Abstract: This study aimed to investigate the effect of thermal modification and nano-zinc oxide (nano-ZnO) particle impregnation on the deterioration of Caribbean pine wood under field conditions. Samples were thermally-modified at various temperature levels (control, 180 °C, 200 °C, and 220 °C). Nano-ZnO impregnation was done with an aqueous solution at 1,5 % in an autoclave under two-steps of pressure and vacuum. Unmodified and thermally-modified, non-impregnated and nano-ZnO impregnated samples were exposed to deterioration for five months in field tests. A deterioration index was used to evaluate the health condition of the samples. The mass loss and occurrence of termite tunnels in percentage were also determined. The nano-ZnO impregnation improved the resistance of unmodified wood to field-deterioration. The thermal modification at 180oC, and 200ºC increased the wood deterioration and nano-ZnO impregnation did not improve their resistance. Unmodified and 220 ºC modified samples had a lower mass loss by xylophages than other thermal treatments regardless of the nanoparticle impregnation. The nano-ZnO impregnation decreases the occurrence of termite tunnels in unmodified, 200 ºC and 220 ºC-modified samples.

ABSTRACT Seed coat plays an important role in the embryo protection and seed germination. This study aimed to characterize the anatomical structure, histochemical and physicochemical aspects of the seed coat of Araucaria angustifolia Kuntze. Light and scanning microscopy usual procedures, and histochemical tests were used to describe and characterize seed layers, as well as to determine their extractive contents. Functional groups of the integument coat layers were observed by Fourier transformed infrared spectroscopy. Color analyses were performed in CIE 1976 L*a*b* color space. Wettability of the layers was evaluated by contact angle analysis. The anatomical and chemical features observed in the seed layers include the rucose cuticle and the presence of many layers of sclerenchyma in the mesotesta; and the chromaticity due to extractive content and phenolic compounds in the endotesta. The wettability varied among layers according to their structure. These features information contribute to a better understanding on the services provided by the Araucaria angustifolia seed coat.

Abstract: During the thermal modification of the wood there is a decreasing gradient of temperature from the surface to its interior, therefore, the most severe chemical modifications occur on the surface. These chemical modifications directly affect the quality and durability of adhesives and coating. Therefore, this study investigated the chemical modification of the surface of thermally-modified teak juvenile wood. Heartwood and sapwood samples were treated at 180 and 200ºC. Chemical analyses were performed by Fourier transform infrared spectroscopy (FTIR) in reflectance mode with a microscope. Spectra showed an increase in cellulose crystallinity and a decrease in relative contents of hydroxyl groups, lignin and extractives - especially quinones, waxes and oils - following thermal modification. Extractive content of the heartwood was relatively higher than that of sapwood. Heartwood was more susceptible to thermal degradation than sapwood.

Abstract: This study investigated the effect of the heat treatment on the wettability of the surface of juvenile teak (Tectona grandis) wood assessed by drop shape analyzer. Heartwood and sapwood samples were heat-treated at 180 and 200ºC. Contact angle measurements were done every 5 s for 120 s using a KRÜSS DSA100. Heartwood had lower wettability than sapwood. Heat-treatment decreased the surface wettability of both heartwood and sapwood, especially in the wood treated at 200ºC. Heartwood had lower wettability than sapwood, even after heat treatment.

RESUMO Este trabalho teve por objetivo avaliar as propriedades tecnológicas de chapas aglomeradas fabricadas com partículas de Acacia mangium e adesivo ureia-formaldeído (UF) mediante adição de tanino comercial de Acacia mearnsii na forma de pó a suas partículas. As chapas foram fabricadas sob diferentes razões de compactação e o efeito destas nas propriedades tecnológicas foi avaliado. Utilizou-se o delineamento inteiramente casualizado no esquema fatorial 4 x 4, sendo quatro porcentagens de adição de tanino em pó às partículas (0, 10, 20 e 30%), após aplicação do adesivo ureia-formaldeído e quatro razões de compactação nominais - 1,39, 1,55, 1,73, e 2,00. Foi utilizado o ciclo de prensagem com pressão de 3,92 MPa e temperatura de 140ºC por 8 minutos. A adição de tanino em pó às partículas encoladas com ureia-formaldeído proporcionou melhoras em algumas propriedades físicas e mecânicas. Os resultados indicam a adição do tanino em pó como alternativa viável de utilização em chapas de partículas, sem necessidade de sua diluição.

ABSTRACT This work aimed to evaluate the technological properties of particleboards manufactured with particles of Acacia mangium and urea-formaldehyde adhesive by addition of powder form commercial tannin of Acacia mearnsii to their particles. The particleboards manufactured under different compaction ratio and the effect of these in the properties of the boards evaluated. It used a completely randomized design in the factorial outline 4 x 4 as follows: four percentages of substitution of powder form tannin to the adhesive urea-formaldehyde - 0, 10, 20 and 30%; and four nominal compaction ratios: 1.39, 1.55, 1.73, and 2.00. The pressing cycle used was 3.92 specific pressure with temperature of 140ºC by 8 minutes. The addition of powder tannin to particles with urea-formaldehyde provided some improvements in the physical and mechanical properties. The results indicate that the addition of tannin powder is a viable alternative of use in particleboards, with no need for dilution.

RESUMO O objetivo deste estudo foi avaliar o efeito da densidade e do teor de extrativos na variação da cor da madeira de teca (Tectona grandis L. f.) proveniente de plantios de diferentes espaçamentos. As análises colorimétricas foram realizadas nas faces radial e tangencial das madeiras de cerne e alburno com o espectrofotômetro CM 2600d no espaço de cor L*a*b*. A densidade e o teor de extrativos foram determinados segundo as normas ASTM D2395 e ASTM D1105. A madeira do maior espaçamento de plantio apresentou maior densidade e maior teor de extrativos. Na seção radial, as madeiras de cerne de maior densidade apresentaram mais pigmento amarelo, enquanto que na seção tangencial elas são mais escuras e apresentam menos pigmento amarelo. As madeiras de alburno de maior densidade são mais escuras e apresentam mais pigmento vermelho em ambas as seções. As madeiras mais escuras e com mais pigmento vermelho apresentaram um maior teor de extrativos.

ABSTRACT The objective of this study was to evaluate the effect of density and extractive content on color variation of teak (Tectona grandis L. f.) wood from plantation of different tree-spacing. Color analyses were performed on radial and tangential sections of heartwood and sapwood by using a CM 2600d spectrophotometer on the L*a*b* color space. Density and extractive content were determined following the ASTM D2395 and ASTM D1105 standards. The wood from larger tree-spacing had higher density and extractive content. In the radial section, denser heartwoods had more yellow hue, while in tangential section, they are darker and had less yellow hue. Denser sapwoods are darker and had more red hue in both sections. Darker woods and with more red hue presented higher extractive content.

O objetivo deste estudo foi estudar a qualidade da superfície usinada da madeira de Eucalyptus grandis, submetida ao processo de tratamento térmico. As operações de usinagens realizadas nas tábuas obtidas a partir do processamento de mecânico de seis árvores foram: desempeno, desengrosso, rasgo na furadeira horizontal, furação, furação para dobradiça e lixamento. Foram selecionadas 208 tábuas de 125 x 25 x 500 mm, sendo 104 não tratadas e 104 tratadas termicamente a uma temperatura final de 190ºC. A avaliação da superfície foi feita de acordo com a norma ASTM D-1666/87. O resultado mostrou que a madeira de Eucalyptus grandis apresenta um bom comportamento durante os testes de usinagem, obtendo notas 1 e 2 (excelente e bom), exceto para os testes de furação para a dobradiça no furo passante e furação com broca de 12, 8 e 6 mm, pois alcançaram notas entre 2 e 4 (bom, regular e ruim). O tratamento térmico diminuiu a quantidade de defeitos nas amostras usinadas, com exceção para o defeito grã arrancada, em algumas operações de usinagem.

The objective of this study was to study the machined surface quality of Eucalyptus grandis wood submitted to heat treatment. The machining operations realized on the boards obtained from the processing of six trees were: planing, thicknessing, tear in horizontal drilling, drilling, drilling hinge and sanding. 208 boards of 125 x 25 x 500 mm were selected, with 104 untreated and 104 heat-treated boards at maximum temperature of 190ºC. The evaluation of the surface was performed according to ASTM D-1666/87 standard. The result showed that the Eucalyptus grandis wood presents a good behavior during the machining tests, obtaining notes 1 and 2 (excellent and good), except for drilling hinge test in the bolt hole and drilling with 12, 8, 6 mm, reaching notes between 2 and 4 (good, regular and bad). The heat treatment reduced the number of defects on the machined samples, except for torn grain in some machining operations.

O objetivo deste estudo foi determinar o efeito de tratamentos termorretificadores nas propriedades físicas (densidade e teor de umidade) da madeira de teca (Tectona grandis L. f.), proveniente de plantios de diferentes espaçamentos. Amostras de madeira de cerne e alburno foram termorretificadas a 180ºC e 200ºC durante 2 horas e 30 minutos. A termorretificação afetou mais a densidade do cerne do que a densidade do alburno. As madeiras de cerne e alburno apresentaram uma redução média de 52% no teor de umidade de equilíbrio, após a termorretificação. O espaçamento entre árvores também afetou as propriedades físicas da madeira após a termorretificação.

The objective of this study was to determine the effect of heat treatments on the physical properties (density and moisture content) of teak (Tectona grandis L. f.) wood from plantations of different spacings. Heartwood and sapwood samples were heat treated at 180 ºC and 200 ºC for 2 hours and 30 minutes. Heat treatment produced greater effect on heartwood density compared with sapwood density. Heartwood and sapwood presented an average reduction of 52% in equilibrium moisture content after heat treatment. Tree spacing also affected the physical properties of wood after heat treatment.

O objetivo deste estudo foi determinar o efeito do tratamento térmico na alteração da cor da madeira de teca (Tectona grandis L. f.), proveniente de plantios de diferentes espaçamentos. Amostras de madeira de cerne e de alburno foram tratadas a 180 e 200ºC durante 2h30min. As análises colorimétricas foram realizadas com o auxílio do espectrofotômetro CM 2600d no sistema CIE L*a*b*. Após o tratamento, a madeira teve perda de luminosidade, tornado-se mais escura, o que se mostrou mais acentuado para o tratamento a 200ºC. As madeiras de cerne e alburno apresentaram comportamentos diferentes para as coordenadas a* e b*, dependendo do espaçamento, antes e após o tratamento. Ocorreu uma maior formação de pigmento vermelho e perda de pigmento amarelo nas madeiras de cerne e alburno tratadas a 200ºC.

The purpose of this study was to determine the effect of heat treatment on color change of teak wood (Tectona grandis L. f.) from plantations of different spacings. Heartwood and sapwood samples were heat treated at 180 and 200ºC for 2.5 hours. Colorimetric analyses were performed using a CM 2600d spectrophotometer in the CIE L*a*b* system. After heat treatment, the wood presented loss of light, becoming darker, which was more pronounced for the treatment at 200ºC. Heartwood and sapwood showed different behaviors for the a* and b* coordinates, depending on the spacing, before and after heat treatments. There was an increase on red hue and a decrease on yellow hue of heartwood and sapwood treated at 200ºC.

Conduziu-se, este estudo, com os objetivos de caracterizar a cor da madeira de Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, Eucalyptus pellita F. Muell, Eucalyptus paniculata Sm. e Eucalyptus grandis Hill ex Maiden; e determinar sua correlação com a densidade da madeira, visando a avaliar o potencial da colorimetria como uma ferramenta para a identificação e qualificação da madeira. As análises colorimétricas foram realizadas segundo o sistema CIE L*a*b* com o auxílio do espectrofotômetro portátil CM 2600d da Konica Minolta. Os resultados indicaram diferenças significativas entre as densidades das espécies estudadas, sendo a madeira de Eucalyptus paniculata a mais densa e a madeira de Eucalyptus grandis a menos densa. As análises de correlação entre acor e a densidade monstraram que as madeiras mais densas, para as espécies do gênero Eucalyptus estudadas, são mais escuras (menor L*) e apresentam mais pigmento vermelho (a*) e amarelo (b*). Entretanto, o comportamento foi diferente para o Corymbia citriodora, cuja madeira apresentou alta densidade, cor clara e pouco pigmento vermelho, indicando que a combinação das variáveis colorimétricas e da densidade apresenta potencial para segregar a espécie Corymbia citriodora das demais espécies de Eucalyptus estudadas. As madeiras mais densas de Eucalyptus pellita são mais escuras na seção radial, enquanto que as madeiras de Eucalyptus paniculata apresentaram mais pigmento amarelo na seção tangencial. Cada espécie apresentou uma coloração específica, dada pelas variáveis colorimétricas, mostrando o potencial da colorimetria na identificação de madeiras

The objectives of this study were to characterize the wood color of Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, Eucalyptus pellita F. Muell, Eucalyptus paniculata Sm. and Eucalyptus grandis Hill ex Maiden; and to determine its correlationship with wood density in order to evaluate the potential of colorimetry as a tool for identification and qualification of wood. Color analysis were performed on the CIE L*a*b* system by using the CM 2600d spectrophotometer from Konica Minolta. Theresults indicated significant differences between wood densities of all species. Eucalyptus paniculata wood presented the highest density while Eucalyptus grandis wood presented the lowest density. Correlation analysis between color and density showed that the denser woods, considering the species from the Eucalyptus genus studied, are darker (lower L*) and present redder (a*) and more yellow (b*) hues. However, the behavior was different for Corymbia citriodora, whose wood had high density, light color and little red hue, indicating that color variables and density combination has potential to segregate the Corymbia citriodora species from other Eucalyptus species studied. The denser woods of Eucalyptus pellita are darker in the radial section, while woods of Eucalyptus paniculata presented more yellow hue (b*) in the tangential section. Each species presented a specific color, given by colorimetric variables, showing the potential of colorimetry for wood identification.

This study investigated the color stability in a heat treatment of teak wood (Tectona grandis) exposed to ultraviolet radiation under accelerated aging conditions. Nine trees from three different spacing levels were used. Samples of 150 mm x 75 mm x 20 mm were prepared and divided into two groups: heartwood and sapwood. Two levels of heat treatment (180 and 200°C) were used. The color was measured every 42 hours with a portable spectrophotometer using the CIE-Lab system. Accelerated aging was performed in a QUV/Spray chamber. The total cycle of exposure to ultraviolet radiation was of 168 hours at 340 nm. Tree planting spacing had no effect on color change after ultraviolet radiation. Untreated sapwood had greater color change than untreated heartwood. However, after heat treatment, sapwood showed high color stability, especially at a temperature of 180°C.

Neste estudo, objetivou-se determinar a modificação da cor original da madeira de Eucalyptus grandis Hill ex. Maiden após a termorretificação. Amostras de madeira foram termorretificadas sob diferentes condições de temperatura (180, 200, 215 e 230ºC) e tempo (15 minutos, 2 e 4 horas). As análises colorimétricas foram realizadas por meio do sistema CIE L*a*b* com o auxílio do espectrofotômetro Color Eye XTH-X-Rite 200d. Todos os tratamentos termorretificadores causaram uma alteração na cor original da madeira. As madeiras termorretificadas apresentaram menores valores de L* (luminosidade), quando comparadas à madeira não tratada (controle), caracterizando o escurecimento da madeira, principalmente para as condições mais severas de temperatura e tempo. As coordenadas cromáticas a* e b* apresentaram comportamentos diferentes, dependendo da combinação temperatura-tempo. A modificação da cor original da madeira possibilitou a criação de novos padrões de cor, podendo agregar maior valor à madeira estudada.

The objective of this study was to determine the modification of original color of Eucalyptus grandis Hill ex. Maiden wood after heat-treatment. Wood samples were heat-treated under different temperatures (180, 200, 215 and 230ºC) and time conditions (15 minutes, 2 and 4 hours). Color analysis were performed on the CIE L*a*b* system by using a Color Eye XTH-X-Rite 200d spectrophotometer. All heat treatments promoted an alteration of the original color of wood. Heat-treated woods presented lower L* (lightness) values than untreated wood (control), characterizing the wood darkness, mainly for more severe conditions of temperature and time. Chromatic coordinates (a* and b*) showed different behaviors depending on the temperature-time combination. The modification of the original color of the wood allowed the creation of new color patterns, which can add greater value to the studied wood.

O objetivo deste estudo foi avaliar a uniformidade da cor da madeira de teca (peças contendo cerne e alburno) após a aplicação de tratamentos termorretificadores. A madeira utilizada foi oriunda de árvores jovens (12 anos) provenientes de plantios de diferentes espaçamentos. Amostras de madeira com 150 x 75 x 20 mm foram termorretificadas a 180 e 200 ºC, durante 2h30. As análises colorimétricas foram realizadas com o auxílio de um espectrofotômetro no espaço CIE-L*a*b*. Os tratamentos termorretificadores proporcionaram maior uniformidade às peças de madeira de teca, sendo o tratamento a 200 ºC o mais efetivo, o que demonstra o potencial da termorretificação para a obtenção de produtos de madeira de maior valor agregado. A cor da madeira termorretificada a 180 ºC apresentou maior uniformidade no espaçamento menos adensado, entretanto ele não apresentou efeito na uniformidade da cor da madeira termorretificada a 200 ºC.

The purpose of this study was to evaluate the uniformity of the color of the teak wood (pieces containing heartwood and sapwood) after application of heat treatments. The wood was originated from young trees (12 years old) from plantations of different spacings. Wood samples of 150 x 75 x 20 mm were heat treated at 180 and 200 ºC during 2:30 hours. Color analysis were performed by using a spectrophotometer in the CIE-L*a*b* space. Heat treatments provided greater uniformity to the teak wood pieces and the treatment at 200 ºC was the most effective, which demonstrates the potential of heat treatment to obtain wood products of higher added value. The color of the wood heat-treated at 180 ºC had higher uniformity in the least dense spacing; however, it had no effect on color uniformity of the wood heat-treated at 200 ºC.

This study aimed to evaluate surface roughness of heat treated Eucalyptus grandis wood after peripheral planning and sanding performed in directions to the grain and against the grain. For machining tests, workpieces were collected from two different regions in the radial direction, as follows: internal, nearby the pit; external, nearby the bark. Heat treatment was carried out by heating samples at a maximum temperature of 190ºC, with total treatment duration of 390 minutes. Heat treated and control samples underwent peripheral planning and sanding tests. The quality of machined surfaces was assessed by means of roughness average (Ra) measurements across and along the grain orientation. Results indicated significant differences in surface roughness as a function of machining feed direction, sandpaper grit size, and heat treatment. Surface roughness has not shown any difference in the radial direction.

Neste estudo, objetivou-se determinar o efeito da densidade da madeira, do tipo de adesivo e da pressão de colagem na resistência ao cisalhamento de juntas coladas de quatorze espécies comerciais de madeira. As madeiras foram classificadas em três classes de densidade (Classe 1: menor que 0,55 g cm-3; Classe 2: entre 0,55 e 0,75 g cm-3; e Classe 3: maior que 0,75 g cm-3) e as juntas foram coladas com dois adesivos: acetato de polivinila (PVA) e ureia-formaldeído (UF), sob duas diferentes pressões de colagem: 6 e 12 kgf cm-2. As juntas coladas com o adesivo PVA apresentaram maior resistência ao cisalhamento que aquelas coladas com o adesivo UF. Quanto à porcentagem de falha na madeira, o adesivo PVA também obteve o melhor desempenho, entretanto, somente as madeiras das Classes 1 e 2 atingiram os valores requeridos pela norma ASTM 3110. As espécies de madeira da Classe 3, coladas com UF, não atingiram os valores de resistência da madeira sólida. A pressão de colagem de 12 kgf cm-2 foi mais eficiente para as madeiras da Classe 3, tanto para a resistência ao cisalhamento quanto para a porcentagem de falha na madeira.

The objective of this study was to determine the effect of wood density, adhesive type and gluing pressure on the shear strength of glued joints of fourteen commercial wood species. Wood pieces were classified in three density classes (Class 1: less than 0.55 g cm-3; Class 2: from 0.55 to 0.75 g cm-3; and Class 3: greater than 0.75 g cm-3) and joints bonded with two adhesives: polyvinyl acetate (PVA) and urea-formaldehyde (UF), under two different pressures: 6 and 12 kgf cm-2. Glued joints bonded with PVA adhesive presented higher shear strength than those bonded with UF adhesive. For percentage of wood failure, the PVA adhesive had the best performance, however, only Classes 1 and 2 reached the values required by ASTM 3110 standard. Glued joints from Class 3, bonded with UF adhesive, did not reach the values of solid wood. The gluing pressure of 12 kgf cm-2 was more efficient for Class 3, for both shear strength and percentage of wood failure.