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  • 301.
    Lindberg, Siv M
    et al.
    RISE, Innventia.
    Hansen, Peeter
    RISE, Innventia.
    Drotz, Mattias
    RISE, Innventia.
    Kihlstedt, Annika
    RISE, Innventia.
    Rosén, Fredrik
    RISE, Innventia.
    Tactile and instrumental characterization of tissue products2015Conference paper (Other academic)
    Abstract [en]

    The feeling of softness and smoothness of paper tissue products is an important performance factor in the market place. In a series of panel tests, the relationship between instrumental measurements and perceived softness and smoothness was investigated. Samples of tissue base paper – napkin and toilet paper – were evaluated for surface roughness. The samples were placed on a hard, smooth glass substrate and the respondents used one finger to stroke along the sample surface. Instrumental measurement and characterization were performed using differentinstruments: Emtec TSA and Lena Softness Tester. The results divide the base paper material into product groups, but general mathematical relationships could be found between the test panel and the measurements when normalized in different ways. Measurements using the Lena produced the best correlation with the panel ratings because its principle resembled the method of the test panel most closely. However, a general relationship usingmaterial properties was shown to produce as good an estimator for the surface roughness as the results obtained with the Lena. This relationship consisted of the ratio between the plasticity and the elasticity of the tissue paper (in-plane properties), normalized for thickness. This suggests that those three material properties are fundamental to the perception of surface roughness as evaluated in this study. Using a trained haptic panel to evaluate test samples of similar grammage with variations in furnish and machine operation settings generated a good correlation to the TSA measurement (r=0.9). The panel was more susceptible to variation in furnish than variation in peak pressure, and this was particularly evident for samples evaluated on the Yankee side.

  • 302.
    Lindberg, Siv M
    et al.
    RISE, Innventia.
    Lindström, Annika
    RISE, Innventia.
    Cederström, Caroline
    RISE, Innventia.
    From, Anders
    Westerlind, Christine
    Shoppers' attention to packaging and in-store media2013Conference paper (Refereed)
  • 303.
    Lindgren, Karin
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Kulander, Ida
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Törngren, Per
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Bialik, Marta
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Soap separation: a new option for removal of NPEs2018In: Technical solutions for today and beyond: TAPPI PEERS conference, 2018, p. 154-159Conference paper (Other academic)
  • 304.
    Lindgren, Karin
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Kulander, Ida
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Törngren, Per
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Bialik, Marta
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Soap separation: A new option for removal of NPEs2018In: Pulping Engineering and Environmental Recycling Sustainability Conference, PEERS 2018: Technical Solutions for Today and Beyond, TAPPI Press , 2018, p. 272-277Conference paper (Other academic)
    Abstract [en]

    Non-process elements (NPEs) are elements present in the process streams without taking part in the desired reaction. With increasing process closure and new NPE-rich input streams such as gasified bark in the lime kiln and the destruction of biosludge in the recovery boiler, the traditional purge points may prove insufficient. A new method to remove NPEs is suggested: Removal of NPEs from tall oil brine. The idea is based on the fact that many elements are enriched in the soap and separated from the black liquor but are later led back to the black liquor with the brine. The results showed strong enrichment of Ba, Ca, Mg, Mn, P and Zn in soap; an enrichment factor of 8 or higher was observed. Laboratory experiments where tall oil brine has been alkalized and subjected to a separation stage have been conducted. The laboratory experiments showed that more than 90% of Al, Ba, Mg, Mn and P precipitates and could be removed with the solid phase if alkalized to pH 11. The separation efficiency varied for Ca and Si from 70-85 %. To conclude, removal of non-process elements from tall oil brine is a promising new kidney, especially for P and Si.

  • 305.
    Lindgren, Karin
    et al.
    RISE, Innventia.
    Samuelsson, Åsa
    RISE, Innventia.
    Kulander, Ida
    RISE, Innventia.
    Full mill model for dissolving pulp based biorefinery2015Conference paper (Other academic)
    Abstract [en]

    Material and energy balances of a modern theoretical dissolving softwood kraft pulp mill, using pre-hydrolysis in water, have been established. The mill produces 1000 ADt/day and there is an energy excess in the mill that could be used to produce power. If lignin is removed with the LignoBoost process the recovery boiler is unloaded enabling an increased pulp production. With a lignin removal of 0.2 ton/ADt the pulp production could increase 8.5%. According to a sensitivity analysis the lignin price has the largest impact on the economic performance.

  • 306.
    Lindgren, Karin
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy.
    Samuelsson, Åsa
    RISE - Research Institutes of Sweden, Bioeconomy.
    Kulander, Ida
    RISE - Research Institutes of Sweden, Bioeconomy.
    Techno economic evaluation of lignin extraction in a dissolving pulp biorefinery2017In: The 7th Nordic Wood Biorefinery Conference held in Stockholm, Sweden, 28-30 Mar. 2017: NWBC 2017, Stockholm: RISE Bioekonomi , 2017, p. 118-123Conference paper (Refereed)
    Abstract [en]

    A simulation model for dissolving pulp production using prehydrolysis kraft process has been developed at Innventia, which reflects a greenfield dissolving softwood kraft pulp mill producing 1,000tpd. The fibrelines comprised a separate prehydrolysis stage before the impregnation stage, with condensate from black liquor evaporation and steam being added to the prehydrolysis stage. The liquor was then removed from the chips and fed to the evaporation plant. The prehydrolysed chips were subjected to impregnation, cooking and oxygen delignification in double stages, with the oxygen delignified pulp being bleached in a four stage sequence D1(EOP)D2P. The simulation program WinGEMS 5.0 was used to establish material and energy balances. A lignin production of 0.2t/t increased pulp production by 8.5%. The heat value of the black liquor decreased but would still be high enough for stable and favourable combustion properties in the recovery boiler. It was found that the lignin price had the largest impact on the economic performance. Lignin removal increased the pulp production and was economically viable, especially if the possibility to produce electricity was low.

  • 307.
    Lindh, Erik L.
    et al.
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Bergenstråhle-Wohlert, Malin
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Terenzi, Camilla
    KTH Royal Institute of Technology, Sweden.
    Salmen, Lennart
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Furo, István
    KTH Royal Institute of Technology, Sweden.
    Non-exchanging hydroxyl groups on the surface of cellulose fibrils: The role of interaction with water2016In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 434, p. 136-142Article in journal (Refereed)
    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.

  • 308.
    Lindh, Erik L.
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia. KTH Royal Institute of Technology, Sweden .
    Terenzi, Camilla
    KTH Royal Institute of Technology, Sweden .
    Salmen, Lennart
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia. KTH Royal Institute of Technology, Sweden .
    Furo, Istvan
    KTH Royal Institute of Technology, Sweden .
    Water in cellulose: evidence and identification of immobile and mobile adsorbed phases by 2H MAS NMR2017In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, p. 4360-4369Article in journal (Refereed)
    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 2H MAS NMR the mobility of water molecules in carefully 2H-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 2H2O 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 2H MAS NMR encourages further applications of the same method to other complex systems that expose heterogeneous hygroscopic surfaces, like wood cell walls.

  • 309.
    Lindh, Erik
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Salmen, Lennart
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Surface accessibility of cellulose fibrils studied by hydrogena€“deuterium exchange with water2017In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 1, p. 21-33Article in journal (Refereed)
    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.

  • 310. Lindström, T.
    et al.
    Aulin, C.
    RISE, Innventia.
    Gimåker, M.
    RISE, Innventia.
    Persson, T.
    The emergence of practical nanocellulose applications for a more sustainable paper/board industry2014In: IPPTA: Quarterly Journal of Indian Pulp and Paper Technical Association, ISSN 0379-5462, Vol. 26, no 1, p. 53-61Article in journal (Refereed)
  • 311.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia.
    Aspects on nanofibrillated cellulose (NFC) processing, rheology and NFC-film properties2017In: Current Opinion in Colloid & Interface Science, ISSN 1359-0294, E-ISSN 1879-0399, Vol. 29, p. 68-75Article in journal (Refereed)
    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.

  • 312.
    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 surfaces2008In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 108, no 2, p. 887-891Article in journal (Refereed)
    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.

  • 313.
    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 equation2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 459-468Article in journal (Refereed)
    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.

  • 314.
    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 paper2012Conference paper (Refereed)
  • 315.
    Lindström, Tom
    et al.
    RISE, STFI-Packforsk.
    Larsson, Per Tomas
    RISE, STFI-Packforsk.
    Alkyl ketene dimer (AKD) sizing: A review2008In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, no 2, p. 202-209Article in journal (Refereed)
    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.

  • 316.
    Lindström, Tom
    et al.
    RISE, Innventia.
    Naderi, Ali
    RISE, Innventia.
    Wiberg, Anna
    RISE, Innventia.
    Large scale applications of nanocellulosic materials: A comprehensive review2015In: Palpu Chongi Gisul/Journal of Korea Technical Association of the Pulp and Paper Industry, Vol. 47, no 6, p. 5-21Article in journal (Other academic)
  • 317.
    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 shear2016In: Journal of Science & Technology for Forest Products and Processes, ISSN 1927-6311, E-ISSN 1927-632X, Vol. 5, no 4, p. 30-37Article in journal (Other academic)
    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.

  • 318.
    Lucisano, Marco
    et al.
    RISE, Innventia.
    Krochak, Paul
    RISE, Innventia.
    Hansson, Åke
    RISE, Innventia.
    Thomsson, Lars
    RISE, Innventia.
    Lofthus, Jon
    RISE, Innventia.
    Norman, Bo
    RISE, Innventia.
    2d fibre and filler grammage maps using movable radiation emitters and detectors2011Conference paper (Refereed)
  • 319.
    Lucisano, Marco
    et al.
    RISE, Innventia.
    Söderberg, Daniel
    KTH Royal Institute of Technology, Sweden.
    Vomhoff, Hannes
    RISE, Innventia.
    Hermansson, Lennart
    RISE, Innventia.
    Rosén, Fredrik
    RISE, Innventia.
    Östlund, Ida
    RISE, Innventia.
    Björk, Elisabeth
    RISE, Innventia.
    Athley, Karin
    RISE, Innventia.
    Norman, Bo
    RISE, Innventia.
    Stratified forming as a tool for resource efficient papermaking2015In: Paper Conference and Trade Show (PaperCon 2015), TAPPI Press, 2015, Vol. 1, p. 767-785Conference paper (Refereed)
    Abstract [en]

    Pilot-scale demonstration of stratified forming with innovative design of vane technology. Stratified dosage of fillers tested for: •SC-paper •Fine paper Dosage of filler and retention aid through the liquid layers gives a wider window of operation (retention-formation). Filler content can be increased with no adverse effects on strength and structure.

  • 320. Lundberg, A.
    et al.
    Ortegren, J.
    Alfthan, E.
    Ström, G.
    RISE, Innventia.
    Microscale droplet absorption into paper for inkjet printing2011In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, no 1, p. 142-150Article in journal (Refereed)
  • 321. Lundell, F.
    et al.
    Söderberg, L.D.
    RISE, Innventia.
    Alfredsson, P.H.
    Fluid mechanics of papermaking2011In: Annual Review of Fluid Mechanics, ISSN 0066-4189, E-ISSN 1545-4479, p. 195-217Article in journal (Refereed)
  • 322.
    Lundqvist, Jon
    et al.
    Lund university, Sweden.
    Jacobs, Anna
    STFI.
    Palm, Magnus
    Lund university, Sweden.
    Zacchi, Guido
    Lund university, Sweden.
    Dahlman, Olof
    STFI.
    Stålbrand, Henrik
    Lund university, Sweden.
    Characterization of galactoglucomannan extracted from spruce (Picea abies) by heat-fractionation at different conditions2003In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 51, no 2, p. 203-211Article in journal (Refereed)
  • 323.
    Lundqvist, Sven-Olof
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Grahn, Thomas
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Olsson, Lars
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Seifert, Thomas
    Stellenbosch University, South Africa.
    Comparison of wood, fibre and vessel properties of drought-tolerant eucalypts in South Africa2017In: Southern Forests, a journal of forest science, ISSN 2070-2620, E-ISSN 2070-2639, Vol. 79, no 3, p. 215-223Article in journal (Refereed)
    Abstract [en]

    Three drought-tolerant eucalypt genotypes have been investigated for a broad spectrum of properties to provide a basis for comparison on their suitability for various end-uses. The genotypes included were a Eucalyptus grandis × E. camaldulensis hybrid, E. gomphocephala and E. cladocalyx, selected based on previous studies that indicated good potential to tolerate arid conditions, reasonably good volume growth and straightness of stems. In this study, information was added on differences between species and parts of stems in growth (volume and biomass) and properties of wood (density and stiffness), fibres (dimensions and microfibril angle) and vessels (size and numbers). We found high wood densities and stiffness values for E. cladocalyx and E. gomphcephala, making them suitable for construction wood. Logs from the mid-part of the stem had the best timber properties, as the butt logs showed the highest microfibril angle and lowest wood stiffness due to longitudinal juvenility. Such juvenility was also to some degree observed for wood density and fibre length. The information gained will be especially helpful for selecting species and processing options for small farm and community plantations for producing higher-value products that may be sold to generate much-needed income as well as for local uses, such as fuelwood and charcoal. © 2017 The Authors

  • 324.
    Magnusson, Mikael
    RISE, Innventia.
    Investigation of interfibre joint failure and how to tailor their properties for paper strength2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 1, p. 109-122Article in journal (Refereed)
    Abstract [en]

    The key property for the load carrying capacity of paper materials is the interfibre joint strength. Due to the difficulty of testing the strength of such microscopic entities, the typical approach is to test isolated fibre-fibre crosses. In such experiments the joint is but one component of the tested structure and the flexural compliance of the long fibre segments results in a mixed mode of loading. Furthermore, the details of the failure mechanisms of such joints are as of yet unknown. A continuum description of the paper sheet is often insufficient to explain governing mechanisms when properties of the underlying structure are changed by mechanical or chemical modifications. Therefore network models are often used to take into account the underlying mechanisms. However, network models in turn rely on the properties of the fibres and of the interfibre joints. This paper aims to characterize the damage behaviour of isolated fibre-fibre crosses from three approaches: identifying typical damage features from an extensive number of mechanical tests of isolated fibre-fibre crosses; study the applicability of using cohesive zones to model the failure behaviour of inter-fibre joints; and, to study the influence of fibre and joint properties to the load carrying capacity of fibre-fibre crosses. The results indicate that the strength in the normal direction is significantly lower than in the shear direction and means on how to tailor the properties of fibres and joints for increasing the load carrying capacity is suggested.

  • 325.
    Magnusson, Mikael
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Holmqvist, Claes
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Textile-like materials with foam forming on a paper machine2019In: PaperCon 2019: Proceedings, TAPPI Press, 2019, article id PF3.2Conference paper (Other academic)
    Abstract [en]

    Research has been carried out into the possibility of producing a paper with textile-like characteristics on a paper machine. The furnish used consisted of a mixture of 25% bleached softwood kraft pulp refined to 30 SR, 25% dissolving pulp and 50% synthetic fibres. The latter fraction consisted of 15% sort-cut (4mm) polylactic acid (PLA) fibres and 35% viscose fibres cut to 5-8mm. A commercial surfactant was used as foaming aid and sheets were formed on a pilot machine from a bubbly dispersion (foam forming). A production method was developed in which the synthetic fibres were only injected intermittently into the pulp flow. Sheets containing 35% of 8mm long viscose fibres, 25% kraft pulp, 25% dissolving pulp and 15% of 4mm long PLA fibres were successfully produced. Sheets had good formation with furnish air fractions as low as 25%. The sheets made from the mixture of kraft pulp and synthetic fibres had softness comparable with facial wipes and other tissue products while also having significantly higher tensile strength. Proactive adjustment of the surfactant addition enabled the surface tension and the forming process to be stably maintained during the sudden changes in the fibre feed flows.

  • 326. Malmberg, F.
    et al.
    Östlund, Catherine
    RISE, STFI-Packforsk.
    Borgefors, G.
    Binarization of phase contrast volume images of fibrous materials2009In: Proceedings of the 4th International Conference on Computer Vision Theory and Applications, 2009, Vol. 2, p. 148-153Conference paper (Refereed)
    Abstract [en]

    In this paper, we present a method for segmenting phase contrast volume images of fibrous materials into fibre and background. The method is based on graph cut segmentation, and s tested on high resolution X-ray microtomography volume images of wood fibres in paper an composites. The new method produces better results than a standard method based on edge-preserving smoothing and hysteresis thresholding. The most important improvement is that the proposed method handles thick and collapsed fibres more accurately than previous methods.

  • 327.
    Mandalika, A.
    et al.
    University of Wisconsin-Madison, US; Louisiana State University Agricultural Center, US.
    Bragg, D.
    USDA Forest Service, US.
    Schuler, J.
    West Virginia University, US.
    Baker, Darren
    RISE - Research Institutes of Sweden, Bioeconomy.
    Elder, T.
    USDA Forest Service, US.
    Groom, L.
    USDA Forest Service, US.
    Potential of natural-origin loblolly pine tree fractions as a bioenergy feedstock2019In: Wood and Fiber Science, ISSN 0735-6161, Vol. 51, no 1, p. 26-40Article in journal (Refereed)
    Abstract [en]

    Chemical characterization was performed on 10 different samples of loblolly pine (Pinus taeda L.), representing the various woody components of trees (bole, slab, tops and branches, and precommercial stem-only) harvested from two naturally regenerated forests in southern Arkansas. Ultimate analysis, proximate analysis using thermogravimetry, and the energy content of the samples were determined to help evaluate their bioenergy utility. Elemental analysis revealed no significant differences between the pine tree fractions, whereas differences were observed in the proximate analysis, particularly in regard to the fixed carbon content. Generally, proximate analyses did not show significant differences between the slabwood and bolewood samples, although the “tops and branches” and “whole stem” samples contained the lowest volatile matter amounts and the greatest amounts of fixed carbon and ash content. In terms of the calorific value, the “tops and limbs” sample reported the lowest energy content, whereas the “whole stem” sample was among the highest reported value with statistical significance. These results indicate that whole stem samples may be an attractive prospect for bioenergy applications such as gasification, pelletization, and combustion, owing to favorable heating content values and relatively low ash content. Although a number of logistical challenges exist in their acquisition and processing, slabs, topwood, and branches offer opportunities for bioenergy applications that can increase the utilization of forest residues without threatening more traditional uses of wood in lumber, panels, and paper. Finally, we then briefly consider the silvicultural implications of these results for naturally regenerated southern pine €“dominated forests.

  • 328.
    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 additives2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 2, p. 308-314Article in journal (Refereed)
    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.

  • 329.
    Marin, Gustav
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Nygårds, Mikael
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Box compression strength of packages in different climates2019In: 29th IAPRI Symposium on packaging, 2019: Serving society innovative perspectives on packaging, 2019Conference paper (Other academic)
    Abstract [en]

    Packages made of five folding box boards made on the same paperboard machinehave been analysed. The paperboards were from the same product series but had different grammage (235, 255, 270, 315, 340 g/m2) and different bending stiffness. Thepaperboards are normally used to make packages, and since the bending stiffnessand grammage varies the packages performance will be different. In this study, twodifferent load cases were defined and Box Compression Tests (BCT) were performedat different levels of relative humidity (30, 50, 70, 90 % RH) and were evaluated as afunction of moisture ratio.The result showed a linear relation between the box compression strength and themoisture ratio. In addition, when the data was normalized with the measurements forthe standard climate (50 % RH) and was evaluated as a function of moisture ratio, theresult indicated that the normalized box compression strength for all the paperboardsand both of the load cases could be expressed as a linear function of moisture, dependent of two constants a and b.Consequently, the study indicates that it is possible to estimate the Box compressionstrength at different climates of a package made of paperboard, by knowing the boxcompression strength for the standard climate (50 % RH and 23 °C) and the constantsa and b.

  • 330.
    Marin, Gustav
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Nygårds, Mikael
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Östlund, Sören
    KTH, Sweden.
    Stiffness and strength properties of five paperboards and their moisture dependency2019In: International Paper Physics Conference 2019, Indianapolis, IN, USA, 5-8 May 2019: preprint proceedings, TAPPI Press, 2019, p. 14-29Conference paper (Other academic)
    Abstract [en]

    Research has been undertaken to characterise the in-plane and out-of-plane stiffness and strength properties of paperboards to enable data for use in determining constitutive parameters needed in finite element simulations. Paperboards with different bending stiffness were analysed, using five folding box boards of varying grammage (235, 255, 270, 315 and 340gsm). The stiffness and strength properties were determined at different relative humidity (RH), namely, 20, 50, 70 and 90%. As well as in-plane tensile test and out-of-plane tensile test, the short-span compression test (SCT) was carried out, together with bending stiffness test and double-notch shear test. The results revealed a linear relation between mechanical properties and moisture ratio for each paperboard. When the data were normalised with data for the standard climate (50% RH) and investigated as a function of moisture ratio, it was determined that the normalised mechanical properties for all paperboards coincided along one single line. Thus they could be expressed as a linear function of moisture ratio and two constants. It has been concluded that by knowing the structural properties for the preferred level of RH and the mechanical property for the standard climate, the mechanical properties of a paperboard could be obtained.

  • 331.
    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, Bioeconomy.
    Water sorption in microfibrillated cellulose (MFC): The effect of temperature and pretreatment2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, p. 1201-1212Article in journal (Refereed)
    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.

  • 332.
    Mihiretu, Gezahegn T.
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, PFI. Stellenbosch University, South Africa.
    Brodin, Malin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Chimphango, Annie F.
    Stellenbosch University, South Africa.
    ֘yaas, Karin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Hoff, Bård H
    NTNU Norwegian University of Science and Technology, Norway.
    Görgens, Johann F.
    Stellenbosch University, South Africa.
    Single-step microwave-assisted hot water extraction of hemicelluloses from selected lignocellulosic materials: A biorefinery approach2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 241, p. 669-680Article in journal (Refereed)
    Abstract [en]

    The viability of single-step microwave-induced pressurized hot water conditions for co-production of xylan-based biopolymers and bioethanol from aspenwood sawdust and sugarcane trash was investigated. Extraction of hemicelluloses was conducted using microwave-assisted pressurized hot water system. The effects of temperature and time on extraction yield and enzymatic digestibility of resulting solids were determined. Temperatures between 170–200 °C for aspenwood and 165–195 °C for sugarcane trash; retention times between 8–22 min for both feedstocks, were selected for optimization purpose. Maximum xylan extraction yields of 66 and 50%, and highest cellulose digestibilities of 78 and 74%, were attained for aspenwood and sugarcane trash respectively. Monomeric xylose yields for both feedstocks were below 7%, showing that the xylan extracts were predominantly in non-monomeric form. Thus, single-step microwave-assisted hot water method is viable biorefinery approach to extract xylan from lignocelluloses while rendering the solid residues sufficiently digestible for ethanol production.

  • 333. Mihranyan, A.
    et al.
    Esmaeili, M.
    Razaq, A.
    Alexeichik, D.
    Lindström, T.
    RISE, Innventia.
    Influence of the nanocellulose raw material characteristics on the electrochemical and mechanical properties of conductive paper electrodes2012In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, no 10, p. 4463-4472Article in journal (Refereed)
  • 334.
    Mikczinski, M. R
    et al.
    OFFIS – Institute for Information Technology, Germany.
    Josefsson, G
    Uppsala University, Sweden.
    Chinga-Carrasco, Gary
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Gamstedt, K
    Uppsala University, Sweden.
    Fatikow, S
    OFFIS – Institute for Information Technology, Germany.
    Nanorobotic Testing to Assess the Stiffness Properties of Nanopaper2014In: IEEE Transactions on robotics, ISSN 1552-3098, E-ISSN 1941-0468, Vol. 30, no 1, p. 115-119Article in journal (Refereed)
    Abstract [en]

    This paper deals with the nanorobotic and nondestructive assessment of the stiffness properties of nanopaper made of microfibrillated cellulose. Back-calculations of the Young's modulus show the agreement of the newly found results with conventional tensile testing results, therewith proving nanorobotics as a reasonable complement for conventional testing.

  • 335.
    Moghaddam, Maziar Sedighi
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik. KTH Royal Institute of Technology, Sweden.
    Heydari, Golrokh
    KTH Royal Institute of Technology, Sweden.
    Tuominen, Mikko
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik.
    Fielden, Matthew
    KTH Royal Institute of Technology, Sweden.
    Haapanen, Janne
    TUT Tampere University of Technology, Finland.
    Mäkelä, Jyrki M.
    TUT Tampere University of Technology, Finland.
    Wålinder, Magnus E. P.
    KTH Royal Institute of Technology, Sweden.
    Claesson, Per M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik. KTH Royal Institute of Technology, Sweden.
    Swerin, Agne
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik. KTH Royal Institute of Technology, Sweden.
    Hydrophobisation of wood surfaces by combining liquid flame spray (LFS) and plasma treatment: Dynamic wetting properties2016In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 70, no 6, p. 527-537Article in journal (Refereed)
    Abstract [en]

    The hydrophilic nature of wood surfaces is a major cause for water uptake and subsequent biological degradation and dimensional changes. In the present paper, a thin transparent superhydrophobic layer on pine veneer surfaces has been created for controlling surface wettability and water repellency. This effect was achieved by means of the liquid flame spray (LFS) technique, in the course of which the nanoparticulate titanium dioxide (TiO2) was brought to the surface, followed by plasma polymerisation. Plasma polymerised perfluorohexane (PFH) or hexamethyldisiloxane (HMDSO) were then deposited onto the LFS-treated wood surfaces. The same treatment systems were applied to silicon wafers so as to have well-defined reference surfaces. The dynamic wettability was studied by the multicycle Wilhelmy plate (mWP) method, resulting in advancing and receding contact angles as well as sorption behavior of the samples during repeated wetting cycles in water. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were employed to characterise the topography and surface chemical compositions and to elucidate the question how the morphology of the nanoparticles and plasma affect the wetting behavior. A multi-scale roughness (micro-nano roughness) was found and this enhanced the forced wetting durability via a superhydrophobic effect on the surface, which was stable even after repeated wetting cycles. The hydrophobic effect of this approach was higher compared to that of plasma modified surfaces with their micro-scale modification.

  • 336. Mäkelä, P.
    et al.
    Fellers, C.
    RISE, Innventia.
    An analytic procedure for determination of fracture toughness of paper materials2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, no 2, p. 352-360Article in journal (Refereed)
  • 337.
    Mäkelä, Petri
    et al.
    RISE, Innventia.
    Nordhagen, H.
    Gregersen, Ø.˜W.
    Validation of isotropic deformation theory of plasticity for fracture mechanics analysis of paper materials2009In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 24, no 4, p. 388-394Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to validate that isotropic deformation theory of plasticity is a suitable material modelling level for fracture mechanics analysis of paper materials, as has been indicated in previous studies. Six different commercial paper grades were investigated. Laboratory material testing was performed for each paper grade using standardised tensile and fracture toughness test methods. The material data was used to calibrate a fracture mechanics model based on isotropic deformation theory of plasticity with a fracture criterion based on the/-integral. The fracture mechanics model was used to predict failures of notched paper webs and corresponding experiments were performed. The experiments and predictions of failures were performed for several different notch lengths for all six studied paper materials. The experimentally determined force and elongation at break of the notched paper webs were predicted excellently by the fracture mechanics model, which shows that isotropic deformation theory of plasticity is a suitable material modelling level for fracture mechanics analysis of paper materials.

  • 338.
    Mörseburg, Kathrin
    et al.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Hill, J
    QualTech AB, Sweden.
    Nyseth, T-E
    BIM Kemi AB, Sweden.
    Johansson, Lars
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Understanding energy efficiency of different refining concepts from fibre and fines quality2014Conference paper (Refereed)
    Abstract [en]

    Comparative pilot refining trials with Norway spruce chips were conducted in order to gain a better understanding of the principal mechanisms on fibre level for achieving radical energy reduction in the novel ATMP refining concept. The ATMP pulping configurations proved superior energy efficiency in pulp quality development, compared to TMP, RTS and F-RTS concepts. Development of high tensile strength did not progress at the expense of light scattering, even with process chemicals present. Extensive testing of individual particles in long fibre, middle and fines fractions in combination with analyses of properties of fraction sheets has shown that Impressafiner/Fiberizer pre-treatment opens the wood structure, allowing for early development of desired single fibre properties and generation of fibrillar fines. Peroxide combined with magnesium hydroxide affected the interior of the fibre walls, thereby facilitating improved fibre flexibility, collapsibility and swelling. Bisulphite mainly affected the fibre length distribution, reducing the coarse fraction R14 and promoting the generation of considerable amounts of coarse fines and middle fraction particles.

  • 339.
    Mörseburg, Kathrin
    et al.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Hill, Jan
    QualTech AB, Sweden.
    Johansson, Lars
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    ATMP refining of Norway spruce - Defibration characteristics and fibre wall properties2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 386-400Article in journal (Refereed)
    Abstract [en]

    Defibration and fibre development patterns were investigated for the novel ATMP refining process, based on pilot scale trials with Norway spruce chips. ATMP refining with different chemical agents was compared to RTS refining with and without Impressa-finer (RT) and Fiberizer (F) pre-treatment. RT-F pre-treatment significantly improved both initial defibration, axial fibre splitting and fibre flexibility, compared to RTS primary stage refining without pre-treatment. Both types of investigated ATMP process chemistry - hydrogen peroxide combined with magnesium hydroxide under alkaline conditions (P) or acid sodium bisulphite (S) added to the primary refiner dilution water - further improved the fibre separation of RT-F pre-treated wood during primary stage RTS refining. This is largely attributed to enhanced fibre swelling. S-treatment facilitated frequent fibre separation within or close to the S2 wall layer, yielding extremely low shive levels and well-fibrillated, thin-walled fibres early in the process. S-treatment also rendered stiffer fibres, which made them susceptible to breakage, axial splitting and internal delamination. P-application is proposed to affect primarily the interior layers of the fibre walls, facilitating rapid fibre wall swelling towards the lumen, fibre softening and flexibilization.

  • 340.
    Mörseburg, Kathrin
    et al.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Imppola, A.
    Johansson, Lars
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Ertsås, P.A.
    Effects of Inlet Pulp Quality and Specific Energy Consumption in Mill-Scale low consistency refining of Mechanical Pulp2013Conference paper (Refereed)
  • 341.
    Naderi, A.
    et al.
    RISE, Innventia.
    Lindström, T.
    RISE, Innventia.
    Sundström, J.
    RISE, Innventia.
    Carboxymethylated nanofibrillated cellulose: Rheological studies2014In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, no 3, p. 1561-1571Article in journal (Refereed)
  • 342.
    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 process2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 372-378Article in journal (Refereed)
    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.

  • 343.
    Naderi, Ali
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia.
    Stevanic Srndovic, Jasna
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia.
    Erlandsson, Johan
    KTH Royal Institute of Technology, Sweden.
    Effect of the size of the charged group on the properties of alkoxylated NFCs2017In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 3, p. 1307-1317Article in journal (Refereed)
    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. 

  • 344.
    Naderi, Ali
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    A comparative study of the rheological properties of three different nanofibrillated cellulose systems2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 354-363Article in journal (Refereed)
    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.

  • 345.
    Naderi, Ali
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Carboxymethylated nanofibrillated cellulose: Effect of monovalent electrolytes on the rheological properties2014In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, p. 3507-14Article in journal (Refereed)
    Abstract [en]

    The effect of the ionic strength on the properties of a carboxymethylated nanofibrillated cellulose (NFC) system was investigated through rheological studies. It was shown that homogenization of pulp suspensions containing a high amount of a monovalent electrolyte leads to the production of NFC systems displaying a lower magnitude in the rheological response as compared with systems prepared at lower ionic strengths conditions. It was further shown that increasing the ionic strength of NFC suspensions after their manufacturing also results in a lowering of the rheological response. The decreased rheological response in the former case was postulated to be caused by a lowering of the delamination deficiency of the homogenization process, due to decreased swelling of the carboxymethylated pulp, caused by the screening of the charges. In the latter case (post-addition of the electrolyte), the lowering of the rheological response was postulated to be due to the compression of the electrostatic double layer, when the electrostatic repulsion between the charged fibrils diminished in the presence of the electrolyte.

  • 346.
    Naderi, Ali
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Erratum to: Nanofibrillated cellulose: properties reinvestigated2017In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 12, p. 5713-5713Article in journal (Refereed)
    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.

  • 347.
    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 step2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 364-371Article in journal (Refereed)
    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.

  • 348.
    Naderi, Ali
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Sundström, Jonas
    RISE, Innventia.
    Flodberg, Göran
    RISE, Innventia.
    Can redispersible low-charged nanofibrillated cellulose be produced by the addition of carboxymethyl cellulose?2015In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, no 4, p. 568-577Article in journal (Refereed)
    Abstract [en]

    Carboxymethyl cellulose (CMC) was added in various amounts (< 10% (w/w)) to a lowcharged (enzymatically pre-treated) NFC, and the suspensions were blended by either a low-shear propeller mixing- or high shear homogenization protocol. The suspensions were thereafter oven-dried, and redispersed using a high shear protocol. It was found that the mixing method has a profound effect on the apparent rheology of the never-dried systems. The addition of highly charged CMC-grades enabled, already at 1% (w/w) addition, the apparent dispersion of dried NFC. The rheological responses (viscosity and storage modulus) of the neverdried NFC-CMC systems were judged as conserved, when the rheological responses of the redispersed systems were compared with those of never-dried systems that had been produced by propeller mixing. The rheological responses of the redispersed systems were on the other hand found to be lower when compared to the rheological responses of the never-dried systems that had been produced by high shearing mixing. However, the mechanical- and barrier properties of the redispersed systems were found to be inferior to the never-dried equivalents - regardless of the mixing protocol.

  • 349.
    Naderi, Ali
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Sundström, Jonas
    RISE, Innventia.
    Pettersson, Torbjörn
    KTH Royal Institute of Technology, Sweden.
    Flodberg, Göran
    RISE, Innventia.
    Erlandsson, Johan
    KTH Royal Institute of Technology, Sweden.
    Microfluidized carboxymethyl cellulose modified pulp: a nanofibrillated cellulose system with some attractive properties2015In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, no 2, p. 1159-1173Article in journal (Refereed)
    Abstract [en]

    A method (Ankerfors and Lindström in Method for providing nanocellulose comprising modified cellulose fibers, 2009) was employed to physically attach anionic carboxymethyl cellulose (CMC) chains onto wood pulp, upon which it was fibrillated by a microfluidizer-type homogenizer at high applied pressures and at dilute conditions [<3 % (w/w)]. It was found that the CMC-modified pulp can be fibrillated at the same consistencies as many of the commercially available NFC products. The NFC manufacturing process was also deemed to be energy efficient, as it lacked the need for mechanical pre-treatment, which is often a prerequisite for the production of many existing NFC systems. The CMC-based NFC was studied with respect to the rheological characteristics, and was also characterized using AFM-imaging. Further, The NFC was made into films, and its tensile strength was determined together with its barrier properties. In general, the rheological characteristics (viscosity and storage modulus) together with the tensile strength and oxygen barrier properties of the films were improved with increasing the number of passes through the microfluidizer. The fibrillated CMC-modified pulp was found to be as efficient as other NFC systems when employed as dry strength additive. The employment of the investigated material, which can be produced at acceptable costs and through environmentally benign and industrially relevant processes can, hence, potentially lead to significant future savings in the energy consumption levels in the paper and cardboard manufacturing processes, which have been recognized as major application areas of NFC products.

  • 350.
    Naderi, Ali
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Weise, Christoph F.
    NMRArc, Sweden.
    Flodberg, Göran
    RISE, Innventia.
    Sundström, Jonas
    RISE, Innventia.
    Junel, Kristina
    RISE, Innventia.
    Erlandsson, Johan
    KTH Royal Institute of Technology, Sweden.
    Runebjörk, Ann-Marie
    RISE, Innventia.
    Phosphorylated nanofibrillated cellulose: Production and properties2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 1, p. 20-29Article in journal (Refereed)
    Abstract [en]

    Phosphate functionalized nanofibrillated cellulose (NFC) was produced through an industrially attractive process, by reacting wood pulp with a phosphate containing salt, followed by mechanical delamination through microfluidization. The degrees of delamination of the phosphorylated NFCs (judged by among others AFM-imaging, rheological studies and tensile strength measurements on NFC films) were found to improve with increasing functionalization of the pulp and number of microfluidization-passes. The NFC systems were found to display similar characteristics as other well-known NFC systems. Interestingly, however, the sufficiently delaminated phosphorylated NFCs exhibited significantly lower oxygen permeability values (at RH 50%) than the published values of several well-known highly delaminated NFC systems. The potential application of the phosphorylated NFC in packaging applications can hence be envisaged.

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