Resumo O principal objetivo deste trabalho foi estabelecer uma correlação entre o envelhecimento natural com o envelhecimento artificial em painéis aglomerados de média densidade produzidos com resina de poliuretano de mamona e Pinus sp. Para tal correlação, foram utilizados os parâmetros climatológicos da cidade de São Carlos, estado de São Paulo, Brasil. A correlação estabelecida foi que 20 ciclos seriam proporcionais à mesma degradação de dois meses de exposição ao envelhecimento natural. A relação entre as propriedades físicas e mecânicas com os efeitos proporcionados pelo número de meses (M) sobre o envelhecimento natural com número de ciclos (Nc) sobre o envelhecimento artificial foi obtida com modelos de regressão polinomial cúbica. Em geral, para propriedades físicas, 20 Nc representa de 7 a 8 meses e para propriedades mecânicas, de 11 a 12 meses, com exceção da tração perpendicular, de 8 meses de envelhecimento natural. As equações que melhor representam a relação entre Nc e M foram o inchamento em espessura às 2h e a absorção de água às 2h e 24h, com R² acima de 93%.

Abstract The main objective of this work was to establish a correlation between natural aging with artificial aging in medium density particleboards produced with polyurethane resin of castor oil and Pinus sp. For such correlation, climatological parameters at São Carlos city, São Paulo state Brazil were used. The established correlation was that 20 cycles would be proportional to the same degradation of two months of exposure under natural aging. The relation between physical and mechanical properties with the effects provided by number of months (M) on the natural aging with number of cycles (Nc) on the artificial aging was obtained with cubical polynomial regression models. In general, for physical properties, 20 Nc represents 7 to 8 months and for mechanical properties, 11 to 12 months, with exception to internal bonding, with 8 months of natural aging. The equations which best represent the relation between Nc and M were thickness swelling at 2h and water absorption at 2 h and 24 h, with R² above 93%.

Abstract The objective of this research is to evaluate the possibility of use of tropical hardwood species (Amburana cearensis and Cedrella fissilis) for grilling plank production. Physical, chemical and organoleptic properties were evaluated and compared with properties of a well-used wood specie for grilling plank across Europe and USA, Western Red Cedar (Thuja plicata). For chemical analysis, three techniques were used: hydro distillation, soxhlet and head space. Normality test and analysis of variance (ANOVA) were used for the comparison between Thuja plicata and tropical hardwoods. The results of organoleptic, chemical and statistical analysis demonstrated the possibility of use of Amburana cearensis and Cedrella fissilis on grilling plank production, with no volatile compound present in these species being toxic, low apparent density and Nerolidol presence, chemical compound used as flavoring agent, enabling their use as grilling planks.

ABSTRACT Thermal rectification is a method that is used to increase the physical, chemical and mechanical properties of the wood, exposing samples to high temperatures. In the present study, the improvements and implications provided by thermal rectification in the Amazon species Angelim Vermelho, Cedro, Quaruba and Muiracatiara were evaluated, regarding changes in physical properties, changes in color, possible cracks, in addition to the anatomical identification of these species. Thermal rectification was carried out at temperatures of 130, 150 and 170 °C. The greatest changes in color were observed in the species Angelim Vermelho and Muiracatiara. The appearance of cracks was observed mainly at 170 °C. The loss of mass was directly proportional to the use of higher temperatures. Changes in the density of the wood were verified after the thermal rectification process, in which Angelim Vermelho stands out following a linear pattern with reduced density according to the increase in applied temperatures. The tests of the volumetric variation revealed a reduction of the hygroscopicity of the treated species in relation to the controls, except for the treatment of Angelim Vermelho at 130 ºC. The anatomical analysis allowed the identification up to species level, being the studied species: Dinizia excelsa Ducke, Cedrela fissilis Vell, Astronium ulei Mattick and Vochysia maxima Ducke, for Angelim Vermelho, Cedro, Muiracatiara and Quaruba.

RESUMO A Termorretificação é um método que se utiliza visando incrementar as propriedades físicas, químicas e mecânicas da madeira, expondo amostras a temperaturas elevadas. No presente estudo, avaliaram-se as melhorias e implicações proporcionadas pela termorretificação nas espécies amazônicas Angelim Vermelho, Cedro, Quaruba e Muiracatiara, quanto às alterações nas propriedades físicas, alterações na coloração, possíveis trincas, além disso, foi realizada a identificação anatômica destas espécies. A termorretificação foi realizada a temperaturas de 130, 150 e 170 °C. As maiores alterações na coloração foram evidenciadas nas espécies Angelim Vermelho e Muiracatiara. O aparecimento de trincas foi observado, principalmente, a 170 °C. A perda de massa foi diretamente proporcional ao emprego de maiores temperaturas. Alterações na densidade da madeira foram verificadas após o processo de termorretificação, com destaque para o Angelim Vermelho, seguindo um padrão linear com redução da densidade de acordo com o aumento das temperaturas aplicadas. Os ensaios da variação volumétrica revelaram uma redução da higroscopicidade das espécies tratadas em relação às testemunhas, exceto para o tratamento do Angelim Vermelho a 130 ºC. A análise anatômica possibilitou a identificação até nível de espécie, sendo as espécies estudadas: Dinizia excelsa Ducke, Cedrela fissilis Vell, Astronium ulei Mattick e Vochysia maxima Ducke, para Angelim Vermelho, Cedro, Muiracatiara e Quaruba.

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 Esta pesquisa objetivou avaliar a influência do período de exposição ao intemperismo (0, 1, 2, 3 e 4 meses), do tipo de agente preservante (CCA ou CCB) e do tipo de revestimento superficial (resina à base de óleo de mamona ou à base de água com filtro solar) nos valores da rugosidade (Ra) de painéis de partículas fabricados com madeira de Pinus sp. e resina poliuretana à base de mamona, assim como, investigar a possibilidade da estimativa da rugosidade em função dos valores dos parâmetros colorimétricos (L*, a* e b*). Os valores de rugosidade (entre 0,07 e 2,82 µm) foram inferiores a 12,5 µm, o que categoriza os painéis produzidos na classe N10 da norma ABNT NBR 8404 (1984), evidenciando assim, a potencialidade dos compósitos fabricados. O uso do revestimento com resina poliuretana forneceu os menores valores da rugosidade, além disso, as rugosidades dos painéis envelhecidos durante os quatro meses foram estatisticamente equivalentes, o que demonstra o bom desempenho dos materiais fabricados quanto às intempéries, e a boa qualidade obtida dos modelos de regressão multivariáveis (R2 = 77,02%) evidenciam a possibilidade da estimativa da rugosidade por meio de parâmetros colorimétricos.

Abstract The aim of this research was to evaluate the influence of the period of exposure (0, 1, 2, 3 and 4 months), the type of preservative agent (CCA and CCB) and the surface coating type (castor oil based polyurethane resin; water-based open pore coating with sunscreen) in the roughness values (Ra) of particleboards manufactured with wood Pinus sp.and castor oil based polyurethane resin, as well as to investigate the possibility of roughness estimation as a function of the measurements of colorimetric parameters (L*, a* and b*). The results of the roughness values (between 0.07 µm and 2.82 µm) were lower than 12.5 µm, which categorizes the panels produced in the N10 class of ABNT NBR 8404 (1984) standard, thus showing the potentiality of the composites manufactured. The use of the castor oil based polyurethane resin coating gave the lowest values of roughness and the roughness values of the aged panels during the four months were statistically equivalent, evidencing the good performance of the fabricated materials. The good quality obtained from the multivariable regression models (R2 = 77.02%) show the possibility of estimating the roughness by colorimetric parameters.

Wood-based panels have been widely used around the world in various segments of timber industry. Thus, alternative raw-materials have been systematically researched in order to reduce of wood demand in particleboard production. The aim of this work was to produce and evaluate particleboards of Eucalyptus grandis and oat hulls (Avena sativa), bonded under pressure with castor oil based polyurethane resin, in the proportion of 10% relative to the dry mass of the particles. The percentages of particles used per material were: Eucalyptus grandis 100, 85, 70 e 0% and oat hulls 0, 15, 30 e 100%, respectively. Physical-mechanical performance of the panels produced was evaluated based on standards ABNT NBR 14810:2006[1] and BS EN 312:2003[2]. By analysis of variance (ANOVA), the fraction of particles of Eucalyptus grandis was significant only in the modulus of rupture (MOR) in static bending. Panels produced with 100% oat hulls presented highest value of MOR.

This paper discusses the potential use of sugarcane bagasse in two different fiber lengths (5 mm and 8 mm) of the same density as a raw material for the production of particleboards, using castor oil-based two-component polyurethane adhesive. The quality of the product that can be manufactured industrially was evaluated based on density, thickness swell (TS), absorption (WA), modulus of elasticity (MOE), modulus of rupture (MOR) in static bending and internal bond (IB), according to the Brazilian NBR 14.810:2006 standard. The results revealed a significant difference between the particleboards made with 5-mm-long fibers and those made with 8-mm-long fibers. An analysis by scanning electron microscopy (SEM) indicates that the interparticle spaces are filled with castor oil-based two-component polyurethane adhesive, contributing to improve the physicomechanical properties of the particleboards. A durability assessment based on accelerated aging tests shows that waterproofed particleboards can be used in moist environments.

Tests simulating exposure to severe weather conditions have been relevant in seeking new applications for particleboard. This study aimed to produce particleboards with residues of CCB (chromium-copper-boron oxides) impregnated Pinus sp. and castor oil-based polyurethane resin, and to evaluate their performance before and after artificial accelerated aging. Panels were produced with different particle mass, resin content and pressing time, resulting eight treatments. Particles moisture and size distribution were determined, beyond panel physical and mechanical properties, according to NBR14810-3: 2006. After characterization, treatments B and G (small adhesive consumption and better mechanical performance, respectively) were chosen to artificial aging tests. Statistical results analysis showed best performances were achieved for waterproof aged samples, of both B and G treatments. As example, in treatment B, MOR and MOE values were 23 MPa and 2,297 MPa, samples before exposure; 26 MPa and 3,185 MPa, 32 MPa and 3,982 MPa for samples after exposure (non-sealed and sealed), respectively.

No presente trabalho, considera-se o estudo do potencial de utilização de resíduos da casca de amendoim, com o intuito de agregar valor a este material, por meio da fabricação de painéis de partículas aglomeradas com resina ureia-formaldeído, prensados à temperatura de 100 ºC. A qualidade dos painéis foi avaliada com base nas prescrições do documento normativo ASTM D 1037:2006 por meio de ensaios físico-mecânicos de densidade, inchamento em espessura, absorção de água e flexão estática. Os painéis avaliados apresentaram densidade média variando de 0,69 a 0,83 g cm-3, MOR 4,37 a 5,34 MPa e MOE 590 a 700 MPa, para painéis com e sem tratamento preservativo. É possível afirmar, baseando-se no documento normativo ANSI A208.1:1993, que o material apresenta potencial para utilização em ambientes internos, como revestimento superficial de residências, construções agrícolas, setor moveleiro e decorativo. Recomenda-se a intervenção no processo de fabricação do painel, para melhorar as propriedades mecânicas e possibilitar o uso estrutural do material.

In this study, the potential use of residues of peanut husks was verified, in order to add value to these materials through the manufacture of panels of particleboards. For this procedure, it was used urea-formaldehyde resin and the panels were mechanical pressed at a temperature of 100 ºC. The quality of the panels was evaluated based on the prescriptions of the normative document ASTM D 1037:2006, through physical and mechanical tests of characteristics, such as: density, swelling in thickness, water absorption and static bending. The panels evaluated showed bulk density varying between 0,69 a 0,83 g cm-3, MOR and MOE between 4,37 - 5,34 MPa and 590 - 700 MPa respectively, for panels with and without preservative treatment. It is possible to claim, based in the normative document ANSI A208.1:1993, that the material presents a potential for use in internal areas as superficial covering of residential buildings, agricultural buildings, furniture and decorative sectors. Intervention in the board production process is recommended, in order to improve the mechanical properties of the material and enable its structural use.

The compaction rate, the relation between the density of the wood panel and the density of the wood used for producing the particles, is an indicator of the product's densification. Among the various types of wood panels, particleboards are widely employed in the lumber industry, mainly for the furniture production. This paper presents a study of the relation between the compaction rate and the properties of tensile strength perpendicular to surface, Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) obtained from a static bending test, thickness swelling and water absorption (2 and 24 hours). These properties were calculated according to the Brazilian ABNT, NBR 14810 standard. Particleboards were produced using the species Pinus elliotti and adhesive ureaformaldehyde. The relation was established by a multiple linear regression, and the most appropriate statistical models were determined. The estimated models indicate statistically significant effects of water absorption in 2 hours and MOR in the particleboards' compaction rate.