Sisal cellulose and its acetates: generation of films and reinforcement in a one-pot process |
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Authors: | Erika V. R. Almeida Daniella L. Morgado Ludmila A. Ramos Elisabete Frollini |
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Affiliation: | 1. Macromolecular Materials and Lignocellulosic Fibers Group, Institute of Chemistry of S?o Carlos, University of S?o Paulo, P. O. Box 780, 13560-970, S?o Carlos, S?o Paulo, Brazil 2. Bahia Specialty Cellulose, Bahia, Brazil
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Abstract: | This study was undertaken to evaluate both the properties of cellulose acetate films as a function of their degree of substitution (DS) and the possibility of generating reinforcements during film preparation. Sisal was selected for the entire study, among other reasons, because it is a rapidly growing source of cellulose. Cellulose acetates with various DS values were prepared in a homogeneous medium (dimethylacetamide/lithium chloride as the solvent system) and characterized. In DMAc/LiCl, cellulose and cellulose acetate films (mixed or not mixed with sisal cellulose) were successfully prepared and characterized. The films with high DS values exhibited lower hygroscopicity, a distinct morphology (scanning electron microscopy images), and lower tensile strength. In some cases, the films prepared from acetates/cellulose exhibited higher tensile strength and/or storage modulus than the acetate films. This result suggested a reinforcing action of the auto-organized cellulose chains that enabled the generation of both a film and reinforcement in a one-pot process. |
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