Extração e caracterização de taninos de cascas de eucalipto cultivado em ambientes contrastantes

• Ano de defesa: 2018
• Autor(a) principal: Chaves, Izabella Luzia Silva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Ciências Florestais; Centro de Ciências Agrárias e Engenharias; UFES; Programa de Pós-Graduação em Ciências Florestais
• Palavras-chave em Português: Polyphenol; Natural adhesives; Water deficit; Polifenóis; Eucalyptus urophylla x E. grandis; Adesivos naturais; Déficit hídrico; Eucalipto; Eucalyptus grandis; Recursos Florestais e Engenharia Florestal; 630
• Link de acesso: http://repositorio.ufes.br/handle/10/7699

Due to the demand for wood, Brazil has a large production of eucalyptus for use in industries and this generates quantities of bark that are not normally used, regardless of the planting site. The objective of this work was to identify the influence of the environment on the chemical composition of the bark of eucalyptus clones, on the production of phenolic compounds, and to evaluate the potential use of these compounds in the manufacture of adhesives based on tannins. For this, pH, total extractive content, lignin and ash content of the bark of trees from two environments with different mean precipitation (A-Nova Almeida - ES and B - Montezuma - MG) were determined. The tannins (extracted in water under reflux and with addition of 5% of sodium sulfite) were evaluated for the total extractive content, the number of Stiasny, the ultraviolet reactivity, the tannin and non tannin content. After the production of the adhesive in composition of 1:1 (tannic extract: distilled water) the technological properties of the adhesive (viscosity, solids content, pH, gel time, density and solubility) were evaluated. In the chemical characterization of the bark, the environment A showed the highest averages for the evaluated properties. In general, clone 5 excelled in all properties and followed for autoclaving with a liquor:bark ratio of 15:1 and addition of 5% sodium sulfite. For the adhesive obtained the environment B presented the best results for viscosity, density and pH and the A for the time of gel formation. The growth environment of the trees influenced the yield of tannins, and the one of greater precipitation presented the best results. The adhesive produced from the barks of the B environment presented desirable characteristics regarding the quality of the adhesives although it was not the environment with the highest yield in tannins.