Development of Diallylimidazolium Methoxyacetate/DMSO (DMF/DMA) Solvents for Improving Cellulose Dissolution and Fabricating Porous Material.

Airong Xu,Rukuan Liu,Wentian Niu,Yongxin Wang,Lin Chen

doi:10.3390/polym11050845

Abstract

Cellulose is the most abundant natural biopolymer, with unique properties such as biodegradability, biocompability, nontoxicity, and so on. However, its extensive application has actually been hindered, because of its insolubility in water and most solvents. Herein, highly efficient cellulose solvents were developed by coupling diallylimidazolium methoxyacetate ([A2im][CH3OCH2COO]) with polar aprotic solvents dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA). Attractively, these solvents showed extraordinarily powerful dissolution performance for cellulose (e.g., 26.1 g·100g−1) in [A2im][CH3OCH2COO]/DMSO(RDMSO = 1.01 solvent even at 25 °C), which is much more advantageous over previously reported solvents. To our knowledge, such powerful cellulose solvents have not been reported before. The cellulose dissolution mechanism is proposed to be of three combined factors: (1) The hydrogen bond interactions of the H2, H4 and H6 in [A2im]+ and the carboxyl O atom in [CH3OCH2COO]−, along with the hydroxyl H atom and O atom in cellulose, are main driving force for cellulose dissolution; (2) the dissociation of [A2im][CH3OCH2COO] by DMF increases the anion and cation concentrations and thus promotes cellulose dissolution; (3) at the same time, DMF also stabilizes the dissolved cellulose chains. Meanwhile, the porous cellulose material with a varying morphologic structure could be facially fabricated by modulating the cellulose solution concentration. Additionally, the dissolution of cellulose in the solvents is only a physical process, and the regenerated cellulose from the solvents retains sufficient thermostability and a chemical structure similar to the original cellulose. Thus, this work will provide great possibility for developing cellulose-based products at ambient temperatures or under no extra heating/freezing conditions.

Highlights

Fossil-based products have created our brilliant and splendid civilization for the development of human society, but in the meantime they have brought some harm to the ecological environment and to human health
The porous cellulose material with a varying morphologic structure could be facially fabricated by modulating the cellulose solution concentration
It is clear that cellulose solubility considerably depends upon this dimethyl sulfoxide (DMSO)(DMF/DMA)/

Summary

Introduction

Fossil-based products have created our brilliant and splendid civilization for the development of human society, but in the meantime they have brought some harm to the ecological environment and to human health. The utilization of ecofriendly and nontoxic products has widely been recognized in modern society. Among the promising alternatives to fossil-based products, cellulose, the most abundant biopolymer resource on earth, has attracted increasing attentions due to its fascinating. The development of efficient solvents for cellulose is of significance. This is because after cellulose is dissolved, it is more favorable to the production of cellulose-based products such as derived cellulose, cellulose fiber, porous cellulose materials, and so on. Many novel solvent systems were developed, including N-methylmorpholine-N-oxide, lithium chloride +

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