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  • 301.
    Larsson, Per
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation.
    Erlandsson, Johan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lopez Duran, Veronica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation.
    Henschen, Jonatan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Tchang Cervin, Nicholas
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Innventia AB, Stockholm, Sweden.
    Al-Ansari, Zeinab
    Univ Copenhagen, Dept Pharm, Copenhagen, Denmark..
    Svagan, Anna Justina
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Crosslinking as a facilitator for novel (nano)cellulose-based applications2017Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Artikel i tidskrift (Övrigt vetenskapligt)
  • 302.
    Larsson, Per Tomas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Svensson, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    A new, robust method for measuring average fibre wall pore sizes in cellulose I rich plant fibre walls2013Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 20, nr 2, s. 623-631Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new, robust method for measuring the average pore size of water-swollen, cellulose I rich fibres is presented. This method is based on the results of solid-state NMR, which measures the specific surface area (area/solids mass) of water-swollen samples, and of the fibre saturation point (FSP) method, which measures the pore volume (water mass/solids mass) of water-swollen samples. These results are suitable to combine since they are both recorded on water-swollen fibres in excess water, and neither requires the assumption of any particular pore geometry. The new method was used for three model samples and reasonable average pore size measurements were obtained for all of them. The structural characterization of water-swollen samples was compared with the dry structure of fibres as revealed using BET nitrogen gas adsorption after a liquid exchange procedure and careful drying. It was concluded that the structure of the water-swollen fibres sets an upper limit on what is obtainable in the dry state.

  • 303.
    Larsson, Per Tomas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Innventia AB, Stockholm, Sweden.;KTH, WWSC, Stockholm, Sweden..
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH Fibre Polymer Tech, Stockholm, Sweden..
    Westlund, Per-Olof
    Umea Univ, Chem, Umea, Sweden..
    Karlsson, Pernilla
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, WWSC, Stockholm, Sweden..
    Internal structure of cellulose I fibril aggregates studied by a combination of structure and dynamics measurements2016Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Artikel i tidskrift (Övrigt vetenskapligt)
  • 304.
    Larsson, Tomas
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Structural characteristics influencing the reactivity of isolated cellulose I2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 305.
    Larsson, Tomas
    et al.
    Innventia AB, Stockholm, Sweden.;Wallenberg Wood Sci Ctr, Stockholm, Sweden..
    Wohlert, Jakob
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Bergenstråhle, Malin
    KTH. KTH, Stockholm, Sweden..
    Changes in the supra-molecular structure of cellulose I during TEMPO-oxidation. Bringing together NMR, MD, and XRD results2017Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Artikel i tidskrift (Övrigt vetenskapligt)
  • 306. Lauberts, Maris
    et al.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Ponomarenko, Jevgenija
    Dizhbite, Tatjana
    Dobele, Galina
    Volperts, Alexandr
    Lauberte, Liga
    Telysheva, Galina
    Fractionation of technical lignin with ionic liquids as a method for improving purity and antioxidant activity2017Ingår i: INDUSTRIAL CROPS AND PRODUCTS, ISSN 0926-6690, Vol. 95, s. 512-520Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alder soda lignin, a by-product of the chemical processing of black alder wood, was fractionated using ionic liquids (ILs) based on the 1-buthyl-3-methylimidazolium [Bmim] cation and the following anions: chloride ([Bmim]Cl), dimethylphosphate ([Bmim]Me2PO4), acetate ([Brhim]OAc) and tosylate ([Bmim]OTs). The aim was to obtain lignin fractions of improved purity for further application as antioxidants. The purity and properties of the IL lignin fractions were compared with those of other lignin fractions obtained using sequential extraction with organic solvents. The original lignin and the lignin fractions were characterized by analytical pyrolysis (Py-GC/MS/FID), size-permeation chromatography (GPC), electron paramagnetic resonance (EPR) spectroscopy and wet chemistry methods. The lignin treatment with [Bmim]DMP, [Bmim]OAc and [Bmim]OTs produced fractions with a lignin content of 98-99%. These fractions along with the n-propanol and methanol fractions obtained using sequential organic solvent extraction were enriched with certain structural features that had a positive impact on lignin antioxidant activity, according to the results from DPPH center dot and ORAC assays.

  • 307.
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Unveiling the structure and ultrastructure of lignin carbohydrate complexes in softwoods2013Ingår i: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 62, s. 705-713Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignocellulose-based polymers are presently being investigated for potential as raw materials for polymer industry. However, covalent bonds between carbohydrates and lignin, so called lignin carbohydrate complexes (LCCs) present one of the factors impeding clean fractionation of the polymers. Understanding the chemical structure of LCCs in relation to the cell wall ultra-structure therefore provides relevant insight for technical fractionation. In the present work, new mild analytical protocols for LCCs were developed and fractions thereof subjected to detailed structural/ultra-structural characterization. When combined with size exclusion chromatography, the application of mono-component ploysaccharidases proved to be crucial for the identification of LCC moieties and provided indirect evidence for existence of lignin-carbohydrate bonds. The carbohydrate composition of the LCC moieties was essential to determination of the ultra-structural origin of the LCC types. Analytical 31P NMR of the LCCs and of their thioacidolysis products was useful in unveiling lignin structure in LCCs. A complete structure/ultra-structure relationship of LCCs in softwood was determined.

  • 308.
    Lawoko, Martin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Van Heiningen, A. R. P.
    University of Maine, USA.
    Fractionation and characterization of completely dissolved ball milled hardwood2011Ingår i: Journal of wood chemistry and technology, ISSN 0277-3813, E-ISSN 1532-2319, Vol. 31, nr 3, s. 183-203Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A simplified method for sequentially dissolving and fractionating ball milled hard wood polymers in high yield is presented. The complete dissolution of the whole ball milled wood, and the fractions recovered from it by applying the sequential fractionation, was accomplished in lithium chloride/ dimethylacetamide solvent system enabling size exclusion chromatography studies. The chromatography applied a four detector system; an Ultraviolet-Visible spectroscopy-, Intrinsic Viscosity-Differential Pressure-, Right Angle Laser Light Scattering- and Refractive Index detectors, a combination hereby proposed to enable interpretation of the complex elution profiles with emphasis on chemical interactions. Indirect evidence of the presence of lignin carbohydrate complexes in hardwoods is provided. It is also proposed that cellulose is severely degraded from a degree of polymerization of 10,000 in wood, down to a value of approximately 400 by either the applied ball milling condition or in subsequent solubilization steps.

  • 309. Lee, Koon-Yang
    et al.
    Aitomaki, Yvonne
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Oksman, Kristiina
    Bismarck, Alexander
    Utilising the full potential of bacterial cellulose in composite materials: Can it be done?2014Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, s. 309-CELL-Artikel i tidskrift (Övrigt vetenskapligt)
  • 310. Lee, Koon-Yang
    et al.
    Aitomäki, Yvonne
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Oksman, Kristiina
    Bismarck, Alexander
    On the use of nanocellulose as reinforcement in polymer matrix composites2014Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 105, s. 15-27Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanocellulose is often being regarded as the next generation renewable reinforcement for the production of high performance biocomposites. This feature article reviews the various nanocellulose reinforced polymer composites reported in literature and discusses the potential of nanocellulose as reinforcement for the production of renewable high performance polymer nanocomposites. The theoretical and experimentally determined tensile properties of nanocellulose are also reviewed. In addition to this, the reinforcing ability of BC and NFC is juxtaposed. In order to analyse the various cellulose-reinforced polymer nanocomposites reported in literature, Cox-Krenchel and rule-of-mixture models have been used to elucidate the potential of nanocellulose in composite applications. There may be potential for improvement since the tensile modulus and strength of most cellulose nanocomposites reported in literature scale linearly with the tensile modulus and strength of the cellulose nanopaper structures. Better dispersion of individual cellulose nanofibres in the polymer matrix may improve composite properties.

  • 311.
    Leijonmarck, Simon
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Carlson, T.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Asp, L. E.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Maples, H.
    Bismarch, A.
    Solid polymer electrolyte coated carbon fibres for batteriesManuskript (preprint) (Övrigt vetenskapligt)
  • 312.
    Leijonmarck, Simon
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Cornell, Ann
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Flexible nano-paper-based positive electrodes for Li-ion batteries- Preparation process and properties2013Ingår i: Nano Energy, ISSN 2211-2855, Vol. 2, nr 5, s. 794-800Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Flexible battery solutions is an emerging field due to a demand for bendable electronic devices. In this study, a route to make flexible positive electrodes for Li-ion batteries by utilizing nanofibrillated cellulose (NFC) as binder material has been examined. These LiFePO4-based electrodes are made by filtration of a water dispersion of NFC, LiFePO4 and Super-P carbon particles, resembling a paper-making process. The resulting electrodes show good mechanical properties both dry as well as when soaked with battery electrolyte with a stress at break of typically at 5.2 and 2.2 MPa, respectively. The cycling performance was 151 mAh/g at C/10 and 132 mAh/g at 1C for samples dried at 170 degrees C. The drying temperature, after the filtration step, was found to be important and to affect both the mechanical properties, rendering the electrodes more ductile at lower temperatures, as well as the electrochemical properties, causing a higher coulombic efficiency at higher temperatures.

  • 313.
    Leijonmarck, Simon
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Cornell, Ann
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Single-paper flexible Li-ion battery cells through a paper-making process based on nano-fibrillated cellulose2013Ingår i: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 1, nr 15, s. 4671-4677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recently, a need for mechanically flexible and strong batteries has arisen to power technical solutions such as active RFID tags and bendable reading devices. In this work, a method for making flexible and strong battery cells, integrated into a single flexible paper structure, is presented. Nano-fibrillated cellulose (NFC) is used both as electrode binder material and as separator material. The battery papers are made through a paper-making type process by sequential filtration of water dispersions containing the battery components. The resulting paper structure is thin, 250 mm, and strong with a strength at break of up to 5.6 MPa when soaked in battery electrolyte. The cycling performances are good with reversible capacities of 146 mA h g(-1) LiFePO4 at C/10 and 101 mA h g(-1) LiFePO4 at 1 C. This corresponds to an energy density of 188 mW h g(-1) of full paper battery at C/10.

  • 314. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Eklund, Patrik
    Lucenius, Jessica
    Österberg, Monika
    Willför, Stefan
    Targeted functionalization of spruce O-acetyl galactoglucomannans-2,2,6,6-tetramethylpiperidin-1-oxyl-oxidation and carbodiimide-mediated amidation2013Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 130, nr 5, s. 3122-3129Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modified spruce O-acetyl galactoglucomannans (GGMs) can be used as molecular anchors to alter the surface properties or to activate the surface of cellulose. To selectively introduce functionalities, GGMs were oxidized on C-6 of hexoses by 2,2,6,6-tetramethylpiperidin-1-oxyl-mediated oxidation. Different degrees of oxidation were successfully obtained by varying the reaction parameters. Low degrees could be obtained by performing the oxidations in bromide-free conditions. The formed uronic acids were further modified by a carbodiimide-mediated amidation reaction, which opens a window for introducing various functionalities selectively on hexoses. The adsorption of the modified GGMs to various cellulose samples was investigated. Indirect bulk sorption to fibers was compared to direct adsorption to nanofibrillated cellulose ultrathin films. GGMs with low degrees of oxidation showed high affinity to cellulose surfaces and could be sorbed onto cellulose in pure water. Moderate amounts of GGMs with high degree of oxidation could be sorbed onto cellulose in the presence of salts.

  • 315. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Liu, Jun
    Wang, Xiaoju
    Pesonen, Markus
    Willfoer, Stefan
    Anionic Polysaccharides as Templates for the Synthesis of Conducting Polyaniline and as Structural Matrix for Conducting Biocomposites2013Ingår i: Macromolecular rapid communications, ISSN 1022-1336, E-ISSN 1521-3927, Vol. 34, nr 13, s. 1056-1061Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A green chemoenzymatic pathway for the synthesis of conducting polyaniline (PANI) composites is presented. Laccase-catalyzed polymerization in combination with anionic polysaccharides is used to produce polysaccharide/PANI composites, which can be processed into flexible films or coated onto cellulose surfaces. Different polysaccharide templates are assessed, including -carrageenan, native spruce O-acetyl galactoglucomannan (GGM), and TEMPO-oxidized cellulose and GGM. The resulted conducting biocomposites derived from natural materials provide a broad range of potential applications, such as in biosensors, electronic devices, and tissue engineering.

  • 316. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Parikka, Kirsti
    Eklund, Patrik
    Sjöholm, Rainer
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Tenkanen, Maija
    Willför, Stefan
    Targeted allylation and propargylation of galactose-containing polysaccharides in water2014Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 100, s. 46-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Galactose units of spruce galactoglucomannan (GGM), guar galactomannan (GM), and tamarind (galacto)xyloglucan (XG) were selectively allylated. Firstly aldehyde functionalities were formed at the C-6 position via enzymatic oxidation by galactose oxidase. The formed aldehydes were further derivatized by an indium mediated Barbier-Grignard type reaction, resulting in the formation of homoallylic alcohols. In addition to allylic halides, the same reaction procedure was also applicable for GGM, when using propargyl bromide as halide. All reaction steps were done in water, thus the polysaccharides were modified in a one-pot reaction. The formation of the allylated, or propargylated, product was identified by MALDI-TOF-MS. All polysaccharide products were isolated and further characterized by GC-MS or NMR spectroscopy. By this chemo-enzymatic process, we have demonstrated a novel method for derivatization of GGM and other galactose-containing polysaccharides. The derivatized polysaccharides are potential platforms for further functionalizations.

  • 317. Lewis, W. J. T.
    et al.
    Agg, A.
    Clarke, A.
    Mattsson, Tuve
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Chew, Y. M. J.
    Bird, M. R.
    Development of an automated, advanced fluid dynamic gauge for cake fouling studies in cross-flow filtrations2016Ingår i: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 238, s. 282-296Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fluid dynamic gauging (FDG) has previously been demonstrated as a technique for the estimation of fouling layer thickness during membrane filtration. Subsequently, FDG has been developed to allow faster, more accurate, and automated readings. Previous experimental data has been re-examined and shortcomings of the methodology used are discussed. In this work the operating procedures of FDG were refined and tested with a mixture of sticky, amorphous foulant and monodispersed glass spheres. The results demonstrate how cake growth rates can be confidently estimated in-situ. The technique also provides strong evidence of a difference in cake structure through destructive thickness testing, despite cake thicknesses being almost equivalent.

  • 318. Lewis, William J. T.
    et al.
    Mattsson, Tuve
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Chew, Y. M. John
    Bird, Michael R.
    Investigation of cake fouling and pore blocking phenomena using fluid dynamic gauging and critical flux models2017Ingår i: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 533, s. 38-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cake growth during a low pressure cross-flow microfiltration (MF) of a Kraft lignin suspension was studied using fluid dynamic gauging (FDG). This is the first paper to discuss the identification of fouling mechanisms and their transition points based on simultaneous, in situ and in real-time FDG measurements of cake layer thickness and flux. The FDG results were used to quantify the significance of membrane pore-level fouling phenomena which occur at an early stage of the filtration. A flux decline of approximately 75% was attributed to membrane pore fouling i.e. deposition on the surface of the membrane which caused direct blocking of the membrane pores. We present here a novel toolset for quick and achievable diagnosis of membrane fouling mechanisms, which can accelerate innovations in membrane technology and process optimisation. Furthermore, this innovative approach showed good agreement with a mathematical approach, based on a critical flux model, which was applied to raw flux data. In addition to cake thickness measurements, destructive strength testing of the fouling layer showed an increase in cohesive strength over time. The results showed that filter cakes formed by Kraft lignin become harder to remove by shear stress as they become thicker during the course of the filtration. A removal mechanism for lignin layer under stress is also proposed. The methodology described here can be applied to rapidly predict and assess routes to performance improvements in cross-flow MF.

  • 319. Lewitus, Dan Y.
    et al.
    Rios, Fabian
    Rojas, Ramiro
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, United States .
    Kohn, Joachim
    Molecular design and evaluation of biodegradable polymers using a statistical approach2013Ingår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, nr 11, s. 2529-2535Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The challenging paradigm of bioresorbable polymers, whether in drug delivery or tissue engineering, states that a fine-tuning of the interplay between polymer properties (e.g., thermal, degradation), and the degree of cell/tissue replacement and remodeling is required. In this paper we describe how changes in the molecular architecture of a series of terpolymers allow for the design of polymers with varying glass transition temperatures and degradation rates. The effect of each component in the terpolymers is quantified via design of experiment (DoE) analysis. A linear relationship between terpolymer components and resulting T-g (ranging from 34 to 86 A degrees C) was demonstrated. These findings were further supported with mass-per-flexible-bond analysis. The effect of terpolymer composition on the in vitro degradation of these polymers revealed molecular weight loss ranging from 20 to 60 % within the first 24 h. DoE modeling further illustrated the linear (but reciprocal) relationship between structure elements and degradation for these polymers. Thus, we describe a simple technique to provide insight into the structure property relationship of degradable polymers, specifically applied using a new family of tyrosine-derived polycarbonates, allowing for optimal design of materials for specific applications.

  • 320.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Iversen, Tommy
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Innventia AB, Drottning Kristinas väg 61, SE-114 86 Stockholm, Sweden.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Hydrophobic materials based on cotton linter cellulose and an epoxy-activated polyester derived from a suberin monomer2015Ingår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Suberin is a natural hydrophobic material that could be used to improve the water repellency of cellulose surfaces. It is also abundant in the outer bark of birch (Betula verrucosa); birch bark is a side-stream product in Scandinavia from the forest industry, which is generally burned for energy production. A suberin monomer, cis-9,10-epoxy-18-hydroxyoctadecanoic acid, was isolated from birch outer bark and polymerized via lipase (immobilized Candida antarctica lipase B). The resulting epoxy-activated polyester was characterized by nuclear magnetic resonance (NMR) imaging, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, and size exclusion chromatography. Then the polyester was cured with tartaric or oxalic acid, and the crosslinked polyesters were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry. Hydrophobic materials were prepared by compression molding of polyester-impregnated cellulose sheets, and the final products were characterized by FTIR, cross-polarization magic angle spinning 13 C NMR, and field-emission scanning electron microscopy. The water contact angle was significantly increased from 0 ° for the original cellulose sheets to over 100 ° for the produced hydrophobic materials.

  • 321.
    Li, Jiebing
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Shi, Chao
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    The methoxy group of beta-O-methyl glucuronic acid is central for the formation of hexenuronic acid during kraft pulping2011Ingår i: O Papel, ISSN 0031-1057, Vol. 72, nr 1, s. 54-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hexenuronic acid is created from 4-O-methyl gluc-uronic acid – a side chain group in xylan, and one of the most important hemicelluloses in both hardwood and softwood - during alkaline conditions, such as kraft pulping. Especially in hardwood kraft pulp, hexenuronic acid corresponds to a large part of the kappa number, and the presence of this component in bleached pulp causes post yellowing. In this work it is shown that glucuronic acid that lacks a methoxy group on the 4-carbon does not form hexenuronic acid under alkaline condition to the same extent as 4-O-methylglucuronic acid. This opens up novel strategies for genetic modification of the hemicellulose structures in wood cultivated for kraft pulping.

  • 322. Li, M.
    et al.
    Chen, Pan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Xu, M.
    Xu, X.
    A novel self-assembly Lentinan-tetraphenylethylene​ composite with strong blue​ fluorescence in water and its properties2017Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, s. 13-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report a unique self-assembly of lentinan, a triple helical β-(1→3)-glucan (t-LNT), in water. By molecular dynamics simulation, it was found that t-LNT aggregated preferentially along the chain direction to form long chains, accompanied by side-direction linkage to form branches. Transmission electron microscopy images demonstrated that t-LNT formed dendrite-like fibers, which further formed fishnet-like porous/mesoporous aggregates with increasing concentration. The meshes in the fishnet were ascribed to the intersection of branches. The major driving force for aggregation was expected to be hydrogen bonding between hydroxyl groups in t-LNT chains. Based on this self-assembly behavior, a novel composite was prepared from t-LNT and tetraphenylethylene (TPE) by entrapping TPE aggregates into the meshes of t-LNT fishnets. The as-prepared t-LNT/TPE composite largely enhanced the blue fluorescence of TPE in water, exhibiting stable optical property and good biocompatibility, and t-LNT is expected to show great potential as a carrier of hydrophobic molecules for biomedical application.

  • 323.
    Li, Yuanyuan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Fu, Qiliang
    Rojas, Ramiro
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Yan, Min
    KTH, Skolan för elektro- och systemteknik (EES).
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Lignin-Retaining Transparent Wood2017Ingår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 17, s. 3445-3451Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80wt% of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83%, haze of 75%, thermal conductivity of 0.23WmK(-1), and work-tofracture of 1.2MJm(-3) (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings.

  • 324.
    Li, Yuanyuan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Fu, Qiliang
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Yang, Xuan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Transparent wood for functional and structural applications2018Ingår i: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 376, nr 2112, artikel-id 20170182Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Optically transparent wood combines mechanical performance with optical functionalities is an emerging candidate for applications in smart buildings and structural optics and photonics. The present review summarizes transparent wood preparation methods, optical and mechanical performance, and functionalization routes, and discusses potential applications. The various challenges are discussed for the purpose of improved performance, scaled-up production and realization of advanced applications. This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.

  • 325.
    Li, Yuanyuan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Fu, Qiliang
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Yu, Shun
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Yan, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance2016Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, nr 4, s. 1358-1364Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Optically transparent wood (TW) with transmittance as high as 85% and haze of 71% was obtained using a delignified nanoporous wood template. The template was prepared by removing the light-absorbing lignin component, creating nanoporosity in the wood cell wall. Transparent wood was prepared by successful impregnation of lumen and the nanoscale cellulose fiber network in the cell wall with refractive-index-matched prepolymerized methyl methacrylate (MMA). During the process, the hierarchical wood structure was preserved. Optical properties of TW are tunable by changing the cellulose volume fraction. The synergy between wood and PMMA was observed for mechanical properties. Lightweight and strong transparent wood is a potential candidate for lightweight low-cost, light-transmitting buildings and transparent solar cell windows.

  • 326.
    Li, Yuanyuan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Yu, Shun
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Chen, Pan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Rojas, Ramiro
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Hajian, Alireza
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Cellulose nanofibers enable paraffin encapsulation and the formation of stable thermal regulation nanocomposites2017Ingår i: Nano Energy, ISSN 2211-2855, Vol. 34, s. 541-548Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Non-leaking, green materials with high content of phase change materials (PCM) can conserve solar energy and contribute to a sustainable society. Here, paraffin was encapsulated by nanocellulose (CNF) through a pickering emulsion method, while simultaneously forming a composite material. The thermodynamic drive for phase separation was confirmed by molecular modeling. Particle formation was characterized by dynamic light scattering and they were processed into stable PCM/CNF composites in the form of PCM paper structures with favorable mechanical properties. The PCM composite was lightweight and showed a solid content of paraffin of more than 72 wt%. Morphology was characterized using FE-SEM. The thermal regulation function of the PCM composite was demonstrated in the form of a model roof under simulated sunlight. No obvious leakage was observed during heating/cooling cycles, as supported by DSC and SAXS data. The PCM composite can be extended to panels used in energy-efficient smart buildings with thermal regulation integrated in load-bearing structures.

  • 327.
    Li, Yuanyuan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Yu, Shun
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Veinot, J. G. C.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Sychugov, Ilya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Luminescent Transparent Wood2017Ingår i: Advanced Optical Materials, ISSN 2195-1071, Vol. 5, nr 1, artikel-id 1600834Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Luminescent transparent wood is prepared by combining the complementary properties of naturally grown anisotropic porous wood and luminescent quantum dots. The wood structure introduces strong diffused luminescence and waveguiding, which can potentially be exploited for optoelectronic and photovoltaic applications, such as for planar illumination sources and luminescent buildings/furniture. Images below show the transparency, haze, and luminescence of quantum dot wood.

  • 328. Liimatainen, Henrikki
    et al.
    Ezekiel, Ngesa
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer.
    Sliz, Rafal
    Ohenoja, Katja
    Sirviö, Juho Antti
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Hormi, Osmo
    Niinimäki, Jouko
    High-Strength Nanocellulose-Talc Hybrid Barrier Films2013Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, nr 24, s. 13412-13418Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hybrid organic inorganic films mimicking natural nacre-like composite structures were fabricated from cellulose nanofibers obtained from sequential periodate chlorite oxidation treatment and talc platelets, using a simple vacuum-filtration method. As a pretreatment, commercial talc aggregates were individualized into well-dispersed talc platelets using a wet stirred media mill with high-shear conditions to promote the homogeneity and mechanical characteristics of hybrids. The nanofiber talc hybrids, which had talc contents from 1 to 50 wt %, were all flexible in bending, and possessed tensile strength and Young's modulus values up to 211 +/- 3 MPa and 12 +/- 1 GPa, respectively, the values being remarkably higher than those reported previously for nanofibrillated cellulose talc films. Because of the lamellar and well-organized structure of hybrids in which the talc platelets were evenly embedded, they possessed a small pore size and good oxygen barrier properties, as indicated by the preliminary results. The talc platelets decreased the moisture adsorption of highly talc-loaded hybrids, although they still exhibited hydrophilic surface characteristics in terms of contact angles.

  • 329.
    Lima, Raquel B.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Qin, Haiying
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Fan, Liangdong
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Direct lignin fuel cell for power generation2011Ingår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry: Proceedings, ISWFPC, 2011, s. 257-262Konferensbidrag (Refereegranskat)
    Abstract [en]

    Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for a direct conversion into electricity using direct carbon fuel cell (DCFC). Two different types of industrial lignins were investigated: lignosulphonate (LS) and kraft lignin (KL), either directly in their commercial forms, after their blending with commercial active carbon (AC) or after alternation of their structures by a pH adjustment to pH 10. It has been found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43∼57 to 85∼101 mA/cm 2. The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.680-0.699 V and a maximum current density of 74∼79 mA/cm 2 from both lignins. Typical power density was 12 (for KL +AC) and 24 mW cm -2 (for LS +AC). It has been concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.

  • 330.
    Lima, Raquel Bohn
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Qin, Haiying
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Direct lignin fuel cell for power generation2013Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, nr 15, s. 5083-5089Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for direct conversion into electricity using direct carbon fuel cells (DCFC). Two different types of industrial lignins were investigated: Lignosulfonate (LS) and Kraft lignin (KL), in their commercial forms, after their blending with commercial active carbon (AC) or after alteration of their structures by a pH adjustment to pH 10. It was found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43-57 to 83-101 mA cm(-2). The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.68-0.69 V and a maximum current density of 74-79 mA cm(-2) from both lignins. Typical power density was 12 (for KL + AC) and 24 mW cm(-2) (for LS + AC). It is concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.

  • 331.
    Limaye, Mukta V.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Bacsik, Zoltan
    Schütz, Christina
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Dembelé, Aissata
    Pléa, Mama
    Andersson, Linnea
    Salazar-Alvarez, German
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Bergström, Lennart
    On the role of tannins and iron in the Bogolan or mud cloth dyeing process2012Ingår i: Textile research journal, ISSN 0040-5175, E-ISSN 1746-7748, Vol. 82, nr 18, s. 1888-1896Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have investigated the chemistry of the Bogolan or mud cloth dyeing process, a traditional technique of coloring cotton cloths deeply rooted in Mali. Textiles produced by the traditional Bogolan process, using tannin-rich plant extract and iron-rich clay-based mud, were compared using infrared (IR) spectroscopy, scanning electron microscopy (SEM) and X-ray absorption near-edge spectroscopy (XANES) with cotton fibers that were impregnated with tannin and iron salt solutions. IR spectroscopy in both reflective mode on the cloth and cotton and in transmission mode on single fibers, together with SEM, showed that gallic and tannic acid adsorb and precipitate onto the cotton fiber surface. IR spectroscopy and comparison with tannin and iron solution-impregnated cotton showed that the black color of the traditional Bogolan cloth is dominated by the formation of iron-tannin complexes. The presence of iron in the Bogolan cloth was confirmed using XANES data, supporting the notion that iron has been transferred from the iron-rich clay-based mud to the cloth. The chemistry of Bogolan cloth is not only historically and culturally significant and of importance in textile conservation, but may also inspire future research on sustainable dyeing and processing techniques based on natural products.

  • 332.
    Lindh, Erik L.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Bergenstråhle-Wohlert, Malin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Terenzi, Camilla
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Salmén, Lennart
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Furó, Istvan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Non-exchanging hydroxyl groups on the surface of cellulose fibrils: The role of interaction with water2016Ingår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 434, s. 136-142Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The interaction of water with cellulose stages many unresolved questions. Here 2H MAS NMR and IR spectra recorded under carefully selected conditions in 1H-2H exchanged, and re-exchanged, cellulose samples are presented. It is shown here, by a quantitative and robust approach, that only two of the three available hydroxyl groups on the surface of cellulose fibrils are exchanging their hydrogen with the surrounding water molecules. This finding is additionally verified and explained by MD simulations which demonstrate that the 1HO(2) and 1HO(6) hydroxyl groups of the constituting glucose units act as hydrogen-bond donors to water, while the 1HO(3) groups behave exclusively as hydrogen-bond acceptors from water and donate hydrogen to their intra-chain neighbors O(5). We conclude that such a behavior makes the latter hydroxyl group unreactive to hydrogen exchange with water.

  • 333.
    Lindh, Erik L.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Salmén, Lennart
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Surface accessibility of cellulose fibrils studied by hydrogen-deuterium exchange with water2016Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 1, s. 21-33Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A problem with cellulose-based materials is that they are highly influenced by moisture, leading to reduced strength properties with increasing moisture content. By achieving a more detailed understanding of the water–cellulose interactions, the usage of cellulose-based materials could be better optimized. Two different exchange processes of cellulose hydroxyl/deuteroxyl groups have been monitored by transmission FT-IR spectroscopy. By using line-shape-assisted deconvolution of the changing intensities, we have been able to follow the exchange kinetics in a very detailed and controlled manner. The findings reveal a hydrogen exchange that mainly is located at two different kinds of fibril surfaces, where the differences arise from the water accessibility of that specific surface. The slowly accessible regions are proposed to be located between the fibrils inside of the aggregates, and the readily accessible regions are suggested to be at the surfaces of the fibril aggregates. It was also possible to identify the ratio of slowly and readily accessible surfaces, which indicated that the average aggregate of cotton cellulose is built up by approximately three fibrils with an assumed average size of 12 × 12 cellulose chains. Additionally, the experimental setup enabled visualizing and discussing the implications of some of the deviating spectral features that are pronounced when recording FT-IR spectra of deuterium-exchanging cellulose: the insufficient red shift of the stretching vibrations and the vastly decreasing line widths.

  • 334.
    Lindh, Erik L.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Innventia AB, Sweden.
    Stilbs, Peter
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Furo, Istvan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Site-resolved H-2 relaxation experiments in solid materials by global line-shape analysis of MAS NMR spectra2016Ingår i: Journal of magnetic resonance, ISSN 1090-7807, E-ISSN 1096-0856, Vol. 268, s. 18-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate a way one can achieve good spectral resolution in H-2 MAS NMR experiments. The goal is to be able to distinguish between and study sites in various deuterated materials with small chemical shift dispersion. We show that the H-2 MAS NMR spectra recorded during a spin-relaxation experiment are amenable to spectral decomposition because of the different evolution of spectral components during the relaxation delay. We verify that the results are robust by global least-square fitting of the spectral series both under the assumption of specific line shapes and without such assumptions (COmponent-REsolved spectroscopy, CORE). In addition, we investigate the reliability of the developed protocol by analyzing spectra simulated with different combinations of spectral parameters. The performance is demonstrated in a model material of deuterated poly(methacrylic acid) that contains two H-2 spin populations with similar chemical shifts but different quadrupole splittings. In H-2-exchanged cellulose containing two H-2 spin populations with very similar chemical shifts and quadrupole splittings, the method provides new site-selective information about the molecular dynamics.

  • 335.
    Lindh, Erik L.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Terenzi, Camilla
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Furo, Istvan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Salmén, Lennart
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Identifying different hydroxyl populations in cellulose by 2H MAS NMR2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 336.
    Lindh, Erik L.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Terenzi, Camilla
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Salmén, Lennart
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Furo, Istvan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Water in cellulose: evidence and identification of immobile and mobile adsorbed phases by H-2 MAS NMR2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 6, s. 4360-4369Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The organization of water molecules adsorbed onto cellulose and the supramolecular hydrated structure of microfibril aggregates represents, still today, one of the open and complex questions in the physical chemistry of natural polymers. Here, we investigate by H-2 MAS NMR the mobility of water molecules in carefully H-2-exchanged, and thereafter re-dried, microcrystalline cellulose. By subtracting the spectral contribution of deuteroxyls from the spectrum of hydrated cellulose, we demonstrate the existence of two distinct (H2O)-H-2 spectral populations associated with mobile and immobile water environments, between which the water molecules do not exchange at the NMR observation time scale. We conclude that those two water phases are located at differently-accessible adsorption sites, here assigned to the cellulose surfaces between and within the microfibril aggregates, respectively. The superior performance of H-2 MAS NMR encourages further applications of the same method to other complex systems that expose heterogeneous hygroscopic surfaces, like wood cell walls.

  • 337.
    Liu, Andong
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Centra, Centrum för Biofibermaterial, BiMaC.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Clay nanopaper composites of nacre-like structure based on montmorrilonite and cellulose nanofibers-Improvements due to chitosan addition2012Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 87, nr 1, s. 53-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Clay nanopaper are nanocomposites with nacre-like structure and multifunctional characteristics including high modulus, significant strength and toughness as well as fire retardancy and low oxygen transmission rate (OTR). Montmorrilonite (MTM) and nanofibrillated cellulose (NFC) hydrocolloids are combined with a chitosan (CS) solution to form high MTM content nanopaper structures by the use of a previously developed papermaking approach. Chitosan functions as flocculation agent and decreases dewatering time to less than 10% compared with MTM-NFC clay nanopaper. The effect of chitosan on the clay nanopaper structure was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Properties were measured by uniaxial tensile testing, thermogravimetric analysis (TGA), OTR and moisture adsorption experiments. A nacre-like multilayered structure was confirmed and the chitosan-clay nanopaper showed favorable mechanical properties at clay contents as high as 44-48 wt%.

  • 338.
    Liu, Andong
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Fire-retardant and ductile clay nanopaper biocomposites based on montmorrilonite in matrix of cellulose nanofibers and carboxymethyl cellulose2013Ingår i: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 49, nr 4, s. 940-949Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nacre-mimetic clay bionanocomposites of high clay content show interesting properties although low strain to failure is a limitation. For this reason, three-component nanocomposite films were prepared based on sodium montmorrilonite clay (MTM), a water-soluble cellulose derivative (CMC) of fairly high molar mass, in combination with nanofibrillated cellulose (NFC) from wood pulp. The nanocomposite is cast from an aqueous colloidal dispersion. First, the effects of CMC content on CMC/MTM compositions with high volume fraction of MTM (36-83 vol.%) were studied by FE-SEM, XRD, UV, DMTA and TGA. In addition, fire retardance and oxygen permeability characteristics were measured. The effect of NFC nanofiber addition to the matrix phase was then evaluated. This two-phase CMC/NFC matrix phase results in significantly improved modulus, strength but also strain to failure. NFC has a favorable effect by shifting catastrophic failure mechanisms to higher strains.

  • 339.
    Liu, Andong
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Walther, Andreas
    Ikkala, Olli
    Belova, Lyuba
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Teknisk materialfysik.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Clay Nanopaper with Tough Cellulose Nanofiber Matrix for Fire Retardancy and Gas Barrier Functions2011Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 12, nr 3, s. 633-641Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nacre-mimicking hybrids of high inorganic content (> 50 wt %) tend to show low strain-to-failure. Therefore, we prepared clay nanopaper hybrid composite montmorillonite platelets in a continuous matrix of nanofibrillated cellulose (NFC) with the aim of harnessing the intrinsic toughness of fibrillar networks. Hydrocolloid mixtures were used in a filtration approach akin to paper processing. The resulting multilayered structure of the nanopaper was studied by FE-SEM, FTIR, and XRD. Uniaxial stress strain curves measured in tension and thermal analysis were carried out by DMTA and TGA. In addition, fire retardance and oxygen permeability characteristics were measured. The continuous NFC matrix is a new concept and provides unusual ductility to the nanocomposite, allowing inorganic contents as high as 90% by weight. Clay nanopaper extends the property range of cellulose nanopaper and is of interest in self-extinguishing composites and in oxygen barrier layers.

  • 340.
    Liu, Dongming
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Wu, Qiong
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Andersson, Richard L.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Farris, Stefano
    Olsson, Richard T.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Cellulose nanofibril core-shell silica coatings and their conversion into thermally stable nanotube aerogels2015Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, nr 30, s. 15745-15754Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A facile water-based one-pot reaction protocol for obtaining 20 nm thick uniform silica coatings on cellulose nanofibrils (CNFs) is herein presented for the first time. The fully covering silica shells result in the thermal stability of the CNFs improved by ca. 70 degrees C and 50 degrees C under nitrogen and oxygen atmospheres, respectively. Heating of the core-shell hybrid fibres to 400 degrees C results in complete degradation/removal of the CNF cores, and demonstrates an inexpensive route to large-scale preparation of silica nanotubes with the CNFs used as templates. The key to a uniform condensation of silica (from tetraethyl orthosilicate) to cellulose is a reaction medium that permits in situ nucleation and growth of the silica phase on the fibrils, while simultaneously matching the quantity of the condensed silica with the specific surface area of the CNFs. Most coatings were applied to bundles of 2-3 associated CNFs, which could be discerned from their negative imprint that remained inside the silica nanotubes. Finally, it is demonstrated that the coated nanofibrils can be freeze-dried into highly porous silica/cellulose aerogels with a density of 0.005 g cm(-3) and how these hybrid aerogels preserve their shape when extensively exposed to 400 degrees C in air (>6 h). The resulting material is the first reported silica nanotube aerogel obtained by using cellulose nanofibrils as templates.

  • 341. Liu, Jun
    et al.
    Korpinen, Risto
    Mikkonen, Kirsi S.
    Willfor, Stefan
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Process Chemistry Centre, c/o Laboratory Wood and Paper Chemistry, Åbo Akademi University, Finland.
    Nanofibrillated cellulose originated from birch sawdust after sequential extractions: a promising polymeric material from waste to films2014Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, nr 4, s. 2587-2598Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The residual cellulose of wood processing waste, sawdust, which was leftover after sequential hot-water extraction processes to isolate hemicelluloses and lignin in a novel forest biorefinery concept, was explored as the starting material for preparation of a highly value-added polymeric material, nanofibrillated cellulose (NFC) also widely termed as cellulose nanofiber, which has provided an alternative efficient way to upgrade sawdust waste. The residual cellulose in sawdust was converted to a transparent NFC suspension in water through the 2,2,6,6-tetramethylpiperidine-1-oxyl radical/NaClO/NaBr oxidization approach. The resultant NFC with a dimension of ca. 5 nm in width and hundreds of nanometers in length were further processed into NFC films. The morphological features of the NFC suspension and its films were assessed by transmission electron microscopy and scanning electron microscopy. Highly even dispersion of NFC fibrils in the films originated from sawdust feasibly contributes to the outstanding mechanical performance of the films. NFC suspension with higher carboxylate content and its resultant NFC films were found to show higher transmission of light.

  • 342.
    Liu, Yingxin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Stockholm Univ, Sweden.
    Gordeyeva, Korneliya
    Bergstrom, Lennart
    Steady-shear and viscoelastic properties of cellulose nanofibril-nanoclay dispersions2017Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 4, s. 1815-1824Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have investigated the steady-shear and viscoelastic properties of composite dispersions of cellulose nanofibrils (CNFs) with medium or high charge density and two different nanoclays, viz. rodlike sepiolite or plate-like bentonite. Aqueous dispersions of CNFs with medium charge density displayed significantly lower steady-state viscosity and storage modulus but higher gelation threshold compared with CNFs with high charge density. Dynamic light scattering (DLS) results showed that the apparent hydrodynamic radius of bentonite particles increased when CNFs were added, implying that CNFs adsorbed onto the amphoteric edges of the plate-like bentonite particles. The sepiolite network in CNF-sepiolite dispersions was relatively unaffected by addition of small amounts of CNFs, and DLS showed that the hydrodynamic radius of sepiolite did not change when CNFs were added. Addition of CNFs at concentrations above the gelation threshold resulted in drastic decrease of the steady-shear viscosity of the sepiolite dispersion, suggesting that the sepiolite network disintegrates and the rod-like clay particles are aligned also at low shear rate. The relative change in the rheological properties of the clay-based dispersions was always greater on addition of CNFs with high compared with medium charge density. This study provides insight into how the rheology of CNF-nanoclay dispersions depends on both the nanoclay morphology and the interactions between the nanoclay and nanocellulose particles, being of relevance to processing of nanocellulose-clay composites.

  • 343. Lozhechnikova, A.
    et al.
    Dax, D.
    Vartiainen, J.
    Willför, S.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Aalto University, Finland.
    Österberg, M.
    Modification of nanofibrillated cellulose using amphiphilic block-structured galactoglucomannans2014Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 110, s. 163-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanofibrillated cellulose (NFC) and hemicelluloses have shown to be highly promising renewable components both as barrier materials and in novel biocomposites. However, the hydrophilic nature of these materials restricts their use in some applications. In this work, the usability of modified O-acetyl galactoglucomannan (GGM) for modification of NFC surface properties was studied. Four GGM-block-structured, amphiphilic derivatives were synthesized using either fatty acids or polydimethylsiloxane as hydrophobic tails. The adsorption of these GGM derivatives was consecutively examined in aqueous solution using a quartz crystal microbalance with dissipation monitoring (QCM-D). It was found that the hydrophobic tails did not hinder adsorption of the GGM derivatives to cellulose, which was concluded to be due to the presence of the native GGM-block with high affinity to cellulose. The layer properties of the adsorbed block-co-polymers were discussed and evaluated. Self-standing NFC films were further prepared and coated with the GGM derivatives and the effect of the surface modification on wetting properties and oxygen permeability (OP) of the modified films was assessed.

  • 344.
    Lu, Huiran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Leijonmarck, Simon
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. Swerea KIMAB AB.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Cornell, Ann M.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Flexible Paper Electrodes for Li-Ion Batteries Using Low Amount of TEMPO-Oxidized Cellulose Nanofibrils as Binder2016Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 28, s. 18097-18106Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Flexible Li-ion batteries attract increasing interest for applications in bendable and wearable electronic devices. TEMPO-oxidized cellulose nanofibrils (TOCNF), a renewable material, is a promising candidate as binder for flexible Li-ion batteries with good mechanical properties. Paper batteries can be produced using a water-based paper making process, avoiding the use of toxic solvents. In this work, finely dispersed TOCNF was used and showed good binding properties at concentrations as low as 4 wt %. The TOCNF was characterized using atomic force microscopy and found to be well dispersed with fibrils of average widths of about 2.7 nm and lengths of approximately 0.1-1 mu m. Traces of moisture, trapped in the hygroscopic cellulose, is a concern when the material is used in Li-ion batteries. The low amount of binder reduces possible moisture and also increases the capacity of the electrodes, based on total weight. Effects of moisture on electrochemical battery performance were studied on electrodes dried at 110 degrees C in a vacuum for varying periods. It was found that increased drying time slightly increased the specific capacities of the LiFePO4 electrodes, whereas the capacities of the graphite electrodes decreased. The Coulombic efficiencies of the electrodes were not much affected by the varying drying times. Drying the electrodes for 1 h was enough to achieve good electrochemical performance. Addition of vinylene carbonate to the electrolyte had a positive effect on cycling for both graphite and LiFePO4. A failure mechanism observed at high TOCNF concentrations is the formation of compact films in the electrodes.

  • 345.
    Lu, Huiran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Guccini, Valentina
    KTH.
    Kim, Hyeyun
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Salazar-Alvarez, German
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Cornell, Ann M.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Effects of Different Manufacturing Processes on TEMPO-Oxidized Carboxylated Cellulose Nanofiber Performance as Binder for Flexible Lithium-Ion Batteries2017Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 43, s. 37712-37720Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carboxylated cellulose nanofibers (CNF) prepared using the TEMPO-route are good binders of electrode components in flexible lithium-ion batteries (LIB). However, the different parameters employed for the defibrillation of CNF such as charge density and degree of homogenization affect its properties when used as binder. This work presents a systematic study of CNF prepared with different surface charge densities and varying degrees of homogenization and their performance as binder for flexible LiFePO4 electrodes. The results show that the CNF with high charge density had shorter fiber lengths compared with those of CNF with low charge density, as observed with atomic force microscopy. Also, CNF processed with a large number of passes in the homogenizer showed a better fiber dispersibility, as observed from rheological measurements. The electrodes fabricated with highly charged CNF exhibited the best mechanical and electrochemical properties. The CNF at the highest charge density (ISSO mu mol g(-1)) and lowest degree of homogenization (3 + 3 passes in the homogenizer) achieved the overall best performance, including a high Young's modulus of approximately 311 MPa and a good rate capability with a stable specific capacity of 116 mAh g(-1) even up to 1 C. This work allows a better understanding of the influence of the processing parameters of CNF on their performance as binder for flexible electrodes. The results also contribute to the understanding of the optimal processing parameters of CNF to fabricate other materials, e.g., membranes or separators.

  • 346.
    Lu, Huiran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Guccini, Valentina
    Kim, Hyeyun
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Salazar-Alvarez, Germán
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Cornell, Ann M.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Influence of the degree of fibrillation of TEMPO-CNF on its performance as electrode binder in flexible lithium-ion batteries.Manuskript (preprint) (Övrigt vetenskapligt)
  • 347.
    Lu, Huiran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Hagberg, Johan
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Cornell, Ann
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Li4Ti5O12 flexible, lightweight electrodes based on cellulose nanofibrils as binder and carbon fibers as current collectors for Li-ion batteries2017Ingår i: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 39, s. 140-150Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    TEMPO oxidized cellulose nanofibrils (TOCNF) were used as binder material to prepare bendable Li4Ti5O12 (LTO) electrodes. Carbon fiber (CF) layers were integrated as current collectors to enhance the mechanical properties and to increase the specific energy of the electrodes. These electrodes combined with CF current collectors (LTO/CF) show good electrochemical properties and are flexible, sustainable, mechanical and chemical stable, lightweight and produced by a water-based easy filtration process. An increase of the active material weight (LTO) from around 19% to 71% of the electrode and current collector combined weight is demonstrated with CF compared with a copper current collector. Additionally, preparation of the current collector material is non-expensive, quick and easy compared to that of carbon nanotube or graphene. To test the flexible battery application, 4000 times repeated bending was carried out on both the LTO electrodes and the LTO/CF electrodes. This had no significant effect on the morphology, mechanical and electrochemical properties of neither the LTO nor the LTO/CF electrodes. Addition of the CF layer improves the mechanical properties and specific capacity of the LTO-electrode. A thicker LTO electrode with only 2 wt% TOCNF is demonstrated which is promising for thicker electrodes with high energy density. A full cell was assembled with the LTO/CF as negative electrode and LiFePO4 (LFP)/CF as positive, which exhibited a stable cycling performance and good energy density.

  • 348.
    López Durán, Vernica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation.
    Larsson, Per A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    On the relationship between fibre composition and material properties following periodate oxidation and borohydride reduction of lignocellulosic fibres2016Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, nr 6, s. 3495-3510Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Periodate oxidation followed by borohydride reduction was performed on four structurally different pulp fibres to clarify the effect of chemical composition on the structural and mechanical properties of sheets made from these fibres. The main purpose was to explore the possibility of extending the use of lignocellulose fibres in novel applications. The degree of oxidation, morphological changes, chemical and physical structure of the fibres, the supramolecular ordering of the cellulose and the mechanical performance of handsheets made from the fibres were studied. The results showed that both periodate oxidation and borohydride reduction are more reactive towards the carbohydrates of the fibres and as a result, there is an improvement in the tensile properties of the sheets. If the carbohydrates of the fibres are only periodate oxidised to produce dialdehydes, inter- and intra-fibre crosslinks can be formed, leading to paper with increase strength and higher stiffness. The borohydride reduction results in fibres and papers with a greater strength and ductility. It was also found that the characteristic ductility of these modified papers, emanating from the dialcohol cellulose produced, is limited with lignin-rich fibres.

  • 349. Löbmann, Korbinian
    et al.
    Wohlert, Jakob
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Müllertz, Anette
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Svagan, Anna J.
    Cellulose Nanopaper and Nanofoam for Patient-Tailored Drug Delivery2017Ingår i: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 4, nr 9, artikel-id 1600655Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of drug delivery systems with tailored drug release can be very challenging especially in the case of problematic drugs. To address this problem, pharmaceutical scientists frequently use different formulation approaches and excipients, often involving a complex and multistep preparation. In this study, new cellulose nanofiber (CNF) based drug formulations are developed that allow controlled drug release in a facile and fast way, i.e., by simply casting drug/CNF dispersions. Altering the processing conditions and utilizing the unique inherent chemicophysical properties of cationic CNF at interfaces, it is possible to produce either drug-loaded CNF nanopapers (containing 21 or 51 wt% drug) or nanofoams (containing 21 wt% drug). The different formulations exhibit tailored release kinetics of the poorly watersoluble model drug indomethacin from immediate (nanopapers, 10-20 min) to slow release (nanofoams, approximate to 24 h). The fast release, from the nanopapers, is a result of the interplay of the molecular and supramolecular structure of indomethacin in addition to observed enhanced intrinsic dissolution of drug in the presence of CNF. The slower drug release is achieved by changing the hierarchical structure, i.e., creating a CNF based foam (porosity 99.2 wt%), and the prolonged release is mainly due to an extended drug diffusion path.

  • 350. Malti, Abdellah
    et al.
    Edberg, Jesper
    Granberg, Hjalmar
    Khan, Zia Ullah
    Andreasen, Jens W.
    Liu, Xianjie
    Zhao, Dan
    Zhang, Hao
    Yao, Yulong
    Brill, Joseph W.
    Engquist, Isak
    Fahlman, Mats
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Crispin, Xavier
    Berggren, Magnus
    An Organic Mixed Ion-Electron Conductor for Power Electronics2016Ingår i: Advanced Science, ISSN 2198-3844, Vol. 3, nr 2, artikel-id UNSP 1500305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

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