| 1. |
- Hadi, Seyed Ehsan, et al.
(författare)
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Highly magnetic hybrid foams based on aligned tannic acid-coated iron oxide nanoparticles and TEMPO-oxidized cellulose nanofibers
- 2023
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Ingår i: RSC Advances. - 2046-2069. ; 13:20, s. 13919-13927
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Tidskriftsartikel (refereegranskat)abstract
- Lightweight iron oxide nanoparticle (IONP)/TEMPO-oxidized cellulose nanofibril (TOCNF) hybrid foams with an anisotropic structure and a high IONP content were produced using magnetic field-enhanced unidirectional ice-templating. Coating the IONP with tannic acid (TA) improved the processability, the mechanical performance, and the thermal stability of the hybrid foams. Increasing the IONP content (and density) increased the Young's modulus and toughness probed in compression, and hybrid foams with the highest IONP content were relatively flexible and could recover 14% axial compression. Application of a magnetic field in the freezing direction resulted in the formation of IONP chains that decorated the foam walls and the foams displayed a higher magnetization saturation, remanence, and coercivity compared to the ice-templated hybrid foams. The hybrid foam with an IONP content of 87% displayed a saturation magnetization of 83.2 emu g−1, which is 95% of the value for bulk magnetite. Highly magnetic hybrid foams are of potential interest for environmental remediation, energy storage, and electromagnetic interference shielding.
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| 2. |
- A. da Cruz, Márcia G., et al.
(författare)
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Electrochemical Depolymerization of Lignin in a Biomass-based Solvent
- 2022
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 15:15
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Tidskriftsartikel (refereegranskat)abstract
- Breaking down lignin into smaller units is the key to generate high value-added products. Nevertheless, dissolving this complex plant polyphenol in an environment-friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, levulinic acid was evaluated as a medium for the reductive electrochemical depolymerization of the lignin macromolecule. Copper was chosen as the electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy revealed lignin-derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. Depolymerized lignin was further evaluated as an anti-corrosion coating, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass-based solvent, a straightforward approach to produce high value-added compounds or tailored biobased materials was demonstrated.
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| 3. |
- Almenara Perez, Naroa, et al.
(författare)
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Lignin–Chitosan Gel Polymer Electrolytes for Stable Zn Electrodeposition
- 2023
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 11:6, s. 2283-2294
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical energy storage technologies offer means to transition toward a decarbonized society and carbon neutrality by 2050. Compared to conventional lithium-ion batteries, aqueous zinc-ion chemistries do not require scarce materials or toxic and flammable organic-based electrolytes to function, making them favorable contenders in the scenario of intensifying climate change and supply chain crisis. However, environmentally benign and bio-based materials are needed to substitute fossil-based battery materials. Accordingly, this work taps into the possibilities of lignin together with chitosan to form gel polymer electrolytes (GPEs) for zinc-ion chemistries. A simple fabrication process enabling free-standing sodium lignosulfonate–chitosan and micellar lignosulfonate–kraft lignin–chitosan GPEs with diameters exceeding 80 mm is developed. The GPEs combine tensile strength with ductility, reaching Young’s moduli of 55 ± 4 to 940 ± 63 MPa and elongations at break of 14.1 ± 0.2 to 43.9 ± 21.1%. Competitive ionic conductivities ranging from 3.8 to 18.6 mS cm–1 and electrochemical stability windows of up to +2.2 V vs Zn2+/Zn were observed. Given the improved interfacial adhesion of the GPEs with metallic Zn promoted by the anionic groups of the lignosulfonate, a stable cycling of the Zn anode is obtained. As a result, GPEs can operate at 5000 μA cm–2 with no short-circuit and Coulombic efficiencies above 99.7%, outperforming conventional separator–liquid electrolyte configurations such as the glass microfiber separator soaked into 2 M ZnSO4 aqueous electrolyte, which short-circuits after 100 μA cm–2. This work demonstrates the potential of underutilized biorefinery side-streams and marine waste as electrolytes in the battery field, opening new alternatives in the sustainable energy storage landscape beyond LIBs.
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| 4. |
- Budnyak, Tetyana M., et al.
(författare)
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Lignin-Inorganic Interfaces : Chemistry and Applications from Adsorbents to Catalysts and Energy Storage Materials
- 2020
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 13:17, s. 4344-4355
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Forskningsöversikt (refereegranskat)abstract
- Lignin is one the most fascinating natural polymers due to its complex aromatic‐aliphatic structure. Phenolic hydroxyl and carboxyl groups along with other functional groups provide technical lignins with reactivity and amphiphilic character. Many different lignins have been used as functional agents to facilitate the synthesis and stabilization of inorganic materials. Herein, the use of lignin in the synthesis and chemistry of inorganic materials in selected applications with relevance to sustainable energy and environmental fields is reviewed. In essence, the combination of lignin and inorganic materials creates an interface between soft and hard materials. In many cases it is either this interface or the external lignin surface that provides functionality to the hybrid and composite materials. This Minireview closes with an overview on future directions for this research field that bridges inorganic and lignin materials for a more sustainable future.
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| 5. |
- Esakkimuthu, Esakkiammal Sudha, et al.
(författare)
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Elucidating intermolecular forces to improve compatibility of kraft lignin in poly(lactic acid)
- 2024
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Ingår i: Frontiers in Chemistry. - 2296-2646. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Owing to its abundant supply from renewable resources, lignin has emerged as a promising functional filler for the development of sustainable composite materials. However, achieving good interfacial compatibility between lignin and synthetic polymers, particularly poly (lactic acid) (PLA), remains a fundamental challenge. To advance the development of high-performance bio-based composites incorporating lignin and PLA, our study has scrutinized to unravel the nuances of interfacial binding interactions with the lignin and PLA composite system. Molecular level and experimental examinations were employed to decipher fundamental mechanisms governing and demonstrating the interfacial adhesion. We synthesized casted films of lignin/PLA and acetylated lignin/PLA at varying weight percentages of lignin (5%, 10%, and 20%) and comprehensively investigated their physicochemical and mechanical properties. The inclusion of acetylated lignin in the composites resulted in improved mechanical strength and Young’s modulus, while the glass transition temperature and melting point were reduced compared to neat PLA. Systematic variations in these properties revealed distinct compatibility behaviors between unmodified lignin and acetylated lignin when incorporated into PLA. Molecular dynamics (MD) simulation results elucidated that the observed changes in material properties were primarily attributed to the acetylation of lignin. Acetylated lignin exhibited lower Coulombic interaction energy and higher van der Waals forces, indicating a stronger affinity to PLA and a reduced propensity for intermolecular aggregation compared to unmodified lignin. Our findings highlight the critical role of controlling intermolecular interactions and lignin aggregation to develop PLA composites with predictable performance for new applications, such as functional packaging materials.
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| 6. |
- Esakkimuthu, Esakkiammal Sudha, et al.
(författare)
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Multifunctional lignin-poly (lactic acid) biocomposites for packaging applications
- 2022
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Ingår i: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media SA. - 2296-4185. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Lignin is the most abundant aromatic biopolymer with many promising features but also shortcomings as a filler in polymer blends. The main objective of this work was to improve the processability and compatibility of lignin with poly (lactic acid) (PLA) through etherification of lignin. Commercial kraft lignin (KL) and oxypropylated kraft lignin (OPKL) were blended with PLA at different weight percentages (1, 5, 10, 20, and 40%) followed by injection molding. Low lignin contents between 1 and 10% generally had a favorable impact on mechanical strength and moduli as well as functional properties of the PLA-based composites. Unmodified lignin with free phenolic hydroxyl groups rendered the composites with antioxidant activity, as measured by radical scavenging and lipid peroxidation tests. Incorporating 5–10% of KL or OPKL improved the thermal stability of the composites within the 300–350°C region. DSC analysis showed that the glass transition temperature values were systematically decreased upon addition of KL and OPKL into PLA polymer. However, low lignin contents of 1 and 5% decreased the cold crystallization temperature of PLA. The composites of KL and OPKL with PLA exhibited good stabilities in the migration test, with values of 17 mg kg−1 and 23 mg kg−1 even at higher lignin content 40%, i.e., well below the limit defined in a European standard (60 mg kg−1). These results suggest oxypropylated lignin as a functional filler in PLA for safe and functional food packaging and antioxidant applications.
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| 7. |
- Ferruti, Federica, et al.
(författare)
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Recombinatorial approach for the formation of surface-functionalised alkaline-stable lignin nanoparticles and adhesives
- 2023
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Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 25:2, s. 639-649
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Tidskriftsartikel (refereegranskat)abstract
- Lignin nanoparticles (LNPs) are considered as intriguing green, renewable alternatives to fossil-based nanomaterials. However, the predisposition of LNPs to dissolve under alkaline conditions makes covalent surface functionalisation in the dispersion state difficult and limits applications demanding morphological stability under challenging pH conditions. Mechanistic studies suggest that during the formation of LNPs by nanoprecipitation the higher molecular weight fractions of lignin likely start precipitating first, while the low molecular weight fractions tend to deposit later and thus locate on the outer shell. Capitalising this aggregation pattern, the present work presents a strategy to prepare surface-functionalised LNPs that can find applications as adhesives and alkaline stable LNPs. The entire process is based on a single-step solvent fractionation of lignin using either ethanol or ethyl acetate, subsequent functionalisation of selected fractions with epichlorohydrin, and recombination according to the original mass proportions in line with the so-called zero waste principle. Aqueous colloidal dispersions of lignins were synthesised by nanoprecipitation of epoxidised low molecular weight (MW) fractions combined with the corresponding unmodified high MW ones, and vice versa. Upon thermal treatment, LNPs containing the epoxidised insoluble fraction underwent intraparticle crosslinking, proving dimensional stability at pH 12. Conversely, LNPs including epoxidised solvent-soluble fractions resulted in interparticle crosslinking upon heating, which confirmed the surface localisation of such low MW fractions. The latter system was exploited to develop green LNP-based adhesives for aminated glass with lap shear strength outperforming prior adhesive systems based on lignin particles.
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| 8. |
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| 9. |
- Lindenbeck, Lucie, et al.
(författare)
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MoS2 nanoflower-decorated lignin nanoparticles for superior lubricant properties
- 2023
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; :20
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Tidskriftsartikel (refereegranskat)abstract
- Lignin has been, for a long time, treated as a low-value waste product. To change this scenario, high-value applications have been recently pursued, e.g., the preparation of hybrid materials with inorganic components. Although hybrid inorganic-based materials can benefit from the reactive lignin phenolic groups at the interface, often responsible for optimizing specific properties, this is still an underexplored field. Here, we present a novel and green material based on the combination of hydroxymethylated lignin nanoparticles (HLNPs) with molybdenum disulfide (MoS2) nanoflowers grown via a hydrothermal route. By bringing together the lubricant performance of MoS2 and the structural stability of biomass-based nanoparticles, a MoS2-HLNPs hybrid is presented as a bio-derived additive for superior tribological performances. While FT-IR analysis confirmed the structural stability of lignin after the hydrothermal growth of MoS2, TEM and SEM micrographs revealed a homogeneous distribution of MoS2 nanoflowers (average size of 400 nm) on the HLNPs (average size of 100 nm). Regarding the tribological tests, considering a pure oil as reference, only HLNPs as bio-derived additives led to a reduction in the wear volume of 18%. However, the hybrid of MoS2-HLNPs led to a considerably higher reduction (71%), pointing out its superior performance. These results open a new window of opportunity for a versatile and yet underexplored field that can pave the way for a new class of biobased lubricants.
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| 10. |
- Liu, Jinrong, 1995-, et al.
(författare)
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Ag-lignin hybrid nanoparticles for high-performance solar absorption in photothermal antibacterial chitosan films
- 2023
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Ingår i: iScience. - 2589-0042. ; 26:10
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Tidskriftsartikel (refereegranskat)abstract
- There is an urgent need for antimicrobial films based on sustainable resources and production methods. In this study, we present a bio-based nanocomposite film composed of chitosan (∼60 wt %), lignin nanoparticles (LNPs, ∼40 wt %), a small amount of glutaraldehyde (1.5 wt %), and a trace level of silver nanoparticles (AgNPs, 0.072 wt %). The uniform dispersion with LNPs prevented aggregation of metallic silver, resulting in small (diameter 3.3 nm) AgNPs. The nanocomposite film absorbs 89% of radiation across the entire solar spectrum and exhibits a remarkable photothermally triggered antibacterial effect, which is further enhanced by the dark color of lignin. Under simulated solar light illumination, the nanocomposite films demonstrated a significant reduction in viable Escherichia coli count compared to control scenarios. The potential applications of these nanocomposites extend to sunlight-activated antimicrobial films and coatings, addressing the growing demand for sustainable and effective antimicrobial materials.
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