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  • 1.
    Abitbol, Tiffany
    et al.
    RISE Research Institutes of Sweden. EPFL, Switzerland.
    Kubat, Mikaela
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Brännvall, Elisabet
    RISE Research Institutes of Sweden.
    Kotov, Nikolay
    KTH Royal Institute of Technology, Sweden.
    Johnson, C Magnus
    KTH Royal Institute of Technology, Sweden.
    Nizamov, Rustem
    University of Turku, Finland.
    Nyberg, Mikael
    University of Turku, Finland.
    Miettunen, Kati
    University of Turku, Finland.
    Nordgren, Niklas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Stevanic Srndovic, Jasna
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Guerreiro, Maria Pita
    RISE Research Institutes of Sweden.
    Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps2023In: ACS Omega, E-ISSN 2470-1343, Vol. 8, no 24, p. 21474-21484Article in journal (Refereed)
    Abstract [en]

    From a circular economy perspective, one-pot strategies for the isolation of cellulose nanomaterials at a high yield and with multifunctional properties are attractive. Here, the effects of lignin content (bleached vs unbleached softwood kraft pulp) and sulfuric acid concentration on the properties of crystalline lignocellulose isolates and their films are explored. Hydrolysis at 58 wt % sulfuric acid resulted in both cellulose nanocrystals (CNCs) and microcrystalline cellulose at a relatively high yield (>55%), whereas hydrolysis at 64 wt % gave CNCs at a lower yield (<20%). CNCs from 58 wt % hydrolysis were more polydisperse and had a higher average aspect ratio (1.5-2×), a lower surface charge (2×), and a higher shear viscosity (100-1000×). Hydrolysis of unbleached pulp additionally yielded spherical nanoparticles (NPs) that were <50 nm in diameter and identified as lignin by nanoscale Fourier transform infrared spectroscopy and IR imaging. Chiral nematic self-organization was observed in films from CNCs isolated at 64 wt % but not from the more heterogeneous CNC qualities produced at 58 wt %. All films degraded to some extent under simulated sunlight trials, but these effects were less pronounced in lignin-NP-containing films, suggesting a protective feature, but the hemicellulose content and CNC crystallinity may be implicated as well. Finally, heterogeneous CNC compositions obtained at a high yield and with improved resource efficiency are suggested for specific nanocellulose uses, for instance, as thickeners or reinforcing fillers, representing a step toward the development of application-tailored CNC grades. © 2023 The Authors. 

  • 2.
    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. 

  • 3.
    Esteves, Claudia
    et al.
    RISE Research Institutes of Sweden.
    Brännvall, Elisabet
    RISE Research Institutes of Sweden, Bioeconomy and Health, Pulp, Paper and Packaging.
    Östlund, Sören
    KTH Royal Institute of Technology, Sweden.
    Sevastyanova, Olena
    KTH Royal Institute of Technology, Sweden.
    Evaluating the Potential to Modify Pulp and Paper Properties through Oxygen Delignification2020In: ACS Omega, E-ISSN 2470-1343, Vol. 5, no 23, p. 13703-13711Article in journal (Refereed)
    Abstract [en]

    The potential to modify pulp and paper properties by oxygen delignification was assessed by looking beyond the ordinary purpose of oxygen delignification. Pulps with the same kappa number were obtained by both pulping and the combination of pulping and oxygen delignification, and the mechanical and chemical properties were compared. The oxidation of pulp components leads to an increase in carboxylic acid groups in the fibers, resulting in a large influence on fiber swelling, seen as an increase in the water retention value and fiber saturation point. The introduction of charged groups appears to replace some of the morphological changes caused by refining and enhance the strength of fiber-fiber joints, generating pulps with better refinability and higher tensile strength. Oxygen delignification was able to improve the tensile index with 6% at the same sheet density and less refining energy, when the amount of total fiber charges was higher than 140 μekv/g.

  • 4.
    Honcharenko, Dmytro
    et al.
    Karolinska Institute, Sweden.
    Druceikaite, Kristina
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development. Karolinska Institute, Sweden.
    Honcharenko, Malgorzata
    Karolinska Institute, Sweden.
    Bollmark, Martin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Tedebark, Ulf
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Strömberg, Roger
    Karolinska Institute, Sweden.
    New Alkyne and Amine Linkers for Versatile Multiple Conjugation of Oligonucleotides2021In: ACS Omega, E-ISSN 2470-1343, Vol. 6, no 1, p. 579-593Article in journal (Refereed)
    Abstract [en]

    Oligonucleotide (ON) conjugates are increasingly important tools for various molecular diagnostics, nanotechnological applications, and for the development of nucleic acid-based therapies. Multiple labeling of ONs can further equip ON-conjugates and provide improved or additional tailored properties. Typically, the preparation of ON multiconjugates involves additional synthetic steps and/or manipulations in post-ON assembly. This report describes the simplified methodology allowing for multiple labeling of ONs on a solid support and is compatible with phosphodiester as well as phosphorothioate (PS) ONs. The current approach utilizes two novel alkyne- A nd amino-functionalized linker phosphoramidites that can be readily synthesized from a common aminodiol intermediate in three steps. The combination of new linkers provides orthogonal functionalities, which allow for multiple attachments of similar or varied moieties. The linkers are incorporated into ONs during automated solid-phase ON synthesis, and the conjugation with functional entities is achieved by either amide bond formation or by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The versatility of the approach is demonstrated by the synthesis of 5′-site ON multiconjugates with small molecules, peptides, and fatty acids as well as in the preparation of an internal peptide-ON conjugate. 

  • 5.
    Larsson, Mikael
    et al.
    University College London, Australia; University of South Australia, Australia.
    Yousefi, Ali
    University of South Australia, Australia; Tarbiat Modares University, Iran.
    Elmas, Sait
    University of South Australia, Australia.
    Lindén, Johan B
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials. University of South Australia, Australia.
    Nann, Thomas
    Victoria University of Wellington, New Zealand.
    Nydén, Magnus
    University College London, Australia; University of South Australia, Australia.
    Electroactive polyhydroquinone coatings for marine fouling prevention-A rejected dynamic ph hypothesis and a deceiving artifact in electrochemical antifouling testing2017In: ACS Omega, E-ISSN 2470-1343, Vol. 2, no 8, p. 4751-4759Article in journal (Refereed)
    Abstract [en]

    Nanometer-Thin coatings of polyhydroquinone (PHQ), which release and absorb protons upon oxidation and reduction, respectively, were tested for electrochemically induced anti-biofouling activity under the hypothesis that a dynamic pH environment would discourage fouling. Antifouling tests in artificial seawater using the marine, biofilm-forming bacterium Vibrio alginolyticus proved the coatings to be ineffective in fouling prevention but revealed a deceiving artifact from the reactive species generated at the counter electrode (CE), even for electrochemical bias potentials as low as |400| mV versus Ag|AgCl. These findings provide valuable information on the preparation of nanothin PHQ coatings and their electrochemical behavior in artificial seawater. The results further demonstrate that it is critical to isolate the CE in electrochemical anti-biofouling testing.

  • 6.
    Mei, N.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Hedberg, J.
    KTH Royal Institute of Technology, Sweden.
    Odnevall Wallinder, I.
    KTH Royal Institute of Technology, Sweden.
    Blomberg, Eva
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation. KTH Royal Institute of Technology, Sweden.
    Influence of Biocorona Formation on the Transformation and Dissolution of Cobalt Nanoparticles under Physiological Conditions2019In: ACS Omega, E-ISSN 2470-1343Article in journal (Refereed)
    Abstract [en]

    Cobalt (Co) nanoparticles (NPs) are produced in different applications and unintentionally generated at several occupational and traffic settings. Their diffuse dispersion may lead to interactions with humans and aquatic organisms via different exposure routes that include their transformation/dissolution in biological media. This paper has investigated the particle stability and reactivity of Co NPs (dispersed by sonication prior to exposure) interacting with selected individual biomolecules (amino acids, polypeptides, and proteins) in phosphate-buffered saline (PBS). No or minor adsorption of amino acids (glutamine, glutamic acid, lysine, and cysteine) was observed on the Co NPs, independent of the functional group and charge. Instead, phosphate adsorption resulted in the formation of a surface layer (a corona) of Co phosphate. The adsorption of larger biomolecules (polyglutamic acid, polylysine, lysozyme, and mucin) was evident in parallel with the formation of Co phosphate. The dissolution of the Co NPs was rapid as 35-55% of the particle mass was dissolved within the first hour of exposure. The larger biomolecules suppressed the dissolution initially compared to exposure in PBS only, whereas the dissolution was essentially unaffected by the presence of amino acids, with cysteine as an exception. The formation of Co phosphate on the NP surface reduced the protective properties of the surface oxide of the Co NPs, as seen from the increased levels of the released Co when compared with the nonphosphate-containing saline. The results underline the diversity of possible outcomes with respect to surface characteristics and dissolution of Co NPs in biological media and emphasize the importance of surface interactions with phosphate on the NP characteristics and reactivity.

  • 7.
    Opedal, Mihaela Tanase
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Ruwoldt, Jost
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Organosolv Lignin as a Green Sizing Agent for Thermoformed Pulp Products2022In: ACS Omega, E-ISSN 2470-1343, Vol. 7, no 50, p. 46583-46593Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the use of organosolv lignin as a sizing agent for thermoformed pulp products as a sustainable material with improved water resistance. For this purpose, an in-house-produced organosolv lignin from softwood (Norway Spruce) was mixed with bleached and unbleached chemi-thermomechanical pulp fibers. In addition, the isolated organosolv lignin was characterized by ATR-FTIR spectroscopy, size-exclusion chromatography, and thermogravimetric analysis. The analysis showed that organosolv lignin was of a high purity and practically ash-free, exhibiting low molecular weight, a glass transition temperature below the thermoforming temperature, and a high content of phenolic OH groups. The mechanical properties and water resistance of the organosolv lignin-sized thermoformed pulp materials were measured. A small decrease in strength and an increase in stiffness and density were observed for the lignin-sized thermoformed materials compared to the reference, that is, unsized materials. The addition of organosolv lignin decreased the wettability and swelling of the thermoformed product. These results are due to the distribution of organosolv lignin on the surface, filling in the pores and cavities, and providing a tighter fit within the thermoformed materials. In conclusion, the results from our study encourage the use of organosolv lignin as a sizing additive to thermoformed products, which can improve the water resistance to use it in sustainable packaging applications.

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  • 8.
    Reeve, P. A. P.
    et al.
    University of Sheffield, Uk.
    Grabowska, U.
    Medivir AB, Sweden; F-star Biotechnology Ltd, UK.
    Oden, L. S.
    Medivir AB, Sweden.
    Wiktelius, D.
    Medivir AB, Sweden; FOI Swedish Defence Research Agency, Sweden.
    Wångsell, Fredrik
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials. Medivir AB, Sweden.
    Jackson, R. F. W.
    University of Sheffield, Uk.
    Radical Functionalization of Unsaturated Amino Acids: Synthesis of Side-Chain-Fluorinated, Azido-Substituted, and Hydroxylated Amino Acids2019In: ACS Omega, E-ISSN 2470-1343, Vol. 4, no 6, p. 10854-10865Article in journal (Refereed)
    Abstract [en]

    A range of enantiomerically pure protected side-chain-fluorinated amino acids has been prepared (13 examples) by treatment of protected amino acids containing unsaturated side chains with a combination of Fe(III)/NaBH4 and Selectfluor. The modification of the conditions by replacement of Selectfluor with NaN3 allowed the preparation of side-chain azido-substituted amino acids (five examples), which upon catalytic hydrogenation gave the corresponding amines, isolated as lactams (four examples). Radical hydration of the unsaturated side chains leading to side-chain-hydroxylated protected amino acids has also been demonstrated.

  • 9.
    Ruwoldt, Jost
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Ultraviolet Spectrophotometry of Lignin Revisited: Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility Parameter, and Determination of Phenolic Hydroxyl Groups2022In: ACS Omega, E-ISSN 2470-1343, Vol. 7, no 50, p. 46371-46383Article in journal (Refereed)
    Abstract [en]

    In this article, we explored solvents with lower harmfulness than established systems for UV spectrophotometry of lignin. By measuring the absorptivity in DMSO solvent at 280 nm, the purity of the lignin samples was addressed and compared with Klason and acid-soluble lignin. The general trend was an increasing absorptivity with increasing lignin purity; however, considerable scattering was observed around the sample mean. The Hansen solubility parameter (HSP) of four technical lignins was furthermore determined. The model was in line with the UV measurements, as solvents closer in HSP correlated with a higher absorptivity. Ethylene glycol was identified as a good solvent for lignin with low UV-cutoff. In addition, mixtures of propylene carbonate, water, and ethanol showed good suitability and a low cutoff of 215 nm. While DMSO itself was poorly suited for recording alkali spectra, blending DMSO with water showed great potential. Comparing three methods for determining phenolic hydroxyl units by UV spectrophotometry showed some discrepancies between different procedures and solvents. It appeared that the calibrations established with lignin model compounds may not be fully representative of the lignin macromolecule. More importantly, the ionization difference spectra were highly affected by the solvent of choice, even when using what are considered "good"solvents. At last, a statistical comparison was made to identify the most suitable solvent and method, and the solvent systems were critically discussed. We thus conclude that several solvents were identified, which are less harmful than established systems, and that the solubility of lignin in these is a crucial point to address when conducting UV spectrophotometry. 

  • 10.
    Ruwoldt, Jost
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. NTNU Norwegian University of Science and Technology, Norway.
    Øye, Gisle
    NTNU Norwegian University of Science and Technology, Norway.
    Effect of Low-Molecular-Weight Alcohols on Emulsion Stabilization with Lignosulfonates2020In: ACS Omega, E-ISSN 2470-1343, Vol. 5, no 46, p. 30168-30175Article in journal (Refereed)
    Abstract [en]

    Lignosulfonates are biobased surfactants and specialty chemicals, which are described as water-soluble polyelectrolyte macromolecules that are generated during the sulfite pulping of lignocellulose biomass. Due to their amphiphilic nature, lignosulfonates have made their way into various applications, such as plasticizers, dispersants, and suspension or emulsion stabilizer. The stabilization efficiency for oil-in-water emulsions is affected, among other aspects, by the presence of alcohols. Low-molecular-weight alcohols can improve the performance of lignosulfonates; however, the effects of such additive have not yet been fully explored. In this article, we hence studied emulsion stability in dependence of alcohol concentration and other parameters, such as salinity. One or two regions of improved stability were found, which occurred at approximately 0.001-0.01 M alcohol in water, and in some cases additionally at 1-3 M. The four lignosulfonate samples responded distinctly to the alcohol additives. Little difference was found for varying lignosulfonate concentration or the alcohol type, that is, methanol, ethanol, or 2-propanol. Adding ethanol at high salinity (720 mM NaCl) showed a destabilizing effect. A decrease in interfacial tension was noted when adding 1 M ethanol or more, but the surface pressure of lignosulfonates decreased progressively at 0.3 M ethanol and above. These effects are counteracting, which could explain why increasing alcohol concentration would either enhance or impair stability. Overall, emulsion stability was affected by concentration effects and not cosurfactant action of the alcohols. Composition changes can influence the dielectric properties of the bulk solvent, further affecting the anionic functional groups, which was evidenced by alcohol addition affecting the lignosulfonates with lower hydrophobicity more strongly and by ethanol exhibiting the destabilizing effect at high salinity. In conclusion, adding low-molecular-weight alcohols may hence influence the behavior of lignosulfonates and render them more accessible for interactions with hydrophobic interfaces. ©

  • 11.
    Sensi, Matteo
    et al.
    Università degli Studi di Modena e Reggio Emilia, Italy.
    Berto, Marcello
    Università degli Studi di Modena e Reggio Emilia, Italy.
    Candini, Andrea
    Istituto per la Sintesi Organica e la Fotoreattività (ISOF)−CNR, Italy; Istituto per la Microelettronica e Microsistemi (CNR-IMM), Italy.
    Liscio, Andrea
    Istituto per la Microelettronica e Microsistemi (CNR-IMM), Italy.
    Cossarizza, Andrea
    Università degli Studi di Modena e Reggio Emilia, Italy; .
    Beni, Valerio
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Biscarini, Fabio
    Università degli Studi di Modena e Reggio Emilia, Italy; Istituto Italiano di Tecnologia, Italy.
    Bortolotti, Carlo Augusto
    Università degli Studi di Modena e Reggio Emilia, Italy.
    Modulating the Faradic Operation of All-Printed Organic Electrochemical Transistors by Facile in Situ Modification of the Gate Electrode2019In: ACS Omega, E-ISSN 2470-1343, Vol. 4, no 3, p. 5374-5381Article in journal (Refereed)
    Abstract [en]

    Organic electrochemical transistors (OECTs) operated in the faradic regime were shown as outperforming transducers of bioelectric signals in vitro and in vivo. Fabrication by additive manufacturing techniques fosters OECTs as ideal candidates for point-of-care applications, as well as imposes limitations on the choice of materials and their processing conditions. Here, we address the question of how the response of fully printed OECTs depends on gate electrode material. Toward this end, we investigate the redox processes underlying the operation of OECTs under faradic regime, to show OECTs with carbon gate (C-gate) that exhibit no current modulation gate voltages <1.2 V. This is a hallmark that no interference with the faradic operation of the device enabled by redox processes occurs when operating C-gate OECTs in the low-voltage range as label-free biosensors for the detection of electroactive (bio)molecules. To tune the faradic response of the device, we electrodeposited Au on the carbon gate (Au-C-gate), obtaining a device that operates at lower gate voltage values than C-gate OECT. The presence of gold on the gate allowed further modification of the electrical performances by functionalization of the Au-C-gate with different self-assembled monolayers by fast potential-pulse-assisted method. Moreover, we show that the presence in the electrolyte solution of an external redox probe can be used to drive the faradic response of both C- and Au-C-gate OECTs, impacting on the gate potential window that yields effective drain current modulation. The results presented here suggest possible new strategies for controlling the faradic operation regime of OECTs sensors by chemical modification of the gate surface.

  • 12.
    Simon, Sebastien
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Saadat, Marzieh
    NTNU Norwegian University of Science and Technology, Norway.
    Ruwoldt, Jost
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. NTNU Norwegian University of Science and Technology, Norway.
    Dudek, Marcin
    NTNU Norwegian University of Science and Technology, Norway.
    Ellis, Ross
    Borregaard AS, Norway.
    Øye, Gisle
    NTNU Norwegian University of Science and Technology, Norway.
    Lignosulfonates in Crude Oil Processing: Interactions with Asphaltenes at the Oil/Water Interface and Screening of Potential Applications2020In: ACS Omega, E-ISSN 2470-1343, Vol. 5, no 46, p. 30189-30200Article in journal (Refereed)
    Abstract [en]

    The goal of this article is to test the potential application of lignosulfonates (LSs) in crude oil production and processing. Three LS samples of varying hydrophobicity and average molecular weight were considered. First, the interfacial tension between brine and xylene and interfacial dilational rheology properties of LS samples were measured. It was found that the most surface-active LS sample has the lowest molecular weight in agreement with the results from the literature. In the presence of asphaltenes, all three LS samples were able to compete with asphaltenes, the most polar crude oil component, at the interface and form mixed LS-asphaltene interfaces. However, only the most surface-active LS sample among the three tested could fully desorb asphaltenes at the highest tested LS concentration (500 ppm). Second, three possible applications were screened. LSs were tested to prevent the formation of w/o crude oil emulsions or to break these. However, the opposite effect was observed, that is, stabilization of water-in-crude oil emulsions. The potential application of LS in produced water (PW) clarification was furthermore considered. The kinetics of PW clarification was found unaffected by the presence of LS, even at very high concentrations (1000 ppm). Finally, the potential of LS for enhanced oil recovery was assessed. The LS flood changed the surface wettability toward water wetness for one of the samples, yet LS injection did not recover additional oil beyond brine recovery. It was concluded that LS has interesting properties, such as the potential to compete with crude oil indigenous components at the oil/water interface. The stabilization action of LS was dominant over any destabilization effect, which led to the conclusion that LSs are more efficient for stabilizing emulsions rather than destabilizing.

  • 13.
    Wärnheim, Alexander
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Edvinsson, Camilla
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Sundell, Per-Erik
    SSAB Europe, Sweden.
    Heydari, Golrokh
    SSAB Europe, Sweden.
    Deltin, Tomas
    Nordic United Coatings, Sweden.
    Persson, Dan
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Depth-Resolved FTIR-ATR Imaging Studies of Coating Degradation during Accelerated and Natural Weathering─Influence of Biobased Reactive Diluents in Polyester Melamine Coil Coating2022In: ACS Omega, E-ISSN 2470-1343, Vol. 7, no 27, p. 23842-Article in journal (Refereed)
    Abstract [en]

    Improved methods to assess the degradation of coil coatings to approximate lifetime have been an area of academic and industrial interest for decades. This work aims to elucidate the differences in the degradation behavior of two coil coating systems: one standard commercial formulation and one formulation with a significant addition of biorenewable reactive diluents. Depth-resolved degradation behavior of samples exposed to accelerated and natural field weathering is assessed. Focal plane array attenuated total reflection-Fourier transform infrared spectroscopy was used to acquire high-resolution chemical data from a sloping cross section. The results agreed with conventional photoacoustic spectroscopy. Degradation profiles for the two coatings were significantly different, with the biobased samples showing a more durable behavior. This study provides a method for detailed assessment of coating degradation, giving a good estimation of its durability. This is both a way to compare the performance of coating systems and to improve the understanding of the impact of exposure conditions, paving the way for the development of more sustainable coil coatings.

  • 14.
    Zhao, Wei
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Sugunan, Abhilash
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Gillgren, Thomas
    BillerudKorsnäs AB, Sweden.
    Larsson, Johan
    BillerudKorsnäs AB, Sweden.
    Zhang, Zhi-Bin
    Uppsala University, Sweden.
    Zhang, Shi-Li
    Uppsala University, Sweden.
    Niklas, Nordgren
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Sommertune, Jens
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Ahniyaz, Anwar
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Surfactant-Free Stabilization of Aqueous Graphene Dispersions Using Starch as a Dispersing Agent2021In: ACS Omega, E-ISSN 2470-1343, Vol. 6, no 18, p. 12050-12062Article in journal (Refereed)
    Abstract [en]

    Attention to graphene dispersions in water with the aid of natural polymers is increasing with improved awareness of sustainability. However, the function of biopolymers that can act as dispersing agents in graphene dispersions is not well understood. In particular, the use of starch to disperse pristine graphene materials deserves further investigation. Here, we report the processing conditions of aqueous graphene dispersions using unmodified starch. We have found that the graphene content of the starch-graphene dispersion is dependent on the starch fraction. The starch-graphene sheets are few-layer graphene with a lateral size of 3.2 μm. Furthermore, topographical images of these starch-graphene sheets confirm the adsorption of starch nanoparticles with a height around 5 nm on the graphene surface. The adsorbed starch nanoparticles are ascribed to extend the storage time of the starch-graphene dispersion up to 1 month compared to spontaneous aggregation in a nonstabilized graphene dispersion without starch. Moreover, the ability to retain water by starch is reduced in the presence of graphene, likely due to environmental changes in the hydroxyl groups responsible for starch-water interactions. These findings demonstrate that starch can disperse graphene with a low oxygen content in water. The aqueous starch-graphene dispersion provides tremendous opportunities for environmental-friendly packaging applications. © 2021 American Chemical Society.

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