Abstract In search of new materials from industrial waste, aiming at cost, efficiency and reduction of environmental liabilities, this study aimed to evaluate the physical, mechanical, acoustic and thermal characteristics of sandwich panels produced with sheets of Schizolobium amazonicum (paricá) and egg carton core made of cardboard, glued with adhesive phenol formaldehyde (FF), urea formaldehyde (UF) and interleaved the sheets glued with both. The panels were evaluated through thermal, acoustic, physical and mechanical tests. The FF and UF adhesives influenced the physical-mechanical properties of the panels. For thermal conductivity and thermal resistance, it was found that all panels met the normative requirements of NBR 15220 (ABNT, 2005) with emphasis on panels produced with FF. Therefore, the use of paricá sheets 32x12x0.2 cm (length, width and thickness, respectively) and egg box as a core with adhesive, proved to be promising for some uses in civil construction, in addition to adding value to the egg crate residues as thermal and acoustic insulators, can minimize the disposal of raw material in the environment.

Resumo Em busca de novos materiais a partir de resíduos industriais, visando ao custo, à eficiência e à redução do passivo ambiental, este trabalho teve como objetivo avaliar as características físicas, mecânicas, acústicas e térmicas de painéis sanduíche produzidos com lâminas de Schizolobium amazonicum (paricá) e núcleo de caixa de ovos feitos de papelão coladas com o adesivo fenol-formaldeído (FF) e com o adesivo ureia-formaldeído (UF), intercalando-se estas com lâminas coladas com ambos (FF+UF). Os painéis foram avaliados por meio de ensaios térmicos, acústicos, físicos e mecânicos. Os adesivos FF e UF influenciaram nas propriedades físico-mecânicas dos painéis. Para a condutividade térmica e resistência térmica, verificou-se que todos os painéis atingiram as exigências normativas da NBR 15220 (ABNT, 2005), com destaque para os painéis produzidos com FF. Sendo assim, a utilização das lâminas de paricá de 32x12x0,2 cm (comprimento, largura e espessura respectivamente) e de caixa de ovo como núcleo com adesivo se mostrou promissora para algumas aplicações na construção civil, além de agregar valor aos resíduos de caixa de ovo como isolantes térmicos e acústicos, por minimizar o descarte de matéria-prima no meio ambiente.

ABSTRACT Despite the increasing use of plaster as a construction material, due to its numerous advantages when compared to cement, its use is still restricted, because of its low mechanical resistance and high solubility in water. In this context, research has been carried out related to the addition of nanomaterials to improve the mechanical and physical properties of plaster in civil construction. A highly available, low-cost nanomaterial with excellent properties is nanotalc. In this work, nanocomposites with dimensions of 40 × 40 × 160 mm were produced with ultrafine micronized nanotalc replacing plaster in proportions of 0%; 0.5%; 1%; 1.5% and 2%. The physical and mechanical properties of the nanocomposites were evaluated according to standards. The nanocomposites produced with 1% nanotalc showed satisfactory results for physical and mechanical properties, with an increase of 1.8% in apparent density and 24.12% in compressive strength, and a decrease in water absorption of 6.23%, compared to the composite without the incorporation of nanotalc. The production of nanocomposites with the incorporation of 1% nanotalc is viable and shown to be promising, presenting potential for application as linings and internal partitions, since they showed low water absorption due to the hydrophobicity of nanotalc.

ABSTRACT Background: Patauá (Oenocarpus bataua Mart.) is a palm tree belonging to the botanical family Arecaceae that occurs throughout the Amazon. Like açaí, an edible pulp is extracted from its fruits, remaining a fiber-rich waste. Revealing the potential of such raw or thermochemically modified fibers for producing bioproducts is a novelty in the literature. Therefore, this work aimed to characterize patauá fibers in natural and alkali-treated conditions to support future bioproduct applications. Alkaline treatments were performed under mechanical stirring combining two NaOH levels (5 and 10%) and two temperatures (80 and 100°C). Morphological characterization was performed by light microscopy and scanning electron microscopy (SEM). The contents of the structural and non-structural chemical components were determined, and chemical groups were evaluated by Fourier-transform infrared spectroscopy (FTIR). The physical characterization included moisture content, apparent density, and water absorption tests. Results: The macerate revealed short fibers with typical elongated morphology, mean cell wall thickness (4.10 µm) greater than the mean lumen width (3.01 µm), and mean length of 445 µm. The alkaline treatments partially individualized the fibers from bundles, cleaned extractives from the surface, and unblocked superficial pits by removing silica-rich structures. They substantially removed non-cellulosic components, but FTIR showed condensed lignin exposed on the fiber surface. Density and water uptake increased concerning natural fibers. Patauá’s short length and susceptibility to modification through thermochemical treatments that concentrated cellulose up to 50% indicated great potential for developing composites and nanofibers. Regardless of the NaOH content, 100°C was more efficient in concentrating cellulose. Conclusion: Patauá fibers have unique natural characteristics. They occur as flatted fiber bundles, have silicon-rich structures obstructing their superficial pits, and comprise more lignin than cellulose.

ABSTRACT Thermal treatment can modify undesirable characteristics of some woods, dimensional instability, and excessive water adsorption. The present research work aimed to assess the effect of thermal treatment on the physical properties of clone GG100 Eucalyptus wood. Wood samples were obtained from 9 year-old trees. Samples were subjected to three types of thermal treatment (T1, T2, and T3). In T1, the wood was kept in a laboratory kiln at 100 °C for 180 min. In T2, hydrothermal treatment was performed in an autoclave at 120 °C for 120 min. In T3, the combined autoclave and laboratory kiln treatments were employed. The properties evaluated were apparent density (ρa); mass loss (ML); longitudinal (βl), radial (βr), tangential (βt), and volumetric shrinkage (βv); anisotropic factor; and equilibrium moisture content. The treatments caused a decrease of ρa and increase of ML. The Equilibrium Moisture Content (EMC) was lowest for T3, and had a negative correlation with ML, βt, and ∆v. The Pearson correlation analysis indicated the results of the thermal treatments were similar, but T1 presented the lowest variation of the physical properties compared to the other treatments, giving it the best predictability for practical uses.

Abstract Peanut crop waste (hulls), which have a chemical composition similar to wood, can be considered as a source of industrial raw material for the production of particleboard, provided that they are of similar quality to wooden panels. The present study aimed to produce and evaluate the physical and mechanical properties of medium density particleboards made of peanut hulls and pine wood particles bonded with urea-formaldehyde adhesive. The panels did not present satisfactory dimensional stability. The mechanical properties were significantly reduced with the addition of peanut hulls. In general, peanut hulls did not represent a good alternative to be used as a source of raw material for the production of particleboard. The inclusion of new parameters in the production process would be essential to improve the technological properties, such as: new particle geometries, use of paraffin, particle treatments and inclusion of denser species in the composition of the panels.

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 Este trabalho teve como objetivo produzir e caracterizar compósitos à base de gesso reforçados com partículas de resíduo de cacau como forma de agregar valor a esse subproduto agrícola e criar um material inovador. Para a produção dos compósitos foram utilizados gesso fino para fundição e partículas de resíduo de cacau. As proporções de reforço inseridas foram de 0,0%; 2,5%; 5,0%; 7,5% e 10,0% em substituição a massa de gesso. Para a produção dos compósitos foram utilizadas fôrmas de madeira com dimensões de 40 x 40 x 160 mm. Foi realizada análise da composição química do resíduo de cacau para determinação dos teores de extrativos totais, cinzas, lignina e holocelulose. Os compósitos foram avaliados nos ensaios físicos, mecânicos, térmico e acústico. Constatou-se que, houve melhorias nas propriedades físicas com o acréscimo de reforço tornando o material mais leve, visto a redução da densidade (1190,69 a 1138,92 kg/m³), e proporcionando a diminuição da higroscopicidade, com teores de umidade decrescendo de 7,74 a 4,01% e de absorção de água decrescendo de 18,37 para 5,28%. Da mesma forma, a resistência térmica aumentou gradativamente ao longo dos tratamentos com valores de 1,90 a 2,41 K.m/W e o isolamento acústico foi maior nos compósitos em comparação com o gesso puro, embora não tenha havido linearidade entre os tratamentos. Já para as propriedades mecânicas, houve diminuição de resistências tanto à flexão (3,60 a 0,84 MPa) quanto à compressão (4,43 a 1,73 MPa). Foi concluído que o resíduo de cacau apresenta potencialidade para ser utilizado no compósito tendo em vista que a inclusão de até 8,15% do mesmo atendeu a normatização em todos os ensaios realizados. Isso fomenta a ideia de que os resíduos lignocelulósicos são alternativas promissoras para criação de materiais de alto valor agregado.

ABSTRACT This work aimed to produce and characterize gypsum-based composites reinforced with cocoa waste particles as a way to add value to this agricultural by-product and create an innovative material. For the production of composites, thin plaster for casting and particles of cocoa waste were used. The reinforcement proportions inserted were 0.0%; 2.5%; 5.0%; 7.5% and 10.0% replacing plaster mass. For the production of composites, wooden molds with dimensions of 40 x 40 x 160 mm were used. Analysis of the chemical composition of the cocoa waste was performed to determine the levels of total extracts, ash, lignin and holocellulose. The composites were evaluated in physical, mechanical, thermal and acoustic tests. It was found that there were improvements in physical properties with the addition of reinforcement making the material lighter, given the reduction in density (1190.69 to 1138.92 kg/m³), ??and providing a decrease in hygroscopicity, with moisture levels decreasing from 7.74 to 4.01% and water absorption decreasing from 18.37 to 5.28%. Likewise, the thermal resistance gradually increased over the treatments with values ??from 1.90 to 2.41 K.m/W and the acoustic insulation was higher in composites compared to pure plaster, although there was no linearity between treatments. As for the mechanical properties, there was a decrease in resistance both to flexion (3.60 to 0.84 MPa) and to compression (4.43 to 1.73 MPa). It was concluded that the cocoa waste has the potential to be used in the composite considering that the inclusion of up to 8.15% of the same met the standard in all tests performed. This promotes the idea that lignocellulosic waste is a promising alternative for creating materials with high added value.

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.

RESUMO O descarte inadequado de polímeros de origem petrolífera contribui para o aumento da poluição ambiental devido ao grande período de tempo que estes materiais levam para degradar. Assim, o desenvolvimento de materiais poliméricos reforçados com resíduos de materiais lignocelulósicos pode proporcionar uma melhor taxa de biodegradação ao polímero, por se tratar de materiais de origem natural, renovável e biodegradável. Neste sentido, o objetivo desta pesquisa foi verificar o potencial de utilização do resíduo de soja como carga em polietileno de baixa densidade (PEBD) através de caracterização físico-mecânica. Foram avaliadas diferentes composições do resíduo de soja em relação à massa total de PEBD 0%, 5%, 10%, 15% e 20%. O resíduo de soja utilizado foi caracterizado quimicamente para determinação do teor de extrativos, lignina, cinzas e hemicelulose. Os pellets formados por extrusão foram prensados a uma temperatura de 160°C sem pressão durante 12 minutos, onde se obteve os corpos de prova para os ensaios físico-mecânicos. Após a produção, os mesmos foram acondicionados em sala de climatização com temperatura de 20±2°C e umidade relativa de 65±3%, sendo posteriormente realizada a determinação da densidade aparente, umidade na base seca, absorção total de água e realizados de flexão e tração. Com base nos resultados, conclui-se que os valores encontrados para os constituintes químicos do resíduo de soja mostram satisfatórios, uma vez que, a substituição parcial do PEBD puro pelo não afetou as propriedades de densidade e resistência à tração do material. O aumento do teor deste resíduo, também contribui para um maior alongamento do polímero. Assim, conclui-se que é possível transformar este polímero de origem petrolífera em um material mais sustentável, tornando algumas propriedades até mais atrativas do que aquelas encontradas no PEBD puro.

ABSTRACT The improper disposal of polymers of petroleum origin contributes to the increase of environmental pollution due to the long period of time that these materials take to degrade. Thus, the development of polymeric materials reinforced with residues of lignocellulosic materials can provide a better rate of biodegradation to the polymer, as they are materials of natural, renewable and biodegradable origin. In this sense, the objective of this research was to verify the potential of using soybean residue as a filler in low density polyethylene (LDPE) through physical-mechanical characterization. Different soy residue compositions were evaluated in relation to the total mass of LDPE 0%, 5%, 10%, 15% and 20%. The soybean residue used was chemically characterized to determine the content of extractives, lignin, ash and hemicellulose. The pellets formed by extrusion were pressed at a temperature of 160 ° C without pressure for 12 minutes, where the specimens were obtained for the physical-mechanical tests. After production, they were stored in an air conditioning room with a temperature of 20 ± 2 ° C and a relative humidity of 65 ± 3%, with the determination of apparent density, moisture on the dry basis, total water absorption and subsequently carried out. flexion and traction. Based on the results, it is concluded that the values found for the chemical constituents of the soy residue are satisfactory, since the partial substitution of pure LDPE by the material did not affect the density and tensile strength properties of the material. The increase in the content of this residue also contributes to a greater elongation of the polymer. Thus, it is concluded that it is possible to transform this petroleum-based polymer into a more sustainable material, making some properties even more attractive than those found in pure LDPE.. Keywords: Polymeric materials. Lignocellulosic waste. Sustainability.

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.

RESUMO As embalagens multicamadas são utilizadas por um período de tempo bastante curto gerando um volume de descarte elevado. Por serem formadas por diferentes materiais devido suas diversas camadas, sua reciclagem é dificultada. Sendo assim, são importantes novas aplicações para essas embalagens pós-consumo, como por exemplo o seu reaproveitamento em compósitos. Neste contexto, o objetivo deste trabalho foi desenvolver e caracterizar compósitos à base de gesso reforçados com embalagens multicamadas trituradas. As proporções utilizadas para a incorporação dos reforços foram de 0%, 7,5%, 15%, 22,5% e 30% em substituição ao gesso. Foram produzidos corpos de prova (três repetições por tratamento) para avaliação das propriedades de absorção de água, umidade, massa específica aparente, compressão e flexão estática, os quais foram confeccionados com dimensões de 40 x 40 x 160 mm. Para o ensaio térmico, as dimensões foram de 200 x 200 x 20 mm. Os reforços adicionados levaram a um aumento em umidade e absorção de água, enquanto que, para massa específica aparente, condutividade térmica, resistência à flexão, resistência à compressão e rigidez na compressão houve decréscimo. A incorporação de embalagens multicamadas em compósitos de gesso mostrou ser uma alternativa viável, visto que, além de aplicar a logística reversa reutilizando estas embalagens que muitas vezes são descartadas no meio ambiente de maneira inadequada, gerando diversos impactos, ainda melhorou a propriedade térmica dos compósitos e diminuiu a densidade destes. Ademais, todas as porcentagens atenderam a normatização para resistência à flexão, e para a resistência à compressão, apenas a substituição de 30% não atendeu a normativa.

ABSTRACT The multilayer packages are used for a very short time generating a high discard volume. Because they are formed by different materials due to their several layers, their recycling is difficult. Therefore, new applications for these post-consumer packages are important, such as their reuse in composites. In this context, the objective of this work was to develop and characterize plaster based composites reinforced with crushed multilayer packages. The proportions used to incorporate reinforcements were 0%, 7.5%, 15%, 22.5% and 30%, replacing gypsum. Test specimens (three replicates per treatment) were produced to evaluate the properties of water absorption, moisture, apparent specific mass, compression and static bending, which were made with dimensions of 40 x 40 x 160 mm. For the thermal test, the dimensions were 200 x 200 x 20 mm. The added reinforcements led to an increase in moisture and water absorption, whereas, for apparent specific mass, flexural strength, compressive strength and stiffness in compression there was decrease. The incorporation of multilayer packages into plaster composites proved to be a viable alternative, since in addition to applying reverse logistics reusing these packages that are often discarded in the environment in an inadequate manner, generating several impacts, it also improved the thermal properties of the composites , their density decreased, all percentages complied with normalization for flexural strength, and for compression strength, only the 30% insertion did not meet the standards.

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.

ABSTRACT The aim of this research was to investigate sugarcane bagasse (SCB) particleboards, using two kinds of particles, from pith and fibers, reinforced with cellulose nanocrystals (NCC). The NCCs were dispersed in the adhesive urea formaldehyde (UF) using a sonificator in two proportions (0 and 1%). The NCCs and UF were applied in the SCB particles using a rotary blender. The particleboards were produced in three layers using two kinds of particles: pith and fibers. After dispersion of the adhesive, the mixture was compressed to produce the particleboards, which were characterized by physical, mechanical and thermal properties. The anatomical and chemical features relating to pith and fiber were very similar. The particleboards made with and without NCCs did not differ statistically for most properties: modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) thermal conductivity (TC), and the volume heat capacity (VHC). Particleboards made only with fibers and without NCCs showed higher internal bond (IB). In the other hand particleboards made only with fibers in the face and pith in the core (without NCCs) showed lower thickness swelling after 24 hours (TS24h). Probably, the NCCs did not improve the particleboards performance, because less links were available for SCB to interact with the adhesive. For the others properties the particleboards made with pith and fibers did not showed statistical difference (MOE, MOR, TC, WA, TC and VHC), demonstrating that separation of pith and fiber are not significant and does not affect the final properties of particleboards.