(643h) Change Regulation of Cellulose Depolymerization during Dissolving Process in Ionic Liquids

Authors: 
Pan, F., Chinese Academy of Sciences, Beijing Key Laboratory of Ionic Liquids Clean Process,CAS Key Labroratory of Green Process and Engineering, Institute of Process Engineering, China
Nie, Y., Beijing Key Laboratory of Ionic Liquids Clean Process,CAS Key Labroratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences
Zhou, L., Chinese Academy of Sciences, Beijing Key Laboratory of Ionic Liquids Clean Process,CAS Key Labroratory of Green Process and Engineering, Institute of Process Engineering, China
Kang, Z., Chinese Academy of Sciences, Beijing Key Laboratory of Ionic Liquids Clean Process,CAS Key Labroratory of Green Process and Engineering, Institute of Process Engineering, China
Zhang, X., Beijing Key Laboratory of Ionic Liquids Clean Process,CAS Key Labroratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences
Zhang, S., Beijing Key Laboratory of Ionic Liquids Clean Process,CAS Key Labroratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences
Abstract

Regenerated cellulose fibers are commercially produced by viscose process using cellulose as raw materials. However, this process exits some drawbacks including high cost, solvent volatility and toxicity. Therefore, it is necessary to develop more efficient and greener technology for cellulose dissolution. Ionic liquids (ILs), as green solvents with attractive properties of non-volatility, thermal stability, and tunable structure, show excellent solubility in dissolving cellulose and spinning, which has been regarded as a promising method for cellulose solution.

However, cellulose degradation is inevitable in the process of cellulose dissolution in ILs, which significantly influences the mechanical properties of regenerated fibers. The mechanical properties of regenerated fiber decreased approximately linearly with cellulose depolymerized. Thus, it’s vital to understand the change regulation of cellulose depolymerization in ILs, and hence guides to obtain regenerated fibers with high tensile strength. Usually, the reduction of degree of polymerization (DP) is used to evaluate the degree of cellulose depolymerization.

In this work, microcrystalline cellulose and wood pulp were dissolved respectively in two ILs, i.e., 1-allyl-3-methylimidazolium chloride (AmimCl) and 1-ethyl-3-methylimidazolium diethyl phosphate (EmimDep). The cellulose depolymerization was investigated within 72 hours at 90~130℃. The results indicate that the DP of regenerated cellulose decrease with time, and the decrease in DP of regenerated cellulose became more pronounced when the temperature is above 100℃. And cellulose depolymerization in EmimDep rather than AmimCl has a slight change with the increasing of reaction temperature and time. Therefore, high-quality regenerated cellulose fiber will be acquired when using EmimDep as solvent and no more than 100℃.

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