Eucalyptus grandis BARK TANNINS REATIVITY TO PRODUCE ADHESIVES

• Autor(a) principal: Carneiro, Angélica de Cássia O.
• Data de Publicação: 2015
• Outros Autores: Vital, Benedito Rocha, Pimenta, Alexandre Santos, Mori, Fábio Akira
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Cerne (Online)
• Texto Completo: https://cerne.ufla.br/site/index.php/CERNE/article/view/361
• topic: Tannins; adhesives; Eucalyptus grandis

The work objectived to study the reactivity of the tannins of the bark of Eucalyptus grandis to paraformaldehyde at different pH values, time of hydrolisis and sulphitezation and to produce tannics adhesives for wood. It was observed that the best gel-time was obtained with tannins sulphited at pH 3, with 3% of sulphite and time of reation of 90 minutes. Sulphited tannins in pH equal to 2 had the worst results, therefore, adesives with pH of formulations lower than 3 should not be used. The best tannic adhesive was that produced with tannins hydrolised and sulphited to which were added 5% of extender and 5% of filler. Adhesives produced with sulphited tannins presented the worst results.