RESUMO Essa pesquisa objetivou avaliar o potencial do bambu Bambusa tuldoides como reforço na matriz de gesso. Foi determinada a densidade básica, dimensões de fibras e constituição química da matéria-prima. Foram produzidos compósitos com substituição em volume da pasta de gesso por 0, 5, 10, 15, 20, 25 e 30% de bambu com uma relação água/gesso de 1:1. Para a caracterização mecânica dos compósitos foram realizados ensaios de flexão estática, compressão e densidade aparente. Os valores obtidos na avaliação da fibra apresentaram valores próximos à literatura. Na caracterização dos compósitos todas as propriedades tiveram regressão quadrática significativa e foi possível verificar o comportamento similar entre propriedades mecânicas e a densidade. Na densidade ocorreu um aumento do seu valor até a porcentagem de 17,41% que pode ser justificado devido à absorção da água pela fibra decorrente da presença de pontuações, o que gera uma diminuição na relação água gesso e um aumento da densidade. Já o decréscimo da densidade a partir de 17,41% está relacionado com a grande quantidade de fibras presente que ficam emaranhadas e causam espaços vazios já que a pasta de gesso não consegue infiltrar nesses locais. Na compressão, as porcentagens entre 3,37 e 26,19% são os que atenderam as exigências normativas (maior que 2 MPa), e na flexão as porcentagens entre 0 e 27,23% são as que estão em conformidade com a norma (maior que 1 MPa). Os resultados mostraram que a utilização do bambu Bambusa tuldoides como reforço é viável entre as porcentagens 3,37 e 26,19% para atender todas as exigências normativas.

ABSTRACT This research aimed to evaluate the potential of Bambusa tuldoides as reinforcement in the plaster matrix. The basic density, fiber dimensions and chemical constitution of the raw material were determined. Composites were produced with volume replacement of gypsum paste by 0, 5, 10, 15, 20, 25 and 30% of bamboo with a water / gypsum ratio of 1: 1. For the mechanical characterization of the composites, static bending, compression and bulk density tests were performed. The values obtained in the fiber evaluation presented values close to the literature. In the characterization of composites all properties had significant quadratic regression and it was possible to verify similar behavior between mechanical properties and density. In density there was an increase of its value up to the percentage of 17.41% that can be justified due to the absorption of water by the fiber due to the presence of scores, which generates a decrease in the water plaster ratio and an increase in density. The decrease in density from 17.41% is related to the large amount of fibers present that get tangled and cause voids since the plaster paste cannot infiltrate these places. In compression, the percentages between 3.37 and 26.19% are those that met the normative requirements (greater than 2 MPa), and in flexion the percentages between 0 and 27.23% are those that comply with the standard (greater than 1 MPa). The results showed that the use of Bambusa tuldoides as reinforcement is viable between 3.37 and 26.19% to meet all regulatory requirements.

RESUMO Devido ao uso dessa árvore na produção de látex, a Hevea brasiliensis tem um papel consolidado na economia brasileira. No entanto, ao final do ciclo produtivo dessa árvore, que dura aproximadamente 25 anos, a madeira resultante desse empreendimento não possui valor agregado e é normalmente utilizada na produção de lenha. Buscando introduzir esta espécie na indústria moveleira e da construção civil, este estudo objetivou avaliar a qualidade de painéis aglomerados produzidos com madeira de Pinus oocarpa misturada com madeira de Hevea brasiliensis em diferentes proporções. Os painéis aglomerados foram produzidos com uma densidade nominal de 0,60 g/cm³ e 8% de adesivo uréia-formaldeído e prensados a 160 °C por 8 minutos a uma pressão de 4,0 MPa. A qualidade dos painéis aglomerados foi avaliada pelos testes de absorção de água e inchamento em espessura, ligação interna, flexão estática e arrancamento de parafusos. A substituição das partículas de Pinus por Hevea resultou em decréscimo da absorção de água e do inchamento em espessura. Os painéis produzidos com maior proporção de Hevea apresentaram melhor estabilidade dimensional devido à maior porosidade das partículas de Pinus oocarpa. A inclusão da madeira de Hevea brasiliensis resultou em um aumento de 75% no módulo de ruptura e um aumento de 300% na ligação interna em comparação com os painéis de partículas produzidos apenas com madeira de Pinus oocarpa. A madeira de Hevea brasiliensis pode ser utilizada para obter produtos de maior valor agregado e contribuir para a diversificação das matérias-primas utilizadas nas indústrias brasileiras de painéis aglomerados.

ABSTRACT The use of the Hevea brasiliensis tree in latex rubber production has resulted in a consolidated role of this tree in the Brazilian economy. However, at the end of the productive cycle of the tree that lasts for approximately 25 years, the timber resulting from this venture has no added value and is usually used for the production of firewood. In order to introduce this species into the furniture and civil construction industry, the current study aimed to evaluate the quality of particleboard produced by adding Pinus oocarpa wood with Hevea brasiliensis wood in different ratios. The particleboards were produced with a nominal density of 0.60 g/cm³ and 8% (wt%) urea-formaldehyde resin and pressed at 160 °C for 8 min at a pressure of 4.0 MPa. The quality of the particleboard was evaluated by water absorption and thickness swelling, internal bonding, static bending, and screw withdrawal tests. The substitution of Pinus particles by Hevea wood resulted in decreased water absorption and thickness swelling. The boards produced with a higher proportion of Hevea had better dimensional stability due to the greater porosity of the Pinus oocarpa particles. The inclusion of Hevea brasiliensis wood resulted in a 75% increase in the modulus of rupture and a 300% increase in internal bonding compared with the particleboards produced only with Pinus oocarpa wood. The results show that Hevea brasiliensis wood could be used to obtain higher value-added products and contribute to the diversification of the raw materials used in the particleboard industries of Brazil.

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.

RESUMO Esse trabalho teve por objetivo avaliar o comportamento físico e mecânico de madeira laminada colada (MLC) de Hevea brasiliensis tratada com arseniato de cobre cromatado (CCA), borato de cobre cromatado (CCB) e piretróide na produção de MLC. As peças foram produzidas com três lâminas com dimensões de 60 x 20 x 1200 mm (largura x espessura x comprimento), unidas com adesivo epóxi sob 1,0 MPa de pressão durante 24h à temperatura ambiente. A madeira de seringueira tinha densidade aparente de 0,624 g cm-3, valor próximo ao da madeira de Eucalyptus grandis, espécie utilizada tradicionalmente na fabricação de MLC. Em relação às peças de MLC, observou-se que o tratamento preservativo com CCA e CCB influenciou nos valores das propriedades mecânicas. Para o módulo de ruptura (MOR), foi verificado redução de 75,44 MPa para 62,36 e 58,57 MPa para as peças sem tratamento e tratadas com CCA e CCB, respectivamente. Já para o tratamento superficial com piretróide não houve diferenças estatísticas. As fotomicrografias da linha de cola mostraram que a redução desses valores ocorreu sobretudo pela penetração das soluções preservativas na estrutura da madeira (lume celular, vasos ou poros), prejudicando a ancoragem do adesivo.

ABSTRACT This work aimed to evaluate the physical and mechanical behavior of glued laminated timber (GLT) - glulam pieces of Hevea brasiliensis treated with chromed copper arsenate (CCA), chromed copper borate (CCB) and pyrethroid in the production of GLT. The pieces were produced using three wooden laminae with dimensions of 60 x 20 x 1200 mm, (width x thickness x length), joined with epoxy adhesive under 1.0 MPa pressure for 24h at room temperature. The rubberwood had an apparent density of 0.624 g cm-3, a value close to that of Eucalyptus grandis wood, a species traditionally used in the manufacture of GLT. Regarding the GLT parts, it was observed that the preservative treatment with CCA and CCB influenced negatively the values of the mechanical properties. For resistance modulus (MOR), a reduction of 75.44 MPa to 62.36 and 58.57 MPa was found for the parts untreated and treated with CCA and CCB, respectively. There was no statistical difference for surface treatment with pyrethroid. The photomicrographs of the glue line showed that the reduction in these values was mainly due to the penetration of preservative solutions into the wood structure (cell lumens and vessels or pores), impairing the anchoring of the adhesive.

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 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.

RESUMO A madeira laminada colada (MLC) é um material compósito obtido a partir da colagem de lâminas de madeira dispostas com as fibras paralelas entre si. O objetivo deste trabalho foi avaliar a influência do número de lâminas no comportamento mecânico de MLC de Toona ciliata produzidas com adesivo poliuretano de base vegetal. As vigas de MLC foram produzidas com lamelas nas dimensões de 6,0 x 1,5 x 120,0 cm, sendo confeccionadas 3 vigas por tratamento, os quais foram estruturalmente compostos por 5, 7 e 9 lâminas. Foi utilizado o adesivo poliuretano à base de óleo de mamona, sendo aplicada gramatura de 350 g m-². Para a caracterização tecnológica da madeira determinou-se a umidade na base seca, densidade aparente, caracterização química, resistência a compressão paralela às fibras, cisalhamento e os módulos de elasticidade (MOE) e ruptura (MOR) no ensaio de flexão estática. Enquanto para as vigas de MLC foram determinadas as propriedades de módulo de elasticidade (MOE), módulo de ruptura (MOR), resistência ao cisalhamento, delaminação e visualização da linha de cola por meio de fotomicrografias das amostras de madeira laminada colada. Os resultados mostraram que as vigas com 5 lâminas apresentaram valores semelhantes a madeira sólida. O aumento do número de lâminas, proporcionou menores valores para rigidez e resistência das vigas. As fotomicrografias comprovaram a qualidade da colagem e os valores satisfatórios para resistência ao cisalhamento e à delaminação, indicando a viabilidade da espécie em estudo para situações com alto teor de umidade.

ABSTRACT The glued laminated timber (glulam) is a composite material obtained from the bonding of wood laminae arranged with parallel fibers put together. The purpose of this paper was to evaluate the influence of the number of laminae on the mechanical behavior of glulam of Toona ciliata produced with vegetable-based polyurethane adhesive. The glulam beams were produced with lamellae in the dimensions of 6.0 x 1.5 x 120.0 cm, with 3 beams being made per treatment, which were structurally composed by 5, 7 and 9 laminae. The polyurethane adhesive based on castor oil was used, applying a grammage of 350 g m-². For the technological characterization of the wood the moisture in the dry base, bulk density, chemical characterization, compressive strength parallel to the fibers, shear and modulus of elasticity (MOE) and rupture (MOR) in the static bending test. While the properties of modulus of elasticity (MOE), modulus of rupture (MOR), shear strength, delamination and visualization of the glue line through photomicrographs of the laminated wood samples were determined for glulam beams. The results showed that the beams with 5 laminae presented values similar to solid wood. The increase in the number of laminae provided lower values for stiffness and strength of the beams. The photomicrographs showed the quality of the bonding and the satisfactory values for shear strength and delamination, indicating the viability of the species under study for situations with high moisture content.

RESUMO Nesta pesquisa, objetivou-se avaliar o potencial da madeira de Eucalyptus grandis e partículas de borracha de pneu na produção de painéis cimento-madeira. Foram utilizadas madeiras de Eucalyptus grandis com 8 anos de idade, provenientes da Companhia Mineira de Metais, localizada no município de Paracatu -MG. Para a formação dos painéis foi utilizado cimento Portland CPV-ARI/Plus de alta resistência inicial como aglutinante mineral e cloreto de cálcio (CaCl2) como acelerador de cura do cimento. Os painéis foram produzidos com os 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 4 MPa, a temperatura ambiente, tempo de prensagem/grampeamento de 24 horas e tempo de maturação de 28 dias. A análise dos resultados obtidos, em relação aos requisitos mínimos de painéis convencionais produzidos pelo processo Bison, permite afirmar que: (1) para as propriedades físicas de densidade aparente, absorção de água e inchamento em espessura todos os tratamentos atenderam as especificações; (2) para as propriedades mecânicas de ligação interna e módulo de ruptura no ensaio de flexão estática, todos os tratamentos atenderam as especificações; (3) para compressão e módulo de elasticidade no ensaio de flexão estática, nenhum dos tratamentos apresentaram valores compatíveis com o processo bison.

ABSTRACT The objective of this research was to evaluate the potential of Eucalyptus grandis wood and rubber tire particles in the production of cement-wood panels. Eucalyptus grandis wood, 8 years old, was obtained from Companhia Mineira de Metais, located in the city of Paracatu -MG. For the formation of the panels, high initial strength CPV-ARI/Plus Portland cement was used as mineral binder and calcium chloride (CaCl2) as a cement cure accelerator. The panels were produced with the following parameters: dimensions of 48,0 x 48,0 x 1,5 cm, nominal density of 1,2 g / cm3, relation wood: cement (1:2.5) and water: cement ratio (1:1.5). The panels were pressed at a specific pressure of 4 MPa, at room temperature, 24 hour pressing/stapling time, and 28 day maturation time. The analysis of the results obtained, in relation to the minimum requirements of conventional panels produced by the Bison process, allows to affirm that: (1) for the physical properties of apparent density, water absorption and swelling in thickness all the treatments met the specifications; (2) for the mechanical properties of internal bonding and modulus of rupture in the static bending test, all treatments met the specifications; (3) for compression and modulus of elasticity in the static bending test, none of the treatments presented values compatible with the bison process.