Different rheological behaviours of cellulose/tetrabutylammonium acetate/dimethyl sulfoxide/water mixtures
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ORIGINAL RESEARCH
Different rheological behaviours of cellulose/ tetrabutylammonium acetate/dimethyl sulfoxide/water mixtures Lei Zhang . Zeming Jiang . Shujuan Yang . Zhinong Zeng . WenTao Zhang . Liping Zhang
Received: 15 March 2020 / Accepted: 22 July 2020 Ó Springer Nature B.V. 2020
Abstract Tetrabutylammonium acetate (TBAA) solution in dimethyl sulfoxide (DMSO) can dissolve cellulose efficient at a mild condition and it seems to have favorable properties for cellulose molding applications, e.g. fiber spinning. However, if water or other hydrogen bond donors are present, the solvent’s ability to dissolve cellulose is greatly reduced. A non-solvent (water) post-added to the cellulose/TBAA/DMSO solutions caused significant changes in flow properties. Specifically, the rheological behaviours of distinct phases formed in 6–8%(w/ w) cellulose/TBAA/DMSO solutions due to the
addition of water was investigated. With the water concentrations increased, a sol–gel transition had been detected. The Cox–Merz rule and Cross model have been used to fit the rheological data. We explain the sol–gel transformation in cellulose/TBAA/DMSO/ water solutions by percolation theory. Meanwhile, a mechanism of cellulose aggregation and the sol–gel transitions have been proposed: water can effectively break the cellulose–Ac- H-bonds and lead to the formation of cellulose–cellulose H-bonds, which grow the aggregation of cellulose, form a network structure in the whole sample and then result in gelation.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10570-020-03363-8) contains supplementary material, which is available to authorized users. L. Zhang Z. Jiang S. Yang Z. Zeng W. Zhang L. Zhang (&) Beijing Key Laboratory of Lignocellulosic Chemistry, MOE Engineering Research Center of Forestry Biomass Materials and Bioenergy, Beijing Forestry University, Haidian District, No. 35 Tsinghua East Road, Beijing 100083, China e-mail: [email protected]
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Cellulose
Graphic abstract Sol-gel transition of cellulose/ tetrabutylammonium acetate/dimethyl sulfoxide solutions with different water concentrations.
Keywords Non-solvent Cellulose Tetrabutylammonium acetate Rheological behaviours Sol–gel transition
Introduction Cellulose is the most popular and almost inexhaustible natural polymer, suitable for many applications such as textile, paper making and membrane industries (Jiang et al. 2019; Yang et al. 2019). However, cellulose is not a thermoplastic polymer, and its processing requires either homogeneous chemical modification or dissolution in a true solvent (Miao et al. 2014, 2016). Therefore, the effective dissolution of cellulose is the main challenge for its further utilization. Traditional cellulose solvents (e.g. LiCl/ DMAc, NMMO, CS2) are not popular due to toxicity, environmental pollution and expensive solvent recovery procedures (Gericke et al. 2012; Isik et al. 2014; Sayyed et al. 2019). The effective solvent system
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