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  • 1.
    Ankerfors, Mikael
    et al.
    RISE., Innventia.
    Aulin, Christian
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Nanocellulose research and developments at Innventia2011Konferansepaper (Fagfellevurdert)
  • 2.
    Ankerfors, Mikael
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Energy efficient manufacture of microfibrillated cellulose by attachment of carboxymethyl cellulose2013Konferansepaper (Fagfellevurdert)
  • 3.
    Ankerfors, Mikael
    et al.
    BillerudKorsnäs AB, Sweden.
    Lindström, Tom
    RISE., Innventia.
    Glad Nordmark, Gunborg
    RISE., Innventia.
    Multilayer assembly onto pulp fibres using oppositely charged microfibrillated celluloses, starches, and wetstrength resins: Effect on mechanical properties of CTMP-sheets2016Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 1, s. 135-141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of multilayering of microfibrillar cellulose (MFC) onto a chemi-thermomechanical pulp (CTMP), from which the fines material had been removed, were investigated with regard to the mechanical properties of hand-sheets. In one series of experiments, the CTMP was multilayered with cationic MFC/anionic MFC (C-MFC/A-MFC) at various addition levels and sheets made in a conventional sheet former, pressed, and dried at room temperature. This experimental series was complemented with a second series, where sheets were made in a Rapid Köthen sheet former. In a third series of experiments, the CTMP was multilayered using a cationic polyamideamine epichlorohydrine resin (PAE) and an AMFC. Sheets were formed using the Rapid Köthen sheet former. Finally, in a fourth series of experiments, the MFC multilayering experiments were compared with multilayering experiments using cationic starch/anionic starch (C-starch/A-Starch). MFC-multilayering (C-MFC/A-MFC) gave inferior strength gain at a low addition level compared to starch multilayering, but (compared on a weight basis) the strength seemed to level off using starches at high addition levels, whereas there were a continuous increase in strength using MFC multilayering. Multilayering using PAE/A-MFC was found to give a higher strength gain than both C-MFC/A-MFC and C-starch/A-starch multilayering. Sheet density was slightly affected (<14%) by the multilayering techniques used in these experiments.

  • 4.
    Ankerfors, Mikael
    et al.
    ÅF Industry, Sweden.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi.
    Glad Nordmark, Gunborg
    RISE - Research Institutes of Sweden, Bioekonomi.
    The effects of different types of wet-end added microfibrillated celluloses on the properties of paper made from bleached kraft pulp2017Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, nr 3, s. 336-345Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Research has been undertaken to compare the effects of different types of microfibrillated cellulose (MFC) on the mechanical properties of paper. Three types of MFC were produced: Enzyme MFC (low anionic charge density), Carboxymethylated MFC (high anionic charge density) and cationic MFC (high cationic charge density). The different MFCs required different retention aid strategies. The simplest retention strategy was selected to secure a high retention of MFC. Some experiments also focused on dewatering and pressability of wet webs with carboxymethylated MFC. Conventional isotropic laboratory handsheets were made using a never-dried unrefined elemental chlorine free (ECF)-bleached softwood kraft pulp. It has been shown that the evolution of the mechanical properties and scattering coefficients when plotted versus MFC content was very similar for the three types. However, Enzyme MFC gave a significantly better reinforcement effect. All three types of MFC had a similar effect on the sheet consolidation, reflected in sheet density. Evaluation of the dewatering and pressability of the wet sheets showed that if the MFC was aggregated by an appropriate retention strategy, the dewatering and pressability were not detrimental to the practical applicability of MFC.

  • 5. Aulin, C.
    et al.
    Johansson, E.
    Wågberg, L.
    Lindström, Tom
    RISE., Innventia.
    Self-organized films from cellulose i nanofibrils using the layer-by-layer technique2010Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 11, nr 4, s. 872-882Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility of forming self-organized films using only charge-stabilized dispersions of cellulose I nanofibrils with opposite charges is presented, that is, the multilayers were composed solely of anionically and cationically modified microfibrillated cellulose (MFC) with a low degree of substitution. The build-up behavior and the properties of the layer-by-layer (LbL)-constructed films were studied using a quartz crystal microbalance with dissipation (QCM-D) and stagnation point adsorption reflectometry (SPAR). The adsorption behavior of cationic/anionic MFC was compared with that of polyethyleneimine (PEI)/anionic MFC. The water contents of five bilayers of cationic/anionic MFC and PEI/anionic MFC were approximately 70 and 50%, respectively. The MFC surface coverage was studied by atomic force microscopy (AFM) measurements, which clearly showed a more dense fibrillar structure in the five bilayer PEI/anionic MFC than in the five bilayer cationic/anionic MFC. The forces between the cellulose-based multilayers were examined using the AFM colloidal probe technique. The forces on approach were characterized by a combination of electrostatic and steric repulsion. The wet adhesive forces were very long-range and were characterized by multiple adhesive events. Surfaces covered by PEI/anionic MFC multilayers required more energy to be separated than surfaces covered by cationic/anionic MFC multilayers.

  • 6. Aulin, C.
    et al.
    Netrval, J.
    Wågberg, L.
    Lindström, Tom
    RISE., Innventia.
    Aerogels from nanofibrillated cellulose with tunable oleophobicity2010Inngår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 6, nr 14, s. 3298-3305Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of structured porous aerogels of nanofibrillated cellulose (NFC) by freeze-drying has been demonstrated. The aerogels have a high porosity, as shown by FE-SEM and nitrogen adsorption/desorption measurements, and a very low density (&lt;0.03 g cm-3). The density and surface texture of the aerogels can be tuned by selecting the concentration of the NFC dispersions before freeze-drying. Chemical vapor deposition (CVD) of 1H,1H,2H,2H- perfluorodecyltrichlorosilane (PFOTS) was used to uniformly coat the aerogel to tune their wetting properties towards non-polar liquids. An XPS analysis of the chemical composition of the PFOTS-modified aerogels demonstrated the reproducibility of the PFOTS-coating and the high atomic fluorine concentration (ca. 51%) in the surfaces. The modified aerogels formed a robust composite interface with high apparent contact angles (* ≫ 90°) for castor oil (γlv = 35.8 mN m-1) and hexadecane (γlv = 27.5 mN m-1).

  • 7. Aulin, C.
    et al.
    Shchukarev, A.
    Lindqvist, J.
    Malmström, E.
    Wågberg, L.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Wetting kinetics of oil mixtures on fluorinated model cellulose surfaces2008Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 317, nr 2, s. 556-567Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The wetting of two different model cellulose surfaces has been studied; a regenerated cellulose (RG) surface prepared by spin-coating, and a novel multilayer film of poly(ethyleneimine) and a carboxymethylated microfibrillated cellulose (MFC). The cellulose films were characterized in detail using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM indicates smooth and continuous films on a nanometer scale and the RMS roughness of the RG cellulose and MFC surfaces was determined to be 3 and 6 nm, respectively. The cellulose films were modified by coating with various amounts of an anionic fluorosurfactant, perfluorooctadecanoic acid, or covalently modified with pentadecafluorooctanyl chloride. The fluorinated cellulose films were used to follow the spreading mechanisms of three different oil mixtures. The viscosity and surface tension of the oils were found to be essential parameters governing the spreading kinetics on these surfaces. XPS and dispersive surface energy measurements were made on the cellulose films coated with perfluorooctadecanoic acid. A strong correlation was found between the surface concentration of fluorine, the dispersive surface energy and the contact angle of castor oil on the surface. A dispersive surface energy less than 18 mN/m was required in order for the cellulose surface to be non-wetting (Ξe &gt; 90 °) by castor oil.

  • 8. Aulin, C.
    et al.
    Varga, I.
    Claesson, P. M.
    Wågberg, L.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Buildup of polyelectrolyte multilayers of polyethyleneimine and microfibrillated cellulose studied by in situ dual-polarization interferometry and quartz crystal microbalance with dissipation2008Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, nr 6, s. 2509-2518Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polyethyleneimine (PEI) and Microfibrillated cellulose (MFC) have been used to buildup polyelectrolyte multilayers (PEM) on silicone oxide and silicone oxynitride surfaces at different pH values and with different electrolyte and polyelectrolyte/colloid concentrations of the components. Consecutive adsorption on these surfaces was studied by in situ dual-polarization interferometry (DPI) and quartz crystal microbalance measurements. The adsorption data obtained from both the techniques showed a steady buildup of multilayers. High pH and electrolyte concentration of the PEI solution was found to be beneficial for achieving a high adsorbed amount of PEI, and hence of MFC, during the buildup of the multilayer. On the other hand, an increase in the electrolyte concentration of the MFC dispersion was found to inhibit the adsorption of MFC onto PEL The adsorbed amount of MFC was independent of the bulk MFC concentration in the investigated concentration range (15-250 mg/L). Atomic force microscopy measurements were used to image a MFC-treated silicone oxynitride chip from DPI measurements. The surface was found to be almost fully covered by randomly oriented microfibrils after the adsorption of only one bilayer of PEI/MFC. The surface roughness expressed as the rms-roughness over 1 ÎŒm2 was calculated to be 4.6 nm (1 bilayer). The adsorbed amount of PEI and MFC and the amount of water entrapped by the individual layers in the multilayer structures were estimated by combining results from the two analytical techniques using the de Feijter formula. These results indicate a total water content of ca. 41% in the PEM.

  • 9. Aulin, C.
    et al.
    Yun, S. H.
    Wåberg, L.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Design of highly oleophobic cellulose surfaces from structured silicon templates2009Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 1, nr 11, s. 2443-2452Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Structured silicon surfaces, possessing hierarchical porous characteristics consisting of micrometer-sized cavities superimposed upon a network of nanometer-sized pillars or wires, have been fabricated by a plasma-etching process. These surfaces have superoleophobic properties, after being coated with fluorinated organic trichlorosilanes, on intrinsically oleophilic surfaces. By comparison with flat silicon surfaces, which are oleophilic, it has been demonstrated that a combination of low surface energy and the structured features of the plasma-etched surface is essential to prevent oil from penetrating the surface cavities and thus induce the observed macroscopic superoleophobic phenomena with very low contact-angle hysteresis and low roll-off angles. The structured silicon surfaces were coated with cellulose nanocrystals using the polyelectrolyte multilayer technique. The cellulose surfaces prepared in this way were then coated with a monolayer of fluorinated trichlorosilanes. These porous cellulose films displayed highly nonwetting properties against a number of liquids with low surface tension, including alkanes such as hexadecane and decane. The wettability and chemical composition of the cellulose/silicon surfaces were characterized with contact-angle goniometry and X-ray photoelectron spectroscopy, respectively. The nano/microtexture features of the cellulose/silicon surfaces were also studied with field-emission scanning electron microscopy. The highly oleophobic structured cellulose surfaces are very interesting model surfaces for the development of biomimetic self-cleaning surfaces in a vast array of products, including green constructions, packaging materials, protection against environmental fouling, sports, and outdoor clothing, and microfluidic systems.

  • 10. Aulin, Christian
    et al.
    Gällstedt, Mikael
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Oxygen and oil barrier properties of microfibrillated cellulose films and coatings2010Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 17, nr 3, s. 559-574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The preparation of carboxymethylated microfibrillated cellulose (MFC) films by dispersion-casting from aqueous dispersions and by surface coating on base papers is described. The oxygen permeability of MFC films were studied at different relative humidity (RH). At low RH (0%), the MFC films showed very low oxygen permeability as compared with films prepared from plasticized starch, whey protein and arabinoxylan and values in the same range as that of conventional synthetic films, e.g., ethylene vinyl alcohol. At higher RH’s, the oxygen permeability increased exponentially, presumably due to the plasticizing and swelling of the carboxymethylated nanofibers by water molecules. The effect of moisture on the barrier and mechanical properties of the films was further studied using water vapor sorption isotherms and by humidity scans in dynamic mechanical analysis. The influences of the degree of nanofibrillation/dispersion on the microstructure and optical properties of the films were evaluated by field-emission scanning electron microscopy (FE-SEM) and light transmittance measurements, respectively. FE-SEM micrographs showed that the MFC films consisted of randomly assembled nanofibers with a thickness of 5-10 nm, although some larger aggregates were also formed. The use of MFC as surface coating on various base papers considerably reduced the air permeability. Environmental scanning electron microscopy (E-SEM) micrographs indicated that the MFC layer reduced sheet porosity, i.e., the dense structure formed by the nanofibers resulted in superior oil barrier properties.

  • 11.
    Aulin, Christian
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Biopolymer Coatings for Paper and Paperboard2011Inngår i: Biopolymers: New Materials for Sustainable Films and Coatings / [ed] Plackett David, John Wiley & Sons, 2011, s. 255-276Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 12.
    Aulin, Christian
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Ström, Göran
    RISE., Innventia.
    Nanocellulose films and coatings with tunable oxygen and water vapor permeability for use in renewable packaging solutions2013Konferansepaper (Fagfellevurdert)
  • 13.
    Blell, Rebecca
    et al.
    CNRS Institut Charles Sadron, France.
    Lin, Xiaofeng
    CNRS Institut Charles Sadron, France.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Ankerfors, Mikael
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Pauly, Matthias
    CNRS Institut Charles Sadron, France; Université de Strasbourg, France.
    Felix, Olivier
    CNRS Institut Charles Sadron, France.
    Decher, Gero
    CNRS Institut Charles Sadron, France; Université de Strasbourg, France; International Center for Frontier Research in Chemistry, France.
    Generating in-Plane Orientational Order in Multilayer Films Prepared by Spray-Assisted Layer-by-Layer Assembly2017Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, nr 1, s. 84-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a simple yet efficient method for orienting cellulose nanofibrils in layer-by-layer assembled films through spray-assisted alignment. While spraying at 90° against a receiving surface produces films with homogeneous in-plane orientation, spraying at smaller angles causes a macroscopic directional surface flow of liquid on the receiving surface and leads to films with substantial in-plane anisotropy when nanoscale objects with anisotropic shapes are used as components. First results with cellulose nanofibrils demonstrate that such fibrils are easily aligned by grazing incidence spraying to yield optically birefringent films over large surface areas. We show that the cellulosic nanofibrils are oriented parallel to the spraying direction and that the orientational order depends for example on the distance of the receiving surface from the spray nozzle. The alignment of the nanofibrils and the in-plane anisotropy of the films were independently confirmed by atomic force microscopy, optical microscopy between crossed polarizers, and the ellipsometric determination of the apparent refractive index of the film as a function of the in-plane rotation of the sample with respect to the plane of incidence of the ellipsometer.

  • 14.
    Coseri, Sergiu
    et al.
    Romanian Academy, Romania.
    Biliuta, Gabriela
    Romanian Academy, Romania.
    Zemlijic, Lidija Fras
    University of Maribor, Slovenia.
    Stevanic Srndovic, Jasna
    RISE., Innventia.
    Larsson, Per Tomas
    RISE., Innventia.
    Strnad, Simona
    University of Maribor, Slovenia.
    Kreze, Tatjana
    University of Maribor, Slovenia.
    Naderi, Ali
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Correction: One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate2015Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, nr 117, s. 96927-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Correction for ‘One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate’ by Sergiu Coseri et al.RSC Adv., 2015, 5, 85889–85897.

    The authors regret that the images presented for Fig. 1 and 3 in the original article present incorrect carbohydrate structures. The amended versions of these images, in which the 3-position hydroxyl groups are equatorial rather than axial, are presented below.

  • 15.
    Coseri, Sergiu
    et al.
    Romanian Academy, Romania.
    Biliuta, Gabriela
    Romanian Academy, Romania.
    Zemlijic, Lidija Fras
    University of Maribor, Slovenia.
    Stevanic Srndovic, Jasna
    RISE., Innventia.
    Larsson, Per Tomas
    RISE., Innventia.
    Strnad, Simona
    University of Maribor, Slovenia.
    Kreze, Tatjana
    University of Maribor, Slovenia.
    Naderi, Ali
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate2015Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, nr 104, s. 85889-85897Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water soluble cellulose derivatives are highly required products for many practical purposes, expanding the limited applications of pure cellulose caused by the highly ordered hydrogen bond network and high crystallinity. In this connection, this paper, presents a new approach to obtain water soluble carboxyl-functionalized cellulosic materials, combining two of the most common selective oxidation protocols for cellulose, i.e. nitroxyl mediated reaction and periodate oxidation, in a one-shot reaction. It was found that, under specific reaction conditions, fully oxidized, 2,3,6-tricarboxy cellulose can be obtained in large amounts. The other valuable oxidized fractions were found to possess large amounts of carboxylic groups, as determined by potentiometric titration. 13C-NMR evidenced the presence of three distinctive carboxylic groups in the fully oxidized product, whereas for the partially oxidized samples, 13C CP-MAS solid-state NMR did not detect any carbonyl signals. The oxidized products were characterized by means of FTIR and X-ray photoelectron spectroscopy (XPS). Moreover, the changes of the degree of polymerization occurring after oxidative treatments were viscometrically determined.

  • 16.
    Duker, Elisabeth
    et al.
    RISE., STFI-Packforsk.
    Ankertors, Mikael
    RISE., STFI-Packforsk.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Glad-Nordmark, Gunnel
    RISE., STFI-Packforsk.
    The use of CMC as a dry strength agent: The interplay between CMC attachment and drying2008Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, nr 1, s. 65-71Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper deals with the ability to use high molecular weight CMC as a dry strength agent in paper and how the drying of the pulp, either before or after the CMC attachment, affects the mechanical properties of the paper. The effect of the counter-ion form used during drying and reslushing was also investigated. In the case of the calcium and hydrogen counter-ion forms, drying after CMC attachment had no impact on the attached amount. The sodium form did, however, result in some detachment of CMC. When the pulp was dried prior to CMC treatment, the counter-ion form had no effect on the attached amount. It was also shown that drying of a CMC-treated pulp reduced the positive effect of CMC on the mechanical properties. Nevertheless, the mechanical properties were still better than those of paper made from the never-dried reference pulp. The relative effect of CMC on the mechanical properties was independent of the drying strategy used and the counter-ion form did not affect the mechanical properties. However, surface carboxymethylation prior to drying resulted in sheets with better final mechanical properties than sheets made from pulp that had first been dried and then surface carboxy-methylated.

  • 17.
    Duker, Elisabeth
    et al.
    RISE., STFI-Packforsk.
    Lindström, Tom
    RISE., STFI-Packforsk.
    On the mechanisms behind the ability of CMC to enhance paper strength2008Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, nr 1, s. 57-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The attachment of CMC to pulp is known to have a strong impact on the tensile strength properties. The mechanisms behind the strength-enhancing ability of the CMC have been investigated by studying the effect of surface carboxymethylation on some basic fibre and sheet properties. Standard methods were used for the strength evaluation, and the relative bonded area was determined from both light-scattering measurements and BET-analysis. The effect of CMC on the shear bond strength was calculated using Page’s equation. The attachment of CMC was shown to increase the shape factor and reduce the number of kinks per fibre, which is beneficial for the tensile strength. Surface carboxymethylation also increased the relative bonded area, but on a small-scale structural level detectable only using BET-analysis and not by the scattering coefficient. The sheet density was not affected by the treatment. CMC attachment also increased the shear bond strength. In order to use Page’s equation for this evaluation, the relative bonded area had to be determined by BET-analysis. The positive effect of CMC on sheet formation also contributed to an increase in tensile strength.

  • 18.
    Flodberg, Göran
    et al.
    RISE., Innventia.
    Helland, I
    Aulin, Christian
    RISE., Innventia.
    Fredriksen, S B
    Lindström, Tom
    RISE., Innventia.
    New barrier for NFC based on CO22014Konferansepaper (Fagfellevurdert)
  • 19. Henriksson, M.
    et al.
    Berglund, L. A.
    Isaksson, P.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Nishino, T.
    Cellulose nanopaper structures of high toughness2008Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Biomacromolecules, Vol. 9, nr 6, s. 1579-1585Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanofibrils offer interesting potential as a native fibrous constituent of mechanical performance exceeding the plant fibers in current use for commercial products. In the present study, wood nanofibrils are used to prepare porous cellulose nanopaper of remarkably high toughness. Nanopapers of different porosities and from nanofibrils of different molar mass are prepared. Uniaxial tensile tests are performed and structure - property relationships are discussed. The high toughness of highly porous nanopaper is related to the nanofibrillar network structure and high mechanical nanofibril performance. Also, molar mass correlates with tensile strength. This indicates that nanofibril fracture controls ultimate strength. Furthermore, the large strain-to-failure means that mechanisms, such as interfibril slippage, also contributes to inelastic deformation in addition to deformation of the nanofibrils themselves. © 2008 American Chemical Society.

  • 20. Horvath, A. T.
    et al.
    Horvath, A. E.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Wågberg, L.
    Adsorption of highly charged polyelectrolytes onto an oppositely charged porous substrate2008Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, nr 15, s. 7857-7866Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The adsorption behavior of highly charged cationic polyelectrolytes onto porous substrates is electrostatic in nature and has been shown to be highly dependent on the poly electrolyte properties. Copolymers of acrylamide (AM) and diallyldimethylammonium chloride (DADMAC) were synthesized to have a range of macromolecular properties (i.e., charge density and molecular mass). Traditional titration methods have been complemented by fluorescence labeling techniques that were developed to directly observe the extent that fluorescently labeled poly(AM-co-DADMAC) adsorbs into the pore structure of a cellulosic substrate. Although contributing to the electrostatic driving force, the charge density acts to limit adsorption to the outermost surface under electrolyte-free conditions. However, adsorption into the pores can occur if both the molecular mass and charge density of poly(AM-co-DADMAC) are sufficiently low. Adsorption initially increases as the electrolyte concentration is increased. However, the electrostatic persistence length of poly(AM-co-DADMAC) restricts the polyelectrolyte from entering the pores. Therefore, changes in the adsorption behavior at moderate electrolyte concentrations have been attributed to swelling of the polyelectrolyte layer at the fiber exterior. The adsorption behavior changes again at high electrolyte concentrations such that poly(AMco-DADMAC) could adsorb into the pore structure. This occurred when the electrolyte concentration was sufficient to screen the electrostatic persistence length of poly(AM-co-DADMAC), provided that the entropie driving force for adsorption still existed. It is suggested that adsorption into the pore structure is a kinetic process that is governed by localized electrostatic interactions between poly(AM-co-DADMAC) and the charges located within the pores.

  • 21. Horvath, A. T.
    et al.
    Horvath, A. E.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Wågberg, L.
    Adsorption of low charge density polyelectrolytes to an oppositely charged porous substrate2008Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, nr 13, s. 6585-6594Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The adsorption behavior of a low charge density cationic polyelectrolyte to cellulosic fibers has been studied. Cationic dextran served as a model polyelectrolyte, as it can be prepared over a range in molecular mass and charge density. The adsorption behavior of the cationic dextran was measured in electrolyte-free conditions using polyelectrolyte titration techniques. By fluorescent labeling the cationic dextran, the extent to which adsorption occurs inside the porous structure was further determined by fluorescent confocal laser scanning microscopy. Cationic dextran having a sufficiently low charge density adsorbed into the pores, although the extent the cationic dextran adsorbed was governed by the molecular mass. The adsorption behavior of the cationic dextran was also studied in various electrolyte concentrations. The adsorbed mass monotonically decreased with increasing electrolyte, as the electrostatic interaction with the substrate was more effectively screened. This behavior also suggests that the interactions between adsorbed polyelectrolyte chains, i.e. lateral correlation effects, are negligible for low charge density polyelectrolytes. Finally, the effect of having a preadsorbed layer of cationic dextran on the adsorption behavior was determined in electrolytefree conditions using fluorescent double staining techniques. The preadsorbed cationic dextran had almost no effect on the adsorption of low molecular mass fractions. Low molecular mass fractions directly adsorbed into the pore structure, as opposed to adsorbing to a free surface and diffusing into the pores. It was also shown that cationic dextran can be selectively adsorbed to different locations, such that the surface of a porous substrate can be treated uniquely from the bulk.

  • 22. Horvath, A. T.
    et al.
    Horvath, A. E.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Wågberg, L.
    Diffusion of cationic polyelectrolytes into cellulosic fibers2008Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, nr 19, s. 10797-10806Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The penetration of cationic polyelectrolytes into anionic cellulosic fibers was evaluated with fluorescent imaging techniques in order to clarify the mechanism and time scales for the diffusion process. The bulk charge of the cellulosic fibers indirectly creates a driving force for diffusion into the porous fiber wall, which is entropic in nature due to a release of counterions as the polyelectrolyte adsorbs. The individual bulk charges in the fiber cell wall also interact with the diffusing polyelectrolyte, such that the polyelectrolyte diffuses to the first available charge and consequently adsorbs and remains fixed. Thus, subsequent polyelectrolyte chains must first diffuse through the adsorbed polyelectrolyte layer before adsorbing to the next available bulk charges. This behavior differs from earlier suggested diffusion mechanisms, by which polyelectrolytes were assumed to first adsorb to the outermost surface and then reptate into the pore structure. The time scales for polyelectrolyte diffusion were highly dependent on the flexibility of the chain, which was estimated from calculations of the persistence length. The persistence length ultimately depended on the charge density and electrolyte concentration. The charge density of the polyelectrolyte had a greater influence on the time scales for diffusion. High charge density polyelectrolytes were observed to diffuse on a time scale of months, whereas the diffusion of low charge density polyelectrolytes was measured on the order of hours. An influence of the chain length, that is, steric interactions due the persistence length of the polyelectrolyte and to the tortuosity of the porous structure of the fiber wall, could only be noted for low charge density polyelectrolytes. Increasing the electrolyte concentration increased the chain flexibility by screening the electrostatic contribution to the persistence length, in turn inducing a faster diffusion process. However, a significant change in the diffusion behavior was observed at high electrolyte concentrations, at which the interaction between the polyelectrolyte charges and the fiber charges was almost completely screened.

  • 23.
    Hua, Kai
    et al.
    Uppsala University, Sweden.
    Ålander, Eva
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Mihranyan, Albert
    Uppsala University, Sweden.
    Strömme, Maria
    Uppsala University, Sweden.
    Ferraz, Natalia
    Uppsala University, Sweden.
    Surface Chemistry of Nanocellulose Fibers Directs Monocyte/Macrophage Response2015Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 16, nr 9, s. 2787-2795Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of surface functionalization of nanofibrillated cellulose (NFC) on monocyte/macrophage (MM) behavior is investigated to understand how the physicochemical properties of nanocelluloses influence the interactions of such materials with biological systems. Films of anionic (a-), cationic (c-), and unmodified (u-) NFC were synthesized and characterized in terms of surface charge. THP-1 monocytes were cultured on the surface of the films for 24 h in the presence and absence of lipopolysaccharide, and the cell response was evaluated in terms of cell adhesion, morphology, and secretion of TNF-α, IL-10, and IL-1ra. The results show that MMs cultured on carboxymethylated-NFC films (a-NFC) are activated toward a proinflammatory phenotype, whereas u-NFC promotes a mild activation of the studied cells. The presence of hydroxypropyltrimethylammonium groups on c-NFC, however, does not promote the activation of MMs, indicating that c-NFC closely behaves as an inert material in terms of MM activation. None of the materials is able to directly activate the MMs toward an anti-inflammatory response. These results may provide a foundation for the design of future NFC-based materials with the ability to control MM activation and may expand the use of NFC in biomedical applications.

  • 24. Ikkala, O.
    et al.
    Ras, R. H. A.
    Houbenov, N.
    Ruokolainen, J.
    Pääkkö, M.
    Laine, J.
    Leskelä, M.
    Berglund, L. A.
    Lindström, Tom
    RISE., Innventia.
    Ten Brinke, G.
    Iatrou, H.
    Hadjichristidis, N.
    Faul, C. F. J.
    Solid state nanofibers based on self-assemblies: From cleaving from self-assemblies to multilevel hierarchical constructs2009Inngår i: Faraday discussions (Online), ISSN 1359-6640, E-ISSN 1364-5498, Vol. 143, s. 95-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Self-assemblies and their hierarchies are useful to construct soft materials with structures at different length scales and to tune the materials properties for various functions. Here we address routes for solid nanofibers based on different forms of self-assemblies. On the other hand, we discuss rational "bottom-up" routes for multi-level hierarchical self-assembled constructs, with the aim of learning more about design principles for competing interactions and packing frustrations. Here we use the triblock copolypeptide poly(l-lysine)-b-poly(γ-benzyl-l-glutamate)-b-poly(l-lysine) complexed with 2′-deoxyguanosine 5′-monophosphate. Supramolecular disks (G-quartets) stabilized by metal cations are formed and their columnar assembly leads to a packing frustration with the cylindrical packing of helical poly(γ-benzyl-l-glutamate), which we suggest is important in controlling the lateral dimensions of the nanofibers. We foresee routes for functionalities by selecting different metal cations within the G-quartets. On the other hand, we discuss nanofibers that are cleaved from bulk self-assemblies in a "top-down" manner. After a short introduction based on cleaving nanofibers from diblock copolymeric self-assemblies, we focus on native cellulose nanofibers, as cleaved from plant cell wall fibers, which are expected to have feasible mechanical properties and to be templates for functional nanomaterials. Long nanofibers with 5-20 nm lateral dimensions can be cleaved within an aqueous medium to allow hydrogels and water can be removed to allow highly porous, lightweight, and flexible aerogels. We further describe inorganic/organic hybrids as prepared by chemical vapour deposition and atomic layer deposition of the different nanofibers. We foresee functional materials by selecting inorganic coatings. Finally we briefly discuss how the organic template can be removed e.g., by thermal treatments to allow completely inorganic hollow nanofibrillar structures.

  • 25.
    Jarnerö, Kirsi
    et al.
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Byggteknik.
    Johansson, Marie
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Byggteknik.
    Lindström, Tom ()
    Royal Institute of Technology, Stockholm, Sweden.
    Digitalisering/robotisering–utvecklingsfronten för trä-/hybridmaterial i byggande: 4 besöksrapporter från studieresa till Schweiz 13-15/3 2019 med besök påuniversitet, högskolor, forskningsinstitut samt företag2019Rapport (Annet vitenskapelig)
  • 26.
    Jiao, Fei
    et al.
    Linköping University, Sweden.
    Edberg, Jesper
    Linköping University, Sweden.
    Zhao, Dan
    Linköpings University, Sweden.
    Puzinas, Skomantas
    Khan, Zia Ullah
    Linköping University, Sweden.
    Makie, Peter
    Naderi, Ali
    RISE - Research Institutes of Sweden, Bioekonomi.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi.
    Oden, Magnus
    Linköpings University, Sweden.
    Engquist, Isak
    Berggren, Magnus
    Linköpings University, Sweden.
    Crispin, Xavier
    Linköping University, Sweden.
    Nanofibrillated Cellulose-Based Electrolyte and Electrode for Paper-Based Supercapacitors2018Inngår i: ADVANCED SUSTAINABLE SYSTEMS, ISSN 2366-7486, Vol. 2, nr 1, artikkel-id 1700121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solar photovoltaic technologies could fully deploy and impact the energy conversion systems in our society if mass-produced energy-storage solutions exist. A supercapacitor can regulate the fluctuations on the electrical grid on short time scales. Their mass-implementation requires the use of abundant materials, biological and organic synthetic materials are attractive because of atomic element abundancy and low-temperature synthetic processes. Nanofibrillated cellulose (NFC) coming from the forest industry is exploited as a three-dimensional template to control the transport of ions in an electrolyte-separator, with nanochannels filled of aqueous electrolyte. The nanochannels are defined by voids in the nanocomposite made of NFC and the proton transporting polymer polystyrene sulfonic acid PSSH. The ionic conductivity of NFC-PSSH composites (0.2 S cm(-1) at 100% relative humidity) exceeds sea water in a material that is solid, feel dry to the finger, but filled of nanodomains of water. A paper-based supercapacitor made of NFC-PSSH electrolyte-separator sandwiched between two paper-based electrodes is demonstrated. Although modest specific capacitance (81.3 F g(-1)), power density (2040 W kg(-1)) and energy density (1016 Wh kg(-1)), this is the first conceptual demonstration of a supercapacitor based on cellulose in each part of the device; which motivates the search for using paper manufacturing as mass-production of energy-storage devices.

  • 27.
    Jiao, Fei
    et al.
    Linköping University, Sweden.
    Naderi, Ali
    BillerudKorsnäs, Sweden.
    Zhao, Dan
    Linköping University, Sweden.
    Schlueter, Joshua
    University of Kentucky, USA.
    Shahi, Maryam
    University of Kentucky, USA.
    Sundström, Jonas
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Granberg, Hjalmar
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Edberg, Jesper
    Linköping University, Sweden.
    Ail, Ujwala
    Linköping University, Sweden.
    Brill, Joseph
    BillerudKorsnäs, Sweden.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Berggren, Magnus
    Linköping University, Sweden.
    Crispin, Xavier
    Linköping University, Sweden.
    Ionic thermoelectric paper2017Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, s. 16883-16888Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ionic thermoelectric materials, for example, polyelectrolytes such as polystyrene sulfonate sodium (PSSNa),constitute a new class of materials which are attracting interest because of their large Seebeck coefficientand the possibility that they could be used in ionic thermoelectric SCs (ITESCs) and field effect transistors.However, pure polyelectrolyte membranes are not robust or flexible. In this paper, the preparation of ionicthermoelectric paper using a simple, scalable and cost-effective method is described. After a compositewas fabricated with nanofibrillated cellulose (NFC), the resulting NFC–PSSNa paper is flexible andmechanically robust, which is desirable if it is to be used in roll-to-roll processes. The robust NFC–PSSNa thermoelectric paper combines high ionic conductivity (9 mS cm1), high ionic Seebeckcoefficient (8.4 mV K1) and low thermal conductivity (0.75 W m1 K1) at 100% relative humidity,resulting in overall figure-of-merit of 0.025 at room temperature which is slightly better than that for thePSSNa alone. Fabricating a composite with cellulose enables flexibility and robustness and this is anadvance which will enable future scaling up the manufacturing of ITESCs, but also enables its use fornew applications for conformable thermoelectric devices and flexible electronics.

  • 28. Jin, H.
    et al.
    Pääkkö, M.
    Netral, J.
    Berglund, L. A.
    Neagu, C.
    Bourban, P. -E
    Ankerfors, Mikael
    RISE., STFI-Packforsk.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Ikkala, O.
    Effects of different drying methods on textural properties of nanocellulose aerogels2009Inngår i: ICCM International Conferences on Composite Materials, 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    There is increasing research interest in nanocellulose aerogels because they have low density, hierarchical structure and they are biodegradable and biocompatible. Typically, aerogels are made by supercritical drying, freeze drying and vacuum drying. This work will report the effects that different drying methods have on textural properties of aerogels.

  • 29. Junka, Kraoliina
    et al.
    Filpponen, Iiari
    Lindström, Tom
    RISE., Innventia.
    Laine, Janne
    Surface and total charge density of functionalized nanofibrillar cellulose dispersions2013Konferansepaper (Fagfellevurdert)
  • 30.
    Klemm, Dieter
    et al.
    Polymet Jena Association, Germany.
    Cranston, Emily D.
    McMaster University, Canada.
    Fischer, Dagmar
    Friedrich Schiller University of Jena, Germany.
    Gama, Miguel
    University of Minho, Portugal.
    Kedzior, Stephanie A.
    McMaster University, Canada.
    Kralisch, Dana
    JeNaCell GmbH, Germany.
    Kramer, Friederike
    Polymet Jena Association, Germany.
    Kondo, Tetsuo
    Kyushu University, Japan.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi.
    Nietzsche, Sandor
    University Hospital Jena, Germany.
    Petzold-Welcke, Karin
    Jenpolymer Materials UG & Co. KG, Germany.
    Rauchfuß, Falk
    University Hospital Jena, Germany.
    Nanocellulose as a natural source for groundbreaking applications in materials science: Today's state2018Inngår i: Materials Today, ISSN 1369-7021, E-ISSN 1873-4103, Vol. 21, nr 7, s. 720-748Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocelluloses are natural materials with at least one dimension in the nano-scale. They combine important cellulose properties with the features of nanomaterials and open new horizons for materials science and its applications. The field of nanocellulose materials is subdivided into three domains: biotechnologically produced bacterial nanocellulose hydrogels, mechanically delaminated cellulose nanofibers, and hydrolytically extracted cellulose nanocrystals. This review article describes today's state regarding the production, structural details, physicochemical properties, and innovative applications of these nanocelluloses. Promising technical applications including gels/foams, thickeners/stabilizers as well as reinforcing agents have been proposed and research from last five years indicates new potential for groundbreaking innovations in the areas of cosmetic products, wound dressings, drug carriers, medical implants, tissue engineering, food and composites. The current state of worldwide commercialization and the challenge of reducing nanocellulose production costs are also discussed.

  • 31.
    Larsson, Per T.
    et al.
    RISE - Research Institutes of Sweden, Bioekonomi.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi.
    Carlsson, Leif A.
    Florida Atlantic University, USA.
    Fellers, Christer
    RISE - Research Institutes of Sweden.
    Fiber length and bonding effects on tensile strength and toughness of kraft paper2018Inngår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 53, nr 4, s. 3006-3015Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fiber length and fiber-to-fiber bonding effects on tensile strength and fracture toughness of kraft paper have experimentally been investigated. Laboratory sheets were made from kraft pulp, each with a distinct set of fiber lengths. Additionally, the fiber–fiber bond strength was improved by carboxymethyl (CMC) grafting. The tensile strength and work of fracture toughness results were compared to predictions from a shear-lag model which considers the fiber–fiber bond shear strength, the fiber tensile strength and fiber pull-out work. The tensile strength and fracture work for papers with weak fiber–fiber bonds increased with fiber length consistent with the shear-lag model. CMC-treated fibers provided strong fiber–fiber bonds. Papers made from such fibers displayed high strength and work of fracture independent of fiber length which indicates that the failure process is governed by fiber failures rather than bond failures. The fracture toughness, expressed as the critical value of the J-integral, increased strongly with fiber length for both untreated and CMC-treated papers. The results show that long fibers and CMC addition are extremely beneficial for improving the fracture toughness. © 2017, Springer Science+Business Media, LLC.

  • 32.
    Lie, Ewa
    et al.
    RISE - Research Institutes of Sweden, Bioekonomi, Biobaserade material.
    Ålander, Eva
    RISE - Research Institutes of Sweden, Bioekonomi, Biobaserade material.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi.
    Possible toxicological effects of nanocellulose: an updated literature study, No. 22017Rapport (Annet vitenskapelig)
    Abstract [en]

    This literature review covers open publications and reports on the subject of nanocellulose and its possible toxicological effects. There is currently a rather low number of peer reviewed articles on the subject. However, from the articles reviewed, caution of inhalation of nanocellulose would be recommended since in vivo tests have shown immunotoxicity effect on lungs even though residues of other production chemicals, biocides and endotoxins from bacterial contamination might affect the results.

  • 33.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Aspects on nanofibrillated cellulose (NFC) processing, rheology and NFC-film properties2017Inngår i: Current Opinion in Colloid & Interface Science, ISSN 1359-0294, E-ISSN 1879-0399, Vol. 29, s. 68-75Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This communication summarizes the salient features and mechanisms in high-pressure homogenization of wood fibres in order to make nanofibrillar cellulose (NFC). The energy-efficiency of delamination of fibres and the clogging tendency of fibres in high-pressure homogenizers/microfluidizers during delamination are critical and ways to alleviate these problems are reviewed. It is shown that the mechanical properties of NFC-films can be estimated from the Page equation. Usually, the evolution of the tensile strength properties of NFC-films increases with the extent of film delamination to reach a saturation value, which can be deduced from first principles using the Page equation. Finally, the evolution of the rheological features of NFC-gels and the barrier properties are reviewed and the estimation the nanofraction content in NFC-gels is being discussed.

  • 34.
    Lindström, Tom
    et al.
    RISE., STFI-Packforsk.
    Banke, K.
    RISE., STFI-Packforsk.
    Larsson, Tomas
    RISE., STFI-Packforsk.
    Glad-Nordmark, Gunborg
    RISE., STFI-Packforsk.
    Boldizar, A.
    Nanoclay plating of cellulosic fiber surfaces2008Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 108, nr 2, s. 887-891Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A basic problem in making cellulose-reinforced composites is achieving a dispersion of cellulosic fibers in an often olephinic polymer matrix. Drying cellulosic fibers results in the formation of fiber flocs/nodules because of their strong interfiber bonding, and this makes the hydrophilic cellulosic fibers difficult to disperse in a hydrophobic matrix material. One common approach to alleviate floe formation is to adsorb cationic surfactant onto anionically charged cellulose, which reduces the interfiber bonding, decreases floe formation and gives better compatibility with the matrix. In this report, a different approach is taken, namely to adsorb nanoclays onto the cellulosic fibers, and thereby reduce the natural hydrogen-bonding affinity between fibers. In a second report, the same technology will be shown to be advantageous to decrease floe formation in oleophinic composites reinforced with cellulosic fibers. This article summarizes experiments aimed at optimizing the chemistry of deposition of montmorillonite clay onto fiber surfaces. The aim was to optimize the chemical conditions for the heterodeposition of the anionic clay onto cationically charged fluff pulp. The experiments were designed to provide a theoretical framework for the deposition of the nanoclay onto the pulp fibers. High Mw p-DADMAC and an exfoliated clay (achieved by passing the clay through a homogenizer) were used. As expected, a certain degree of charge overcompensation by adding an electrolyte was necessary to bring about deposition. The adsorbed amount of clay could be calculated from the charge balance between the overcompensated charge and the net clay charge, constituting the theoretical framework for nanoclay heterodeposition. As expected, montmorillonite clay greatly destroyed the joint strength between fibers (determined by evaluating the strength of paper made from treated fibers). The surface coverage (determined by ESCA) was shown to be a linear function of the attached amount of clay, and ∌3% clay was required to fully cover the fiber surfaces. © 2008 Wiley Periodicals, Inc.

  • 35.
    Lindström, Tom
    et al.
    RISE., Innventia.
    Fellers, Christer
    RISE., Innventia.
    Ankerfors, Mikael
    BillerudKorsnäs AB, Sweden.
    Glad Nordmark, Gunborg
    RISE., Innventia.
    On the nature of joint strength of paper: Effect of dry strength agents - Revisiting the Page equation2016Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 3, s. 459-468Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This report deals with the effects of various chemical-treatments - carboxymethylcellulose-grafted (CMC) pulp in different ionic forms (Na+, Ca2+, and Al3+), cationic starch, anionic polyacrylamide, and microfibrillated cellulose (MFC) as well as PFI-refining on the strength properties of never-dried bleached soft-wood kraft pulp. The general in-plane strength properties were measured together with z-strength and interlaminar shear strength. The sheet density was varied by pressing the wet sheets to various dry solids content. The relative bonded area of the sheets was determined by the BET surface area of the sheets using krypton adsorption. Interlaminar shear strength is introduced as a measure for fibre-fibre bond strength and validates its use in the Page equation from first principles and it was shown to hold over a large range of tensile strengths. Only at very high tensile index values the calculated tensile index deviated from measured tensile index. This was most likely due to a shift from adhesive to cohesive failure of the joint. The various strength reinforcement methods used were all based on carbohydrate based additives and for those additives the specific joint strength was found to be independent of the specific additive, so the strength reinforcement is only related to the increased relative bonded area upon the addition of the strength adjuvant, although the additives consolidate the sheet on various structural levels.

  • 36.
    Lindström, Tom
    et al.
    RISE., Innventia.
    Fellers, Christer
    RISE., Innventia.
    Ankerfors, Mikael
    RISE., Innventia.
    Glad Nordmark, Gunborg
    RISE., Innventia.
    The effects of various chemical treatments on fibre-fibre joint strength in paper2012Konferansepaper (Fagfellevurdert)
  • 37.
    Lindström, Tom
    et al.
    RISE., STFI-Packforsk.
    Larsson, Per Tomas
    RISE., STFI-Packforsk.
    Alkyl ketene dimer (AKD) sizing: A review2008Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, nr 2, s. 202-209Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Over the years, there have been great efforts to try to develop cellulose reactive sizing agents. The assumption in these developments have been that the covalent linkage allows permanent attachment of hydrophobic groups in a highly oriented state, which makes sizing possible at very low levels of added chemical. The main requirement of the molecule is that it should have a balance between the reactivity towards water, because of the necessity of making stable emulsions or dispersions, and its reactivity towards cellulose. These assumptions are to some extent mutually exclusive and a compromise must be sought. Although, many different types have been tried out over the years the most important sizes used are the Alkyl Ketene Dimers (AKD) and the Alkenyl Succinic Anhydrides (ASA). These sizing agents are at the opposite in terms of stability of hydrolysis and reactivity towards cellulose, where AKDs are the least reactive species and fairly stable towards hydrolysis, whereas ASAs are very reactive towards cellulose, but also sensitive to hydrolysis. The mechanism of action is fairly well known for AKD, but less known for ASA and AKD-sizing can be regarded as a pretty mature field from a scientific point of view. The aim of this contribution is to summarize the fundamental features of AKD-sizing and discuss and highlight the most important aspects for the practical papermaker. Over the years there have been many reviews (e.g. (Dumas 1975; Reynolds 1989; Eklund and Lindström 1991; Hodgson 1994; Roberts 1997; Hubbe 2006)) in the field of AKD-sizing, but there have been extensive recent research activities over the past 10 years and there is a need for a comprehension of these research activities.

  • 38.
    Lindström, Tom
    et al.
    RISE., Innventia.
    Naderi, Ali
    RISE., Innventia.
    Wiberg, Anna
    RISE., Innventia.
    Large scale applications of nanocellulosic materials: A comprehensive review2015Inngår i: Palpu Chongi Gisul/Journal of Korea Technical Association of the Pulp and Paper Industry, Vol. 47, nr 6, s. 5-21Artikkel i tidsskrift (Annet vitenskapelig)
  • 39.
    Lindström, Tom
    et al.
    RISE., Innventia.
    Swerin, Agne
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik. KTH Royal Institute of Technology, Sweden.
    On the mechanical and chemical factors governing retention and formation of a fine paper stock: The case of headbox elongational shear2016Inngår i: Journal of Science & Technology for Forest Products and Processes, ISSN 1927-6311, E-ISSN 1927-632X, Vol. 5, nr 4, s. 30-37Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The relation between formation and retention is of key importance in papermaking. This paper deals with how various variables (mix-to-wire speed difference, softwood/hardwood ratio, pulp consistency, headbox contraction, and various amounts of added two-component retention aid) affect the forming of paper and in turn retention and paper formation. The experiments were conducted using the EuroFEX paper machine at Innventia, which can be operated under steady-state conditions of the white water system.

    It was found that formation is worst when the mix-to-wire speed difference is close to zero or when the oriented shear is lowest. Retention, on the other hand, is to a large extent independent of mix-to-wire speed. Higher consistency during forming is generally associated with an enhanced susceptibility of fibres to flocculate, but a higher consistency in the  headbox is, in this study, also associated with increased headbox contraction, which increases elongational shear. The higher the headbox consistency, the higher will be the first-pass retention because of the closer proximity of particles, which is beneficial for bridging flocculation. It is known that elongational shear is in general more beneficial to fibre dispersion than transverse shear and also that for weaker fibre flocs (higher hardwood pulp content), the effect of high headbox contraction (higher consistency) actually reverses the effect of consistency on sheet formation because elongational shear overcomes the effects of fibre crowding at high headbox consistency on sheet formation.

    In conclusion, we show how the effects of mix-to-wire speed difference, softwood/hardwood ratio, headbox consistency, headbox contraction, and amount of retention aid added (cationic polyacrylamide and colloidal silica) affect retention and formation of paper.

  • 40. López-Rubio, A.
    et al.
    Lagaron, J. M.
    Ankerfors, Mikael
    RISE., STFI-Packforsk.
    Lindström, Tom
    RISE., STFI-Packforsk.
    Nordqvist, D.
    Mattozzi, A.
    Hedenqvist, M. S.
    Erratum to "Enhanced film forming and film properties of amylopectin using micro-fibrillated cellulose" [Carbohydr. Polym. 68 (2007) 718-727] (DOI:10.1016/j.carbpol.2006.08.008)2008Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 71, nr 3, s. 482-Artikkel i tidsskrift (Fagfellevurdert)
  • 41.
    Marais, Andrew
    et al.
    KTH Royal Institute of Technology, Sweden.
    Enarsson, Lars-Erik
    SCA R&D Centre, Sweden.
    Pettersson, Gunilla
    Mid Sweden University, Sweden.
    Lindström, Tom
    RISE., Innventia.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Pilot-scale papermaking using Layer-by-Layer treated fibres: Comparison between the effects of beating and of sequential addition of polymeric additives2016Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 2, s. 308-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Layer-by-Layer (LbL) deposition technique was used to treat fibres before papermaking on a pilot scale. Following a laboratory pre-study performed earlier to determine the adsorption isotherms and the kinetics of formation of multilayers of polyamideamine epichlorydrine (PAE) and carboxymethylated cellulose (CMC) on unbeaten, bleached softwood fibres, online LbL treatment of the furnish was carried out on the EuroFEX pilot paper machine. Papers from fibres coated with up to four layers of polyelectrolytes were produced. Two different LbL systems were investigated, with anionic CMC in combination with either PAE or cationic starch (CS). The results showed that the mechanical strength of the paper significantly increased when the fibres were LbL-treated online. A comparison with conventional beating of the fibres revealed that the LbL treatment was a potential substitute to beating treatment, as the density of the LbL-treated papers remained constant while the mechanical properties were significantly improved. At the same time, the press solids content was significantly higher (2%) when using LbL-treated fibres than with beaten fibres.

  • 42.
    Mericer, Caglar
    et al.
    University of Bologna, Italy.
    Minelli, Matteo
    University of Bologna, Italy.
    Giacinti Baschetti, Marco
    University of Bologna, Italy.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi.
    Water sorption in microfibrillated cellulose (MFC): The effect of temperature and pretreatment2017Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, s. 1201-1212Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water sorption behavior of two different microfibrillated cellulose (MFC) films, produced by delamination of cellulose pulp after different pretreatment methods, is examined at various temperatures (16–65 °C) and up to 70% RH. The effect of drying temperature of MFC films on the water uptake is also investigated. The obtained solubility isotherms showed the typical downward curvature at moderate RH, while no upturn is observed at higher RH; the uptakes are in line with characteristic values for cellulose fibers. Enzymatically pretreated MFC dispersion showed lower solubility than carboxymethylated MFC, likely due to the different material structure, which results from the different preparation methods The experimental results are analyzed by Park and GAB models, which proved suitable to describe the observed behaviors. Interestingly, while no significant thermal effect is detected on water solubility above 35 °C, the uptake at 16 and 25 °C, at a given RH, is substantially lower than that at higher temperature, indicating that, in such range, sorption process is endothermic. Such unusual behavior for a cellulose-based system seems to be related mainly to the structural characteristics of MFC films, and to relaxation phenomena taking place upon water sorption. The diffusion kinetics, indeed, showed a clear Fickian behavior at low temperature and RH, whereas a secondary process seems to occur at high temperature and higher RH, leading to anomalous diffusion behaviors.

  • 43.
    Meriçer, Çağlar
    et al.
    University of Bologna, Italy.
    Minelli, Matteo
    University of Bologna, Italy.
    De Angelis, Maria G.
    University of Bologna, Italy.
    Giacinti Baschetti, Marco
    University of Bologna, Italy.
    Stancampiano, Augusto
    University of Bologna, Italy.
    Laurita, Romolo
    University of Bologna, Italy.
    Gherardi, Matteo
    University of Bologna, Italy.
    Colombo, Vittorio
    University of Bologna, Italy.
    Trifol, Jon
    DTU Technical University of Denmark, Denmark.
    Szabo, Peter
    DTU Technical University of Denmark, Denmark.
    Lindström, Tom
    RISE., Innventia.
    Atmospheric plasma assisted PLA/microfibrillated cellulose (MFC) multilayer biocomposite for sustainable barrier application2015Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 93, s. 235-243Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fully bio-based and biodegradable materials, such as polylactic acid (PLA) and microfibrillated cellulose (MFC), are considered in order to produce a completely renewable packaging solution for oxygen barrier applications, even at medium-high relative humidity (R.H.). Thin layers of MFC were coated on different PLA substrates by activating film surface with an atmospheric plasma treatment, leading to the fabrication of robust and transparent multilayer composite films, which were then characterized by different experimental techniques. UV transmission measurements confirmed the transparency of multilayer films (60% of UV transmission rate), while SEM micrographs showed the presence of a continuous, dense and defect free layer of MFC on PLA surface. Concerning the mechanical behavior of the samples, tensile tests revealed that the multilayer films significantly improved the stress at break value of neat PLA. Moreover, the oxygen barrier properties of the multilayer films were improved more than one order of magnitude compared to neat PLA film at 35 °C and 0% R.H. and the permeability values were maintained up to 60% R.H. The obtained materials therefore showed interesting properties for their possible use in barrier packaging applications as fully biodegradable solution, coupling two primarily incompatible matrices in a multilayer film with no need of any solvent or chemical.

  • 44.
    Naderi, Ali
    et al.
    RISE., Innventia.
    Erlandsson, Johan
    KTH Royal Institute of Technology, Sweden.
    Sundström, Jonas
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Enhancing the properties of carboxymethylated nanofibrillated cellulose by inclusion of water in the pre-treatment process2016Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 3, s. 372-378Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Well-delaminated carboxymethylated nanofibrillated cellulose (NFCCarb) systems are prerequisites for many industrial applications. In this study it was shown that addition of water, in a narrow range, not only improves the efficiency of the carboxymethylation process, but also enhances the degree of delamination of NFCCarb, which leads to improved properties. The observations were proposed to be due to a more homogeneous distribution of the charged groups, brought about by the higher swelling of fibers with inclusion of water.

  • 45.
    Naderi, Ali
    et al.
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Stevanic Srndovic, Jasna
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioekonomi. RISE., Innventia.
    Erlandsson, Johan
    KTH Royal Institute of Technology, Sweden.
    Effect of the size of the charged group on the properties of alkoxylated NFCs2017Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 3, s. 1307-1317Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impact of the size of the charged group on the properties of alkoxylated NFC was studied by two chloroalkyl acid reagents. It was found that the employment of the larger 2-chloropropionic acid reagent leads to improved properties, e.g. higher fraction of nano-sized materials, and significantly better redispersion as compared to when the smaller monochloroacetic acid was employed. The differences in the impacts of the different reagents were hypothesized to be due to a more efficient disruption of the cohesion between the nanofibrils when a larger charged group was employed. 

  • 46.
    Naderi, Ali
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    A comparative study of the rheological properties of three different nanofibrillated cellulose systems2016Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 3, s. 354-363Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The rheological properties of NFC systems in different conditions are of important for their handling and implementation in various industrial applications. In this investigation, the existence of wall-slip effects and the rheological characteristics of three different nano-fibrillated cellulose (NFC) systems - enzymatically pre-treated (NFCEnz), carboxymethyl cellulose grafted (NFCCMC) and carboxymethylated (NFCCarb) - were investigated. It was found that the rheological properties of NFCCarb are less affected by wall-slip effects when geometries with serrated surfaces are employed. The other systems showed, however, different degrees of susceptibility to these effects. The thixotropic properties of the different NFC systems, together with the impact of ambient ionic strength and temperature on the rheological properties of the systems, were also studied. It was found that the different systems displayed different rheological behaviours. In short, all systems regained most of their original properties as soon as severe shearing was ceased. The apparent viscosities of NFCEnz and NFCCMC were found to be little affected by the ionic strength of the system. However, the viscosity of the systems decreased somewhat with increasing temperatures. The viscosity of NFCCarb decreased on the other hand with the increasing ionic strength, but otherwise showed little sensitivity towards the ambient temperature. Hence, it was concluded that the rheological properties of NFCCarb were primarily governed by the electrosteric interactions between the NFC entities rather than the viscous properties of the liquid phase.

  • 47.
    Naderi, Ali
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Erratum to: Nanofibrillated cellulose: properties reinvestigated2017Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 12, s. 5713-5713Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the original publication of the article, the co-author name Tom Lindströ¶m was mistakenly missed out. Also the affiliation of the corresponding author was provided incorrectly. It has been updated in this erratum.

  • 48.
    Naderi, Ali
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Rheological measurements on nanofibrillated cellulose systems: A science in progress2015Inngår i: Cellulose and Cellulose Derivatives: Synthesis, Modification and Applications / [ed] Mondal M.I.H., Nova Science Publishers, Inc., 2015, s. 187-204Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Nanofibrillated cellulose (NFC) systems are today on the height of the attention of the research community and the industry, thanks to their perceived potential in a sustainable society scenario. A related field that has seen an upsurge of interest is the rheology of NFC-based systems, as it is in the heart of the processing of these materials both in the manufacturing step and its industrial applications. However, despite considerable efforts the progress in the field has been sluggish. This is partly traced to, among others, the unsatisfactory disclosure of the experimental set-up in the published work (which hinders independent evaluations) and unawareness of the different characteristics of different NFC systems, which require careful set-up of the experiments. In this light, a few of the complicating aspects with regard to rheological studies of NFC-based systems are exemplified, and some of the more important features of the rheology of nanocellulosic systems with emphasis on single-component NFC systems are reviewed. The authors thereby hope to contribute to a better understanding of the already- published results, and inspire future contributors to address the earlier-mentioned inadequacies.

  • 49.
    Naderi, Ali
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Rheological measurements on nanofibrillated cellulose systems: A science in progress2015Inngår i: Cellulose and cellulose derivatives, Nova Science , 2015, , s. 13Kapittel i bok, del av antologi (Fagfellevurdert)
  • 50.
    Naderi, Ali
    et al.
    RISE., Innventia.
    Lindström, Tom
    RISE., Innventia.
    Erlandsson, Johan
    KTH Royal Institute of Technology, Sweden.
    Sundström, Jonas
    RISE., Innventia.
    Flodberg, Göran
    RISE., Innventia.
    A comparative study of the properties of three nano-fibrillated cellulose systems that have been produced at about the same energy consumption levels in the mechanical delamination step2016Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 3, s. 364-371Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The viscosity, tensile strength- and barrier properties of enzymatically pre-treated- (NFCEnz), carboxymethylated- (NFCCarb) and carboxymethyl cellulose (CMC) modified (NFCCMC) nanofibrillated cellulose systems (NFC) that have been produced at about the same energy consumption levels in the mechanical delamination step in the manufacturing of the different NFCs are reported. It was found that NFCEnz and NFCCMC are characterized by low degrees of fibrillation. Carboxymethylated NFC displayed superior tensile strength properties, lower fiber fragment content and a higher viscosity when compared to NFCEnz and NFCCMC. Interestingly, NFCEnz displayed equal or better barrier properties compared to the highly fibrillated NFCCarb.

12 1 - 50 of 61
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