From a new cellulose solvent to the cyclodextrin induced formation of hydrogels

Medronho, Bruno; Duarte, Hugo; Magalhaes, Solange; Alves, Luis; Valente, Artur J. M.; Romano, Anabela

http://hdl.handle.net/10400.1/12926

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Resumo(s)

A new efficient solvent for cellulose dissolution was developed based on the mixture of aqueous tetrabutylammonium hydroxide, TBAH(aq) and an organic co-solvent, dimethylsulfoxide (DMSO). Clear cellulose solutions were readily obtained at mild conditions in a few minutes. The viscoeleastic properties of the dopes formed are found to be dependent on the cellulose content and TBAH(aq)/DMSO ratio. Additionally, stiff hydrogels are formed when adding beta-cyclodextrin (beta-CD) to the cellulose dopes. The formation of a host-guest complex between the beta-CD and the tetrabutylammonium cations (TBA(+)), which presumably destabilizes the cellulose solution state triggering the hydrogel formation, is suggested as mechanism. The robust hydrogels formed have been characterized regarding their viscoelasticity, microscopic morphology and release properties. The kinetics and released amount of the TBA(+) from the cellulose gel matrixes are found to be strongly dependent on the balance between average pore diameter, surface area and free volume of the hydrogels. (C) 2017 Elsevier B.V. All rights reserved.

Palavras-chave

Aqueous Tetrabutylammonium Hydroxide N-Butylphosphonium Hydroxide Wheat-Straw Dissolution Mechanisms Diffusion Biomass Nmr

URI

http://hdl.handle.net/10400.1/12926

Editora

Elsevier Science Bv

DOI

10.1016/j.colsurfa.2017.03.047

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FCT2-Artigos (em revistas ou actas indexadas)

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