Characterization of wood decay by rot fungi using colorimetry and infrared spectroscopy

Amostras de madeiras de marup\ue1 ( Simarouba amara ) e andiroba ( Carapa guianenis ) foram submetidas ao ataque dos fungos Trametes versicolor (podrid\ue3o branca) e Gloeophylum trabeum (podrid\ue3o parda). A colorimetria foi empregada para determinar as cores das madeiras antes e ap\uf3s o ataque dos fungos. Para acompanhar a varia\ue7\ue3o do teor dos compostos qu\uedmicos foi utilizada a t\ue9cnica de espectroscopia de reflet\ue2ncia difusa no infravermelho m\ue9dio. Ambas as esp\ue9cies foram consideradas n\ue3o resistentes ao fungo de podrid\ue3o branca. Para o fungo de podrid\ue3o parda, a andiroba foi considerada resistente e o marup\ue1 n\ue3o resistente. Ambas as esp\ue9cies de madeira se apresentaram mais escuras ap\uf3s o ataque do fungo Gloeophyllum trabeum. J\ue1 o ataque do fungo Trametes versicolor causou clareamento na madeira da andiroba e escureceu ligeiramente o marup\ue1. Os resultados da an\ue1lise dos espectros de infravermelho mostraram que em ambas as esp\ue9cies de madeira houve redu\ue7\ue3o na intensidade das bandas de celulose, hemiceluloses e lignina ap\uf3s o ataque do Trametes versicolor, e redu\ue7\ue3o somente na intensidade da banda de celulose ap\uf3s o ataque do Gloeophyllum trabeum.Wood samples of marup\ue1 ( Simarouba amara ) and andiroba ( Carapa guianenis ) were submitted to Trametes versicolor (white rot) and Gloeophylum trabeum (brown rot) fungi attack. Colorimetry was used to determine the color of the wood before and after wood decaying fungi. To evaluate the changes in chemical compounds levels in the wood samples, the diffuse reflectance medium infrared spectroscopy was used. Both wood were non resistant against white rot fungus, while with brown rot attack andiroba was resistant and marup\ue1 was not. After Gloeophyllum trabeum attack both woods changed to a darken color, and after Trametes versicolor attack andiroba changed to a lighter color and marup\ue1 darkened slightly, The analysis showed a reduction in the peak intensity of cellulose, hemicellulose and lignin, for both species, after Trametes versicolor attack and a reduction in the peak intensity of cellulose after Gloeophyllum trabeum attack

Effect of ultraviolet radiation on the color of freij\uf3 wood ( Cordia goeldiana Huber) after application of finishing products

A radia\ue7\ue3o ultravioleta \ue9 considerada a mais prejudicial ao uso da madeira afetando suas propriedades, sobretudo a sua cor superficial. A aplica\ue7\ue3o de produtos de acabamentos, como os vernizes, os stains, as tintas, podem minimizar a atua\ue7\ue3o dessa radia\ue7\ue3o. Este trabalho teve como objetivo avaliar o efeito da radia\ue7\ue3o ultravioleta, relativo ao envelhecimento artificial acelerado, na colora\ue7\ue3o da madeira de freij\uf3 ( Cordia goeldiana Huber) tratadas com polisten e seladora (nitrocelulose), com monitoramento por meio de um espectrocolorimetrico. As amostras da madeira foram submetidas a ciclos de radia\ue7\ue3o ultravioleta em um reator fotoqu\uedmico, em tempos de 84 e 168 horas. Os par\ue2metros colorim\ue9tricos (L*, a*, b* C e h*) foram medidos antes a ap\uf3s os tratamentos. O tratamento com polisten foi o que ofereceu maior prote\ue7\ue3o \ue0s radia\ue7\uf5es ultravioletas, dando uma maior estabilidade aos par\ue2metros. O tratamento com seladora foi o que apresentou uma maior altera\ue7\ue3o da cor ap\uf3s a simula\ue7\ue3o de envelhecimento no reator fotoqu\uedmico.Ultraviolet radiation is considered the most damaging radiation to wood, affecting its properties and especially its color. The application of finishing products such as varnishes, stains and inks can minimize the action of this radiation. This study aimed to evaluate the effect of ultraviolet radiation, through artificially accelerated aging, on the color of freij\uf3 wood ( Cordia goeldiana Huber) treated with \u201cpolisten\u201d and sealer (nitrocellulose), by means of spectrocolorimetric tracking. The samples of wood were subjected to cycles of ultraviolet radiation in a photochemical reactor for 84 and 168 hours. The colorimetric parameters (L*, a*, b*, C, h*) were measured before and after the treatments. The treatment with \u201cpolisten\u201d offered greater protection against ultraviolet radiation, yielding greater stability to the parameters. The treatment with sealer led to a greater change in color after the simulation of aging in the photochemical reactor

TECHNOLOGICAL CHARACTERISTICS OF THE WOOD OF Eucalyptus grandis W.Hill ex Maiden AND Eucalyptus cloeziana F. Muell, AS A SUPPLY FOR THE FURNITURE INDUSTRY

Este trabalho se desenvolveu na Universidade de Bras\uedlia e no Laborat\uf3rio de Produtos Florestais (IBAMA), Bras\uedlia, DF. Foram estudadas duas esp\ue9cies de eucalipto ( Eucalyptus grandis W.Hill ex Maiden e Eucalyptus cloeziana ) para confec\ue7\ue3o de pe\ue7as mobili\ue1rias. A madeira de E. grandis apresenta propriedades f\uedsicas (densidade e retratibilidade) e mec\ue2nicas (flex\ue3o est\ue1tica e dureza) extremamente positivas para a ind\ufastria moveleira, sendo complementado por seu bom desempenho perante equipamentos e m\ue1quinas, al\ue9m de receber bem produtos de acabamento. A cor da madeira e o seu desenho levaram os consumidores a mostrar \uf3tima aceita\ue7\ue3o do m\uf3vel fabricado com a esp\ue9cie. A madeira de Eucalyptus cloeziana, apesar de mostrar propriedades f\uedsicas e mec\ue2nicas com valores mais elevados que as do Eucalyptus grandis W.Hill ex Maiden, apresenta caracter\uedsticas desejadas para ind\ufastria moveleira. A sua colora\ue7\ue3o cinza oliva \ue9 uma op\ue7\ue3o para o consumidor. Alguns cuidados especiais com essa esp\ue9cie dever\ue3o ser tomados durante opera\ue7\uf5es com m\ue1quinas e equipamentos. Os valores da propriedade dureza apresentados por essa madeira a indicam para fabrica\ue7\ue3o de piso.This work was carried out at Universidade de Bras\uedlia at the Wood Products of Forestry Laboratory (IBAMA, Bras\uedlia, DF, Brazil). Two species of eucalypt wood ( Eucalyptus grandis W.Hill ex Maidenand Eucalyptus cloeziana ) were studied to supply the furniture making industry. The wood of Eucalyptus grandis W.Hill ex Maiden shows physical properties (density and retractibility) and mechanical properties (static bending and hardness) very suitable for the industry of wood furniture. Such characteristics are complemented by its excellent behaviour in machining and also good finishing with varnishes. The colour and patterns the wood bring to the consumers a good feeling as well as for the furnitures built with such a species. The wood of Eucalyptus cloeziana, in spite of its mechanical and physical properties higher than those of Eucalyptus grandis W.Hill ex Maiden, presents good characteristics for the manufacture of furniture. Its grey-olive colouring is consistent with a good choice and taste for the consumers. However, some precaution must be observed during the machining of the wood. This wood\u2019s hardness makes it suitable for parquetry

COLORIMETRY CHARACTERIZATION OF THE WOOD OF MUIRAPIRANGA ( Brosimum rubescens Taub.) AND OF RUBBER TREE (Hevea brasiliensis, clone Tjir 16 M\ufcll Arg.) AIMING AT INSIDE USE

Ainda que recente, a t\ue9cnica para a determina\ue7\ue3o da cor da madeira por meio da colorimetria quantitativa mostra-se precisa e eficaz. O sistema CIELAB 1976, que determina os par\ue2metros colorim\ue9tricos L*, a*, b*, C e h*, mostrou-se eficiente para a determina\ue7\ue3o da cor das madeiras de muirapiranga (Brosimum rubescens) e de seringueira (Hevea brasiliensis, clone Tjir 16). A madeira de muirapiranga \ue9 de cor vermelha-amarronzada (L* de 42,39), tendo o pigmento vermelho (a* de 22,02) como determinante, apesar de o pigmento amarelo (b*) ter influ\ueancia significativa na defini\ue7\ue3o de sua cor. A madeira de seringueira apresenta cor amarela (L* de 77,55), fortemente influenciada pelo pigmento amarelo (b* de 19,61). Considerando o par\ue2metro cor, ambas as madeiras apresentam potenciais para serem utilizadas em interiores.Although recent, the technique for the determination of wood color through the quantitative colorimetry seems to be efficient. The CIELAB 1976 system cuhich determines the L *, a *, b *, C and h * colorimetric parameters, seemed to be efficient for the determination of the color of the muirapiranga wood (Brosimum rubescens) and of rubbertree (Hevea brasiliensis, clone Tjir 16). The muirapiranga wood is of brownish red color (L * of 42,39), having the red pigment (a * out of 22,02) as determinant, although the yellow pigment (b *) has significant influences on the definition of its color. The rubbertree wood presents yellow color (L * of 77,55), strongly influenced by the yellow pigment (b * of 19,61). Considering the color as a parameter, both wood presents potentials for use