Impactos de modificações físico-químicas das fibras de eucalipto na qualidade da polpa branqueada

• Autor(a) principal: Jardim, Carolina Marangon
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/546
• topic: Eucalipto; Polpa; Papel; Modificações de fibras; Peróxido de hidrogênio; Hemicelulose; Carboximetil celulose; Plasma; Eucalyptus; Pulp; Paper; Modifications to fibers; Hydrogen peroxide; Hemicellulose; Carboxymethylcellulose; Plasma; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS

Globally, pulp and paper industry has undergoing transformations due to changes in the industrial acceleration scenario linked to the rapid emergence of technology and demand for improvements in the final product quality. When improvements in paper properties are required modification of eucalyptus fiber is a very attractive alternative, which may contribute to the prosperity of the industry sector. In this context, the present study aims to discuss changes in physical-chemical and structural properties of eucalyptus fiber with the specific purpose of producing papers with improved quality. To this end, changes were addressed by oxidative treatment (hydrogen peroxide), polymers adsorption (xylan and carboxymethylcellulose), and atmospheric plasma technology, using dielectric barrier discharge (DBD). In general, the treatments applied to pulp (oxidative and polymers adsorption) resulted in changes of the functional groups profile of fibrous material, being reported an increase in the range of 10-30% in the content of carboxylic groups, depending on dosage and type of treatment applied. In addition, the pulps presented development of absorption properties, marked by increased rates of water retention value and reduced phenomenon of fiber hornification. Moreover, increase in refinability was observed, with significant reduction in energy demand during this stage. Improvements on physical-mechanical and optical properties were found and are, remarkably, dependent on the development of inter-fibers linkages due to the treatments. Atmospheric plasma treatment, by DBD, when applied to the paper formed from bleached eucalyptus pulp was effective in increasing the wet tensile properties. Moreover, under specific instrumentation conditions, paper dried resistance might also be increased. The specific charge density of the fibrous material remained unchanged when DBD treatment was applied, being the rising in strength assigned to the development of fiber cross-linking. Moisture absorption/retention properties have been added by controlling the dosage of DBD treatment where image analysis obtained by atomic force microscopy demonstrated fiber surface modification, especially observation of surface regularization. Conclusively, the treatments, when applied to the paper industry, paying attention to their inherent peculiarities, can produce products with differentiated quality aspects that are higher than the currently produced.