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  • 1.
    Brodin, Malin
    et al.
    RISE - Research Institutes of Sweden, Bioekonomi, PFI.
    Vallejos, Maria
    Instituto de Materiales de Misiones (IMAM), Argentina.
    Opedal, Mihaela Tanase
    RISE - Research Institutes of Sweden, Bioekonomi, PFI.
    Area, Maria C.
    Instituto de Materiales de Misiones (IMAM), Argentina.
    Chinga-Carrasco, Gary
    RISE - Research Institutes of Sweden, Bioekonomi, PFI.
    Lignocellulosics as sustainable resources for production of bioplastics: a review2017Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 162, s. 646-664Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The bio-based economy requires a sustainable utilization of bioresources for production of a range of products, including pulp, paper, chemicals, biofuel and bioplastics. Currently, various types of bioplastics are produced industrially, competing in performance and price with the conventional fossil-oil based plastics. However, there is also a major interest in utilizing non-food crops, such as lignocellulosics, for production of drop-in polymers or new dedicated bioplastics. Lignocellulosic resources have a potential to replace plastics and materials, which have been traditionally based on fossil resources. This is important, as the development of high performance bio-based and renewable materials is one important factor for sustainable growth of the bio-based industry. However, production of bioplastics from forestry biomass requires a dedicated fractionation into the major components, i.e. cellulose, hemicelluloses and lignin, effective purification processes and cost-effective routes for conversion into monomers and platform molecules, utilized as a basis for bioplastics production. These processes are now technologically demanding and not profitable. The intention of this work was thus to review the current advances that have been made during the years within fractionation and purification of lignocelluloses and the processes that may feasible for production of bioplastics, based on wood components.

  • 2.
    Chinga-Carrasco, Gary
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Zarna, Chiara
    NTNU, Norway.
    Rodriguez Fabia, Sandra
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Leirset, Ingebjörg
    RISE Research Institutes of Sweden.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Molteberg, Dag
    Norske Skog Saugbrugs, Norway.
    Echtermeyer, Andreas
    NTNU, Norway.
    Hindersland, Leif
    Alloc AS, Norway.
    Side streams from flooring laminate production – Characterisation and recycling in biocomposite formulations for injection moulding2022Inngår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 153, artikkel-id 106723Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Side streams were collected from three locations in a flooring factory and their suitability in biocomposite formulations was assessed. The side stream (S3) that contained mainly residues from high-density fibreboards (HDF) was selected for further material testing. The effect of different fractions of S3, thermomechanical pulp (TMP) fibres and polylactic acid (PLA) were assessed in terms of their mechanical, melt flow and thermal properties. A biocomposite made from PLA, 20 wt% TMP fibres and 10 wt% S3 revealed a significant increase in modulus (5800 MPa), compared to the neat PLA (3598 MPa), and a similar melt-flow index (MFI = 4.5). The tensile strength was however somewhat reduced from 66 to 58 MPa. Importantly, numerical modelling and simulations were applied to demonstrate that building a model chair out of biocomposite can potentially reduce the material volume by 12% while maintaining similar load bearing capacity, compared to neat PLA. © 2021 The Author(s)

  • 3.
    Ghoreishi, Solmaz
    et al.
    University of Bergen, Norway.
    Løhre, Camilla
    University of Bergen, Norway.
    Hermundsgård, Dag Helge
    University of Bergen, Norway; Arbaflame AS, Norway.
    Lindgaard Molnes, Joakim
    University of Bergen, Norway.
    Tanase Opedal, Mihaela
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Brusletto, Rune
    Arbaflame AS, Norway.
    Barth, Tanja
    University of Bergen, Norway.
    Identification and quantification of valuable platform chemicals in aqueous product streams from a preliminary study of a large pilot-scale steam explosion of woody biomass using quantitative nuclear magnetic resonance spectroscopy2024Inngår i: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823, Vol. 14, s. 3331-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Steam explosion breaks down the polymeric matrix and enables the recovery of valuable compounds from lignocellulosic feedstock. In the steam explosion process, biomass is treated with high-pressure steam which subsequently generates large quantities of a condensed aqueous liquid (process effluent) and a filtered aqueous liquid (filtrate) that contain furfural, 5-hydroxymethylfurfural, 5-methylfurfural, methanol, and acetic acid as major constituents. This study addresses the identification and quantification of value-added chemicals in the aqueous product streams using quantitative analytical nuclear magnetic resonance spectroscopy with water suppression. This work reports a screening study for two different types of sawdust (Norway spruce and birch) at two different scales (4 L and 10 L reactors) using different reaction temperatures (190–223 °C) and corresponding pressures (13–24 bar), with and without the addition of SO2 gas. The duration of all experiments was 8 min. The process effluents contained acetic acid, methanol, formic acid, 5-methylfurfural, and furfural. Acetic acid (0.5 g/kg dry input biomass) and furfural (1.0 g/kg dry input biomass) were more abundant than methanol, formic acid, and 5-methylfurfural for both feedstocks. The addition of SO2 increased the furfural yields, indicating more efficient hydrolysis of hemicelluloses under acidic conditions. Filtrate samples also contained 5-hydroxymethylfurfural, with the highest concentrations (5.7–6.0 g/kg dry input biomass) in the filtrates from spruce. The different feedstocks and steam explosion temperatures strongly influenced the overall yields of the target compounds, in some cases tripling the concentrations. The results can be used to improve the profit margins in a pellets and chemicals biorefinery, as demonstrated in the ArbaOne pellets plant. © 2022, The Author(s).

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  • 4.
    Gulbrandsen, Torea A.
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Johnsen, Ingvild A.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Opedal, Mihaela Tanase
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Toven, Kai
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Øyaas, Karin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Pranovich, Andrey V.
    Åbo Akademi University, Finland.
    Mikkola, Jyri Pekka T.
    Åbo Akademi University, Finland; Umeå University, Sweden.
    Hoff, Bård H.
    NTNU Norwegian University of Science and Technology, Norway.
    Extracting hemicelluloses from softwood and bagasse as oligosaccharides using pure water and microwave heating2015Inngår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 49, nr 2, s. 117-126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of the study was to identify conditions for hemicelluloses extraction in oligomeric form. Using microwave assisted hot water extraction (HWE), the effects of both retention time and temperature on hemicelluloses yields, as well as the degree of polymerization (DP) as analyzed by SEC-MALLS, were investigated using both softwood (sawmill shavings) and sugarcane bagasse. The results are discussed in the light of the unavoidable yield-DP compromise resulting from the application of batch mode operations. Nevertheless, significant differences between the two raw materials could be observed, as expected. For softwood shavings, data interpolation indicated that about 50% of the hemicelluloses could be obtained as oligomers at an average DP of 30 when extracted at 183 °C for 5 minutes. For bagasse, longer extraction times seemed optimal. After hot water extraction at 183 °C for 12 minutes, about 62% of the bagasse hemicelluloses were extracted as oligomers at an average DP of about 100.

  • 5.
    Hermundsgård, Dag Helge
    et al.
    University of Bergen, Norway; Arbaflame AS, Norway.
    Ghoreishi, Solmaz
    University of Bergen, Norway.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Brusletto, Rune
    Arbaflame AS, Norway.
    Barth, Tanja
    University of Bergen, Norway.
    Investigating solids present in the aqueous stream during STEX condensate upgrading—a case study2022Inngår i: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Steam explosion (STEX) of woody biomass is an efficient pretreatment method in the production of water-resistant wood pellets. The STEX process also generates an aqueous condensate stream containing dissolved organic compounds, with furfural as the most abundant and valuable component. An industrial-scale recovery process for furfural and other organic by-products is therefore in the process of being developed and built. One challenge in the process has turned out to be the formation of solid particulate matter that can clog filters in the process unit. We have analyzed both the solid deposits and the fluids present at different points in the process unit to try to identify the origin of the particles using spectroscopic and chromatographic analysis, elemental analysis, and scanning electron microscopy. The aqueous fluids deriving from condensed steam contain furfural and other small organic molecules, with a separate low-density organic layer occurring at some points. This layer largely consists of wood extractives, typically terpenoids. In addition, a heavy organic phase comprising mostly furfural was found at one sampling point. The particles comprise a black, largely insoluble material with a H/C ratio of 0.88 and an O/C ratio of 0.26 and a very low ash content. IR spectra show a low content of C–H functional groups, and chromatographic analysis supports an interpretation that the particles are dominantly furfural-sourced humin-like polymers with adsorbed or co-polymerized terpenoids. Particle formation has been reproduced in a laboratory setting with conditions similar to those in the full-scale process. © 2022, The Author(s).

  • 6.
    Joseph, P.
    et al.
    NTNU, Norway.
    Ottesen, V.
    NTNU, Norway; Innlandet Fylkeskommune, Norway.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden.
    Moe, S. T.
    NTNU, Norway.
    Morphology of lignin structures on fiber surfaces after organosolv pretreatment2022Inngår i: Biopolymers, ISSN 0006-3525, E-ISSN 1097-0282, Vol. 113, nr 9, artikkel-id e23520Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The redeposition of lignin to the fiber surface after organosolv pretreatment was studied using two different reactor types. Results from the conventional autoclave reactor suggest that redeposition occurs during the cooling down stage. Redeposited particles appeared to be spherical in shape. The size and population density of the particles depends on the concentration of organosolv lignin in the cooking liquor, which is consistent with the hypothesis that reprecipitation of lignin occurs when the system is cooled down. The use of a displacement reactor showed that displacing the spent cooking liquor with fresh cooking liquor helps in reducing the redeposition and the inclusion of a washing stage with fresh cooking liquor reduced the reprecipitation of lignin, particularly on the outer fiber surfaces. Redeposition of lignin was still observed on regions that were less accessible to washing liquid, such as fiber lumens, suggesting that complete prevention of redeposition was not achieved. © 2022 The Authors. 

  • 7.
    Joseph, Prajin
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Moe, Störker
    NTNU Norwegian University of Science and Technology, Norway.
    The O-factor: using the H-factor concept to predict the outcome of organosolv pretreatment2023Inngår i: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823, Vol. 13, s. 6727-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The H-factor, a parameter used extensively to analyze and predict the outcome of kraft pulping, is applied to organosolv pretreatment. The total solid yield after organosolv pretreatment fits well with the H-factor. The concept has been extended to apply to the individual biomass polymers using unique values for the activation energy for the depolymerization of the individual biomass polymers, giving the O-factor concept analogous to the P factor used for analyzing prehydrolysis kinetics. The results showed a linear relationship between ln(L0/L) and O-factor at an activation energy of 96 kJ/mol. The best linear fit for mannan and xylan degradation was obtained at O-factor activation energies of 104 kJ/mol and 142 kJ/mol, respectively, and the formation of furfural and 5-HMF gave a good linear fit using an O-factor activation energy of 150 kJ/mol. The O-factor is thus a useful concept for analyzing organosolv pretreatment when the temperature during pretreatment is not constant. © 2021, The Author(s).

  • 8.
    Joseph, Prajin
    et al.
    NTNU, Norway.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Moe, Størker T.
    NTNU, Norway.
    Polymer properties of softwood organosolv lignins produced in two different reactor systems2023Inngår i: Biopolymers, ISSN 0006-3525, E-ISSN 1097-0282, Vol. 114, nr 12, artikkel-id e23566Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lignin, the second most abundant biopolymer on earth and with a predominantly aromatic structure, has the potential to be a raw material for valuable chemicals and other bio-based chemicals. In industry, lignin is underutilized by being used mostly as a fuel for producing thermal energy. Valorization of lignin requires knowledge of the structure and different linkages in the isolated lignin, making the study of structure of lignin important. In this article, lignin samples isolated from two types of reactors (autoclave reactor and displacement reactor) were analyzed by FT-IR, size exclusion chromatography, thermogravimetric analysis (TGA), and Py-GC-MS. The average molecular mass of the organosolv lignins isolated from the autoclave reactor decreased at higher severities, and FT-IR showed an increase in free phenolic content with increasing severity. Except for molecular mass and molecular mass dispersity, there were only minor differences between lignins isolated from the autoclave reactor and lignins isolated from the displacement reactor. Carbohydrate analysis, Py-GC–MS and TGA showed that the lignin isolated using either of the reactor systems is of high purity, suggesting that organosolv lignin is a good candidate for valorization. 

  • 9.
    Moe, S. T.
    et al.
    NTNU, Norway.
    Marcotullio, G.
    Via Francia 17, Italy.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Brusletto, R.
    Arbaflame AS, Norway.
    Formation of 5-methylfurfural and 2-acetylfuran from lignocellulosic biomass and by Cr3+-catalyzed dehydration of 6-deoxyhexoses2022Inngår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 522, artikkel-id 108672Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During autocatalyzed steam explosion of lignocellulose, polysaccharides in the cell wall are hydrolyzed and dehydrated to form various furaldehydes. In addition to furfural, 5-methylfurfural and 2-acetylfuran were identified in condensates from autocatalyzed steam explosion of Scandinavian softwood (Norway spruce, Picea abies). The presence of 5-methylfurfural can be explained by an acid-catalyzed dehydration of 6-deoxyaldohexoses, which are known to be present in lignocellulosic biomass. However, the presence of 2-acetylfuran cannot be explained by previously published reaction mechanisms since the required substrate (a 1-deoxyhexose or a 1-deoxyhexosan) is not known to be present in lignocellulosic biomass. In model experiments, it was shown that 2-acetylfuran is formed from rhamnose and fucose upon heating in the presence of the Lewis acid Cr3+. Possible reaction pathways for the formation of 2-acetylfuran from 6-deoxyaldohexoses are suggested. This reaction can potentially enable the targeted production of 2-acetylfuran from renewable biomass feedstocks. © 2022 The Authors

  • 10.
    Opedal, Mihaela Tanase
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, PFI.
    Espinosa, E.
    Universidad de Córdoba, Spain.
    Rodríguez, A.
    Universidad de Córdoba, Spain.
    Chinga-Carrasco, Gary
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, PFI.
    Lignin: A biopolymer from forestry biomass for biocomposites and 3D printing2019Inngår i: Materials, E-ISSN 1996-1944, Vol. 12, nr 18, artikkel-id 3006Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biopolymers from forestry biomass are promising for the sustainable development of new biobased materials. As such, lignin and fiber-based biocomposites are plausible renewable alternatives to petrochemical-based products. In this study, we have obtained lignin from Spruce biomass through a soda pulping process. The lignin was used for manufacturing biocomposite filaments containing 20% and 40% lignin and using polylactic acid (PLA) as matrix material. Dogbones for mechanical testing were 3D printed by fused deposition modelling. The lignin and the corresponding biocomposites were characterized in detail, including thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction analysis (XRD), antioxidant capacity, mechanical properties, and scanning electron microscopy (SEM). Although lignin led to a reduction of the tensile strength and modulus, the reduction could be counteracted to some extent by adjusting the 3D printing temperature. The results showed that lignin acted as a nucleating agent and thus led to further crystallization of PLA. The radical scavenging activity of the biocomposites increased to roughly 50% antioxidant potential/cm2, for the biocomposite containing 40 wt % lignin. The results demonstrate the potential of lignin as a component in biocomposite materials, which we show are adequate for 3D printing operations. © 2019 by the authors.

  • 11.
    Opedal, Mihaela Tanase
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Ghoreishi, S.
    University of Bergen, Norway.
    Hermundsgård, D. H.
    University of Bergen, Norway.
    Barth, T.
    University of Bergen, Norway.
    Moe, S. T.
    NTNU, Norway.
    Brusletto, R.
    Arbaflame AS, Norway.
    Steam explosion of lignocellulosic residues for co-production of value-added chemicals and high-quality pellets2024Inngår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 181, artikkel-id 107037Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The demand of pellets as energy carrier and the competitiveness of wood biomass are the drivers for finding alternative raw materials for production of pellets. The aim of this study was to investigate the steam explosion of lignocellulosic residues such as, straw, sawdust birch, sawdust spruce, GROT (mixture of 30 % bark and 70 % industrial chips), and their mix to co-production of value-added chemicals and high-quality pellets. The raw materials were first impregnated with water/acetic acid prior to steam explosion process, while leaching and washing of steam exploded biomass was used to reduce the ash content. The value-added chemicals were extracted with MIBK, and a gas chromatography was used to determine which value-added chemicals are present in the MIBK filtrates after extraction of the steam exploded biomass. Thermogravimetric analysis and Fourier transform infrared spectroscopy, elemental analysis, calorific values, compression strength and density were used to assess and compare the quality of steam exploded biomass and pellets quality. The results from the extraction experiments shows that furfural, HMF, vanillin, syringaldehyde and coniferaldehyde are the most value-added chemicals extracted from lignocellulosic residues where higher yield of the valuable chemicals was obtained when the biomass was presoaked in acetic acid. The ash content was reduced by 83 % for straw material by washing and leaching of steam exploded straw material when the biomass was presoaked in acetic acid. High quality pellets with high calorific value (20 MJ/kg), high compression strength (228 kN/m), high density (1300 kg/m3) and low ash content (0,06 %) were produced from sawdust spruce and GROT:Spruce mix used in our study. Based on our results, we can therefore suggest that steam explosion process of lignocellulosic residues improves the quality of the biomass to pellets production and at the same time open for the possibility to produce value-added chemicals. 

    Fulltekst (pdf)
    fulltext
  • 12.
    Opedal, Mihaela Tanase
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Ruwoldt, Jost
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Organosolv Lignin as a Green Sizing Agent for Thermoformed Pulp Products2022Inngår i: ACS Omega, E-ISSN 2470-1343, Vol. 7, nr 50, s. 46583-46593Artikkel i tidsskrift (Fagfellevurdert)
    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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  • 13. Opedal, Mihaela Tanase
    et al.
    Stenius, P.
    Johansson, L.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Colloidal stability and removal of extractives from process water in thermomechanical pulping2011Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, s. 248-257Artikkel i tidsskrift (Fagfellevurdert)
  • 14. Opedal, Mihaela Tanase
    et al.
    Stenius, Per
    Gregersen, Øjvind
    Johansson, Lars
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Hill, J.
    Flocculation of colloidal wood extractives in process water from precompression of chips in thermo-mechanical pulping2011Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, s. 64-71Artikkel i tidsskrift (Fagfellevurdert)
  • 15. Opedal, Mihaela Tanase
    et al.
    Stenius, Per
    Gregersen, Øjvind
    Johansson, Lars
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Hill, J.
    Removal of dissolved and colloidal substances in water from compressive pre-treatment of chips using dissolved air flotation: Laboratory Tests.2011Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, s. 72-80Artikkel i tidsskrift (Fagfellevurdert)
  • 16. Opedal, Mihaela Tanase
    et al.
    Stenius, Per
    Johansson, Lars
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Hill, J
    Sandberg, C.
    Removal of dissolved and colloidal substances in water from compressive pre-treatment of chips using dissolved air flotation: Pilot Trial2011Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, s. 364-371Artikkel i tidsskrift (Fagfellevurdert)
  • 17.
    Ruwoldt, Jost
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Chinga Carrasco, Gary
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Sustainable Materials from Organosolv Fibers and Lignin, Kraft Fibers, and Their Blends2024Inngår i: Polymers, E-ISSN 2073-4360, Vol. 16, nr 3, artikkel-id 377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to investigate new materials from organosolv fibers, organosolv lignin, kraft fibers, and their blends. The organosolv fibers showed reprecipitated lignin on the surface, a comparably low fiber length of 0.565 mm on average, and a high fines content of 82.3%. Handsheets were formed and thermopressed at 175 °C and 50 MPa, yielding dense materials (1050–1100 kg/m3) with properties different to that of regular paper products. The thermopressing of organosolv fibers alone produced materials with similar or better tensile strength (σb = 18.6 MPa) and stiffness (E* = 2.8 GPa) to the softwood Kraft reference pulp (σb = 14.8 MPa, E* = 1.8 GPa). The surface morphology was also smoother with fewer cavities. As a result, the thermopressed organosolv fibers exhibited higher hydrophobicity (contact angle > 95°) and had the lowest overall water uptake. Combinations of Kraft fibers with organosolv fibers or organosolv lignin showed reduced wetting and a higher density than the Kraft fibers alone. Furthermore, the addition of organosolv lignin to Kraft fibers greatly improved tensile stiffness and strength (σb = 23.8 MPa, E* = 10.5 GPa), likely due to the lignin acting as a binder to the fiber network. In conclusion, new thermopressed materials were developed and tested, which show promising potential for sustainable fiber materials with improved water resistance.

    Fulltekst (pdf)
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  • 18.
    Ruwoldt, Jost
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Green materials from added-lignin thermoformed pulps2022Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 185, artikkel-id 115102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, added-lignin thermoformed pulps (ALTP) were explored as a new alternative for green materials. Technical lignin was added to mechanical pulp and subsequently thermoformed, yielding a biobased material with lignin contents above natural levels. This material was tested for its mechanical properties, water-uptake, and density. In addition, FTIR and TGA-DSC were used to characterize the lignin samples, i.e., Soda, Kraft, and hydrolysis lignin, as well as lignosulfonates. The material properties were significantly changed at 20 – 40 wt% added-lignin per dry fiber. Lignin addition increased density and reduced water-uptake and wettability. The effect on mechanical properties could vary, however, pure lignin had a more beneficial effect than hydrolysis lignin containing residual cellulose. Higher stiffness was observed for the pure lignin samples at constant or decreasing tensile strength. In conclusion, ALTP is a promising material for developing new pulp products and plastics-replacements, where the ratio and type of added-lignin may be used to fine-tune the desired characteristics. © 2022 The Authors

  • 19.
    Ruwoldt, Jost
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Ultraviolet Spectrophotometry of Lignin Revisited: Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility Parameter, and Determination of Phenolic Hydroxyl Groups2022Inngår i: ACS Omega, E-ISSN 2470-1343, Vol. 7, nr 50, s. 46371-46383Artikkel i tidsskrift (Fagfellevurdert)
    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. 

  • 20.
    Ruwoldt, Jost
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Purification of soda lignin2024Inngår i: Sustainable Chemistry for the Environment, ISSN 2949-8392, Vol. 6, artikkel-id 100102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purity of technical lignin is one of the main obstacles in the utilization of lignin to value-added chemicals, products, and materials. The objective of this study was to investigate and compare single and two stage purification methods for obtaining soda lignin with high purity. Extensive washing and extraction with water was found effective, increasing the abundance of acid insoluble lignin while reducing its ash content. Extraction with organic solvents was conducted with 2-propanol or blends of n-heptane/1-butanol or cyclohexane/acetone. These solvents were shown to have little effect on the total lignin content, as determined by wet-chemical methods. Two-stage treatments (washing with water followed by solvent extraction) were hence not better than single stage water extraction in terms of the lignin purity. Still, selective removal of low molecular weight components after solvent extraction was noted, reducing the overall polydispersity of the lignin. Evaporation at 40 °C also showed little effect, whereas calcination at 150 °C significantly increased the molecular weight of the soda lignin. The latter effect was explained by thermally induced cross-linking. In addition, the UV absorbance of the calcinated lignin increased, which is likely related to changes in the aromatic structure. Such effect also entailed that UV/vis spectrophotometry was found less reliable in determining the total lignin content. At last, a mathematical model was adapted to predict the total lignin content from FTIR spectrometry. In conclusion, the tested procedures can be used to purify soda lignin and adjust its molecular weight.

    Fulltekst (pdf)
    fulltext
  • 21.
    Zarna, Chiara
    et al.
    NTNU, Norway.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Echtermeyer, Andreas
    NTNU, Norway.
    Chinga-Carrasco, Gary
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Reinforcement ability of lignocellulosic components in biocomposites and their 3D printed applications – A review2021Inngår i: Composites Part C: Open Access, ISSN 2666-6820, Vol. 6, artikkel-id 100171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biocomposites based on lignocellulosic components (e.g. pulp fibers, nanocellulose and lignin) are of interest as sustainable replacements for thermoplastic fossil-based materials, which find their application in household items, construction, automotive, 3D-printing, etc. Nanocellulose, a nano-structural component of pulp fibers, is considered having potential as a high-performance reinforcement for bioplastics, due to its high aspect ratio and potentially strong mechanical properties. Lignin, a biodegradable polymer isolated from pulp fibers, can be considered as an essential bioresource for the production of biocomposites, due to the aromatic structure and functional groups. In this review the reinforcing ability of selected lignocellulosic components and their applicability in 3D printing is presented, considering their mechanical properties. At this point, there are challenges in processing nanocellulose that may reduce its attractiveness as a reinforcement in thermoplastic biocomposites. The objective of the review is to identify current challenges and opportunities for the application of 3D printed lignocellulosic biocomposites. Optimization of 3D printing process parameters are considered to be a key to further improve the mechanical properties of the end-product. Importantly, this review revealed that greater efforts in mechanical fatigue research may contribute to assess and improve the potential of lignocellulosic reinforcements for structural applications. © 2021 The Authors

  • 22.
    Öyaas, K.
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Johnsen, I.A.
    Hoff, B.H.
    Opedal, Mihaela Tanase
    Toven, K.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Gulbrandsen, T.Aa.
    Hot water extraction of hemicellulose from softwood and sugarcane bagasse using microwave heating technology2012Konferansepaper (Fagfellevurdert)
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