Utilization of cotton waste for regenerated cellulose fibres: Influence of degree of polymerization on mechanical properties
Introduction
The global fibre production for the textile industry in 2014 was around 90 million tonnes (Lenzing.com, 2015). Fibre production is expected to continue to increase with the growing world population combined with rapid changes in fashion trends. In textiles cotton is the most used fibre and therefore considerable attention is given to recycling cotton waste. To date cotton waste is recycled typically by a mechanical process, the recycled cotton is generally of poor quality when compared to virgin cotton. Due to these poor properties only a small fraction of recycled cotton is utilized and is often blended with virgin cotton. (Gordon & Hsieh, 2006; Halimi, Hassen, & Sakli, 2008). A possible solution to improving the amount of recycled cotton which can be utilized is to employ a chemical recycling process and produced regenerated cotton (Asaadi et al., 2016, De Silva et al., 2014; Haule, Carr, & Rigout, 2016; Nikolić, Lazić, Veljović, & Mojović, 2017; Wang, Yao, Zhou, & Zhang, 2017). This regenerated cotton among other things could be utilized in textiles by developing a regenerated cellulose fibre, RCF. Viscose is the more commonly known RCF process. Viscose is produced by taking wood pulp and dissolving it in aqueous sodium hydroxide and carbon disulphide. The fibre is produced by wet spinning process. Limitations associated with viscose are the potential environmental concerns associated with the production of CS2 a toxic gas as a side product of the dissolving solvent (Heinze and Liebert, 2001, Zhu et al., 2006). Lyocell is an alternative to viscose, here the wood pulp is dissolved in N-methyl morpholine Oxide (NMMO) and the fibre is spun using a dry-wet spinning process. Typically Lyocell is considered to be an environmentally friendly alternative to viscose, however NMMO does suffer from runaway thermal reactions (Kotek, 2007, Woodings, 2000).
Due to these mentioned limitations of both the viscose and the Lyocell processes, a new range of solvents for cellulose processing has over the past decade attracted significant interest. In recent times ionic liquids have been considered as cellulose dissolving solvents and few groups have successfully spun regenerated cellulose fibres from wood pulp (De Silva, Vongsanga, Wang, & Byrne, 2016; Gibril and Yue, 2012, Hauru et al., 2014; Hauru, Hummel, Nieminen, Michud, & Sixta, 2016; Heinze and Koschella, 2005, Pinkert et al., 2009; Zhu et al., 2006). Ioncell is a regenerated cellulose fibre produced from wood pulp in a process similar to Lyocell however the NMMO is replaced with the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-enium acetate (DBNAC), it has been reported that the mechanical properties are enhanced due to the ability to achieve higher draw ratios when spinning from the IL (Hauru et al., 2014). The mechanical properties of regenerated cellulose fibres can be influenced by many different factors where one important factor is the degree of polymerization DP (Adusumali, Reifferscheid, Weber, Roeder, Sixta, & Gindl, 2006; Krässig and Kitchen, 1961, Pang et al., 2013). It is known that higher DP results in improved tensile properties, however both NMMO and aqueous sodium hydroxide and carbon disulphide are limited in their ability to dissolve high DP cellulose materials which has limited the chemical recycling of cotton lint.
Here we use an ionic liquid dissolving solvent to dissolve high DP cotton lint waste and produced regenerated fibres. We measure the properties of the regenerated fibre and find that the higher degree of polymerization of cotton lint provides a new opportunity to improve the mechanical properties of the regenerated fibre. As such we explore the complete relationship between tensile properties and different degree of polymerizations by systematically degrading the cotton lint waste. A plateau in the tensile properties of the RCF is found for DP values of 1000 or higher. We characterise other important properties of the RCF from cotton lint waste.
Section snippets
Starting materials
1-Allyl-3-methylimidazolium chloride (AMIMCl >98%; lot no. 100319.2.1) was purchased from Io-Li-Tec, Germany. The IL was dried under reduced pressure at 85 °C to remove water prior to dissolution. The water content of AMIMCl was measured using a Karl-Fischer coulometer and was determined to be less than 0.8% for all dissolutions. Bleached soft wood kraft pulp (Pinus elliottii) (>90% cellulose, DP ∼ 1092), and waste cotton lint (>92% cellulose, DP ∼ 3133) were provided by the Cotton Research and
Rheology of cellulose solutions
In order to be able to spin a fibre, the rheology of the spinning dope is an important consideration. Indeed the rheological properties of the spinning dope can influence the formation and the properties of the spun fibre (Fink, Weigel, Purz, & Ganster, 2001; Olsson & Westman, 2013). Fig. 1a shows the dynamic viscosity of cellulose (waste cotton lint) solutions as a function of shear rate at 40 °C at 3 different DPs 2680, 904 and 495. All solutions show a Newtonian behaviour at low shear rates
Conclusion
Here cotton lint waste was studied as a possible feedstock for producing regenerated cellulose fibres. We show that higher tensile properties could be obtained by using the cotton lint when compared to wood pulp. The higher tensile values obtained was shown to be due to the degree of polymerization of the cotton lint waste. By systematically degrading the cotton lint to give different DP values we demonstrated the link between tensile strength and DP. The use of cotton lint waste as a feedstock
References (33)
- et al.
Homer Kissinger and the Kissinger equation
Thermochimica Acta
(2012) - et al.
Structure formation of regenerated cellulose materials from NMMO-solutions
Progress in Polymer Science
(2001) - et al.
Cotton waste recycling: Quantitative and qualitative assessment
Resources, Conservation and Recycling
(2008) - et al.
Preparation and physical properties of regenerated cellulose fibres from cotton waste garments
Journal of Cleaner Production
(2016) - et al.
Unconventional methods in cellulose functionalization
Progress in Polymer Science
(2001) - et al.
Production of bioethanol from pre-treated cotton fabrics and waste cotton materials
Carbohydrate Polymers
(2017) - et al.
Reuse of waste cotton cloth for the extraction of cellulose nanocrystals
Carbohydrate Polymers
(2017) Standard test method for intrinsic viscosity of cellulose
(2013)- et al.
Mechanical properties of regenerated cellulose fibres for composites
Macromolecular Symposia
(2006) - et al.
Renewable high-performance fibers from the chemical recycling of cotton waste utilizing an ionic liquid
ChemSusChem
(2016)
Recycling textiles: The use of ionic liquids in the separation of cotton polyester blends
RSC Advances
Understanding key wet spinning parameters in an ionic liquid spun regenerated cellulosic fibre
Cellulose
Cellulose molecular weights determined by viscometry
Journal of Applied Polymer Science
Fourier transform infrared spectroscopy for natural fibres. Fourier transform–materials analysis
FTIR spectroscopic studies on the heterogeneous transformation of cellulose I into cellulose II
Acta Polymerica
Current status of applications of ionic liquids for cellulose dissolution and modifications: Review
Int J Eng Sci Technol
Cited by (102)
Exploring hydrogen-bond structures in cellulose during regeneration with anti-solvent through two-dimensional correlation infrared spectroscopy
2024, International Journal of Biological MacromoleculesPreparation and characterization of bacterial cellulose synthesized by kombucha from vinegar residue
2024, International Journal of Biological MacromoleculesWeldable and calligraphy programmable humidity-actuated regenerated cellulose film from waste cotton fabric
2024, Journal of Cleaner ProductionRapid in situ quantification of rheo-optic evolution for cellulose spinning in ionic solvents
2023, Carbohydrate PolymersTextile waste management in Australia: A review
2023, Resources, Conservation and Recycling Advances