability decreased as the wood substitution by maize cob increased.

Os resíduos agrícolas são materiais gerados em grande quantidade no Brasil, podendo se acumular no ambiente, gerando graves problemas. Um desses resíduos que merecem destaque é o sabugo de milho. Uma das alternativas para o reaproveitamento do sabugo seria a produção de painéis aglomerados em mistura com madeira. Objetivou-se, neste trabalho, avaliar a viabilidade da utilização do sabugo de milho para a produção de painéis aglomerados. As porcentagens de sabugo de milho utilizadas foram de 0%, 25%, 50%, 75% e 100% associadas com partículas de madeira de Pinus oocarpa. Os painéis foram produzidos com 8% de uréia-formaldeído e 1% de parafina (base massa seca de partículas). Na prensagem dos painéis, foi utilizada pressão de 3,92 MPa e temperatura de 160º C por um período de 8 minutos. O aumento da substituição da madeira de pinus pelo resíduo sabugo de milho promoveu melhoras significativas para as propriedades de absorção de água, após duas horas e inchamento em espessura, após duas e vinte e quatro horas. As propriedades mecânicas apresentam relação decrescente com a porcentagem de incorporação de sabugo de milho.

Agricultural residues are materials generated in large quantities in Brazil and can accumulate to such extent as to cause environmental problems. Among agricultural residues, maize cob is one worthy of notice, and an alternative use for maize cob would be to produce particleboard panels in association with wood particles. This study aimed to evaluate the feasibility of using maize cob for production of particleboard panels. The following maize cob percentages were used: 0%, 25%, 50%, 75% and 100%, in association with particles of Pinus oocarpa wood. Panels were made with 8% of urea formaldehyde and 1% of paraffin (based on dry weight of particles). For compressing the panels, a pressure of 3.92 MPa was applied at a temperature of 160º C, for 8 minutes. Increased replacement of pinewood by maize cob residue promoted significant improvements to the properties water absorption after two hours of immersion, thickness swelling after two and after twenty-four hours of immersion. Mechanical properties had a decreasing correlation with the maize cob percentage being incorporated.

Studies concerning the production of particleboards with sugarcane bagasse as an alternative fibrous material have been carried out as an attempt to provide a sustainable and viable destination for this residue. This work aimed to evaluate the influence of several processing variables related to the microstructure of sugarcane bagasse particleboards (mat type, adhesive type and adhesive content) on their permeability and water sorption properties. Air permeability data was collected by the rotameter method. Superficial air permeability (kg), Darcian constant (k1) and non-Darcian constant (k2) were measured. kg was related to sorption behavior of the particleboards. 1-layer particleboards presented significantly higher kg values than the 3-layer particleboards. In general, adhesive type, position and content did not influence kg of particleboards. However, these processing variables influenced interactions between fluid and material and tortuosity of the porous media. Particleboards produced with urea-formaldehyde with high kg presented higher water absorption and thickness swelling after 24 hours. Such relations were not observed in particleboards produced with melamine-urea-formaldehyde.

ABSTRACT The physical properties of commercial particle-boards made of sugar cane bagasse and wood were studied. Thickness swelling and water absorption tests were conducted in order to compare the materials and their types of absorption: total, lateral and superficial. Tests for comparison between particle-boards made of different materials showed that sugar cane bagasse particle-boards presented higher water absorption, but lower thickness swelling. For sugar cane bagasse particle-board, the highest value was found for lateral water absorption. For wood particle-board, the total absorption was highest after 2 hours of immersion, but it became equal to the superficial absorption after 24 hours.

RESUMO As propriedades físicas de painéis aglomerados comerciais produzidos com bagaço de cana e madeira foram estudadas. Os testes de absorção de água e inchamento em espessura foram realizados para comparação entre os materiais estudados e entre os tipos de absorção de cada material: total, superficial e lateral. Nos testes de comparação entre painéis de bagaço de cana e painéis de madeira, foi observado que os primeiros apresentaram maiores valores de absorção de água, mas menores inchamentos em espessura. O aglomerado de bagaço de cana apresentou maiores valores de absorção de água lateral. Já no de madeira, a absorção total foi superior após 2 horas, mas igualou-se à absorção superficial após 24 horas.