Utilization of tannin adhesive in the production of particleboards and OSB. / Utilização de adesivos à base de taninos na produção de painéis de madeira aglomerada e OSB.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The general objective of this work was to evaluate the possibility of use of tannin from wattle (acacia) and its mixtures with tannin of barks from E. pellita and with adhesive Phenol- Formaldehyde for glueing of particleboards and OSB. This work was divided in three chapters. In the first one, tannins from Eucalyptus pellita bark had been gotten in different processes of extration. The properties of the tannin were evaluated as also the properties of wattle tannin and the adhesive Phenol-Formaldehyde (PF). In the second chapter, particleboards were produced through two pressing times (6 and 9 minutes). In the third chapter the production of OSB panels was evaluated with pressing time of 9 minutes. The barks of Eucalyptus pellita were extracted under reflux for 2 hours, with distilled water and with distilled water under addition of different chemical products. The extractive content (%), the condensed tannin content (stiasny index) and reactivity, the tannin yields (%), the no-tannin yields (%) and pH of extracts were determinated. The treatment that had the best yield of tannin was chosen as reference for the extraction of tannin. The tannin extracted had been used for production of tannin solutions 45%. Tannin solutions of the wattle (acacia) (45%), of the bark from E. pellita (45%) and from wattle (acacia): bark of E. pellita in the ratio of 90:10, 80:20 and 70:30 were prepared and their properties as the viscosity, gel time and pH were determineted. The adhesive Phenol-Formaldehyde (PF) and their modifications with wattle tannin (90:10, 80:20 and 70:30) was evaluated second the glueing properties. Particleboards and OSB panels were produced with particles of Pinus caribaea var. caribaea, using adhesive PF, adhesive Taninn-Formaldehyde (TF) of wattle (acacia), adhesive PF modified with 10% and 20% of tannins of wattle (acacia) and adhesive TF of wattle (acacia) with 10% and % of tannin from barks of the Eucalyptus pellita. The adhesive content was 10%, based on dry weight of particles, and the density of particleboards and OSB was 0,70 g/cm3. The following physical and mechanical properties of particleboards and OSB were evaluated: density, thickness and water absorption after 2 and 24 hours of immersion in water, static bending (modulus of rupture - MOR and modulus of elasticity - MOE) and tensile strenght perpendicular to surface (internal bond). The particleboards presented good dimensional stability and the modulus of rupture and internal bond was presented also average values above the minimum recomended by CS 236-66 norm. The results showed also that it is possible to produce particleboards with tannin adhesive of wattle (acacia) and tannin of acacia modified with 10% and 20% of tannin of bark of E. pellita. Results of the dimensional stability and mechanical properties of the OSB panels were in according to the type OSB/1 in attention to the EN 300 norm.

ASSUNTO(S)

colagem polyphenols resin resina casca recursos florestais e engenharia florestal wattle, eucalyptus glueing polifenóis bark eucalipto acácia negra

ACESSO AO ARTIGO

Documentos Relacionados