Superbase-based protic ionic liquids for cellulose filament spinning

Sherif Elsayed,Marja Rissanen,Michael Hummel,Chamseddine Guizani,Herbert Sixta,Daisuke Sawada

doi:10.1007/s10570-020-03505-y

Sherif Elsayed, Marja Rissanen + Show 4 more

Open Access

https://doi.org/10.1007/s10570-020-03505-y

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Journal: Cellulose	Publication Date: Oct 20, 2020
Citations: 32	License type: open-access

Affiliation: Aalto University

Abstract

Lyocell fibers have received increased attention during the recent years. This is due to their high potential to satisfy the rising market demand for cellulose-based textiles in a sustainable way. Typically, this technology adopts a dry-jet wet spinning process, which offers regenerated cellulose fibers of excellent mechanical properties. Compared to the widely exploited viscose process, the lyocell technology fosters an eco-friendly process employing green direct solvents that can be fully recovered with low environmental impact. N-methylmorpholine N-oxide (NMMO) is a widely known direct solvent that has proven its success in commercializing the lyocell process. Its regenerated cellulose fibers exhibit higher tenacities and chain orientation compared to viscose fibers. Recently, protic superbase-based ionic liquids (ILs) have also been found to be suitable solvents for lyocell-type fiber spinning. Similar to NMMO, fibers of high mechanical properties can be spun from the cellulose-IL solutions at lower spinning temperatures. In this article, we study the different aspects of producing regenerated cellulose fibers using NMMO and relevant superbase-based ILs. The selected ILs are 1,5-diazabicyclo[4.3.0]non-5-ene-1-ium acetate ([DBNH]OAc), 7-methyl-1,5,7-triazabicyclo[4.4.0] dec-5-enium acetate ([mTBDH]OAc) and 1,8-diazabicyclo[5.4.0]undec-7-enium acetate ([DBUH]OAc). All ILs were used to dissolve a 13 wt% (PHK) cellulose pulp. The study covers the fiber spinning process, including the rheological characterization of the various cellulose solutions. Moreover, we discuss the properties of the produced fibers such as mechanical performance, macromolecular properties and morphology.Graphic abstract

Highlights

Cellulosic fibers long dominated the man-made fiber market until the synthetic fiber production surpassed cellulosics in the late 1960s (The Fiber Year 2013)
We study the different aspects of producing regenerated cellulose fibers using NMMO
Lyocell is a generic name which is derived from the Greek word lyein and cell from cellulose, and describes a process in which cellulose is dissolved without chemical modification in a direct solvent and spun in a dry-jet wet spinning process via an air gap into an aqueous coagulation bath

Summary

Introduction

Cellulosic fibers long dominated the man-made fiber market until the synthetic fiber production surpassed cellulosics in the late 1960s (The Fiber Year 2013). The continuous expansion of the global lyocell capacity reflects the increasing demand for sustainably produced bio-based fibers This and certain stability issues associated with NMMO (Buijtenhuijs et al 1986; Rosenau et al 2001; Jusner et al 2020), have motivated research on other cellulose solvents that allow for direct dissolution and subsequent fiber spinning. We found earlier that the amidine-based ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene-1-ium acetate ([DBNH]OAc) is an excellent solvent to process cellulose in a lyocell-type spin process (Hummel et al 2016; Michud et al 2016b; Sixta et al 2015) It contains acetate as an established anion that provides the necessary hydrogen bond basicity to dissolve cellulose.

Materials and methods

Results and discussion

Conclusion

Compliance with ethical standards