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  • 401.
    Ratto, P.
    et al.
    RISE, Innventia.
    Hornatowska, J.
    RISE, Innventia.
    Changhong, X.
    Terasaki, O.
    Cracking mechanisms of clay-based and GCC-based coatings2011In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, no 4, p. 485-492Article in journal (Refereed)
  • 402.
    Rees, A
    et al.
    Swansea University WCPC.
    Powell, L.C
    Centre for NanoHealth, College of Engineering, Swansea University, Swansea, UK.; Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, UK..
    Chinga-Carrasco, Gary
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Gethin, D.T
    Swansea University WCPC.
    Claypole, T.C
    Swansea University WCPC.
    Deganello, D
    Swansea University WCPC.
    Syverud, Kristin
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Studies on the 3D Printing of Nanocellulose Structures2014Conference paper (Refereed)
    Abstract [en]

    Nanocellulose has a variety of advantages, which make the material most suitable for use in biomedical devices such as wound dressings. The material is strong, can be used for producing transparent films, can keep a moist environment and form elastic gels with bio-responsive characteristics. In this study we explore the application of nanocellulose as a bioink for use in a bioprinting process. Two different nanocelluloses were used, prepared with TEMPO mediated oxidation and a combination of carboxymethylation and periodate oxidation. The combination of carboxymethylation and periodate oxidation produced a homogeneous material with short nanofibrils. The small dimensions of the nanofibrils reduced the viscosity of the nanocellulose thus yielding a material with good rheological properties for use as a bioink. We also demonstrated that both nanocelluloses inhibited bacterial growth, which is an interesting property of these novel materials.

  • 403. Rezayati Charani, P.
    et al.
    Dehghani-Firouzabadi, M.
    Afra, E.
    Blademo, Åsa
    RISE, Innventia.
    Naderi, Ali
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Production of microfibrillated cellulose from unbleached kraft pulp of Kenaf and Scotch Pine and its effect on the properties of hardwood kraft:: Microfibrillated cellulose paper2013In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, no 5, p. 2559-2567Article in journal (Refereed)
  • 404. Rodionova, G.
    et al.
    Saito, T.
    Lenes, M.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Eriksen, Ø.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Gregersen, Ø.
    Mechanical and oxygen barrier properties of films prepared from fibrillated dispersions of TEMPO-oxidized Norway spruce and Eucalyptus pulps2012In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 19Article in journal (Refereed)
  • 405. Rodionova, G.
    et al.
    Saito, T.
    Lenes, M.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Eriksen, Ø.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Gregersen, Ø.
    TEMPO-mediated oxidation of Norway Spruce and Eucalyptus Pulps:: Preparation and Characterization of Nanofibres and Nanofiber Dispersions2012In: Journal of polymers and the environment, ISSN 1566-2543, E-ISSN 1572-8919, Vol. 21Article in journal (Refereed)
  • 406.
    Rosén, Fredrik
    RISE, Innventia.
    Packaging 2020: Innventia global outlook2013Conference paper (Refereed)
  • 407.
    Rosén, Fredrik
    et al.
    RISE, STFI-Packforsk.
    Söderberg, Daniel
    RISE, STFI-Packforsk.
    Lucisano, Marco F. C.
    RISE, STFI-Packforsk.
    Östlund, Catherine
    RISE, STFI-Packforsk.
    Estimation of fibre segment orientation using steerable filtering2008In: Paper Conference and Trade Show: PaperCon '08, TAPPI Press, 2008, Vol. 2, p. 1097-1144Conference paper (Refereed)
    Abstract [en]

    This work investigates the combined approach of sheet splitting by heat-seal pouch lamination and fibre segment orientation analysis by steerable filtering to characterize both in-plane and z-directional variations in local fibre orientation. The use of steerable filters allows the orientation of individual fibre segments to be estimated from a series of rotated versions of a two-dimensional fibre template. The performance of steerable filtering is compared to the widely spread method based on local gradients in the image. The results are based on a 60 g/m2 oriented handsheet formed with a dynamic sheet former from decrilled softwood kraft pulp. The sheet was split in 10 z-directional layers and the fibre orientation was estimated on a 10ח10 mm2 sub-area. Despite an observed visual difference in the 2D filter response between the two techniques, the result showed only small differences in the estimated fibre orientation angle and anisotropy. The effect of a decreased signal-to-noise ratio, due to e.g. fines and filler aggregates, was simulated by adding a statistical small-scale noise. The fibre orientation distribution estimated by steerable filtering was more or less unaffected by the introduced noise, whereas the estimation based on gradient filtering showed a decreased anisotropy by 35%. The results indicate that, for routine measurements of local fibre orientation, the more selective properties of steerable filtering do not motivate the more complex computations involved. For most cases, gradient filtering should give similar results. The use of steerable filtering is however recommended as an alternative for non-standard applications, e.g. in the presence of a high "noise" level or to minimize problems related to scanning imperfections. The theoretical possibility to use steerable filtering to determine fibre width distributions is also discussed.

  • 408. Rusu, M.
    et al.
    Mörseburg, Kathrin
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Gregersen, Øjvind
    Yamakawa, A.
    Liukkonen, S.
    Relation between fibre flexibility and cross-sectional properties2011In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, p. 641-655Article in journal (Refereed)
  • 409.
    Rättö, P.
    et al.
    RISE, Innventia.
    Hornatowska, J.
    RISE, Innventia.
    Barbier, C.
    Influence of the distribution of the shape and size distribution of pigment particles on cracking in coating layers during creasing2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, no 4, p. 714-720Article in journal (Refereed)
  • 410.
    Rättö, Peter
    et al.
    RISE, Innventia.
    Blohm, Erik
    RISE, Innventia.
    Chinga-Carrasco, Gary
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Film splitting during offset printing - the influence of paper surface properties on film splitting geometry2011Conference paper (Refereed)
  • 411.
    Rättö, Peter
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Dahlman, Olof
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Junel, Kristina
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Pilot coating with a hemicellulose-based barrier2018In: PaperCon 2018: Shaping the future through innovation, TAPPI , 2018, article id FF1.3Conference paper (Refereed)
    Abstract [en]

    A hemicellulose-based barrier formulation was produced from wood chips to pilot coating application in a bladecoater. The development process is described from a project planning point of view with network plan and decisionpoints.Different hemicelluloses were produced and compared in the research laboratory. Oxygen barrier properties fromfilms and rheology of water suspensions were evaluated for different laboratory produced hemicelluloses originatingfrom wood chips or from kraft pulps. The viscosity at low and high shear rates were evaluated. From these results,hemicellulose produced from birch wood chips was chosen.Hemicellulose was then produced at in kg quantities. The hemicellulose was produced employing pre-hydrolysistreatment of birch wood chips. The concentration of hemicellulose pre-hydrolyses was increased from 3.3% to11.5% by membrane filtration. The barrier properties of the hemicellulose coated material were evaluated inlaboratory scale. A pre-coating was also evaluated in laboratory scale.Trials were performed at Iggesund PaperBoard in their pilot scale coater. A pre-coating was applied during the firstday, and the hemicellulose-based coating was applied on the second day. The pilot trials went well without anylarger obstacles. Quick barrier evaluations showed that the hemicellulose-based barrier coating had a good greaseresistance even if the coating consumption during the trials indicated a low application grammage.

  • 412.
    Rättö, Peter
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy.
    Thorman, Sofia
    RISE - Research Institutes of Sweden, Bioeconomy.
    Rådsten Ekman, Maria
    RISE - Research Institutes of Sweden, Bioeconomy.
    Löfgren, Cathrine
    RISE - Research Institutes of Sweden, Bioeconomy.
    Impact of base substrate on perceived and measured surface properties2017In: 28th PTS Coating symposium, September 5-6, 2017, Munich, Germany, 2017, p. 138-154Conference paper (Other academic)
  • 413.
    Rönnols, Jerk
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy.
    Aldaeus, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy.
    Jacobs, Anna
    RISE - Research Institutes of Sweden, Bioeconomy.
    Freichels, Helene
    Magritek, Germany.
    Danieli, Ernesto
    Magritek, Germany.
    Benchtop NMR measurements on kraft lignin2017In: 19th International symposium on wood, fibre and pulping chemistry, August 28 - September 1, 2017, Porto Seguro, Brazil, 2017, p. 434-438Conference paper (Refereed)
    Abstract [en]

    The use of NMR spectroscopy at high magnetic fields is a common tool in the analysis of lignin samples. In the presented study, NMR measurements on a group of softwood and hardwood kraft lignins at low field (1.0 T) with a benchtop NMR spectrometer, containing a permanent magnet, are investigated and evaluated. NMR based diffusion measurements were performed, for which the results were found to be fast, repeatable, and in good agreement numbers to measurements at high field. Measurements were also performed on a sample in alkaline solution, as a model for black liquor analysis, with promising initial results.

  • 414.
    Rönnols, Jerk
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy.
    Jacobs, Anna
    RISE - Research Institutes of Sweden, Bioeconomy.
    Aldaeus, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy.
    Consecutive determination of softwood kraft lignin structure and molar mass from NMR measurements2017In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 71, no 7-8, p. 563-570Article in journal (Refereed)
    Abstract [en]

    The general molecular properties and in particular, the molar mass of lignin are of central importance for industrial applications, as these data govern important thermal and mechanical characteristics. The focus of the present paper is pulsed field gradient-nuclear magnetic resonance (PFG-NMR), which is suitable for determination of lignins’ weight-Average molar mass, based on diffusion constants. The method is calibrated by lignin fractions characterized by matrix-Assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). It could be demonstrated on a set of softwood kraft lignins that the PFG-NMR approach gives results in very good agreement with those obtained using conventional size exclusion chromatography (SEC).

  • 415.
    Rönnols, Jerk
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Jacobs, Anna
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Aldaeus, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Recent advances in NMR spectroscopy of lignin and black liquor2018In: 15th European workshop on lignocellulosics and pulp: proceedings for oral presentations, 2018, p. 57-60Conference paper (Other academic)
    Abstract [en]

    This paper describes improvements in the methodology for NMR spectroscopic analysis of dissolved kraft lignins and black liquors, for structural analysis as well as for reaction monitoring. The described methodologies are variations and applications of non-uniform sampling (NUS) in 2D spectra and diffusion ordered spectroscopy (DOSY), with reduced experiment time and/or increased resolution and novel ways to track reactions through monitoring of diffusion of a reactant mixture.

  • 416.
    Rönnols, Jerk
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Jacobs, Anna
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Aldaeus, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Larsson, Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Digging in the structure and functionality of lignocellulosic raw material: from academic knowledge towards industrial applications2018In: The 8th Nordic Wood Biorefinery Conference: NWBC 2018 : proceedings / [ed] Hytönen Eemeli, Vepsäläinen Jessica, Espoo: VTT , 2018, p. 205-205Conference paper (Other academic)
  • 417.
    Rönnols, Jerk
    et al.
    RISE, Innventia.
    Larsson, Karolina
    RISE, Innventia.
    Jacobs, Anna
    RISE, Innventia.
    Aldaeus, Fredrik
    RISE, Innventia.
    Absolute determination of softwood kraft lignin molar mass using MALDI-TOF mass spectrometry and pulsed field gradient NMR2016In: 14th European Workshop on Lignocellulosics and Pulp: EWLP 2016, 2016, p. 143-146Conference paper (Other academic)
    Abstract [en]

    Knowledge of the molecular properties, e.g. the molar mass, of lignin are of central importance for industrial applications, since thermal and mechanical characteristics are governed by these. Here, a method for absolute determination of weight-average molar mass of kraft lignin, based on diffusion constants gained from PFG-NMR calibrated with lignin fractions characterized by MALDI-TOF-MS, is presented. The NMR method is compared to polystyrene calibration, and size exclusion chromatography with tetrahydrofuran as mobile phase.

  • 418.
    Rönnols, Jerk
    et al.
    RISE, Innventia.
    Schweinebarth, Hannah
    RISE, Innventia.
    Jacobs, Anna
    RISE, Innventia.
    Stevanic Srndovic, Jasna
    RISE, Innventia.
    Olsson, Anne-Mari
    RISE, Innventia.
    Reimann, Anders
    RISE, Innventia.
    Aldaeus, Fredrik
    RISE, Innventia.
    Structural changes in softwood kraft lignin during nonoxidative thermal treatment2015In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, no 4, p. 550-561Article in journal (Refereed)
    Abstract [en]

    Heat treatment is a promising pre-processing method in the conversion of kraft lignins to carbon fibers. In this study, a kraft lignin was subjected to heat treatment at different lengths of time and at different temperatures. The molecular structure of the untreated and four heat treated lignins were investigated mainly by a variety of nuclear magnetic resonance spectroscopy (NMR) methods. The results were compared to structural information obtained by pyrolysis-gas chromatography-/mass spectrometry (py-GC/MS) and Fourier transform infrared spectroscopy (FTIR). It was observed that during the thermal treatment, the amount of β-O-4 ether moieties decreased, and an intramolecular conversion of secoisolariciresinol residues to cyclic ethers occurred. The effects on shape and size of the lignins were investigated by size exclusion chromatography (SEC) and NMR-diffusion measurements, by which the hydrodynamic radii were found to increase as a result of thermal treatment. It is discussed whether this depends on reduced flexibility and/or increased molar mass. In addition, the trends from the SEC and NMR analyses were compared to changes in glass transition temperature as determined by differential scanning calorimetry (DSC).

  • 419.
    Rönnols, Jerk
    et al.
    RISE, Innventia.
    Schweinebarth, Hannah
    RISE, Innventia.
    Jacobs, Anna
    RISE, Innventia.
    Stevanic Srndovic, Jasna
    RISE, Innventia.
    Olsson, Anne-Mari
    RISE, Innventia.
    Reimann, Anders
    RISE, Innventia.
    Aldaeus, Fredrik
    RISE, Innventia.
    Structural changes in softwood kraft lignin during thermal treatment2015In: 18th International Symposium on Wood, Fiber and Pulping Chemistry: 18th ISWFPC, 2015, Vol. 2, p. 366-369Conference paper (Other academic)
  • 420. Saadatmand, S.
    et al.
    Edlund, U.
    Albertsson, A.-C.
    Danielsson, S.
    Dahlman, O.
    RISE, Innventia.
    Prehydrolysis in softwood pulping produces a valuable biorefinery fraction for material utilization2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, no 15, p. 8389-8396Article in journal (Refereed)
  • 421.
    Salmen, L.
    et al.
    RISE, Innventia.
    Hornatowska, J.
    RISE, Innventia.
    A comparison of fibre deformations from mill like and laboratory kraft cooking of softwood2014In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 2, p. 211-217Article in journal (Refereed)
  • 422.
    Salmen, L.
    et al.
    RISE, Innventia.
    Lundqvist, F.
    RISE, Innventia.
    Effects of mechanical forces on strength delivery in softwood kraft cooking2011In: Appita journal, ISSN 1038-6807, no 1, p. 89-94Article in journal (Refereed)
  • 423.
    Salmen, L.
    et al.
    RISE, Innventia.
    Viforr, S.
    RISE, Innventia.
    Mårtensson, T.
    RISE, Innventia.
    Sixta, H.
    Aalto University, Finland.
    Ylonen, T.
    Aalto University, Finland.
    Fernando, D.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Daniel, G.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Sandström, P.
    SCA, Sweden.
    Moberg, A.
    StoraEnso, Sweden.
    Paulsson, M.
    AkzoNobel, Sweden; Mid Sweden University, Sweden.
    Back, R.
    SCA, Sweden.
    Enzymatic chip treatment for TMP: Prospects2014Conference paper (Refereed)
    Abstract [en]

    In order to evaluate enzyme pre-treatments of chips as means of lowering the energy demand in mechanical pulping, impregnation and refining trials were performed. Wing refining showed that property development was similar to that of reference pulps in the case of pectinase and xylanase while for chips treated with mannanase a less favourable development of the tensile index was noted. Considering the highly increased possibility for enzymatic interactions reached with greater disintegration of chips it could well be that the possibilities for enzymes to attack desired fibre wall structures may have been too few even in the case of Impressafiner treated material used here.

  • 424.
    Salmen, Lennart
    RISE, Innventia.
    Role of lignin in the structure of wood fibres2015In: Proceedings of the 8th Plant Biomechanics International Conference, 2015Conference paper (Refereed)
    Abstract [en]

    Wood materials are nowadays being viewed with increasing interest, as a green resource. Its utilization in new types of applications is also highly desired. Thus a better understanding of the wood ultrastructure and how the wood components are interacting in building up its properties is highly demanded. In the wood, the cellulose fibril aggregates dominates properties especially along the grain why the contribution from the other wood polymers and its role in the arrangement of the cell wall structure is often neglected. However their importance both in affecting transverse fiber properties and in their role as a spacer affecting cellulose aggregation during processing cannot be neglected. As the cellulose microfibrils make up a highly irregular lenticular three-dimensional structure the role of the matrix polymers in-between may be viewed in different ways. The understanding of the load bearing capacities of the lignin in different structural elements may be a key factor.

  • 425.
    Salmen, Lennart
    RISE, Innventia.
    Wood morphology and properties from molecular perspectives2015In: Annals of Forest Science, ISSN 1286-4560, E-ISSN 1297-966X, Vol. 72, no 6, p. 679-684Article in journal (Refereed)
    Abstract [en]

    • Background

    It is with increasing interest that wood materials are now being considered as a green resource. For improving the product performance of wood derived materials new ways of separating them from wood are required. Thus, there is a great demand for a better understanding of the ultrastructure of wood and how the components are interaction on a molecular level in building up its properties.

    • Material and method

    By the use of microscopic and spectroscopic techniques combined with mechanical forces, new knowledge regarding especially the role of the matrix polymers, the hemicelluloses and lignin, has been gained. This relates specifically to molecular interaction and orientation.

    • Results

    It is here demonstrated that all of the wood polymers within the secondary cell wall exhibit a preferred orientation along the fibrils. The degree of orientation decreases in the order cellulose, hemicelluloses to the lignin which only shows a small degree of orientation, probably induced by structural constrains.

    • Conclusion

    This orientation distribution is probably what has to be considered to better predict transverse cell wall properties. Moisture accessible regions are also aligned in a parallel arrangement in the cellulose fibrils explaining its high moisture resistance. The lignin is surprisingly inactive in the stress transfer in the secondary wall. This could perhaps be related to the function of lignin providing compressive, hydrostatic resistance in the lenticular spaces between fibrils, when longitudinally straining the fibre. This knowledge of the ultrastructural properties of the wood polymers, here presented, provides for a better understanding of the cell wall properties.

  • 426.
    Salmen, Lennart
    et al.
    RISE, Innventia.
    Axegård, Peter
    RISE, Innventia.
    Utilization of the wood fibre for biorefinery products2014Conference paper (Refereed)
  • 427.
    Salmen, Lennart
    et al.
    RISE, Innventia.
    Bergnor, Elisabeth
    RISE, Innventia.
    Olsson, Anne-Mari
    RISE, Innventia.
    Åkerström, Mårten
    RISE, Innventia.
    Uhlin, Anders
    RISE, Innventia.
    Extrusion of Softwood Kraft Lignins as Precursors for Carbon Fibres2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 4, article id 7544Article in journal (Refereed)
    Abstract [en]

    There is much interest in using less expensive raw materials as precursors for carbon fibre manufacture to increase the utilisation of strong, light-weight composite materials in the transportation sector. One such potential raw material is lignin. Most studies exploring melt spinning of lignin have used lignins from organosolv or hardwood kraft delignification processes. There has been little success reported in utilisation of the more commercially available softwood kraft lignins. In this study, lignins from different softwood kraft cooking processes were investigated with respect to their melt spinning performance and conversion to carbon fibres. The isolated lignins differed mainly in molecular weight, glass transition temperature, and softening temperature. All of the lignins produced from the laboratory cooks could be extruded without any plasticizer addition. However, the lignins contained volatiles that resulted in bubbles being formed along the length of the fibres. After vacuum drying, at elevated temperatures to remove volatiles, only the lignin originating from conventional kraft cooking was able to be melt extruded without plasticiser addition; this lignin had the lowest molecular weight amongst the samples. The stabilisation and carbonisation of these fibres gave carbon fibres with strengths comparable to those produced from lignins of other origins.

  • 428.
    Salmen, Lennart
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Larsson, Per A
    KTH Royal Institute of Technology, Sweden.
    On the origin of sorption hysteresis in cellulosic materials2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 182, p. 15-20Article in journal (Refereed)
    Abstract [en]

    Moisture sorption and moisture sorption hysteresis of carbohydrates are phenomena which affect the utilisation of products made thereof. Although extensively studied, there is still no consensus regarding the mechanisms behind sorption hysteresis. Attempts have been made to link the behaviour to molecular properties, in particular to softening properties, and the moisture sorption hysteresis has therefore here been investigated by modifying cellulosic fibres to affect their softening properties. The results show that the moisture sorption hysteresis diminishes with decreasing softening temperature, and was even completely absent at the higher degrees of modification. The moisture sorption characteristics also changed from a type II sorption to a more type III sorption behaviour, a feature more prominent the higher the degree of modification and the higher the temperature. For the highest degree of modification studied the sorption characteristics changed from sorbing less water the higher the temperature to sorbing more water with increasing temperature.

  • 429.
    Salmen, Lennart
    et al.
    RISE, Innventia.
    Lindström, Mikael
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Improved pulp yield and strength by retained glucomannans in kraft pulping of softwood2015In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, no 4, p. 584-590Article in journal (Refereed)
    Abstract [en]

    The possibilities of improving yield and strength properties of softwood bleached kraft pulps by retaining a higher content of glucomannan during kraft cooking using additives that decrease the rate of carbohydrate degradation were looked upon. In addition the effect of an increased alkaline concentration, favouring stopping reactions over peeling reactions was explored. Yield increases in the range of 2 to 4%-units were achieved using additives. In the case of the higher alkali charge instead a small yield decrease was noticed. Higher alkali charge in general resulted in a larger loss of xylan in the pulp. When examining the effects of the application of shearing forces at the end of the cook, mimicking industrial pulps, all cooks using high alkali conditions were affected by a large decrease in strength properties, both in tensile index and tear index as well as in fibre strength measured as re-wet Zero-span. For pulps cooked with polysulphide and H2S additions, stabilising the glucomannan degradation, the strength reductions were smaller than for the reference pulps. This resulted in pulps with both a higher yield and similar or better strength properties than those for the reference pulp. These pulps also had better beatability, i.e. the tensile strength increased faster during PFI-beating than for the reference pulp.

  • 430.
    Salmen, Lennart
    et al.
    RISE, Innventia.
    Olsson, Anne-Mari
    RISE, Innventia.
    Physical properties of cellulosic materials related to moisture changes2016In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 50, no 1, p. 81-89Article in journal (Refereed)
    Abstract [en]

    Moisture affects the mechanical properties of paper to a high degree. Moreover, the creep properties of paper may be highly affected while the relative humidity is changing, exhibiting mechano-sorptive creep. The reasons for the great sensitivity to moisture changes of papers are not fully explained. In this study, thin papers were examined during sorption processes and the moisture content within the paper, paper length and dynamic elastic modulus during RH changes were measured. It is demonstrated that the dimensional changes of the paper exactly reflected the changes in moisture content within the sample. During both absorption and desorption, the elastic modulus changed so that it was lower than the equilibrium value corresponding to its moisture content. This was especially evident during absorption where the modulus dropped below the equilibrium value at the end RH, i.e. the value was approached from below. The modulus drop was highly related to RH changes made at higher RH and could possibly be related to the softening of carbohydrates.

  • 431.
    Salmen, Lennart
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Stevanic Srndovic, Jasna
    Effect of drying conditions on cellulose microfibril aggregation and "€œhornification"2018In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, no 11, p. 6333-6344Article in journal (Refereed)
    Abstract [en]

    Drying of chemical pulps results in a decreased swelling of the fibres, leading to lower density and strength properties of paper sheets. To investigate how variation of pulp pH, drying process temperature, and final moisture content affect this phenomenon, structural studies were performed on a cellulose-rich pulp. Interrupting the drying at moisture contents of around 20%, using drying temperatures of 80 °C and 140 °C, resulted in a more severe degree of hornification than if the pulp was completely dried at the same temperatures. This increased loss of swelling was accompanied by increased cellulose microfibril aggregation. No change of the cellulose microfibril size or of the cellulose crystallinity, as determined by NMR, could be seen. Further, the accessibility of the cellulose microfibril surfaces, including surfaces between microfibrils, was unaffected by the drying. Thus, hornification should not primarily be related to a reduction of accessible cellulosic surfaces.

  • 432.
    Salmen, Lennart
    et al.
    RISE, Innventia.
    Stevanic Srndovic, Jasna
    RISE, Innventia.
    Olsson, Anne-Mari
    RISE, Innventia.
    Contribution of lignin to the strength properties in wood fibres studied by dynamic FTIR spectroscopy and dynamic mechanical analysis (DMA)2016In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 70, no 12, p. 1155-1163Article in journal (Refereed)
    Abstract [en]

    A deeper insight into the molecular interactions in the highly intermixed structure of the wood cell wall, from the point of view of both basic and applied science, is necessary. In particular, the role of the different matrix materials within the cell wall needs to be better understood, especially concerning how lignin contributes to the mechanical properties. In the present paper, the mechanical properties of spruce wood have been studied on a molecular scale by means of dynamic Fourier transform infrared (FTIR) spectroscopy. To this purpose, native spruce wood was subjected to chemical changes by impregnation and a mild pre-cooking with white liquor with a composition usual for kraft pulping. For comparison, lignin-rich primary cell wall material was also isolated by means of thermomechanical pulp (TMP) refining. Dynamic FTIR spectroscopy revealed that lignin took part in the stress transfer in all investigated samples. This finding is in contrast to literature data. A strong indirect coupling between lignin and cellulose was seen in the primary cell wall (P) material. In case of native wood, the lignin signal was much weaker and also indicated an indirect coupling to cellulose. In the case of pre-cooked wood samples (submitted to mild pulping), the interactions were modified so that the molecular straining of lignin was stronger and more directly related to that of cellulose. In other words, in these samples, lignin played a more active role in the stress transfer as compared to native wood. These findings were supported by a narrower lignin-softening region as measured by dynamic mechanical analysis (DMA). The interpretation is plausible in terms of the superior stiffness seen for high-yield pulps of a similar yield as the studied pre-cooked wood samples.

  • 433. Salminen, K.
    et al.
    Lappalainen, T.
    Kinnunen-Raudaskoski, K.
    Andersson, M.
    Carlsson, Gilbert
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Mira, Isabel
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science.
    Foam forming-the effects of surfactant type on characteristics of fiber-foam suspension and properties of formed fiber network2014In: Paper Conference and Trade Show, PaperCon 2014, TAPPI Press, 2014, p. 758-765Conference paper (Refereed)
    Abstract [en]

    The properties and behavior of pure aqueous foams have been quite extensively studied. On the other hand, very little is known about the chemical interactions between foaming agents and paper/board making raw materials in aqueous fiber-foam suspensions. The objective of this examination was to increase the understanding of basic mechanisms affecting fiber-foam suspension. In particular, gaining understanding of the chemical interactions between foaming agents and paper/board making raw materials was of great interest. The foaming behavior of pulp formulations in the presence of three anionic and four non-ionic foaming aids was tested with a tailor-made foaming test environment. Foaming aids for testing were chosen based on their reported good foaming properties, environmental safety, and availability as bulk chemicals, as well as their insensitivity to changes in temperature and pH within limits relevant to the foam forming process. Foam formed hand sheets with different furnish recipes were made and tested to evaluate the effect of the three selected foaming agents (selected based on their foaming characteristics) on the formation and retention processes, the technical properties of the hand sheets, and the performance of other chemicals used in paper/board manufacturing in the presence of the foaming aids. Additionally, the potential of utilizing the selected foaming aids in practical foam forming of paper or board was verified in a small-scale pilot trial. The results obtained in these laboratory and pilot-scale studies showed that the type and amount of foaming aids used have significant effects on foam properties, filler retention, sizing, dewatering, bulk, and mechanical properties of the fiber network. In fact, the selection of the foaming aid and its interaction with other wet end additives seems to be one of the key factors affecting the processability and quality of foam formed products.

  • 434.
    Salmén, Kristina
    RISE, Innventia.
    Software for exposure calculation of chemicals migrated from food packaging to foods in Europe2015Conference paper (Other academic)
  • 435. Saltberg, A.
    et al.
    Brelid, H.
    Lundqvist, Fredrik
    RISE, Innventia.
    The effect of calcium on kraft delignification: Study of aspen, birch and eucalyptus2009In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 24, no 4, p. 440-447Article in journal (Refereed)
    Abstract [en]

    Metal ions can be removed from wood chips by acidic leaching. The rate of kraft delignification may be enhanced by such a chip pre-treatment, but whether this effect is present or not, is dependent on wood species and cooking liquor composition. Acidic chip leaching of birch (Betula pendula) and aspen (Populus tremula) was shown to give a large increase in the rate of delignification when carbonate-free white liquor, prepared in the laboratory, was used. Removal of calcium ions from the wood chips during the acidic leaching was shown to be the principal reason for the increase in the delignification rate. In trials where the cook was not preceded by acidic leaching, the addition of carbonate to the white liquor eliminated the retarding effect of calcium. The addition of the chelating agent DTPA (diethylenetriaminepentaacetic acid) also counteracted the calcium-effect. Since carbonate forms solid calcium carbonate precipitates and DTPA forms Ca-DTPA complexes, it can be concluded that non-chelated calcium ions in the cooking liquor decrease the rate of lignin solubilisation. The delignification rate of eucalyptus (Eucalyptus globulus) was not significantly affected by calcium-removal or by the addition of carbonate or DTPA to the white liquor. A tentative explanation for this could be that substances released from eucalyptus during cooking form complexes with calcium ions and may thereby prevent the calcium-effect on delignification. This explanation is supported by results from trials where birch and eucalyptus chips were cooked together.

  • 436.
    Samuelsson, Åsa
    et al.
    RISE, Innventia.
    Kulander, Ida
    RISE, Innventia.
    Conversion of a kraft mill to dissolving pulp and lignin production2014Conference paper (Refereed)
  • 437.
    Sandberg, Mats
    et al.
    Linköping University, Sweden.
    Tordera, Daniel
    Linköping University, Sweden.
    Granberg, Hjalmar
    RISE, Innventia.
    Sawatdee, Anurak
    RISE, Swedish ICT, Acreo.
    Dedic, Dina
    RISE, Innventia.
    Berggren, Magnus
    Linköping University, Sweden.
    Jonsson, Magnus P.
    Linköping University, Sweden.
    Photoconductive zinc oxide-composite paper by pilot paper machine manufacturing2016In: Flexible and Printed Electronics, ISSN 2058-8585, Vol. 1, article id 044003Article in journal (Refereed)
    Abstract [en]

    Smartmaterials can be used for awide variety of applications, including sensing and energy harvesting.Implementation of smartmaterials in large area devices requires scalablemanufacturing. The use ofpaper-making techniques would offer an enormous production capacity, allowing for low-cost andlarge-scalemanufacturing. In thisworkwe present a successful pilot scale papermachinemanufacturingof functional composite papers(100mmin−1 with aweb width of 30 cm) based on cellulose fibres andcommercial tetrapodal zinc oxidemicrowhiskers(ZnO-Ts).Carbon electrodes could successfully beprinted on the paper to form complete electronic devices where the paper itself is the active material.Thisenabled development of aZnO-composite paper photosensor,where we characterized its stability,sensitivity and speed. The devices show excellent photosensing properties over awide range of lightirradiances(0.01–1Sun), including short response times (∼10 s) and long-term stability. Under simulatedsunlight and a bias voltage of 1 V, small(0.5 cm2) two-probe interdigitated photosensor devices provided12μAphotocurrent.Under the same conditions, four-probe measurements of the composite papershowed a sheet resistance of 6.9·107Ω/sq. Four-probe measurements also demonstrated that the paperconductivity varies linearlywith light irradiance. To the best of ourknowledge, this is thefirst example ofpilot paper machine production of an optoelectronic paper, demonstrating the potential for large-scalepapermanufacturing of active smart paper from low-cost industrial bulk materials.

  • 438.
    Santos, Sara M.
    et al.
    INIA, Spain.
    Carbajo, José M.
    INIA, Spain.
    Gomez, Nuria
    INIA, Spain.
    Quintana, Ester
    INIA, Spain.
    Ladero, Miguel
    Complutense University of Madrid, Spain.
    Sanchez, Arsenio
    National Library of Spain, Spain.
    Chinga-Carrasco, Gary
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Villar, Juan C.
    INIA, Spain.
    Use of bacterial cellulose in degraded paper restoration. Part I: application on model papers2016In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 51, no 3, p. 1541-1552Article in journal (Refereed)
    Abstract [en]

    The disappearance of bibliographic heritage is one of the biggest problems facing libraries. One of the most common methods used to restore paper, lining, is to apply a reinforcing layer to the document. This study focuses on lining papers with bacterial cellulose (BC) sheets from Gluconacetobacter sucrofermentans. For this purpose, several model papers have been selected. They have been characterized before and after the lining with this BC and a specific Japanese paper (JP) to compare both materials. Taking into account the differences between bacterial and vegetal cellulose is expected that the results may be similar to other BC and JP. The samples have been characterized before and after an aging process. There are no significant differences in some of the characteristics studied. Nevertheless, BC-lined papers present higher gloss values and b* coordinate. The wettability decreases with both BC and JP. However, in papers lined with BC, the wettability decreases more markedly and independently of the model paper used. This is related to the sealing of the surface structure by BC, which also leads to a reduction of air permeability. When the lined papers go through an aging process, there are no significant changes in any characteristic, except in b* and L* color coordinates. Additionally, the wettability rate decreases in all cases. This study indicates that papers lined with BC are stable over time. Finally, the use of BC as reinforcing material may offer advantages for specific conservation treatments, being more suitable for certain types of paper than JP.

  • 439.
    Santos, Sara M.
    et al.
    INIA, Spain.
    Carbajo, José M.
    INIA, Spain.
    Gomez, Nuria
    INIA, Spain.
    Quintana, Ester
    INIA, Spain.
    Ladero, Miguel
    Complutense University of Madrid, Spain.
    Sanchez, Arsenio
    National Library of Spain, Spain.
    Chinga-Carrasco, Gary
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Villar, Juan C.
    INIA, Spain.
    Use of bacterial cellulose in degraded paper restoration. Part II: application on real samples2016In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 51, no 3, p. 1553-1561Article in journal (Refereed)
    Abstract [en]

    Preservation of documentary heritage is one of the biggest challenges facing paper conservators today. The singular properties of bacterial cellulose (BC) lead us to propose to reinforce paper with BC sheets. In the first part of this study, the reinforcing capability of BC was tested on model papers of well-known fiber composition. The aim of the present study was to verify the suitability of rebuilding degraded old papers with BC. The degraded papers were characterized before and after the reinforcement. In addition, lined samples were characterized before and after an aging process in order to study the stability in time. The same methodology was used with Japanese paper (JP), a material commonly used by paper conservators, in order to compare both materials as reinforcement. Mechanical properties of paper lined with BC are as good as those obtained with JP. Papers lined with BC have more marked modifications on their optical properties than those restored with JP. Nevertheless, letters in books lined with BC are more legible. Moreover, only the papers restored with BC show high changes in porosity. The aging process leads to a slight decrement in burst index. Changes on tear index and optical properties with the aging process depend on the paper to be restored. This study suggests that BC improves deteriorated paper quality, without altering the information contained therein, and that this improvement is maintained over time. Hence, BC is a promising alternative material for the restoration of paper.

  • 440.
    Schachtl, M.
    et al.
    BASF SE, Germany.
    Erren, S.
    BASF SE, Germany.
    Scliönhaber, D.
    BASF SE, Germany.
    Dahlbom, P.
    Norske Skog Skogn, Norway.
    Steinsli, J. H.
    Norske Skog Skogn, Norway.
    Johansson, Lars
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Experiences with "dithionite Based Additives (DBA) in (C)TMP" in lab, pilot and mill scale: Synergies between high brightness, less specific energy consumption and development of pulp properties2016In: International Mechanical Pulping Conference 2016 (IMPC 2016), TAPPI Press, 2016, p. 59-69Conference paper (Other academic)
    Abstract [en]

    The purpose of this paper is to report about our experiences with treating softwood mechanical pulp (MP) with DBA directly injected into the gap of high consistency (HC) refiners used as chemical reactors to improve the competitiveness and the ecological footprint of (C)TMP based products. After the description of the main factors and pros and cons of conventional oxidative and reductive bleaching of sofhvood MP the basic principles of the treatment of MP with DBA in the (C)TMP refiner are outlined. By means of exemplary results of trials in lab, pilot and mill scale as well as of productions the main advantages of "DBA in (C)TMP" are illustrated: efficient brightness gain, reduction of anionic trash, high wood yield, reduction of hard chelating agents, saving of refining energy and increase of strength properties. Using the example of Norske Skog Skogn it is demonstrated how the system works in practice in the production of high bright and standard newsprint made from normal and lower quality wood. Finally it is pointed out that to a certain extent DBAs can be tailored to the needs of the respective mill.

  • 441.
    Schweinebarth, Hannah
    et al.
    RISE, Innventia.
    Baker, Darren A.
    RISE, Innventia.
    Tomani, Per
    RISE, Innventia.
    Lignin: evaluation of properties for applications2015In: NWBC 2015: The 6th Nordic Wood Biorefinery Conference, Espoo: VTT , 2015, p. 387-388Conference paper (Refereed)
    Abstract [en]

    Utilization of abundant lignin-rich natural resources will provide new revenue streams for today’s kraft pulp mills. Owing to its phenol-rich structure, Lignin is very versatile and has much potential for application in many areas, for example: as a foundation for bulk chemical production, for conversion to fuel products, a binder material, a fertilizer, anti-oxidant, as a precursor for carbon fibres and nanofibres and for activated carbons.

  • 442.
    Sewring, Tor
    et al.
    Chalmers University of Technology, Sweden; KTH Royal Institute of Technology, Sweden.
    Zhu, Weizhen
    Chalmers University of Technology, Sweden; Stora Enso; Sweden.
    Sedin, Maria
    RISE, Innventia.
    Theliander, Hans
    Chalmers University of Technology, Sweden; KTH Royal Institute of Technology, Sweden.
    Estimation of the deprotonation degree of phenolic groups on kraft lignin2015In: NWBC 2015: The 6th Nordic Wood Biorefinery Conference, Espoo: VTT , 2015, p. 442-449Conference paper (Refereed)
    Abstract [en]

    Research has been undertaken into the deprotonation degree of the phenolic groups on softwood kraft lignin in black liquor. An attempt was made to mathematically model the ion concentration distributions around lignin fragments in black liquor by studying the possibility of using a modified Poisson-Boltzmann cell model and extending the validity of this model by extrapolating the valid ionic concentration range using the Pitzer method. The model has been utilised to predict the pH dependent deprotonation degree under various conditions that are relevant to the LignoBoost process. It has been demonstrated that the pH and temperature strongly affected the deprotonation degree of phenolic groups on kraft lignin. The effect of the molecular weight of lignin and a small increase in ionic strength on the deprotonation degree was very small in black liquor systems of high ionic strength. It was observed that the pH at the surface of lignin macromolecules was approximately the same in black liquor systems of high ionic strength.

  • 443. Sjöde, A.
    et al.
    Winestrand, S.
    Nilvebrant, N. -O.
    RISE, STFI-Packforsk.
    Jönsson, L. J.
    Enzyme-based control of oxalic acid in the pulp and paper industry2008In: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 43, no 2, p. 78-83Article in journal (Refereed)
    Abstract [en]

    Enzymatically catalyzed decomposition of oxalic acid in bleaching filtrates from the pulp and paper industry offers a possibility to enduringly prevent oxalate scaling problems by specific removal of the oxalic acid in the system rather than by attempting to avoid calcium oxalate precipitation by countermeasures aiming at improved solubility. To achieve a broad evaluation of various oxalate-degrading enzymes and to cover conditions encountered in various types of processes, 16 different bleaching filtrates were collected from pulp mills engaged in mechanical pulping of softwood, mechanical pulping of aspen, and kraft pulping of softwood. A novel oxalate-degrading enzyme provided by Novozymes was compared with commercially available oxalate oxidase from barley and oxalate decarboxylase from Aspergillus niger. The activity of the enzymes in the filtrates was investigated using kinetic analysis and multivariate data analysis. Kinetic analysis indicated that the degradation rates were governed more by inhibitors in the filtrates than by the concentration of oxalic acid. Multivariate data analysis suggested links between high concentrations of certain compounds in the filtrates and high or low enzyme activity, as exemplified by the link between high concentrations of chelators in filtrates from mechanical pulping and low activity of oxalate oxidase from barley. All three enzymes could degrade oxalic acid in all filtrates, despite the fact that very high concentrations of residual hydrogen peroxide were found in several of the filtrates.

  • 444.
    Sjöholm, Elisabeth
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia.
    18th International Symposium on Wood, Fibre and Pulp Chemistry (ISWFPC) September 8-11 2015, Vienna, Austria2017Other (Other academic)
    Abstract [en]

    A brief overview of the oral presentations and plenary lectures.

  • 445.
    Sjöholm, Elisabeth
    RISE, Innventia.
    Carbon fibres from lignin2014Conference paper (Refereed)
  • 446.
    Sjöholm, Elisabeth
    RISE, Innventia.
    Kolfiber från vedens molekyler2015Conference paper (Other academic)
  • 447.
    Sjöholm, Elisabeth
    et al.
    RISE, Innventia.
    Drougge, Rickard
    RISE, Innventia.
    Lignin based carbon fibres: recent progress2012Conference paper (Refereed)
  • 448.
    Sjöholm, Elisabeth
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy.
    Törngren, Per
    RISE - Research Institutes of Sweden, Bioeconomy.
    Rönnols, Jerk
    RISE - Research Institutes of Sweden, Bioeconomy.
    Microwave assisted etherification of lignin2017In: International symposium on green chemistry (ISGC 2017), May 16-19, 2017, La Rochelle, France, 2017, article id 1271Conference paper (Other academic)
    Abstract [en]

    The content of phenol and aliphatic groups of softwood kraft lignin has been altered to control the reactivity and the physical properties of the lignin. The influence of microwave assisted alkylation was evaluated using dimethyl carbonate (DMC) or diethyl carbonate (DEC) together with different bases. The influence of reaction conditions on the final lignin products were compared by NMR.

  • 449.
    Sjöstedt, Anna
    et al.
    KTH Royal Institute of Technology, Sweden.
    Wohlert, Jakob
    KTH Royal Institute of Technology, Sweden.
    Larsson, Per Tomas
    RISE, Innventia.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Structural changes during swelling of highly charged cellulose fibres2015In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, no 5, p. 2943-2953Article in journal (Refereed)
    Abstract [en]

    Structural changes of fibrils and fibril aggregates in the fibre wall were studied after oxidation of the cellulose by 2,2,6,6-tetramethyl-1-piperidinyloxy to high charge densities (highest charge density: 1300 μeq/g). The increase in pore volume was measured by mini-WRV at two different pH levels, and the supramolecular structure in the fibre wall in terms of aggregate size, specific surface area and average pore size was measured by solid state NMR, DVS desorption and BET N2 gas adsorption. A structural change in the arrangement of the fibrils inside the fibril aggregates was observed although the oxidation did not lead to a complete liberation of individual fibrils, i.e. they still exist as an aggregated structure after oxidation. Theoretical estimates suggest that the electrostatic repulsion energy connected with the increase in surface charge of the fibrils can be sufficient to gradually separate the fibrils enough to expose all fibril surfaces to oxidation chemicals.

  • 450.
    Sjöström, Lars
    et al.
    RISE, STFI-Packforsk.
    Jacobs, Anna
    RISE, STFI-Packforsk.
    Rådeström, Rune
    RISE, STFI-Packforsk.
    Nordlund, Maria
    RISE, STFI-Packforsk.
    Effects of released organic substances on sizing efficiency: Influence of origin, composition and molecular properties of the organic material2006In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 21, no 5, p. 575-585Article in journal (Refereed)
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