Desenvolvimento de propriedades de papéis reciclados por tratamento ultrassônico e adição de xilanas

• Autor(a) principal: Manfredi, Mauro
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3041
• topic: Papéis; Reciclagem; Ultrasson; Xilanas; Hemiceluloses; Propriedades; Papers; Recycling; Ultrasound; Xylans; Hemicelluloses; Properties; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS

This study evaluates the potential of ultrasonic treatment and hemicelluloses addiction to develop mechanical properties of recycled papers. Initially a study was conducted which aimed to determine the better condition to performing the ultrasonic treatment. Were evaluated the effect of pH, pulp consistency and treatment time. Pulp consistency didn t affect the results. On the other hands, increasing pH and treatment time greater is the development of properties. After the optimization of ultrasonic treatment was performing a study to compare the effects of ultrasonification and the effects of refine in PFI. The ultrasonic treatment was efficient to develop the mechanical strength of paper. The properties were developed as a similar manner to that observed when pulp was refines in PFI, although less pronounced. The ultrasonic treatment acted mainly causing fibre external defibrillation. To the same bulk, the ultrasonification developed more the mechanical strength of the paper compared to refine in PFI. After, was performed a study where aimed increase the recycled paper quality by addiction of hemicelluloses to the pulp. The results showed that increasing the content of hemicelluloses the paper strength is enhanced as a more intense manner than observed by refine in PFI or ultrasonification of the pulp. Low charges of hemicelluloses were enough to increase significantly the paper strength. The development of properties due to hemicelluloses addiction was enhanced by refine in PFI, reaching a maximum value of the properties with low levels of refine. With that, the hemicelluloses addiction decreased the need of refine. The level of ultrasonification of the pulp didn t affect the results of hemicelluloses addiction.