Renewable High‐Performance Fibers from the Chemical Recycling of Cotton Waste Utilizing an Ionic Liquid

Abstract

A new chemical recycling method for waste cotton is presented that allows the production of virgin textile fibers of substantially higher quality than that from the mechanical recycling methods that are used currently. Cotton postconsumer textile wastes were solubilized fully in the cellulose-dissolving ionic liquid 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH]OAc) to be processed into continuous filaments. As a result of the heterogeneous raw material that had a different molar mass distribution and degree of polymerization, pretreatment to adjust the cellulose degree of polymerization by acid hydrolysis, enzyme hydrolysis, or blending the waste cotton with birch prehydrolyzed kraft pulp was necessary to ensure spinnability. The physical properties of the spun fibers and the effect of the processing parameters on the ultrastructural changes of the fibers were measured. Fibers with a tenacity (tensile strength) of up to 58 cN tex (870 MPa) were prepared, which exceeds that of native cotton and commercial man-made cellulosic fibers.

Identifying the challenges of implementing a European bioeconomy based on forest resources: Reality demands circularity

“…Continuous development in technologies for second-generation biofuel production, i.e. more cost-effective and sustainable lignocellulose and waste to bioethanol conversion by making microbial processes more efficient [1,14,19,25,26,31].…”

“…European countries are becoming increasingly dependent on imported fossil energy. In the EU25, the demand for fuels is predicted to rise from about 50 EJ yr -1 (1 EJ = 1 exajoule = 10 18 J) today to more than 70 EJ yr -1 in 2030, at the same time imported energy will increase from 50 % to 70 % [1,43]. At the same time need for land for food production will be increased by 50 % [28,43,60].…”

“…Contributing to greenhouse gas emissions reduction is concurrently possible mainly by substitution with low carbon products, increasing energy and materials efficiency and recycling of materials and utilisation of waste. The key challenge on a global level, that is also recognised in the EU, is how to generate a sustainable approach in utilising natural resources, especially biomass considered to be CO 2 neutral [1][2][3]. The EU has set a milestone for cutting its carbon emissions by 2030 to levels 40 % below the levels of 1990 through domestic consumption reductions, improved energy efficiency and the greater use of renewable energy sources [4,5].…”

“…Through increased market globalisation, European countries became exposed to growing competitive challenges whilst attempting to achieve the sustainability image amongst bio-based materials sector companies [1,2]. From the necessity to merge two opposing streams, social well-being defined through sustainability, on the one hand, and economic development through competitiveness of European forest-based business, on the other hand, European countries will have to make large investments and face profit loss in the short term, if they wish to place bio-based products on the market, especially if the main overseas competitors are going to continue to produce cheaper fossil fuels-based products [8].…”

High performance cellulose fibers regenerated from 1‐butyl‐3‐methylimidazolium chloride solution: Effects of viscosity and molecular weight

“…Imidazolium‐based ILs containing halides reacted with the cellulose, causing degradation at elevated temperatures (>90 °C) . A series of studies were conducted using 1,5‐diazabicyclo[4.3.0]non‐5‐enium acetate, a nonimidazolium‐based IL solvent that allows a low processing temperature and thus prevents cellulose degradation, and regenerated cellulose fibers with high tensile strength were obtained …”