| 1. |
- Abdelaziz, Omar, et al.
(författare)
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A Rapid and Tunable Approach for the Fractionation of Technical Kraft Lignin
- 2023
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Ingår i: Chemical Engineering Transactions. - : Italian Association of Chemical Engineering - AIDIC. - 1974-9791 .- 2283-9216. ; 99, s. 67-72
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Tidskriftsartikel (refereegranskat)abstract
- Reducing the heterogeneity of technical lignin is essential to obtain predictable and high-performance polymeric materials that are suitable for high-value applications. Organic solvents with different polarities and solubilities can be used to fractionate lignin and reduce the complexity and diversity of its chemical structure. Among the various solvents and solvent mixtures, acetone-water mixtures offer an energy-efficient, cost-effective, and environmentally friendly means of lignin fractionation. In the present study, temperature-induced acetone-water fractionation was investigated to refine the properties of a technical softwood Kraft lignin, i.e., LignoBoost™ lignin. Relatively mild operating conditions were tested, namely, temperatures of 70-110°C and autogenous pressure. A factorial experimental design was developed using the Design-Expert® software, and three factors (temperature, time, and acetone concentration) were investigated. It was found that temperature-induced fractionation could increase lignin homogeneity and maintain high lignin solubilization with a short processing time (<1 h). It was also possible to tune the properties of the soluble lignin fraction (yield and weight-average molecular weight) based on the factorial models developed. The techno-economic evaluation confirmed the commercial viability of this fractionation process.
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| 2. |
- Baker, Darren, et al.
(författare)
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Lignin-based carbon fiber : effect of softwood kraft lignin separation method on multifilament melt-spinning performance and conversion
- 2019
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Ingår i: 20th International symposium on wood, fiber, and pulping chemistry.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A reference lignin separated from an industrial softwood kraft black liquor via an improved LignoBoost process was compared to four other lignins derived from the same liquor. The four lignins were produced by using a) pH-fractionation within the LignoBoost process, b) ultrafiltration of black liquor prior to the LignoBoost process, and c) solvent leaching of the reference lignin using methanol and d) ethanol.Lignin compositional characteristics and thermal properties were compared, and monofilament extrusion used to assess their potential for successful melt spinning at the 24 filament scale. The lignin prepared by ethanol leaching of the reference lignin was found to be most appropriate for potential pilot scale fibre production. This was owing to a high purity, lower comparative glass transition temperature (Tg), and good spinning performance.Thermal pretreatments of the ethanol leached lignin gave a selection of enhanced lignins which were characterized for comparison, and melt spun on pilot multifilament equipment. The enhanced lignins could be continuously melt spun giving filaments with diameters as low as 10 μm and with minimal defects. Conversion of selected filaments provided carbon fibres with a tensile strength of 1259 ± 159 MPa, tensile modulus of 67 ± 3 GPa and diameter of 7.3 ± 0.5 μm.
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| 3. |
- Bostan, Lars, et al.
(författare)
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Upscaling of lignin precursor melt spinning by bicomponent spinning and its use for carbon fibre production
- 2021
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Ingår i: Philosophical Transactions. Series A. - : Royal Society Publishing. - 1364-503X .- 1471-2962. ; 379:2209
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Tidskriftsartikel (refereegranskat)abstract
- Upscaling lignin-based precursor fibre production is an essential step in developing bio-based carbon fibre from renewable feedstock. The main challenge in upscaling of lignin fibre production by melt spinning is its melt behaviour and rheological properties, which differ from common synthetic polymers used in melt spinning. Here, a new approach in melt spinning of lignin, using a spin carrier system for producing bicomponent fibres, has been introduced. An ethanol extracted lignin fraction from LignoBoost process of commercial softwood kraft black liquor was used as feedstock. After additional heat treatment, melt spinning was performed in a pilot-scale spinning unit. For the first time, biodegradable polyvinyl alcohol (PVA) was used as a spin carrier to enable the spinning of lignin by improving the required melt strength. PVA-sheath/lignin-core bicomponent fibres were manufactured. Afterwards, PVA was dissolved by washing with water. Pure lignin fibres were stabilized and carbonized, and tensile properties were measured. The measured properties, tensile modulus of 81.1 ± 3.1 GPa and tensile strength of 1039 ± 197 MPa, are higher than the majority of lignin-based carbon fibres reported in the literature. This new approach can significantly improve the melt spinning of lignin and solve problems related to poor spinnability of lignin and results in the production of high-quality lignin-based carbon fibres. This article is part of the theme issue 'Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)'. © 2021 The Author(s).
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| 4. |
- Edberg, Jesper, 1988-, et al.
(författare)
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A Forest-Based Triboelectric Energy Harvester
- 2022
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Ingår i: Global Challenges. - : John Wiley and Sons Inc. - 2056-6646. ; 6:10
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Tidskriftsartikel (refereegranskat)abstract
- Triboelectric nanogenerators (TENGs) are a new class of energy harvesting devices that have the potential to become a dominating technology for producing renewable energy. The versatility of their designs allows TENGs to harvest mechanical energy from sources like wind and water. Currently used renewable energy technologies have a restricted number of materials from which they can be constructed, such as metals, plastics, semiconductors, and rare-earth metals. These materials are all non-renewable in themselves as they require mining/drilling and are difficult to recycle at end of life. TENGs on the other hand can be built from a large repertoire of materials, including materials from bio-based sources. Here, a TENG constructed fully from wood-derived materials like lignin, cellulose, paper, and cardboard, thus making it 100% green, recyclable, and even biodegradable, is demonstrated. The device can produce a maximum voltage, current, and power of 232 V, 17 mA m–2, and 1.6 W m–2, respectively, which is enough to power electronic systems and charge 6.5 µF capacitors. Finally, the device is used in a smart package application as a self-powered impact sensor. The work shows the feasibility of producing renewable energy technologies that are sustainable both with respect to their energy sources and their material composition. © 2022 The Authors.
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| 5. |
- Edberg, Jesper, et al.
(författare)
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Laser-induced graphitization of a forest-based ink for use in flexible and printed electronics
- 2020
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Ingår i: npj Flexible Electron.. - : Nature Research. - 2397-4621. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced graphitization (LIG) is a method of converting a carbon-rich precursor into a highly conductive graphite-like carbon by laser scribing. This method has shown great promise as a versatile and low-cost patterning technique. Here we show for the first time how an ink based on cellulose and lignin can be patterned using screen printing followed by laser graphitization. Screen printing is one of the most commonly used manufacturing techniques of printed electronics, making this approach compatible with existing processing of various devices. The use of forest-based materials opens the possibility of producing green and sustainable electronics. Pre-patterning of the ink enables carbon patterns without residual precursor between the patterns. We investigated the effect of the ink composition, laser parameters, and additives on the conductivity and structure of the resulting carbon and could achieve low sheet resistance of 3.8 Ω sq-1 and a high degree of graphitization. We demonstrated that the process is compatible with printed electronics and finally manufactured a humidity sensor which uses lignin as the sensing layer and graphitized lignin as the electrodes.
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| 6. |
- Gao, Yu, et al.
(författare)
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Analysis of gas chromatography/mass spectrometry data for catalytic lignin depolymerization using positive matrix factorization
- 2018
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Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 20:18, s. 4366-4377
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Tidskriftsartikel (refereegranskat)abstract
- Various catalytic technologies are being developed to efficiently convert lignin into renewable chemicals. However, due to its complexity, catalytic lignin depolymerization often generates a wide and complex distribution of product compounds. Gas chromatography/mass spectrometry (GC-MS) is a common analytical technique to profile the compounds that comprise lignin depolymerization products. GC-MS is applied not only to determine the product composition, but also to develop an understanding of the catalytic reaction pathways and of the relationships among catalyst structure, reaction conditions, and the resulting compounds generated. Although a very useful tool, the analysis of lignin depolymerization products with GC-MS is limited by the quality and scope of the available mass spectral libraries and the ability to correlate changes in GC-MS chromatograms to changes in lignin structure, catalyst structure, and other reaction conditions. In this study, the GC-MS data of the depolymerization products generated from organosolv hybrid poplar lignin using a copper-doped porous metal oxide catalyst and a methanol/dimethyl carbonate co-solvent was analyzed by applying a factor analysis technique, positive matrix factorization (PMF). Several different solutions for the PMF model were explored. A 13-factor solution sufficiently explains the chemical changes occurring to lignin depolymerization products as a function of lignin, reaction time, catalyst, and solvent. Overall, seven factors were found to represent aromatic compounds, while one factor was defined by aliphatic compounds.
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| 7. |
- Gond, Ritambhara, et al.
(författare)
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A Lignosulfonate Binder for Hard Carbon Anodes in Sodium-Ion Batteries : A Comparative Study
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society. - 2168-0485. ; 9:37, s. 12708-
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Tidskriftsartikel (refereegranskat)abstract
- An important factor in the development of sodium-ion batteries (SIBs) is the use of cheap and sustainable materials. Sodium lignosulfonate, a lignin derivative, is demonstrated here as an attractive, "green", water-soluble, and potentially cost-effective binder for use in hard carbon anodes for SIBs. A comparison of its battery cycling performance is made against other binders including sodium carboxymethyl cellulose and lignin, obtained from the kraft process, as well as sodium alginate, derived from algae. Apart from lignin, which requires processing in N-methyl-2-pyrrolidone, the other three binders are water-soluble. Lignosulfonate shows comparable or better performance, with high capacity retention and stability, when using 1 M NaPF6 in propylene carbonate or ethylene carbonate:diethyl carbonate electrolytes for both half- and full-cells (against a Prussian white cathode). Further improvements are observed when including styrene-butadiene rubber as a co-binder. X-ray photoelectron spectroscopy demonstrates similar solid electrolyte interphase compositions after the initial sodium insertion for both lignosulfonate and carboxymethyl cellulose binders. However, after subsequent cycling, the surface layer composition and thickness are found to be dependent on the binder. For the lignosulfonate-based electrode, the layer appears thicker but comprises a smaller fraction of carbon-oxygen species. © 2021 The Authors.
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| 8. |
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| 9. |
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| 10. |
- Liu, Cong, et al.
(författare)
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Effects of nanocrystalline cellulose on the micro-creep properties of phenol formaldehyde resin
- 2018
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Ingår i: Materials Research Express. - : Institute of Physics Publishing. - 2053-1591. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- The use of nanocrystalline cellulose (NCC) has become increasingly prevalent in recent years, with limited studies on the the time-dependent characteristics of wood-adhesive composite reinforced by it. To analyze the viscoelasticity of control phenol formaldehyde (PF) resin and wood-resin composites added with three types of NCC, the micro-creep properties of control phenol formaldehyde (PF) resin and PF resin with cellulose nanofibrils (CNF), cellulose microfibrils (CMF), and cellulose nanocrystals (CNC) were investigated by nanoindentation (NI). The sample creep curves proved that adding CNC, CMF, and CNF into the PF resin remarkably impacted the creep properties of the wood-resin sample interface. The cured resin sample had the lowest strength and the most deformation, and the pure wood sample performed slightly better. Among the three NCC-added wood-resin samples, the CNF-added wood-resin sample has the least deformation in the same load and the least permanent deformation after unloading followed by CMF-added and CNC-added wood-resin samples. In the derivative of creep curve function, the depth tendency of CNC-added and CNF-added wood-resin samples showed a gently increasing slope with time in contrast to CMF-added ones. Furthermore, scanning probe microscopy (SPM) images supported that PF resin had filled up the pores of the wood microstructures and strengthened the wood-resin sample in the company of NCC, which was then able to carry the load.
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