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  • 1.
    Achtel, Christian
    et al.
    Friedrich Schiller University of Jena, Germany.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF. Friedrich Schiller University of Jena, Germany.
    Kosan, Birgit
    TITK Thuringian Institute of Textile and Plastics Research, Germany.
    Seoud, Omar. A.El
    University of São Paulo, Brazil.
    Heinze, Thomas
    Friedrich Schiller University of Jena, Germany.
    Dissolution capacity of novel cellulose solvents based on triethyloctylammonium chloride2017In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 218, no 21, article id 1700208Article in journal (Refereed)
    Abstract [en]

    Dissolution of cellulose from various sources (microcrystalline cellulose and different dissolving grade pulp fibers) is investigated in solvent systems based on triethyl(n-octyl)ammonium chloride (N2228Cl). Clear cellulose solutions are obtained with N2228Cl in a variety of solvents, e.g., dimethyl sulfoxide, N,N-dimethylacetamide, and acetone. It is possible to prepare clear cellulose solutions from pulp fibers with concentrations up to 15 wt%. However, it is found that the cellulose is degraded, especially when neat (i.e., molten) N2228Cl is used as a solvent. The present work includes comprehensive rheological characterization of the cellulose solutions, both with shear and extensional rheology. In most cases, the viscosity values are low (complex viscosities below 100 Pa s for 5–10 wt% dissolved cellulose), and the solutions show more Newtonian than viscoelastic behavior. 

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  • 2.
    Achtel, Christian
    et al.
    Friedrich Schiller University Jena, Germany.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Kostag, Marc
    University of Sao Paulo, Brazil.
    El Seoud, Omar A.
    University of Sao Paulo, Brazil.
    Heinze, Thomas
    Friedrich Schiller University Jena, Germany.
    Surprising Insensitivity of Homogeneous Acetylation of Cellulose Dissolved in Triethyl(n-octyl)ammonium Chloride/Molecular Solvent on the Solvent Polarity2018In: Macromolecular materials and engineering, ISSN 1438-7492, E-ISSN 1439-2054, Vol. 303, no 5Article in journal (Refereed)
    Abstract [en]

    The homogeneous acetylation of microcrystalline cellulose (MCC) by acetyl chloride and acetic anhydride in triethyl(n-octyl)ammonium chloride (N2228Cl)/molecular solvents (MSs) is investigated. The reaction with both acylating agents shows the expected increase of the degree of substitution (DS) on reaction temperature and time. Under comparable reaction conditions, however, DS is surprisingly little dependent on the MS employed, although the MSs differ in empirical polarity by 7 kcal mol−1 as calculated by use of solvatochromic probes. The empirical polarities of (MCC + N2228Cl + MS) differ only by 0.8 kcal mol−1. The formation a polar electrolyte sheath around cellulose chains presumably contributes to this “leveling-off” of the dependence DS on the polarity of the parent MS employed. N2228Cl recovery and recycling is feasible. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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  • 3.
    Argyropoulos, Dimitris
    et al.
    North Carolina State University, USA.
    Crestini, Claudia
    Ca’ Foscari University of Venice, Italy.
    Dahlstrand, Christian
    Ren FuelK2B AB, Sweden.
    Furusjö, Erik
    RISE Research Institutes of Sweden, Bioeconomy and Health, Biorefinery and Energy. Luleå University of Technology, Sweden.
    Gioia, Claudio
    Universityof Trento, Italy.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Henriksson, Gunnar
    KTH Royal Institute of Technology, Sweden.
    Hulteberg, Christian
    Lund University, Sweden.
    Lawoko, Martin
    KTH Royal Institute of Technology, Sweden.
    Pierrou, Clara
    RenFuel Materials AB, Sweden.
    Samec, Joseph
    RenFuel Materials AB, Sweden; Stockholm University, Sweden; Chulalongkorn University, Thailand; Ren FuelK2B AB, Sweden.
    Subbotina, Elena
    Yale University, USA.
    Wallmo, Henrik
    Valmet AB, Sweden.
    Wimby, Martin
    Valmet AB, Sweden.
    Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges.2023In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, article id e202300492Article in journal (Refereed)
    Abstract [en]

    Kraft lignin, a by-product from the production of pulp, is currently incinerated in the recovery boiler during the chemical recovery cycle, generating valuable bioenergy and recycling inorganic chemicals to the pulping process operation. Removing lignin from the black liquor or its gasification lowers the recovery boiler load enabling increased pulp production. During the past ten years, lignin separation technologies have emerged and the interest of the research community to valorize this underutilized resource has been invigorated. The aim of this review is to give (1) a dedicated overview of the kraft process with a focus on the lignin, (2) an overview of applications that are being developed, and (3) a techno-economic and life cycle asseeements of value chains from black liquor to different products. Overall, it is anticipated that this effort will inspire further work for developing and using kraft lignin as a commodity raw material for new applications undeniably promoting pivotal global sustainability concerns.

  • 4.
    Bengtsson, Andreas
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Bengtsson, Jenny
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Kakkonen, Markus
    Fibrobotics Oy, Finland.
    Tanhuanpää, Olli
    Fibrobotics Oy, Finland.
    Brännvall, Elisabet
    RISE Research Institutes of Sweden, Bioeconomy and Health.
    Sedin, Maria
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Continuous Stabilization and Carbonization of a Lignin-Cellulose Precursor to Carbon Fiber2022In: ACS Omega, E-ISSN 2470-1343, Vol. 7, no 19, p. 16793-16802Article in journal (Refereed)
    Abstract [en]

    The demand for carbon fibers (CFs) based on renewable raw materials as the reinforcing fiber in composites for lightweight applications is growing. Lignin-cellulose precursor fibers (PFs) are a promising alternative, but so far, there is limited knowledge of how to continuously convert these PFs under industrial-like conditions into CFs. Continuous conversion is vital for the industrial production of CFs. In this work, we have compared the continuous conversion of lignin-cellulose PFs (50 wt % softwood kraft lignin and 50 wt % dissolving-grade kraft pulp) with batchwise conversion. The PFs were successfully stabilized and carbonized continuously over a total time of 1.0-1.5 h, comparable to the industrial production of CFs from polyacrylonitrile. CFs derived continuously at 1000 °C with a relative stretch of-10% (fiber contraction) had a conversion yield of 29 wt %, a diameter of 12-15 μm, a Young's modulus of 46-51 GPa, and a tensile strength of 710-920 MPa. In comparison, CFs obtained at 1000 °C via batchwise conversion (12-15 μm diameter) with a relative stretch of 0% and a conversion time of 7 h (due to the low heating and cooling rates) had a higher conversion yield of 34 wt %, a higher Young's modulus (63-67 GPa) but a similar tensile strength (800-920 MPa). This suggests that the Young's modulus can be improved by the optimization of the fiber tension, residence time, and temperature profile during continuous conversion, while a higher tensile strength can be achieved by reducing the fiber diameter as it minimizes the risk of critical defects. © 2022 The Authors. 

  • 5.
    Bengtsson, Andreas
    et al.
    KTH Royal Institute of Technology, Sweden.
    Bengtsson, Jenny
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Olsson, Carina
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Sedin, Maria
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Papermaking and Packaging.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Sjöholm, Elisabeth
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Biobased Materials.
    Improved yield of carbon fibres from cellulose and kraft lignin2018In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, no 12, p. 1007-1016Article in journal (Refereed)
    Abstract [en]

    To meet the demand for carbon-fibre-reinforced composites in lightweight applications, cost-efficient processing and new raw materials are sought for. Cellulose and kraft lignin are each interesting renewables for this purpose due to their high availability. The molecular order of cellulose is an excellent property, as is the high carbon content of lignin. By co-processing cellulose and lignin, the advantages of these macromolecules are synergistic for producing carbon fibre (CF) of commercial grade in high yields. CFs were prepared from precursor fibres (PFs) made from 70:30 blends of softwood kraft lignin (SW-KL) and cellulose by dry-jet wet spinning with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) as a solvent. In focus was the impact of the molecular mass of lignin and the type of cellulose source on the CF yield and properties, while membrane-filtrated kraft lignin and cellulose from dissolving kraft pulp and fully bleached paper-grade SW-KP (kraft pulp) served as sources. Under the investigated conditions, the yield increased from around 22% for CF from neat cellulose to about 40% in the presence of lignin, irrespective of the type of SW-KL. The yield increment was also higher relative to the theoretical one for CF made from blends (69%) compared to those made from neat celluloses (48-51%). No difference in the mechanical properties of the produced CF was observed.

  • 6.
    Bengtsson, Jenny
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Bengtsson, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Ulmefors, Hanna
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Sedin, Maria
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Preventing fiber-fiber adhesion of lignin-cellulose precursors and carbon fibers with spin finish application2023In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434XArticle in journal (Refereed)
    Abstract [en]

    Adhesion of fibers within a spun tow, including carbon fibers and precursors, is undesirable as it may interrupt the manufacturing process and entail inferior fiber properties. In this work, softwood kraft lignin was used together with a dissolving pulp to spin carbon fiber precursors. Lignin-cellulose precursors have previously been found to be prone to fiber fusion, both post-spinning and during carbon fiber conversion. In this study, the efficiency of applying different kinds of spin finishes, with respect to rendering separable precursors and carbon fibers, has been investigated. It was found that applying a cationic surfactant, and to a similar extent a nonionic surfactant, resulted in well separated lignin-cellulose precursor tows. Furthermore, the fiber separability after carbon fiber conversion was evaluated, and notably, precursors treated with a silicone-based spin finish generated the most well-separated carbon fibers. The underlying mechanism of fiber fusion post-spinning and converted carbon fibers is discussed. 

  • 7.
    Bengtsson, Jenny
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Biobased Materials. Chalmers University of Technology, Sweden.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Hedlund, Artur
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Mass transport and yield during spinning oflignin-cellulose carbon fiber precursors2019In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 73, no 5, p. 509-516Article in journal (Refereed)
    Abstract [en]

    Lignin, a substance considered as a residue in biomass and ethanol production, has been identified as a renewable resource suitable for making inexpensive carbon fibers (CFs), which would widen the range of possible applications for light-weight CFs reinforced composites. Wet spinning of lignin-cellulose ionic liquid solutions is a promising method for producing lignin-based CFs precursors. However, wet-spinning solutions containing lignin pose technical challenges that have to be solved to enable industrialization. One of these issues is that a part of the lignin leaches into the coagulation liquid, which reduces yield and might complicate solvent recovery. In this work, the mass transport during coagulation is studied in depth using a model system and trends are confirmed with spinning trials. It was discovered that during coagulation, efflux of ionic liquid is not hindered by lignin concentration in solution and the formed cellulose network will enclose soluble lignin. Consequently, a high total concentration of lignin and cellulose in solution is advantageous to maximize yield. This work provides a fundamental understanding on mass transport during coagulation of lignin-cellulose solutions, crucial information when designing new solution-based fiber forming processes.

  • 8.
    Bengtsson, Jenny
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Dry-jet wet-spun lignin-based carbon fibre precursors2018Conference paper (Other academic)
  • 9.
    Bengtsson, Jenny
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF. Chalmers University of Technology, Sweden.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Identifying breach mechanism during air-gap spinning of lignin–cellulose ionic-liquid solutions2019In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, article id 47800Article in journal (Refereed)
    Abstract [en]

    To be able to produce highly oriented and strong fibers from polymer solutions, a high elongational rate during the fiber-forming process is necessary. In the air-gap spinning process, a high elongational rate is realized by employing a high draw ratio, the ratio between take-up and extrusion velocity. Air-gap spinning of lignin–cellulose ionic-liquid solutions renders fibers that are promising to use as carbon fiber precursors. To further improve their mechanical properties, the polymer orientation should be maximized. However, achieving high draw ratios is limited by spinning instabilities that occur at high elongational rates. The aim of this experimental study is to understand the link between solution properties and the critical draw ratio during air-gap spinning. A maximum critical draw ratio with respect to temperature is found. Two mechanisms that limit the critical draw ratio are proposed, cohesive breach and draw resonance, the latter identified from high-speed videos. The two mechanisms clearly correlate with different temperature regions. The results from this work are not only of value for future work within the studied system but also for the design of air-gap spinning processes in general.

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  • 10.
    Bengtsson, Jenny
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles. Chalmers University of Technology, Sweden.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Köhnke, Tobias
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    The challenge of predicting spinnability: Investigating benefits of adding lignin to cellulose solutions in air-gap spinning2021In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 138, no 26, article id 50629Article in journal (Refereed)
    Abstract [en]

    In this study, the underlying mechanism for improved spinnability when mixing lignin and cellulose in solution was investigated. Co-processing of lignin and cellulose has previously been identified as a potential route for production of inexpensive and bio-based carbon fibers. The molecular order of cellulose contributes to the strength of the fibers and the high carbon content of lignin improves the yield during conversion to carbon fibers. The current work presents an additional benefit of combining lignin and cellulose; solutions that contain both lignin and cellulose could be air-gap spun at substantially higher draw ratios than pure cellulose solutions, that is, lignin improved the spinnability. Fibers were spun from solutions containing different ratios of lignin, from 0 to 70 wt%, and the critical draw ratio was determined at various temperatures of solution. The observations were followed by characterization of the solutions with shear and elongational viscosity and surface tension, but none of these methods could explain the beneficial effect of lignin on the spinnability. However, by measuring the take-up force it was found that lignin seems to stabilize against diameter fluctuations during spinning, and plausible explanations are discussed

  • 11.
    Bengtsson, Jenny
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Theliander, T
    Coagulation of dry-jet wet-spun lignin-based carbon fibre precursors2018In: Proceedings of the 15th European workshop on lignocellulosics and pulp, 2018, p. 123-126Conference paper (Refereed)
  • 12.
    Bengtsson, Jenny
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Peterson, Anna
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Idström, Alexander
    Chalmers University of Technology, Sweden.
    de la Motte, Hanna
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Chemical Recycling of a Textile Blend from Polyester and Viscose, Part II: Mechanism and Reactivity during Alkaline Hydrolysis of Textile Polyester2022In: Sustainability, E-ISSN 2071-1050, Vol. 14, no 11, article id 6911Article in journal (Refereed)
    Abstract [en]

    Chemical recycling of textiles holds the potential to yield materials of equal quality and value as products from virgin feedstock. Selective depolymerization of textile polyester (PET) from regenerated cellulose/PET blends, by means of alkaline hydrolysis, renders the monomers of PET while cellulose remains in fiber form. Here, we present the mechanism and reactivity of textile PET during alkaline hydrolysis. Part I of this article series focuses on the cellulose part and a possible industrialization of such a process. The kinetics and reaction mechanism for alkaline hydrolysis of polyester packaging materials or virgin bulk polyester are well described in the scientific literature; however, information on depolymerization of PET from textiles is sparse. We find that the reaction rate of hydrolysis is not affected by disintegrating the fabric to increase its surface area. We ascribe this to the yarn structure, where texturing and a low density assures a high accessibility even without disintegration. The reaction, similar to bulk polyester, is shown to be surface specific and proceeds via endwise peeling. Finally, we show that the reaction product terephthalic acid is pure and obtained in high yields. © 2022 by the authors. 

  • 13.
    El Seoud, Omar A
    et al.
    University of São Paulo, Brazil.
    Kostag, Marc
    University of São Paulo, Brazil.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Malek, Naved I
    Sardar Vallabhbhai National Institute of Technology, India.
    Cellulose in Ionic Liquids and Alkaline Solutions: Advances in the Mechanisms of Biopolymer Dissolution and Regeneration.2019In: Polymers, E-ISSN 2073-4360, Vol. 11, no 12, article id E1917Article in journal (Refereed)
    Abstract [en]

    This review is focused on assessment of solvents for cellulose dissolution and the mechanism of regeneration of the dissolved biopolymer. The solvents of interest are imidazole-based ionic liquids, quaternary ammonium electrolytes, salts of super-bases, and their binary mixtures with molecular solvents. We briefly discuss the mechanism of cellulose dissolution and address the strategies for assessing solvent efficiency, as inferred from its physico-chemical properties. In addition to the favorable effect of lower cellulose solution rheology, microscopic solvent/solution properties, including empirical polarity, Lewis acidity, Lewis basicity, and dipolarity/polarizability are determinants of cellulose dissolution. We discuss how these microscopic properties are calculated from the UV-Vis spectra of solvatochromic probes, and their use to explain the observed solvent efficiency order. We dwell briefly on use of other techniques, in particular NMR and theoretical calculations for the same purpose. Once dissolved, cellulose is either regenerated in different physical shapes, or derivatized under homogeneous conditions. We discuss the mechanism of, and the steps involved in cellulose regeneration, via formation of mini-sheets, association into "mini-crystals", and convergence into larger crystalline and amorphous regions. We discuss the use of different techniques, including FTIR, X-ray diffraction, and theoretical calculations to probe the forces involved in cellulose regeneration.

  • 14.
    El Seoud, Omar
    et al.
    University of São Paulo, Brazil.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Kostag, Marc
    University of São Paulo, Brazil.
    Possidonio, Shirley
    UNIFESP, Brazil.
    Cellulose, chitin and silk: the cornerstones of green composites2022In: Emergent Materials, ISSN 2522-5731, Vol. 5, no 3, p. 785-Article in journal (Refereed)
    Abstract [en]

    This overview article is concerned with fabrication and applications of the composites of three major biopolymers, cellulose (Cel), chitin (Chn)/chitosan (Chs), and silk fibroin (SF). A brief discussion of their molecular structures shows that they carry functional groups (-OH, -NH-COCH3, -NH2, -CONH-) whose hydrogen-bonding, and der Waals interactions lead to semi-crystalline structures in the solid phase. There are several classes of solvents that disrupt these interactions, hence dissolve the above-mentioned biopolymers. These include solutions of inorganic and organic electrolytes in dipolar aprotic solvents (DASs), ionic liquids (ILs), and their solutions in DASs. Mixing of biopolymer solutions leads to efficient mutual interactions, hence formation of relatively homogeneous composites. These are then regenerated in non-solvents (water, ethanol, acetone) in different physical forms, e.g., fibers, nanoparticles and films. We discuss the fabrication of these products that have enormous potential use in the textile industry, in medicine, in the food industry, and decontamination of fluids. These applications will most certainly expand due to the attractive characteristics of these composites (renewability, sustainability, biodegradation) and the increased public concern about the adverse environmental impact of petroleum-based polymers, as recently shown by the presence of microplastics in air, water, land, and food (Akdogan & Guven in Environ Pollut. 254:113011 (2019)).

  • 15.
    El Seoud, Omar
    et al.
    University of São Paulo, Brazil.
    Kostag, Marc
    University of São Paulo, Brazil.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Malek, Naved
    Sardar Vallabhbhai National Institute of Technology, India.
    Cellulose Regeneration and Chemical Recycling: Closing the “Cellulose Gap” Using Environmentally Benign Solvents2020In: Macromolecular materials and engineering, ISSN 1438-7492, E-ISSN 1439-2054, Vol. 305, no 4, article id 1900832Article in journal (Refereed)
    Abstract [en]

    Strategies to mitigate the expected “cellulose gap” include increased use of wood cellulose, fabric reuse, and recycling. Ionic liquids (ILs) are employed for cellulose physical dissolution and shaping in different forms. This review focuses on the regeneration of dissolved cellulose as nanoparticles, membranes, nonwoven materials, and fibers. The solvents employed in these applications include ILs and alkali solutions without and with additives. Cellulose fibers obtained via the carbonate and carbamate processes are included. Chemical recycling (CR) of polycotton (cellulose plus poly(ethylene terephthalate)) is addressed because depending on the recycling approach employed, this process is akin to regeneration. The strategies investigated in CR include preferential dissolution or depolymerization of one component of the blend, and separation of both components using ILs. It is hoped that this review focuses the attention on the potential applications of regenerated cellulose from its solutions and contributes to the important environmental issue of recycling of used materials.

  • 16.
    Jedvert, Kerstin
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF. University of Jena, Germany.
    Elschner, Thomas
    University of Maribor, Slovenia.
    Heinze, Thomas
    University of Jena, Germany.
    Adsorption Studies of Amino Cellulose on Cellulosics2017In: Macromolecular materials and engineering, ISSN 1438-7492, E-ISSN 1439-2054, Vol. 302, no 7, article id 1700022Article in journal (Refereed)
    Abstract [en]

    Adsorption of a typical example of a new class of amino cellulose, namely 6-deoxy-6-(2-aminoethyl)amino cellulose at different pH-values and in the presence of electrolytes, onto cellulose model substrates is studied with surface plasmon resonance and quartz crystal microbalance with dissipation monitoring. Unexpectedly, adsorption is consistently higher at a higher pH-value of 10, indicating that solubility and interactions between amine moieties and cellulose are more important than electrostatic interactions. The findings are highly relevant for the process to modify material surfaces with amino cellulose in water-based systems as a universal tool for changing the surface properties and chemistry. Potential applications for an antimicrobial all biobased material could be found, e.g., as medical textiles or in the biotechnology sector.

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  • 17.
    Jedvert, Kerstin
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF. Friedrich Schiller University Jena, Germany.
    Heinze, Thomas
    Friedrich Schiller University Jena, Germany.
    Cellulose modification and shaping – a review2017In: Journal of polymer engineering, ISSN 0334-6447, E-ISSN 2191-0340, Vol. 37, no 9, p. 845-860Article in journal (Refereed)
    Abstract [en]

    This review aims to present cellulose as a versatile resource for the production of a variety of materials, other than pulp and paper. These products include fibers, nonwovens, films, composites, and novel derivatized materials. This article will briefly introduce the structure of cellulose and some common cellulose derivatives, as well as the formation of cellulosic materials in the micro- and nanoscale range. The challenge with dissolution of cellulose will be discussed and both derivatizing and nonderivatizing solvents for cellulose will be described. The focus of the article is the critical discussion of different shaping processes to obtain a variety of cellulose products, from commercially available viscose fibers to advanced and functionalized materials still at the research level.

  • 18.
    Jedvert, Kerstin
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Idström, Alexander
    RISE Research Institutes of Sweden, Materials and Production.
    Köhnke, Tobias
    Alkhagen, Mårten
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Cellulosic nonwovens produced via efficient solution blowing technique2020In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 137, no 5, article id 48339Article in journal (Refereed)
    Abstract [en]

    The demand for nonwoven materials has increased during the last few years and is expected to increase further due to its use in a broad range of new application areas. Today, the majority of nonwovens are from petroleum-based resources but there is a desideratum to develop sustainable and competitive materials from renewable feedstock. In this work, renewable nonwovens are produced by solution blowing of dissolved cellulose using 1-ethyl-3-methylimidazolium acetate (EMIMAc) as solvent. Properties of cellulose solutions and process parameters, such as temperature, flow rate, air pressure, and distance to collector, are evaluated in respect to spinnability and material structural properties. Nonwovens with fiber diameters mainly in the micrometer range were successfully produced and it was shown that high temperature or low flow rate resulted in thinner fibers. The produced materials were stiffer (higher effective stress and lower strain) compared to commercial polypropylene nonwoven. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48339. © 2019 The Authors.

  • 19.
    Jedvert, Kerstin
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Viklund, Linnea
    RISE Research Institutes of Sweden. Chalmers University of Technology, Sweden.
    Alkhagen, Mårten
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Köhnke, Tobias
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Tailoring the physical characteristics of solution blown cellulosic nonwovens by various post-treatments2021In: Nordic Pulp & Paper Research Journal, Vol. 36, no 4, p. 682-695Article in journal (Refereed)
    Abstract [en]

    Nonwovens are increasing in demand due to their versatility which enables use in a broad range of applications. Most nonwovens are still produced from fossil-based resources and there is thus a need to develop competitive materials from renewable feedstock. In this work, nonwovens are produced from cellulose via a direct solution blowing method. 

  • 20.
    Kostag, Marc
    et al.
    University of São Paulo, Brazil.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Achtel, Christian
    Friedrich Schiller University of Jena, Germany.
    Heinze, Thomas
    Friedrich Schiller University of Jena, Germany.
    El Seoud, Omar A
    University of São Paulo, Brazil.
    Recent Advances in Solvents for the Dissolution, Shaping and Derivatization of Cellulose: Quaternary Ammonium Electrolytes and their Solutions in Water and Molecular Solvents.2018In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, no 3, article id E511Article in journal (Refereed)
    Abstract [en]

    There is a sustained interest in developing solvents for physically dissolving cellulose, i.e., without covalent bond formation. The use of ionic liquids, ILs, has generated much interest because of their structural versatility that results in efficiency as cellulose solvents. Despite some limitations, imidazole-based ILs have received most of the scientific community's attention. The objective of the present review is to show the advantages of using quaternary ammonium electrolytes, QAEs, including salts of super bases, as solvents for cellulose dissolution, shaping, and derivatization, and as a result, increase the interest in further investigation of these important solvents. QAEs share with ILs structural versatility; many are liquids at room temperature or are soluble in water and molecular solvents (MSs), in particular dimethyl sulfoxide. In this review we first give a historical background on the use of QAEs in cellulose chemistry, and then discuss the common, relatively simple strategies for their synthesis. We discuss the mechanism of cellulose dissolution by QAEs, neat or as solutions in MSs and water, with emphasis on the relevance to cellulose dissolution efficiency of the charge and structure of the cation and. We then discuss the use of cellulose solutions in these solvents for its derivatization under homogeneous and heterogeneous conditions. The products of interest are cellulose esters and ethers; our emphasis is on the role of solvent and possible side reactions. The final part is concerned with the use of cellulose dopes in these solvents for its shaping as fibers, a field with potential commercial application.

  • 21.
    Kostag, Marc
    et al.
    University of São Paulo, Brazil.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    El Seoud, Omar
    University of São Paulo, Brazil.
    Engineering of sustainable biomaterial composites from cellulose and silk fibroin: Fundamentals and applications2021In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 167, p. 687-718Article in journal (Refereed)
    Abstract [en]

    This review addresses composites prepared from cellulose (Cel) and silk fibroin (SF) to generate multifunctional, biocompatible, biodegradable materials such as fibers, films and scaffolds for tissue engineering. First, we discuss briefly the molecular structures of Cel and SF. Their structural features explain why certain solvents, e.g., ionic liquids, inorganic electrolyte solutions dissolve both biopolymers. We discuss the mechanisms of Cel dissolution because in many cases they also apply to (much less studied) SF dissolution. Subsequently, we discuss the fabrication and characterization of Cel/SF composite biomaterials. We show how the composition of these materials beneficially affects their mechanical properties, compared to those of the precursor biopolymers. We also show that Cel/SF materials are excellent and versatile candidates for biomedical applications because of the inherent biocompatibility of their components.

  • 22.
    Liu, Jiliang
    et al.
    ESRF European Synchrotron Radiation Facility, France.
    Bengtsson, Jenny
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Yu, Shun
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Burghammer, Manfred
    ESRF European Synchrotron Radiation Facility, France.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Variation in the hierarchical structure of lignin-blended cellulose precursor fibers2023In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 225, p. 1555-Article in journal (Refereed)
    Abstract [en]

    Regenerated cellulose fibers have been considered as potential precursor fibers for carbon fibers because of their balanced cost and performance. Increased attention has been paid to blending lignin with the regenerated cellulose to generate precursor fibers which render good mechanical properties and higher carbon yield. The mechanical properties of carbon fibers have been found closely correlated to the structure of precursor fibers. However, the effects of lignin blending on molecular- and morphological structure of the precursor are still unclear. This study aims at clarifying the structural information of lignin–cellulose precursor fibers from molecular level to mesoscale by scanning X-ray microdiffraction. We present the existence of a skin–core morphology for all the precursor fibers. Increase of lignin content in precursor fiber could reduce the portion of skin and cause obvious disorder of the meso- and molecular structure. By correlating structural variations with lignin blending, 30% lignin blending has been found as a potential balance point to obtain precursor fibers maintaining structural order together with high yield rate. 

  • 23.
    Peterson, Anna
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Wallinder, Johan
    RISE Research Institutes of Sweden, Bioeconomy and Health, Pulp, Paper and Packaging.
    Bengtsson, Jenny
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Idström, A.
    Chalmers University of Technology, Sweden.
    Bialik, Marta
    RISE Research Institutes of Sweden, Bioeconomy and Health, Pulp, Paper and Packaging.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Pulp, Paper and Packaging.
    de la Motte, Hanna
    RISE Research Institutes of Sweden, Bioeconomy and Health, Pulp, Paper and Packaging.
    Chemical Recycling of a Textile Blend from Polyester and Viscose, Part I: Process Description, Characterization, and Utilization of the Recycled Cellulose2022In: Sustainability, E-ISSN 2071-1050, Vol. 14, no 12, article id 7272Article in journal (Refereed)
    Abstract [en]

    Material recycling requires solutions that are technically, as well as economically and ecologically, viable. In this work, the technical feasibility to separate textile blends of viscose and polyester using alkaline hydrolysis is demonstrated. Polyester is depolymerized into the monomer terephthalic acid at high yields, while viscose is recovered in a polymeric form. After the alkaline treatment, the intrinsic viscosity of cellulose is decreased by up to 35%, which means it may not be suitable for conventional fiber-to-fiber recycling; however, it might be attractive in other technologies, such as emerging fiber processes, or as raw material for sugar platforms. Further, we present an upscaled industrial process layout, which is used to pinpoint the areas of the proposed process that require further optimization. The NaOH economy is identified as the key to an economically viable process, and several recommendations are given to decrease the consumption of NaOH. To further enhance the ecological end economic feasibility of the process, an increased hydrolysis rate and integration with a pulp mill are suggested. © 2022 by the authors.

  • 24.
    Svenningsson, Leo
    et al.
    Chalmers University of Technology, Sweden.
    Bengtsson, Jenny
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Schlemmer, Werner
    Graz University of Technology, Austria.
    Theliander, Hans
    Chalmers University of Technology, Sweden; Wallenberg Wood Science Center, Sweden.
    Evenäs, Lars
    Chalmers University of Technology, Sweden; Wallenberg Wood Science Center, Sweden.
    Disassociated molecular orientation distributions of a composite cellulose–lignin carbon fiber precursor: A study by rotor synchronized NMR spectroscopy and X-ray scattering2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 254, article id 117293Article in journal (Refereed)
    Abstract [en]

    Cellulose–lignin composite carbon fibers have shown to be a potential environmentally benign alternative to the traditional polyacrylonitrile precursor. With the associated cost reduction, cellulose–lignin carbon fibers are an attractive light-weight material for, e.g. wind power and automobile manufacturing. The carbon fiber tenacity, tensile modulus and creep resistance is in part determined by the carbon content and the molecular orientation distribution of the precursor. This work disassociates the molecular orientation of different components in cellulose–lignin composite fibers using rotor-synchronized solid-state nuclear magnetic resonance spectroscopy and X-ray scattering. Our results show that lignin is completely disordered, in a mechanically stretched cellulose–lignin composite fiber, while the cellulose is ordered. In contrast, the native spruce wood raw material displays both oriented lignin and cellulose. The current processes for fabricating a cellulose–lignin composite fiber cannot regain the oriented lignin as observed from the native wood. © 2020 The Author(s)

1 - 24 of 24
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