Please use this identifier to cite or link to this item: http://repositorio.ufla.br/jspui/handle/1/42992
Title: Structural changes in microfibrillated cellulose submitted to redispersion methods
Other Titles: Mudanças estruturais em celulose microfibrilada submetida a métodos de redispersão
Authors: Tonoli, Gustavo Henrique Denzin
Sena Neto, Alfredo Rodrigues de
Glen, Greggory
Moreira Neto, João
Ferreira, Saulo Rocha
Youngblood, Jeffrey
Hart-Cooper, William
Keywords: Celulose microfibrilada
Secagem em estufa
Liofilização
Hornificação
Dodecil sulfato de sódio
Oven-drying
Freeze-drying
Hornification
Sodium chloride
Sodium dodecyl sulfate
Issue Date: 11-Sep-2020
Publisher: Universidade Federal de Lavras
Citation: SILVA, L. E. Structural changes in microfibrillated cellulose submitted to redispersion methods. 2020. 67 p. Tese (Doutorado em Engenharia de Biomateriais) – Universidade Federal de Lavras, Lavras, 2020.
Abstract: Microfibrillated cellulose (MFC) represents a material of great interest for several industries, such as composites, pharmaceuticals, electronics and many others. Due to its structure and size, it has different properties compared to macrofibers. However, drying causes aggregation of these particles, which makes it lose its unique characteristics. Therefore, the present study seeks to elucidate different approaches to MFC drying and to present possible drying methods. In the first article presented, the relationship between the number of drying cycles and temperature, and their consequent influence on the MFC structure was studied. The results show that the greater number of drying cycles and a higher temperature cause a greater aggregation in the MFC, growth of the particles, loss of stability in water and loss of mechanical properties. Once-dried at room temperature (20°C) was the most promising, with morphology and particle size close to never-dried MFC; which makes this treatment the most suitable when using the oven-drying method. In the second article, the presence of additives to aid redispersion of freeze-dried MFC was analyzed. The sample dried with no additive obtained the worst result, with great formation of aggregates, larger particle size and considerable loss in mechanical properties. The presence of sodium chloride helped the redispersion, but it still showed a considerable difference in relation to never-dried MFC. The use of the surfactant sodium dodecyl sulfate has assured redispersion to the point of being compared, in terms of morphology and structure, to never-dried MFC. Trace amount of the surfactant caused the mechanical properties to surpass the never-dried MFC, causing the treatment not only to carry out the redispersion but also the interaction between MFC and the surfactant to improve the properties.
URI: http://repositorio.ufla.br/jspui/handle/1/42992
Appears in Collections:Engenharia de Biomateriais – Doutorado (Teses)

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