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Publikasjoner (10 av 34) Visa alla publikasjoner
Jedvert, K., Idström, A., Köhnke, T. & Alkhagen, M. (2020). Cellulosic nonwovens produced via efficient solution blowing technique. Journal of Applied Polymer Science, 137(5), Article ID 48339.
Åpne denne publikasjonen i ny fane eller vindu >>Cellulosic nonwovens produced via efficient solution blowing technique
2020 (engelsk)Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 137, nr 5, artikkel-id 48339Artikkel i tidsskrift (Fagfellevurdert) Published
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.

sted, utgiver, år, opplag, sider
John Wiley and Sons Inc., 2020
Emneord
cellulose, nonwovens, solution blowing, Polypropylenes, 1-ethyl-3-methylimidazolium acetates, Cellulose solutions, Effective stress, Micrometer ranges, Non-wovens, Nonwoven materials, Process parameters, Renewable feedstocks, Nonwoven fabrics
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-39851 (URN)10.1002/app.48339 (DOI)2-s2.0-85070821248 (Scopus ID)
Merknad

Funding details: Svenska Forskningsrådet Formas, 942‐2015‐388; Funding text 1: The Swedish Research Council Formas (Grant No. 942‐2015‐388) is gratefully acknowledged for the financial support.

Tilgjengelig fra: 2019-08-30 Laget: 2019-08-30 Sist oppdatert: 2019-12-06bibliografisk kontrollert
Bengtsson, J., Jedvert, K., Köhnke, T. & Theliander, H. (2019). Identifying breach mechanism during air-gap spinning of lignin–cellulose ionic-liquid solutions. Journal of Applied Polymer Science, Article ID 47800.
Åpne denne publikasjonen i ny fane eller vindu >>Identifying breach mechanism during air-gap spinning of lignin–cellulose ionic-liquid solutions
2019 (engelsk)Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, artikkel-id 47800Artikkel i tidsskrift (Fagfellevurdert) Published
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. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47800.

sted, utgiver, år, opplag, sider
John Wiley and Sons Inc., 2019
Emneord
cellulose and other wood products, extrusion, fibers, manufacturing, viscosity and viscoelasticity, Air, Carbon fibers, Cellulose, High speed cameras, Ionic liquids, Lignin, Manufacture, Wood, Carbon fiber precursors, Extrusion velocity, High draw ratios, High-speed video, Solution property, Spinning process, Temperature regions, Viscosity and viscoelasticities, Spinning (fibers)
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-38493 (URN)10.1002/app.47800 (DOI)2-s2.0-85063743075 (Scopus ID)
Tilgjengelig fra: 2019-05-03 Laget: 2019-05-03 Sist oppdatert: 2019-06-18bibliografisk kontrollert
Bengtsson, J., Jedvert, K., Hedlund, A., Köhnke, T. & Theliander, H. (2019). Mass transport and yield during spinning oflignin-cellulose carbon fiber precursors. Holzforschung, 73(5), 509-516
Åpne denne publikasjonen i ny fane eller vindu >>Mass transport and yield during spinning oflignin-cellulose carbon fiber precursors
Vise andre…
2019 (engelsk)Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 73, nr 5, s. 509-516Artikkel i tidsskrift (Fagfellevurdert) Published
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.

Emneord
biomass; carbon fiber; ionic liquids; lignin; wet spinning
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-37686 (URN)10.1515/hf-2018-0246 (DOI)
Tilgjengelig fra: 2019-01-31 Laget: 2019-01-31 Sist oppdatert: 2019-07-01bibliografisk kontrollert
Hedlund, A., Theliander, H. & Köhnke, T. (2019). Mass transport during coagulation of cellulose-ionic liquid solutions in different non-solvents. Cellulose (London)
Åpne denne publikasjonen i ny fane eller vindu >>Mass transport during coagulation of cellulose-ionic liquid solutions in different non-solvents
2019 (engelsk)Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882XArtikkel i tidsskrift (Fagfellevurdert) Epub ahead of print
Abstract [en]

Abstract: Cellulose can be regenerated from cellulose-ionic liquid (IL) solutions by immersion in water or alcohols. These compounds are potent non-solvents due to their proton-donating ability in hydrogen bonds to IL anions. Although they share this fundamental way of reducing IL solvent quality, coagulation in water is distinctly different from coagulation in alcohols with regard to the microstructures formed and the mechanisms that generate the microstructures. In this study, the possibility of mass-transport effects on microstructures was investigated. The mass-transport of all components: non-solvent (EtOH, 2PrOH), IL ([C2mim][OAc]), and a co-solvent (DMSO), during coagulation was studied. The data was compared to previous data with water as the non-solvent. Results showed that diffusion is essentially limited to a continuous non-solvent-rich phase that is formed during phase separation in all non-solvents. There were also significant differences between non-solvents. For instance, [C2mim][OAc] diffusion coefficients were 6–9 times smaller in 2PrOH than in water, and there were apparent effects from cellulose concentration in 2PrOH that were not observed in water. The differences stem from the interactions between solvent, non-solvents, and cellulose, which can be both mutual and competitive. Weaker [C2mim][OAc]-non-solvent interactions with alcohols give more persistent [C2mim][OAc]-cellulose interactions than with water as the non-solvent, which has consequences for mass-transport. Graphic abstract: [Figure not available: see fulltext.]. © 2019, The Author(s).

sted, utgiver, år, opplag, sider
Springer Netherlands, 2019
Emneord
Alcohol, Cellulose, Coagulation, Ionic liquids, Mass transport, Non-solvent, Precipitation, Water, Alcohols, Hydrogen bonds, Mass transfer, Microstructure, Phase separation, Praseodymium compounds, Precipitation (chemical), Cosolvents, Immersion in waters, Liquid solution, Non-solvents, Rich phase, Solvent quality, Transport effects, Solvents
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-39853 (URN)10.1007/s10570-019-02649-w (DOI)2-s2.0-85070798486 (Scopus ID)
Merknad

 Funding text 1: Open access funding provided by Chalmers University of Technology. This research would not have been possible without financing from the Södra Skogsägarna Foundation for Research, Development and Education. The scientists at the Swedish NMR Centre in Gothenburg as well as the other partners within the Avancell Project are gratefully acknowledged for their help in this Project. 1 The hydroxyl groups of cellulose cannot be very much stronger hydrogen-bond donors than other alcohols are (e.g. methanol has αα = 0.43 and ethandiol has αα = 0.58).

Tilgjengelig fra: 2019-08-30 Laget: 2019-08-30 Sist oppdatert: 2019-08-30bibliografisk kontrollert
Hedlund, A., Köhnke, T., Hagman, J., Olsson, U. & Theliander, H. (2019). Microstructures of cellulose coagulated in water and alcohols from 1-ethyl-3-methylimidazolium acetate: contrasting coagulation mechanisms. Cellulose (London), 26(3), 1545-1563
Åpne denne publikasjonen i ny fane eller vindu >>Microstructures of cellulose coagulated in water and alcohols from 1-ethyl-3-methylimidazolium acetate: contrasting coagulation mechanisms
Vise andre…
2019 (engelsk)Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, nr 3, s. 1545-1563Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Abstract: Coagulation of cellulose solutions is a process whereby many useful materials with variable microstructures and properties can be produced. This study investigates the complexity of the phase separation that generates the structural heterogeneity of such materials. The ionic liquid, 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), and a co-solvent, dimethylsulfoxide (DMSO), are used to dissolve microcrystalline cellulose in concentrations from 5 to 25 wt%. The solutions are coagulated in water or 2-propanol (2PrOH). The coagulated material is then washed and solvent exchanged (water → 2PrOH → butanone → cyclohexane) in order to preserve the generated microstructures upon subsequent drying before analysis. Sweep electron microscopy images of 50 k magnification reveal open-pore fibrillar structures. The crystalline constituents of those fibrils are estimated using wide-angle X-ray spectroscopy and specific surface area data. It is found that the crystalline order or crystallite size is reduced by an increase in cellulose concentration, by the use of the co-solvent DMSO, or by the use of 2PrOH instead of water as the coagulant. Because previous theories cannot explain these trends, an alternative explanation is presented here focused on solid–liquid versus liquid–liquid phase separations. Graphical abstract: [Figure not available: see fulltext.].

Emneord
Cellulose, Co-solvent, Ionic liquid, Microstructure, Non-solvent, Regeneration, Coagulation, Crystallite size, Ionic liquids, Ketones, Phase separation, Praseodymium compounds, Solvents, X ray spectroscopy, 1-ethyl-3-methylimidazolium acetates, Cosolvents, Electron microscopy images, Micro-crystalline cellulose, Microstructures and properties, Non-solvents, Structural heterogeneity
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-36913 (URN)10.1007/s10570-018-2168-6 (DOI)2-s2.0-85058662143 (Scopus ID)
Tilgjengelig fra: 2018-12-28 Laget: 2018-12-28 Sist oppdatert: 2019-07-01bibliografisk kontrollert
Nechyporchuk, O. & Köhnke, T. (2019). Regenerated Casein-Nanocellulose Composite Fibers via Wet Spinning. ACS Sustainable Chemistry and Engineering, 7(1), 1419-1426
Åpne denne publikasjonen i ny fane eller vindu >>Regenerated Casein-Nanocellulose Composite Fibers via Wet Spinning
2019 (engelsk)Inngår i: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 7, nr 1, s. 1419-1426Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Development of sustainable biobased fibers is required to displace their fossil-based counterparts, e.g., in textile, nonwoven, or composite applications. Regenerated protein fibers have a potential in this regard if their mechanical properties are improved. Herein, we study for the first time the use of nanocellulose as reinforcement in regenerated protein fibers produced using wet spinning. The influence of cellulose nanocrystals (CNC) incorporated into regenerated casein fibers is examined in terms of mechanical and morphological properties. The influence of different conditions for fiber chemical cross-linking is also investigated. Incorporation of CNC (up to 37.5 wt %) into spin dopes results in a continuous increase of fiber Young's modulus (up to twofold) in the dry state. Both maximum and breaking tenacity of dry fibers are enhanced by CNC, with a maximum at 7.0-10.5 wt % of CNC. When testing after being wetted, both breaking tenacity and Young's modulus of the composite fibers decrease, likely due to weakening of hydrogen bonds between CNC in the presence of water. We also demonstrate that the presence of salt during chemical cross-linking is crucial to produce intact and separated fibers in the yarn.

Emneord
Casein, Cellulose nanocrystals, Composite fibers, Nanocellulose, Proteins, Wet spinning, Cellulose, Cellulose derivatives, Crosslinking, Elastic moduli, Fibers, Hydrogen bonds, Nanocrystals, Tenacity, Weaving, Breaking tenacities, Cellulose nano-crystals, Cellulose nanocrystal (CNC), Chemical cross-linking, Composite applications, Morphological properties, Spinning (fibers)
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-37014 (URN)10.1021/acssuschemeng.8b05136 (DOI)2-s2.0-85059641118 (Scopus ID)
Tilgjengelig fra: 2019-01-21 Laget: 2019-01-21 Sist oppdatert: 2019-01-21bibliografisk kontrollert
Bengtsson, J., Jedvert, K., Köhnke, T. & Theliander, T. (2018). Coagulation of dry-jet wet-spun lignin-based carbon fibre precursors. In: Proceedings of the 15th European workshop on lignocellulosics and pulp: . Paper presented at 15th European workshop on lignocellulosics and pulp, Aveiro, June 26-29 (pp. 123-126).
Åpne denne publikasjonen i ny fane eller vindu >>Coagulation of dry-jet wet-spun lignin-based carbon fibre precursors
2018 (engelsk)Inngår i: Proceedings of the 15th European workshop on lignocellulosics and pulp, 2018, s. 123-126Konferansepaper, Publicerat paper (Fagfellevurdert)
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-34842 (URN)
Konferanse
15th European workshop on lignocellulosics and pulp, Aveiro, June 26-29
Tilgjengelig fra: 2018-08-15 Laget: 2018-08-15 Sist oppdatert: 2019-06-18bibliografisk kontrollert
Nechyporchuk, O., Håkansson, K., Gowda.V, K., Lundell, F., Hagström, B. & Köhnke, T. (2018). Continuous Assembly of Cellulose Nanofibrils and Nanocrystals into Strong Macrofibers through Microfluidic Spinning. Advanced Materials Technologies, Article ID 1800557.
Åpne denne publikasjonen i ny fane eller vindu >>Continuous Assembly of Cellulose Nanofibrils and Nanocrystals into Strong Macrofibers through Microfluidic Spinning
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2018 (engelsk)Inngår i: Advanced Materials Technologies, ISSN 2365-709X, artikkel-id 1800557Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Microfluidic fiber spinning is a promising technique for assembling cellulose nanomaterials into macroscopic fibers. However, its implementation requires upscalabe fabrication processes while maintaining high strength of the fibers, which could not be previously achieved. Herein, a continuous wet spinning process based on microfluidic flow focusing is developed to produce strong fibers from cellulose nanofibrils (CNFs) and nanocrystals (CNCs). Fibers with an average breaking tenacity as high as 29.5 cN tex−1 and Young's modulus of 1146 cN tex−1 are reported for the first time, produced from nonhighly purified CNF grades. Using the same developed method, wet spinning of fibers from CNCs is achieved for the first time, reaching an average Young's modulus of 1263 cN tex−1 and a breaking tenacity of 10.6 cN tex−1, thus exhibiting strength twice as high as that of common CNC films. A rather similar stiffness of CNC and CNF spun fibers may originate from similar degrees of alignment, as confirmed by wide-angle X-ray scattering (WAXS) and birefringence measurements, whereas lower strength may primarily arise from the shorter length of CNCs compared to that of CNFs. The benefit of CNCs is their higher solids content in the dopes. By combining both CNCs and CNFs, the fiber properties can be tuned.

Emneord
cellulose nanocrystals, cellulose nanofibrils, flow focusing, microfluidic fiber spinning, nanocellulose, Cellulose, Cellulose derivatives, Elastic moduli, Fibers, Microfluidics, Nanocrystals, Nanofibers, Tenacity, X ray scattering, Birefringence measurements, Cellulose nano-crystals, Cellulose nanofibrils (CNFs), Fabrication process, Fiber spinning, Wet spinning process, Spinning (fibers)
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-36675 (URN)10.1002/admt.201800557 (DOI)2-s2.0-85058288929 (Scopus ID)
Tilgjengelig fra: 2018-12-21 Laget: 2018-12-21 Sist oppdatert: 2019-03-07bibliografisk kontrollert
Bengtsson, J., Jedvert, K., Köhnke, T. & Theliander, H. (2018). Dry-jet wet-spun lignin-based carbon fibre precursors. In: : . Paper presented at ACS National meeting, March 18-22, New Orleans, USA.
Åpne denne publikasjonen i ny fane eller vindu >>Dry-jet wet-spun lignin-based carbon fibre precursors
2018 (engelsk)Konferansepaper, Oral presentation only (Annet vitenskapelig)
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-34841 (URN)
Konferanse
ACS National meeting, March 18-22, New Orleans, USA
Tilgjengelig fra: 2018-08-15 Laget: 2018-08-15 Sist oppdatert: 2019-03-06bibliografisk kontrollert
Hedlund, A., Köhnke, T. & Theliander, H. (2017). Coagulation of cellulose solutions and controlling properties of regenerated cellulose materials. In: Monica Ek (Ed.), Cellulosic material Properties and industrial potential: Final meeting in COST FP1205. Paper presented at Final meeting in COST FP1205, Cellulosic material Properties and industrial potential, Stockholm, March 7-9, Stockholm (pp. 64-66).
Åpne denne publikasjonen i ny fane eller vindu >>Coagulation of cellulose solutions and controlling properties of regenerated cellulose materials
2017 (engelsk)Inngår i: Cellulosic material Properties and industrial potential: Final meeting in COST FP1205 / [ed] Monica Ek, 2017, s. 64-66Konferansepaper, Publicerat paper (Fagfellevurdert)
Emneord
cellulose, coagulation, microstructures, mass transport
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-34203 (URN)
Konferanse
Final meeting in COST FP1205, Cellulosic material Properties and industrial potential, Stockholm, March 7-9, Stockholm
Tilgjengelig fra: 2018-07-17 Laget: 2018-07-17 Sist oppdatert: 2019-06-27bibliografisk kontrollert
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-1259-6414
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