Avaliação da qualidade de juntas coladas da madeira de clones de Eucalyptus

Abstract

With the aim to evaluate the quality of bonding as to shearing resistance and percentage of failure on wood and correlate the anatomic characteristics and the content of total extractive content of each ; with bonding quality, bonding junctions of the wood of four clones Eucalyptus (parent species, E. urophylla e E. camaldulensis) of the Vazante region (MG) with three commercial adhesives (polyvinyl acetate, urea-formaldehyde and resorcinol) utilized according to the manufactures´ recommendations have been manufactured. The tests were conducted according to the ASTM D 905-98 (1998) Norm. For data analysis, the completely randomized design model was utilized and Tukey test for comparison of means. For shearing resistance on the adhesive line as related with the clone, the best performance of clone 26 was observed, the sort of adhesives and the adhesive x clone interaction were not significant. But the percentage of failure on wood presented significance at the level of 5% of probability for clone, pointing out clone 39 as the best, and for sticker, indicating the adhesive based on urea-formaldehyde as the one of best performance. Measurements as for length and breadth of fibers, cell wall thickness, height, breadth and frequency of rays, diameter and frequency of vessels and total extractive content were performed. The anatomic characteristics concerning frequency and diameter of conducting vessels and radial parenchyma and total extractives showed correlation with the quality of bonding of the wood of clones 26 and 39 by Pearson correlation (t test at 1 and 5% of probability) as to shearing resistance on the adhesive line and percentage of failure on wood.