Study of the bonding of Eucalyptus grandis W. Hill ex Maiden thermosetting adhesive resorcinol-formaldehyde / Estudo do comportamento da colagem da madeira de Eucalyptus grandis W. Hill ex Maiden com adesivo termoendurecedor resorcinol-formaldeído

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The study aimed to evaluate the resistance of bonded joints with thermosetting adhesive resorcinol-formaldehyde from three radial positions and three positions of the longitudinal log of Eucalyptus grandis W. Hill ex Maiden (Myrtaceae), 18 old years, to correlate the basic density of wood anatomical characteristics and the total extractives content of the species concerned with the quality of bonding, the interface view wood - adhesive, measure the thickness of the line glue and correlate this variable with the quality of glue joints produced. The bonded joints were prepared in accordance with ASTM D 2339 -98. For data analysis, we used the model of a completely randomized and Scott-Knott test at 95% probability for the comparison of means. There was a trend in the average values of the density in the pith-bark and longitudinally no significant variation. The higher average values of shear strength of joints were obtained from the positions close to the shell and the base of the log. A lower percentage of wood failure in joints was obtained from the positions near the base and the bark of the log. Histological slides were prepared for anatomical study. The determination of the total extractives content and the preparation of bonded joints were held in accordance with the standards ABTCP M 3 / 69 ABTCP (1974) and ASTM D 2339 -98, respectively. We used the correlation coefficient of Pearson, the 1% probability by t test, analysis of the data. It was found that there was no correlation between resistances to shear tests with the following characteristics: vessel diameter, wall width, length and width of the fiber, the width of the radius and total extractives content. And the percentage of wood failure, there was a correlation between this with the following characteristics: the frequency of vessels, thickness of the heat of fiber, and high frequency of lightning. To visualize the wood-adhesive interface withdrew two bonded joints of each region (radial and longitudinal) of the log. It was possible to characterize the line of glue produced by the connection between the adhesive and wood. There was penetration of the adhesive in vessels, fibers and rays, and the perforation plates there was no penetration of the adhesive. The thickness of glue line main ranged in a radial and longitudinal.

ASSUNTO(S)

radial bonded joints longitudinal eucalyptus longitudinal position juntas coladas tratamento da madeira posição radial eucalipto

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