Efeito da adição de carga e extensor nas propriedades do adesivo uréia-formaldeído e dos compensados de pinus e paricá / Effect of the addition of filler and extender on urea- formaldehyde adhesives and on pinus and paricá plywood properties

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The objective of this study was to evaluate the effect of the addition of extender (wheat flour) and filler (babaçu flour) on urea-formaldehyde adhesive properties and on quality of plywood manufactured with Pinus elliottii e Schizolobium amazonicum (paricá) veneers. Ninety six three-layer plywood were produced, being forty eight produced with Pinus elliottii wood and 48 with Schizolobium amazonicum wood, with 3 replicates. Adhesive amout of 250g/m were used to glue the plywood venners. Also, 0, 10, 20 and 30 parts of extender and/or filler per weight of the adhesive were added. Ammonium sulfate was used as catalyst, in the proportion of 1.5% on dry weight of solid content. The following properties of the adhesive were determined: viscosity, solid content, gel time, working life, density, pH and the kinetic parameters obtained by the technique of differential scanning calorimetry (DSC). The plywood physical and mechanical properties were determined in accordance with this Standards: ABNT NBR 9486/86 (modified), NRB 9535/86 (modified), NBR ISO 12466- 1:2006, NBR 9533/86 and ASTM D1084-97. The results showed that S. amazonicum plywood presented lower values of thickness swelling and average values of shear strength (wet and dry) above those found for the P. elliottii panels. The presence of additives in the formulation of the adhesive changes the physicochemical properties of the reactions of curing of the adhesives. The babaçu flour, considered, initially, as an inert material, showed similar properties to wheat flour. It contributed to increase modulus of elasticity of the P. elliottii panels. In general, the production of Schizolobium amazonicum and Pinus elliottii plywood is feasible with the addition of up to 30% of wheat and/or babaçu flour on urea-formaldehyde adhesive.

ASSUNTO(S)

urea-formaldehyde extender paricá carga uréia-formaldeído paricá plywood extensor tecnologia e utilizacao de produtos florestais load

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