Using the Ioncell process, the recycling of low DP textile waste via four case studies, white, blue, and black viscose and white modal fibers, was investigated. The most common man-made cellulose fiber (MMCF) is viscose, a low DP material made of plant-based cellulose, and it accounts for less than 6% of the total amount of textile fibers. Modal, a high-wet modulus viscose fiber, is made by a similar process and presents increased mechanical properties, making it a more durable fiber. Within manufacturing processes, the cellulose polymer is weakened and degraded to an extent that complicates recyclability through conventional methods. The Ioncell technology, a Lyocell-type process developed for the sustainable production of MMCFs, provides the opportunity to repurpose resources from various lignocellulosic waste materials through fiber-to-fiber recycling to create a circular economy. Moreover, the resulting fibers are often stronger than the original fibers, providing textiles of higher quality. Herein, we present the potential of the Ioncell technology for the recycling of low DP textile waste materials. The fibers exhibit exceptional properties, with tenacities up to 1.9 times higher in the dry state compared with their original materials. The fibers were turned into yarn and further used to produce small demonstrators.

A semi-continuous and industrial-like process to produce regenerated cellulose films, based on the Ioncell (R) technology, is demonstrated. The demand for commercial films, mainly fossil-based, is immense and expected to triple by 2060. This overconsumption leads to drawbacks like fossil reserves depletion and environmental pollution. Therefore, finding sustainable alternative processes compatible with existing industrial operations to produce films from renewable materials like cellulose is crucial. The films herein presented are generated by extruding a cellulose-ionic liquid solution through a distribution plate (DP) and slit nozzle into an aqueous coagulation bath, via an air gap. This study evaluates how different DPs and slit geometries affect the extrusion process and the film properties. Moreover, an automated continuous washing and drying system has been successfully implemented. The produced films are thin (13-17 mu m), homogeneous, highly transparent (89-91%) and strong. The use of DPs resulted in very strong films (242 MPa, 10% elongation at break) but led to extrusion instabilities. Trials without any DP were stable, with films showcasing tensile strengths of 226 MPa and 9% elongation at break. Additionally, a numerical simulation was performed to understand the effects of the DPs and spinnerets' geometry on the dope flow.

New technologies for the production of man-made cellulose fibers are being developed to produce fibers sustainably for various textile applications. The Ioncell® process uses an ionic liquid in which cellulose is dissolved to form a spinning solution. This spinning solution is spun into an aqueous coagulation bath using dry-jet wet spinning technology to produce Ioncell fibres. In order to develop a sustainable and economically viable process, the ionic liquid must be efficiently recycled in the process. Organic compounds resulting from degradation reactions of the cellulosic materials used for fiber production might accumulate in the ionic liquid over time and reduce its dissolution power. This study aimed to tentatively identify the main carbohydrate transformation products from aqueous ionic liquid solution. In addition to the actual coagulation bath sample, carbohydrate transformation reactions were studied using model samples. The main monomeric carbohydrate constituents of a hardwood pulp, glucose and xylose, were mixed with an ionic liquid and water and heated to 90 °C for 8 h to accelerate the transformation reactions. Most of the original monosaccharides were converted into other compounds, so that after the heat treatment only 11 wt% of the glucose and 1.1 wt% of the xylose remained. The liquid chromatography/time-of-flight mass spectrometry analyses revealed that both the spin bath sample and model samples contained mainly hydroxycarboxylic acids and carboxylic acids. The superbase of ionic liquid catalyzed the alkaline transformation reactions of carbohydrates.

In this study, acetic anhydride and iodine were used as acetylating agents to produce cellulose acetate (CA) from cotton linter-dissolving pulp (LDP). The conditions for acetylation, as well as the crystallinity and reactivity of LDP with high cellulose purity, were investigated and compared with our previous research on low-grade pulp. The properties of the CA, including yield, degree of substitution (DS), differential scanning calorimetry (DSC) analysis, and film characteristics were examined. The results reveal that LDP due to its high cellulose purity (98

The chemical recycling of cotton towels via the Ioncell (R) technique is demonstrated. Cotton is the most common natural fiber. The season's value jumped 31% to 54.3 billion US$ in 2020/2021, and annually the average value in quota-free periods accounts to 46.3 billion US$. Consequently, enormous amounts of cotton wastes are emerging. Especially, European countries are forced by the new legislation of the union to develop new recycling strategies. Due to uncountable cotton applications, various types of garments exist, which require different recycling strategies. The recycling of an additional cotton waste side stream of Lindstrom Oy white pre and dyed and white postconsumer cotton roll towels was pursued. The mechanical properties of the fibers and yarns have been evaluated. Thereby, the following elongations and tenacities of conditioned fibers produced at DR11 have been achieved: 10.4%/59.5 cN/tex for preconsumer and 10.6%/60.4 cN/tex for postconsumer white cotton, 10.4%/60.0 cN/tex for postconsumer blue cotton. The achieved elongations at break are close to values reported in literature (7%-14%), however, the tenacities exceed reported values (40-58 cN/tex). Highly oriented fibers of high quality have been produced and with regards to the mechanical properties, a technique to perform fiber-to-fiber upcycling is illustrated.

This study highlights the substantially improved hydrothermal stability of 7-methyl-1,5,7-triazabicyclo[4.4.0] dec-5-enium [mTBDH]+ in [mTBDH][MeOCH2COO] compared to [mTBDH][OAc], as well as the strong cellulose dissolution capability of [mTBDH][MeOCH2COO] and excellent spinnability with a maximum draw ratio of 14. These findings demonstrate the high potential of using [mTBDH][MeOCH2COO] as the solvent to advance Ioncell fiber spinning technology by reducing the hydrolysis rate of [mTBDH]+, thereby minimizing loss during solvent recycling processes.

StExCell, a novel sulfur-free and chlorine-free biorefinery concept, based on mild steam explosion followed by mild caustic extraction, oxygen delignification and bleaching, is introduced to produce dissolving pulp for textile application. Steam explosion of Betula pendula at 210 degrees C for 7 isothermal min (equivalent to a P-factor of ca. 1,250), combined with a total-chlorine-free purification sequence resulted in a fully bleached pulp with only 3.6 % xylan, a slightly wider cellulose molar mass distribution and a higher pulp yield, while consuming only about half of the chemicals, in reference to a prehydrolysis-kraft process. The chemical recovery and valorization of the extracted wood component were not covered by the scope of this work but speculated to be simpler than in a kraft process.

In this work, regenerated cellulose textile fibers, Ioncell-F, dry-wet spun with different draw ratios, have been investigated by scanning wide-angle X-ray scattering (WAXS) using a mesoscopic X-ray beam. The fibers were found to be homogeneous on the 500 nm length scale. Analysis of the azimuthal angular dependence of a crystalline Bragg spot intensity revealed a radial dependence of the degree of orientation of crystallites that was found to increase with the distance from the center of the fiber. We attribute this to radial velocity gradients during the extrusion of the spin dope and the early stage of drawing. On the other hand, the fiber crystallinity was found to be essentially homogeneous over the fiber cross section.

Regenerated cellulose fibres from dissolving pulp are a versatile alternative to cotton fibres on the path to the sustainable textile industry. In this study, cellulose fibres obtained by the Ioncell-F® process (Ioncell fibres) were modified by adding 10% (w/w) of suberin compounds isolated from cork (SUB) or a cutin fraction from grape skins (CUT) in the spinning dope. Although both SUB and CUT modified fibres revealed higher hydrophobicity than unmodified fibres, fibres doped with CUT showed better waterproof performance than those doped with SUB. This was explained by the better retention of CUT than SUB on the regenerated fibres and by the higher hydrophobicity of CUT. Differences in the strength properties of Ioncell fibres obtained by pilot-scale dry-jet wet spinning were related to their physical structure, whereas dirt repellence and susceptibility to enzymatic hydrolysis depended on the occurrence and amounts of retained CUT or SUB

What is at stake? Results on environmental impacts Key messages 1.The importance of environmental impacts: wood-based textiles and wood buildings 2. Wood-based textile fibres 2.1 Environmental impacts of wood-based textile fibres 2.1.1Environmental impacts across life cycle stages 2.1.2Environmental performance of wood-based fibre and their counterparts 2.2 Latest developments in wood-based fibres 2.3 Limitations and knowledge gaps 3. Modern wood buildings 3.1 Environmental impacts of modern wood buildings 3.1.1Environmental impacts across life cycle stages 3.1.2Environmental performance of modern wood buildings and their counterparts 3.2 Latest developments in wood buildings 3.3 Limitations and knowledge gaps 4. Lessons learned Methodology

Superbase-based ionic liquids (ILs) have demonstrated excellent dissolution capability for cellulose, and employing the dry-jet wet spinning process, high-tenacity regenerated textile fibers have been made. Among a range of superbase-based ILs, [mTBDH][OAc] exhibited not only good spinnability but also exceptional recyclability, making it highly suitable for a closed-loop production of regenerated cellulose fibers. To further optimize the spinning process, we investigated the influence of the cellulosic raw materials and the IL with residual water on spinnability and fiber properties. In addition, single-filament spinning and multifilament spinning using spinnerets with different hole densities were investigated to reveal the upscaling challenges of the dry-jet wet spinning process. The air gap conditions, for example, temperature and moisture concentration were simulated using COMSOL multiphysics. The results indicate that the presence of a small amount of water (3 wt%) in the IL has a positive effect on spinnability, while the mechanical properties of the fibers remain unchanged.

The Ioncell process is capable of producing high-quality regenerated cellulose fibers from dissolving pulps with a wide range of intrinsic viscosity and different molecular mass distributions.

The textile industry is facing growing pressure to adopt sustainable practices, including the development of biodegradable and recyclable fibers derived from waste streams. In this study, we explored the use of keratin from waste textiles as a potential raw material for sustainable fiber production. We investigated the dissolution of keratin in 7-methyl-1,5,7-triazabicyclo(4.4.0)dec-5-ene (mTBD)-based ionic liquids (ILs) and its regeneration in various coagulation solvents. The viscoelastic properties of the keratin solution were characterized using small angle oscillation shear rheology (SAOS), and the results showed that the keratin solution was not suitable for the dry-jet spinning process and the pure regenerated keratin fiber was too weak to hold the stretching in fiberline. To bypass these issues, we blended high molar mass cellulose with keratin during the dissolution step to adjust the rheological properties and mechanical strength of the extruded fibers. The resulting hybrid fibers exhibited high strength, low fibrillation tendency, and soft texture. We also demonstrated the further processability of these fibers by spinning a yarn and knitting a piece of fabric. Our findings suggest that hybrid fibers derived from keratin waste textiles and cellulose could be promising materials for sustainable fashion applications.

Dissolving pulp as a purified chemical pulp with high cellulose content, is an important raw material for many applications such as cellulose derivatives and regenerated cellulose, hence paper-grade bagasse pulp as a cheap alternative non-wood raw material can be used to produce dissolving-grade pulp. In this work, the potential of ECF and TCF bleached paper-grade soda bagasse pulp in the production of dissolving pulp was studied. To find an effective method, bleaching sequences followed by the different hemicellulose extraction processes including CCE, xylanase treatment, IONCELL-P, combination of xylanase treatment and IONCELL-P were investigated. The unbleached bagasse pulp was subjected to the IONCELL-P process using mixtures of 1-ethyl-3-methylimidazolium acetate/water for the extraction of xylan from an initial of 30.5 to 7.0%. The ECF (ODEpQP 1.5% ) sequence resulted in the optimum bleached pulp in terms of physical and chemical properties and the consumption of bleaching chemicals, which was selected for subsequent treatments to remove xylan to produce dissolving pulp. In the IONCELL-P treatment of bleached pulp, the xylan content could even be reduced to 5.9% (80% removal) and in X-IONCELL-P to 3.3% (90% removal). All the extraction methods investigated in this study removed xylan with differences in the selectivity and efficiency successfully.

In this study, we propose a full gamma-valerolactone (GVL) organosolv biorefinery concept including the utilization of all pulping streams, solvent recovery, and preliminary material and energy balances. GVL is a renewable and non-toxic solvent that fractionates woody biomass. The silver birch chips were pulped (45–65 wt% GVL, 150 °C, 2 h) under a series of acid-catalyzed conditions (5–12 kg H2SO4/t), and the fully bleached pulp was spun into fibers by the IONCELL® process and knitted into the fabric. The dissolved lignin was precipitated by water from spent liquor (1:1) and processed into polyhydroxyurethane. Most of the dissolved hemicelluloses were in the form of xylose, therefore, the crystallization efficiency of xylose from spent liquor in the presence of residual GVL was studied. The GVL recovery rate in the lab column was 66%, however by increasing the number of equilibrium stages, 99% recovery could be achieved.

In recent years, the search for alternatives to petroleum derived products, such as plastic films, has become a priority due to the growing depletion of fossil reserves and the pollution of water resources by microplastics, microscopically small plastic particles which are harmful to ocean and aquatic life. Cellulose-based films, e.g., cellophane and cuprophane, have been on the market for almost a century. Despite being a more ecological option compared to plastic films, the manufacture of these cellulose films involves high production costs and the use of harmful chemicals. As an alternative, a sustainable and eco-friendly process based on the Lyocell-type Ioncell ® technology is presented to produce cellulose films. Regenerated cellulose films are created by continuous extrusion via dry-jet wet spinning of an ionic liquid–cellulose solutions. The influence of the polymer concentration (8–13 wt%) and processing temperature (50–100 °C) on the properties of the films were studied by the determination of the thickness, mechanical properties, physical appearance, morphology, chemical composition, and hydrophobicity. The obtained films are thin (12–21 μm), transparent (transmittance = 91%) and of homogeneous structure. Moreover, they exhibit excellent mechanical properties: stress values up to 210 MPa and elongations up to 19% in machine (longitudinal) direction. These values clearly outperform commercial cellophane, which presents stress values of 125 MPa and elongations of 22%. The films presented herein hold great potential to become an eco-friendly and sustainable option to commercial films.

A conjugated‐polymer‐based n‐type yarn for thermoelectric textiles is presented. Thermoelectric textile devices are intriguing power sources for wearable electronic devices. The use of yarns comprising conjugated polymers is desirable because of their potentially superior mechanical properties compared to other thermoelectric materials. While several examples of p‐type conducting yarns exist, there is a lack of polymer‐based n‐type yarns. Here, a regenerated cellulose yarn is spray‐coated with an n‐type conducting‐polymer‐based ink composed of poly(benzimidazobenzophenanthroline) (BBL) and poly(ethyleneimine) (PEI). The n‐type yarns display a bulk electrical conductivity of 8 × 10 −3 S cm −1 and Seebeck coefficient of −79 µV K −1 . A promising level of air‐stability for at least 13 days can be achieved by applying an additional thermoplastic elastomer coating. A prototype in‐plane thermoelectric textile, produced with the developed n‐type yarns and p‐type yarns, composed of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)‐coated regenerated cellulose, displays a stable device performance in air for at least 4 days with an open‐circuit voltage per temperature difference of 1 mV °C −1 . Evidently, polymer‐based n‐type yarns are a viable component for the construction of thermoelectric textile devices.

The chemical recycling of hemp fabric into high-tenacity man-made cellulose fibers was demonstrated. The fabric was laundered 25 and 50 times to mimic the wear cycles of post-consumer textile waste. Despite the launderings, the molar mass of the material was still too high for recycling via dry-jet-wet spinning. Thus, the fabrics were treated with an aqueous sulfuric acid solution to adjust the intrinsic viscosity to the targeted level of 400–500 ml/g. The acid hydrolyzed sample was dissolved in 1,5-diazabicyclo[4.3.0]non-5-enium acetate and man-made cellulose fibers were regenerated by dry-jet-wet spinning. The properties of hemp and regenerated fibers were determined by tensile testing, birefringence measurements, and X-ray diffraction. Regenerated fibers were spun into yarn and knitted into a fabric. The tensile properties of the yarn and the abrasion and pilling resistance of the fabric were determined. Regenerated fibers showed a higher modulus of toughness (55.9 MPa) compared with hemp fibers (28.7 MPa). The fineness and staple length uniformity of regenerated fibers resulted in a high yarn structure evenness, a yarn tenacity of 28.1 cN/tex, and an elongation at break of 7.5%. Due to the even fabric structure, the fabric from regenerated fibers showed higher abrasion resistance than the hemp fabric.

Acid-catalyzed organosolv GVL pulping can yield high-purity dissolving pulp from birch with qualities comparable to commercial acid sulfite dissolving pulp.

The hydrolysis kinetics of 7-methyl-1,5,7-triazabicyclo [4.4.0] dec-5- enium acetate [mTBDH] [OAc] was investigated in a comprehensive study by the utilization of the well-known Schlenk technique to achieve a better understanding of its stability for dry-jet wet spinning applications (e.g., Ioncell) and due to the course of operation for recovery methods like fractional distillation. Decomposition behavior as a function of temperature, time, acid-base stoichiometry, and water content was extensively analyzed and characterized by nuclear magnetic resonance spectroscopy (NMR), capillary electrophoresis (CE), and thermogravimetric analysis (TGA). Furthermore, kinetic models were formulated for the prediction of the stability and the results were compared with the closely related amidine-based analogues 1,5- diazabicyclo[4.3.0]non-5-enium acetate [DBNH] [OAc] and 1,8-diazabicyclo[5.4.0]undec-7-enium acetate [DBUH] [OAc].