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Carboxymethylation of cellulose in the new solvent dimethyl sulfoxide/tetrabutylammonium fluoride

Ramos, L.A. ; Frollini, E. ; Heinze, Th

Carbohydrate polymers, 2005-05, Vol.60 (2), p.259-267 [Periódico revisado por pares]

Oxford: Elsevier Ltd

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Título:
Carboxymethylation of cellulose in the new solvent dimethyl sulfoxide/tetrabutylammonium fluoride
Autor: Ramos, L.A. ; Frollini, E. ; Heinze, Th
Assuntos: Applied sciences ; carboxymethylcellulose ; Carboxymethylcellulose, CMC ; Cellulose and derivatives ; Cellulose solvent ; chemical structure ; Cotton linters ; Dimethyl sulfoxide/tetrabutylammonium fluoride trihydrate ; Exact sciences and technology ; Natural polymers ; Pattern of substitution ; Physicochemistry of polymers ; Sisal ; Size exclusion chromatography ; solvents
É parte de: Carbohydrate polymers, 2005-05, Vol.60 (2), p.259-267
Descrição: The new cellulose solvent dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride (TBAF) was applied as reaction medium for the carboxymethylation of mercerized cellulose from sisal and cotton linters. The reaction parameters studied were the molar ratio of reagent and NaOH to anhydroglucose unit (AGU) and the addition of the NaOH either as an aqueous solution or as solid particles. Size Exclusion Chromatography results (SEC) indicated that the dissolution medium and/or derivatizing method used in the present work causes a certain depolymerization on the cellulose chains The pattern of substitution within the AGU and along the polymer chains of the carboxymethylcellulose (CMC), which was analyzed by 1H NMR spectroscopy and HPLC after acidic depolymerization of the CMC, is in the order O-6>O-2≥O-3. With regard to the mole fractions of the different repeating units, samples prepared using aqueous NaOH possess a statistic content, while by using solid NaOH a deviation from statistically calculated values was observed. As a consequence of the non-statistics, the solubility in water of these samples starts at a DS 0.85, while conventionally prepared CMC are water-soluble at a DS as low as 0.4.
Editor: Oxford: Elsevier Ltd
Idioma: Inglês

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Carboxymethylation of cellulose in the new solvent dimethyl sulfoxide/tetrabutylammonium fluoride

Ramos, L.A. ; Frollini, E. ; Heinze, Th

Oxford: Elsevier Ltd

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