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  • 1. Agnihotri, S.
    et al.
    Johnsen, I.A.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Moe, S.
    Gregersen, Ø.
    More selective biorefining of softwood by combined hot water and ethanol organosolv pretreatment2011Konferensbidrag (Refereegranskat)
  • 2.
    Agnihotri, Swarnima
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Johnsen, Ingvild A.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Böe, Maren S.
    NTNU Norwegian University of Science and Technology, Norway.
    Öyaas, Karin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Moe, Størker
    NTNU Norwegian University of Science and Technology, Norway.
    Ethanol organosolv pretreatment of softwood (Picea abies) and sugarcane bagasse for biofuel and biorefinery applications2015Ingår i: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 49, nr 5, s. 881-896Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ethanol derived from biomass has the potential to be a renewable transportation fuel that can replace gasoline. This work was carried out to establish an optimized ethanol organosolv pretreatment of Norway spruce (Picea abies) for bioethanol production (63 wt% EtOH, pH ~3.5 in aqueous phase, 170–240 °C, 90 min) utilizing hydrolytic enzymes in the saccharification step. To test the generality of the method, a series of ethanol organosolv pretreatments were also performed on sugarcane bagasse (50 wt% EtOH, pH ~3.5 in aqueous phase, 155–210 °C, 90–120 min). The degree of delignification increased with increasing temperature during pretreatment, and the fastest increase was observed with sugarcane bagasse. The pretreatments were carried out in a batch mode. The maximum degree of delignification of ~65 % was reached at ~235 °C for Norway spruce, while sugarcane bagasse reached ~80 % at ~210 °C. Cellulose was subjected to degradation (5–10 % points) at these temperatures. Subsequent enzymatic hydrolysis (30 FPU/g cellulose, 32 pNPGU/g cellulose, 50 °C, 48 h) of ethanol organosolv-pretreated biomass achieved complete conversion for both raw materials at the highest degrees of delignification.

  • 3. Alexandrescu, L.
    et al.
    Syverud, K.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Belosi, F.
    Nanofibers against nanoparticles:: Cellulosic nanoparticles for nanoparticle aerosol filtration2012Konferensbidrag (Refereegranskat)
  • 4. Alexandrescu, L.
    et al.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Iotti, M.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Gregersen, Ø.
    Belosi, F.
    Gatti, A.M.
    Air filtration of nano-particles using cellulose nanofibrils2012Konferensbidrag (Refereegranskat)
  • 5.
    Alexandrescu, Laura C.
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute. NTNU Norwegian University of Science and Technology, Norway.
    Gatti, Antonietta Maria
    ISTEC-CNR, Italy.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Cytotoxicity tests of cellulose nanofibril-based structures2013Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cellulose nanofibrils based on wood pulp fibres are most promising for biomedical applications. Bacterial cellulose has been suggested for some medical applications and is presently used as wound dressing. However, cost-efficient processes for mass production of bacterial cellulose are lacking. Hence, fibrillation of cellulose wood fibres is most interesting, as the cellulose nanofibrils can efficiently be produced in large quantities. However, the utilization of cellulose nanofibrils from wood requires a thorough verification of its biocompatibility, especially with fibroblast cells which are important in regenerative tissue and particularly in wound healing. The cellulose nanofibril structures used in this study were based on Eucalyptus and Pinus radiata pulp fibres. The nanofibrillated materials were manufactured using a homogenizer without pre-treatment and with 2,2,6,6-tetramethylpiperidine-1-oxy radical as pre-treatment, thus yielding nanofibrils low and high level of anionic charge, respectively. From these materials, two types of nanofibril-based structures were formed; (1) thin and dense structures and (2) open and porous structures. Cytotoxicity tests were applied on the samples, which demonstrated that the nanofibrils do not exert acute toxic phenomena on the tested fibroblast cells (3T3 cells). The cell membrane, cell mitochondrial activity and the DNA proliferation remained unchanged during the tests, which involved direct and indirect contact between the nano-structured materials and the 3T3 cells. Some samples were modified using the crosslinking agent polyethyleneimine (PEI) or the surfactant cetyl trimethylammonium bromide (CTAB). The sample modified with CTAB showed a clear toxic behaviour, having negative effects on cell survival, viability and proliferation. CTAB is an antimicrobial component, and thus this result was as expected. The sample crosslinked with PEI also had a significant reduction in cell viability indicating a reduction in DNA proliferation. We conclude that the neat cellulose nanostructured materials tested in this study are not toxic against fibroblasts cells. This is most important as nano-structured materials based on nanofibrils from wood pulp fibres are promising as substrate for regenerative medicine and wound healing.

  • 6. Aslan, M.
    et al.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Sørensen, B.F.
    Madsen, B.
    Strength Variability of Single Flax Fibres2011Ingår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 46Artikel i tidskrift (Refereegranskat)
  • 7.
    Bardet, Raphael
    et al.
    Université Grenoble Alpes, France; CNRS, France.
    Reverdy, Charlène
    Université Grenoble Alpes, France; CNRS, France.
    Belgacem, Naceur
    Université Grenoble Alpes, France; CNRS, France.
    Leirset, Ingebjørg
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute. NTNU Norwegian University of Science and Technology, Norway.
    Bardet, Michel
    Université Grenoble Alpes, France; CEA, France.
    Bras, Julien
    Université Grenoble Alpes, France; CNRS, France.
    Substitution of nanoclay in high gas barrier films of cellulose nanofibrils with cellulose nanocrystals and thermal treatment2015Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, nr 2, s. 1227-1241Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study is to design a nanocellulose based barrier film. For this purpose, cellulose nanofibrils (CNFs) are used as a matrix to create an entangled nanoporous network that is filled with two different nanofillers: nanoclay (reference), i.e. the mineral montmorillonite (MMT) and the bio-based TEMPO-oxidized cellulose nanocrystal (CNC-T), to produce different types of nanocelluloses and their main physical and chemical features were assessed. As expected, films based on neat CNFs exhibit good mechanical performance and excellent barrier properties at low moisture content. The introduction of 32.5 wt% of either nanofiller results in a significant improvement of barrier properties at high moisture content. Finally, thermal treatment of a dried CNF/CNC-T film results in a decrease of the oxygen permeability even at high moisture content (>70 %). This is mainly attributed to the hornification of nanocellulose. A key result of this study is that the oxygen permeability of an all-nanocellulose film in 85 % relative humidity (RH), is similar to CNF film with mineral nanoclay (MMT), i.e. 2.1 instead of 1.7 cm3 µm m−2 day−1 kPa−1, respectively.

  • 8.
    Brodin, Fredrik Wernersson
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Eriksen, Øyvind
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Preparation of individualised lignocellulose microfibrils based on thermomechanical pulp and their effect on paper properties2015Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, nr 3, s. 443-451Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although mechanical pulp can be considered as a potential raw material for preparation of microfibrils, suitable pre-treatment methods have been missing. Consequently, the objectives of this study were firstly to find a suitable procedure to prepare lignocellulose microfibrils (LCMF) from fractionated thermo-mechanical pulp (TMP) and secondly to evaluate if these TMP-based materials could be used as paper additives to increase paper strength. Carboxymethylation was found to be a suitable pretreatment for both TMP fines and TMP fibres to enable preparation of individualised LCMF after subsequent homogenisation treatment. After air drying, this material formed dense continuous films in conformity with films prepared from cellulose microfibrils (CMF) originating from chemical pulp. Homogenisation only or sulphonation followed by homogenisation did not fibrillate the TMP samples into individualised LCMF. Analysis of paper properties showed that addition of 20% LCMF to a standard TMP furnish improved tensile strength index by 15%. The LCMF-containing papers were also more brittle (less elongation) than the other paper sheets in this study. Similar tensile strength index was also obtained for TMP fines treated by sulphonation followed by homogenisation.

  • 9. Celaya, J.
    et al.
    Bridgwater, A.V.
    Toven, K.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Fast pyrolysis bio-oil production from Scandinavian forest residues2012Konferensbidrag (Refereegranskat)
  • 10. Celaya, J.
    et al.
    Bridgwater, A.V.
    Toven, K.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Fast pyrolysis bio-oil production from Scandinavian forest residues2012Konferensbidrag (Refereegranskat)
  • 11.
    Celaya Romeo, Javier
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Wernersson Brodin, Fredrik
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Toven, Kai
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Re-homogenization of phase separated forest residue pyrolysis oil by blending2016Ingår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 163, s. 60-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The wood processing industry generates large amounts of forest residues like branches and tops which represent a significant unexploited resource for sustainable biofuel production. A feasible thermochemical route to valorise these residues is fast pyrolysis. However, the main product of this technology, pyrolysis oil or bio-oil, shows several disadvantages in comparison with conventional fuels. One of the main drawbacks of bio-oil is its instability which results in liquid phase separation in many cases. The purpose of this study is to verify whether homogenous single-phase heating fuels for district heating etc. can be formed from aged, phase separated forest residue pyrolysis oils by blending. Aged, phase separated pyrolysis oils were blended with either methanol or 1-butanol and the amount of alcohol needed to form homogeneous and storage stable fuel blends was evaluated. Homogeneity of the fuel blends was analysed by water concentration profile analysis and image analysis. Storage stability was analysed by analysing homogeneity as function of storage time. Essential fuel characteristics were analysed. The results revealed that phase separated forest residue pyrolysis oil can be homogenized by adding moderate amounts of alcohol and that some of the blends are stable longer than two months. Alcohol addition also improves essential product properties for pyrolysis oils as heating fuels. This work forms part of the ReShip Project partly funded by the Research Council of Norway (The ENERGIX programme).

  • 12. Chacha, N.
    et al.
    Toven, K.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Mtui, G.
    Katima, J.
    Mrema, G.
    Steam pretreatment of pine (Pinus patula) for fuel ethanol production in Tanzania2011Konferensbidrag (Refereegranskat)
  • 13. Chacha, N.
    et al.
    Toven, K
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Mtui, G
    Katima, J
    Mrema, G
    Steam Pretreatment of Pine (Pinus patula) wood residue for the production of reducing sugars2011Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 45, s. 495-501Artikel i tidskrift (Refereegranskat)
  • 14.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Advanced biomaterials based on nanofibrillated cellulose: from nanopapers to nanomedicine2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nanofibrillated cellulose (NFC) offers a wide range of interesting opportunities and advantages, being biodegradable, renewable and thus environmentally sound. Extensive research has been performed on the effective production and application of NFC. The proposed applications extend from being a component in paper, coatings and composite materials to being applied in bio-medicine as part of wound dressings or in drug delivery systems. Some of the major advantages of NFC are the dimensions and the structural and chemical composition of nanofibrils, which lead to the formation of dense networks with optimized optical and mechanical properties. In this respect, the concept of nanopaper has been introduced. Nanopapers are strong structures, with high light transmittance and smooth surfaces. These characteristics open for novel applications, including the formation of smooth substrates for printing functionality. A recently explored example is the printing of bioactive biomacromolecules and conductive structures on tailor-made nanopapers, which could form the basis for novel biosensors. Additionally, nanobarriers are most promising in novel packaging applications where the self-assembly properties of the material facilitate the formation of dense structures with high barrier against oxygen. However, NFC alone does not seem to be sufficient for the formation of adequate nanobarriers due to the brittle and hygroscopic characteristics of the material. Novel biocomposite concepts need thus closer attention, where the strong and high barrier properties of NFC could be complemented with adequate bioplastics and additives for the formation of ductile films, suitable for conversion processes. From the biomedical point of view, NFC offers several advantages. Depending on the structural and chemical composition of the material and the cross-linking with adequate polymers and particles, micro-porous and elastic gels can be formed. Such gels can hold a considerable amount of water, thus being an excellent material for keeping a moist environment during wound healing and for facilitating the regeneration process of human tissue. Additionally, NFC gels based on oxidized nanofibrils can have pH-sensitive characteristics, a property with potential in drug delivery. With the intention of giving an extensive description of NFC and its modern applications, this presentation will be divided into three main sections; i) production and definition, ii) characterization including structural, chemical and biological aspects and iii) novel applications of NFC from nanopapers to biomedical devices.

  • 15.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view2011Ingår i: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 6Artikel i tidskrift (Refereegranskat)
  • 16.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Complementary microscopy techniques for surface characterisation of uncoated and mineral pigment coated paper2012Ingår i: Current microscopy contributions to advances in science and technology / [ed] Méndez-Vilsa A., Formatex Research Center, 2012, s. 1448-1455Kapitel i bok, del av antologi (Refereegranskat)
  • 17.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Complementary Microscopy Techniques for Surface Characterisation of Uncoated and Mineral Pigment Coated Paper2012Ingår i: Current Microscopy Contributions to Advances in Science and Technology, Formatex Research Center , 2012, , s. 8Kapitel i bok, del av antologi (Refereegranskat)
  • 18.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Microscopy and computerized image analysis of wood pulp fibres multiscale structures2010Ingår i: Microscopy: Science, technology, applications and education / [ed] Méndez-Vilas A., Formatex Research Center, 2010, s. 2182-2189Kapitel i bok, del av antologi (Refereegranskat)
  • 19.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Microscopy and computerized image analysis of wood pulp fibres multiscale structures2010Ingår i: Microscopy: Science, technology, application and education, Formatex Research Center , 2010, , s. 8Kapitel i bok, del av antologi (Refereegranskat)
  • 20.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Optical methods for the quantification of the fibrillation degree of bleached MFC materials2013Ingår i: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 48Artikel i tidskrift (Refereegranskat)
  • 21.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Aasrød, K.
    Leinsvang, Berit
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Bouveng, Mikael
    RISE., Innventia.
    Johansson, Per-Åke
    RISE., Innventia.
    Structural effects on print-through and set-off2012Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, s. 596-603Artikel i tidskrift (Refereegranskat)
  • 22.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Averianova, N.
    Gibadullin, M.
    Petrov, V.
    Leirset, Ingebjörg
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Micro-structural characterisation of homogeneous and layered MFC nano-composites2013Ingår i: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 44Artikel i tidskrift (Refereegranskat)
  • 23.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Averianova, N
    Kazan National Research Technological University, Russia.
    Kondalenko, O
    Kazan National Research Technological University, Russia.
    Garaeva, M
    Kazan National Research Technological University, Russia.
    Petrov, V
    Kazan National Research Technological University, Russia.
    The effect of residual fibres on the micro-topography of cellulose nanopaper2014Ingår i: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 56, s. 80-84Artikel i tidskrift (Refereegranskat)
  • 24.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Brodin, Malin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Karlsen, Trond
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Wood pulp fibres and nanocellulose: Characterization and application in biocomposite materials2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    A composite can be defined as a material composed of two or more components having distinct morphology and chemistry, and giving synergetic effects. In this paper the term biocomposite is used, referring to i) a material having at least one bio-component (e.g. wood pulp fibres and nanofibrils) or ii) biomaterials intended for biomedical applications. The utilization of wood pulp fibres in composite materials has gained major interest during the last years. There are various wood pulp fibres that can be used as reinforcement in composites, e.g. thermo-mechanical pulp (TMP), chemi-thermo-mechanical pulp (CTMP) and kraft pulp fibres. Depending on the pulping process (TMP, CTMP or kraft pulp), the pulp fibres differ greatly with respect to the fibre morphology and chemistry. Kraft pulp fibres have been one of the most used raw materials for producing nanocellulose. Nanocellulose from wood refers to various cellulose nano-materials such as cellulose nanocrystals and nanofibrillated cellulose. Nanofibrillated cellulose is composed of a major fraction of structurally homogeneous nanofibrils having typical widths in the nanometre scale and lengths in the micrometre scale. Wood pulp fibres and nanofibrils have been proposed as reinforcement in composite materials. Some of the major motivations have been the potential improvements by using fibres and nanofibrillated materials with respect to e.g. strength, biodegradability and functionality. The purpose of the present work is to review some advances in biocomposite research and development, including three focus areas; structured biocomposites, flexible biocomposites and biomaterials.

  • 25.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Kirsebom, H.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Designing nanocellulose qualities for wound dressings2013Konferensbidrag (Refereegranskat)
  • 26.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Kuznetsova, N.
    Garaeva, M.
    Leirset, Ingebjörg
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Galiullina, G.
    Bleached and unbleached MFC nanobarriers:: Properties and hydrophobisation with hexamethyldisilazane2012Ingår i: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 14Artikel i tidskrift (Refereegranskat)
  • 27.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Miettinen, A
    Hendriks, C.L.L
    Gamstedt, K
    Kataka, M
    Structural characterisation of kraft pulp fibres and their nanofibrillated materials for biodegradable composite applications2011Ingår i: Nanocomposites and Polymers with Analytical Methods, InTech , 2011Kapitel i bok, del av antologi (Refereegranskat)
  • 28.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Powell, L.C
    Cardiff University School of Dentistry, UK; Swansea University, UK.
    Khan, S
    Cardiff University, UK.
    Hill, K.E
    Cardiff University UK.
    Thomas, D.W
    Cardiff University, UK.
    Wood nanocellulose: Characterization and potential application as barrier against wound bacteria2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wood nanocellulose is a novel biomaterial for wound dressing applications. Wood nanocellulose was produced from never-dried P. radiata pulp fibres. The applied pre-treatment was 2,2,6,6-tetramethylpiperidinyl-1-oxyl  (TEMPO) mediated oxidation. To characterise bacterial growth, P. aeruginosa PAO1 biofilms were grown in Mueller Hinton broth on air-dried films. Various microscopy techniques, including atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM) and field-emission scanning electron microscopy (FESEM), were applied to characterise the nanocellulose material and the bacterial-nanocellulose interactions.   Multiscale assessments, including FESEM and AFM, revealed the effective fibrillation of the fibre wall structure, yielding nanofibrils with diameters less than 20 nm and lengths in the micrometre-scale. Importantly, we have demonstrated that the growth of PAO1 was inhibited in the presence of the nanocellulose suspensions when compared to the control. Additionally, SEM imaging revealed distinct clusters of PAO1 cells growing on the surfaces of nanocellulose films. This work highlights the potential usefulness of novel nanocellulose materials in wound dressings with optimized characteristics.

  • 29.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Powell, L.C
    Cardiff University School of Dentistry, UK; Swansea University, UK.
    Nordli, H.R
    NTNU Norwegian University of Science and Technology, Norway.
    Khan, S
    Cardiff University, UK.
    Hill, K.E
    Cardiff University, UK.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Thomas, D.W
    Cardiff University, UK.
    Nanocellulose from wood as a biomaterial for biomedical applications2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    During the last decades major efforts have been made to produce nanocellulose from wood, where the cellulose fibres are disintegrated into individualized nanofibrils with diameters < 20 nm and lengths in the micrometre scale. Production procedures include various pre-treatments, which yield nanocelluloses with varying chemical and structural properties. One important area of research is nanocellulose as a biomaterial with potential applications within the health sector. As an example, the superior mechanical properties, good moisture retention capability and the ability to form elastic macro-porous structures are advantageous properties for utilizing nanocellulose substrates for wound dressings. However, the utilization of nanocellulose as a substrate for wound dressings requires a thorough assessment of the biocompatibility of the material.  In this respect, it has been demonstrated in-vitro that nanocellulose does not exert acute toxic phenomena on fibroblast cells. However, in addition to in-vitro cytotoxicity testing, in-vivo testing of nanocellulose and the ability of nanocellulose to resist bacterial colonization need a closer attention. This presentation will give an overview of the current research on nanocellulose as a biomaterial for wound dressing applications, considering the morphology of nanocellulose structures, mechanical properties, moisture absorption, cytotoxicity tests and nanocellulose-bacteria interactions.

  • 30.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Solheim, O.
    Lenes, M.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Larsen, Å.
    A method for estimating the fibre length in fibre-PLA composites2013Ingår i: Journal of Microscopy, ISSN 0022-2720, E-ISSN 1365-2818, Vol. 250Artikel i tidskrift (Refereegranskat)
  • 31.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Cellulose nanofibrils: production, characterization and applications2011Ingår i: Fine Structure of Papermaking Fibres, Swedish University of Agricultural Sciences , 2011, , s. 13Kapitel i bok, del av antologi (Refereegranskat)
  • 32.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    On the porosity and oxygen barrier properties of cellulose nanofibril-based films2011Konferensbidrag (Refereegranskat)
  • 33.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    On the structure and oxygen transmission rate of biodegradable cellulose nanobarriers2012Ingår i: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 7Artikel i tidskrift (Refereegranskat)
  • 34.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Pretreatment-dependent surface chemistry of wood nanocellulose for pH-sensitive hydrogels2014Ingår i: Journal of biomaterials applications, ISSN 0885-3282, E-ISSN 1530-8022, Vol. 3, nr 29, s. 423-432Artikel i tidskrift (Refereegranskat)
  • 35.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Tobjörk, D.
    Österbacka, R.
    Inkjet-printed silver nanoparticles on nano-engineered cellulose films for electrically conducting structures and organic transistors:: concept and challenges2012Ingår i: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 14Artikel i tidskrift (Refereegranskat)
  • 36.
    Chinga-Carrasco, Gary
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Yu, Y.
    Diserud, O.
    Quantitative Electron Microscopy of Cellulose Nanofibril Structures from Eucalyptus and Pinus Radiata Kraft Pulp Fibres2011Ingår i: Microscopy and Microanalysis, ISSN 1431-9276, E-ISSN 1435-8115, Vol. 17Artikel i tidskrift (Refereegranskat)
  • 37.
    Chniga-Carrasco, Gary
    et al.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Miettinen, Arttu
    Luengo Hendriks, Cris L.
    Gamstedt, Kristofer E.
    Kataja, Markku
    Structural characterisation of kraft pulp fibres and their nanofibrillated materials for biodegradable composite applications2011Ingår i: Nanocomposites and polymers with analytical methods / [ed] Cuppoletti John, InTech, 2011Kapitel i bok, del av antologi (Refereegranskat)
  • 38.
    Djafari Petroudy, Seyed Rahman
    et al.
    Shahid Beheshti University, Iran.
    Ghasemian, Ali
    Gorgan University of Agricultural Sciences and Natural Resources, Iran.
    Resalati, Hossein
    Sari University of Agricultural Sciences and Natural Resources, Iran.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute. NTNU Norwegian University of Science and Technology, Norway.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    The effect of xylan on the fibrillation efficiency of DED bleached soda bagasse pulp and on nanopaper characteristics2015Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, nr 1, s. 385-395Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Xylan is the second most abundant polysaccharide and the most abundant hemicellulose component of soda bagasse pulp. In this study, bleached soda bagasse pulp (SB) and bleached bagasse dissolving pulp (DB) with varying amounts of xylan were fibrillated with a homogenization process. The produced fibrillated materials were used for making nanopaper structures. The surface, physical, mechanical and optical properties of the nanopaper were measured, and the effect of xylan was assessed. Laser profilometry (LP) and field emission scanning electron microscopy were applied to study the degree of the fibrillation. The pulp having the highest xylan content, SB, showed the highest yield of cellulose nanofibrils. Nanopaper produced from SB had a more consolidated structure than that produced from DB. Additionally, SB nanopaper yielded higher tensile strength, lower LP roughness, a higher barrier against oxygen and lower opacity. These results indicate a higher degree of fibrillation of the SB pulp compared to the DB pulp. Hence, the positive effect of xylan for facilitating the fibrillation of the starting pulp fibers was demonstrated.

  • 39. Djafari Petroudy, S.R.
    et al.
    Syverud, Kristin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Ghasemain, A.
    Resalati, H.
    Gregersen, Ø.W.
    Oriented nanopaper (ONP) made of bagasse nanofibrils2012Konferensbidrag (Refereegranskat)
  • 40. Dyrset, N.
    et al.
    Øyaas, K.
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Hobley, T.J.
    Alfrén, J.
    Hreggvidson, G.
    Uusitalo, J.
    Schenck, A.V.
    RISE, Innventia.
    Sustainable Biofuel: Innovations in Bioethanol Production Technologies (SusBioFuel)2012Konferensbidrag (Refereegranskat)
  • 41. Dyrset, Nils
    et al.
    Öyaas, Karin
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Hobley, Timothy John
    Alfthen, Johan
    RISE, Innventia.
    Hreggvidsson, Gudmundir
    Uusitalo, Jaana
    von Schenck, Anna
    RISE, Innventia.
    Ochoa-Fernandez, Esther
    Einen, Jörn
    Sustainable biofuel: innovations in bioethanol production technologies (SusBioFuel)2012Konferensbidrag (Refereegranskat)
  • 42. Enberg, S
    et al.
    Rundlöf, M
    Paulsson, M
    Axelsson, P
    Eriksson,  Ø
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Some causes of formation of colour during storage of hydrogen-peroxide bleached Norway spruce mechanical pulp2014Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 2, nr 29, s. 356-366Artikel i tidskrift (Refereegranskat)
  • 43. Enberg, S
    et al.
    Rundlöf, M
    Paulsson, M
    Axelsson, P
    Eriksson,  Ø
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    The influence of process waters on optical properties during storage of hydrogen-peroxide bleached Norway spruce mechanical pulp2014Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 2, nr 29, s. 344-355Artikel i tidskrift (Refereegranskat)
  • 44.
    Eriksen, O.
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Holmqvist, Claes
    RISE., STFI-Packforsk.
    Mohlin, Ulla-Britt
    RISE., STFI-Packforsk.
    Fibre floc drainage - a possible cause for substantial pressure peaks in low-consistency refiners2008Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, nr 3, s. 321-326Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Is floc drainage a cause for substantial pressure peaks in low-consistency refiners? High-resolution pressure measurements using a sensor mounted in a stator bar have been performed. These show that during the initial stage of a bar crossing, a substantial pressure is sometimes generated, which can reach a level of several MPa. A theoretical model that explains the pressure pulses is presented. The analysis is based on the assumption that a floc of fibres is trapped between the leading edges of the approaching bar surfaces. Water needs to be expelled from the part of the floc that is compressed and enters into the refiner gap. The hydrodynamic resistance to expel the liquid from within the floc is shown to give rise to substantial pressures in the region close to the leading edge of the rotor bar. The estimated pressures are of the same order as the measured values.

  • 45.
    Eriksen, O.
    et al.
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Holmqvist, Claes
    RISE., STFI-Packforsk.
    Mohlin, Ulla-Britt
    RISE., STFI-Packforsk.
    Theoretical outline of the cause for observed cavitation in a low-consistency refiner2008Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, nr 3, s. 315-320Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-frequency pressure measurements in the refining zone have exposed features that strongly indicate that cavitation occurs regularly in low-consistency refiners. In order to explain the cavitation, it is assumed that pulp fibres are trapped between opposing bars on the discs in such a way that liquid is hindered to enter into the refining gap at the leading edge of the stator bar. In order to prevent a void as the rotor bar drags liquid away from the trapped fibres, a counter flow towards the trapped fibres then needs to be set up. This necessitates a low pressure in the gap, in order that liquid from the groove in front of the rotor is accelerated into the gap at the required rate. It appears that this mechanism can yield gap pressures several hundred kPa below that in the grooves. Cavitation bubbles may then form, which subsequently collapse and cause shock waves when the pressure rises after the bar passage.

  • 46.
    Gamelas, José A. F.
    et al.
    University of Coimbra, Portugal.
    Pedrosa, Jorge
    University of Coimbra, Portugal.
    Lourenco, Ana F.
    University of Coimbra, Portugal.
    Mutjo, Peré
    University of Girona, Spain.
    Gonzalez, Israel
    University of Girona, Spain.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Singh, Gurvinder
    NTNU Norwegian University of Science and Technology, Norway.
    Ferreira, Paulo J. T.
    University of Coimbra, Portugal.
    On the morphology of cellulose nanofibrils obtained by TEMPO-mediated oxidation and mechanical treatment2015Ingår i: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 72, s. 28-33Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The morphological properties of cellulose nanofibrils obtained from eucalyptus pulp fibres were assessed. Two samples were produced with the same chemical treatment (NaClO/NaBr/TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidation), but distinct mechanical treatment intensities during homogenization. It was shown that the nanofibrils production yield increases with the mechanical energy. The effect of mechanical treatment on the yield was confirmed by laser profilometry of air-dried nanocellulose films. However, no significant differences were detected regarding the nanofibrils width as measured by atomic force microscopy (AFM) of air-dried films. On the other hand, differences in size were found either by laser diffraction spectroscopy or by dynamic light scattering (DLS) of the cellulose nanofibrils suspensions as a consequence of the differences in the length distribution of both samples. The nanofibrils length of the more nanofibrillated sample was calculated based on the width measured by AFM and the hydrodynamic diameter obtained by DLS. A length value of ca. 600. nm was estimated. The DLS hydrodynamic diameter, as an equivalent spherical diameter, was used to estimate the nanofibrils length assuming a cylinder with the same volume and with the diameter (width) assessed by AFM. A simple method is thus proposed to evaluate the cellulose nanofibrils length combining microscopy and light scattering methods.

  • 47. Ghose, A.
    et al.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Environmental Aspects of Norwegian production of pulp fibres and printing paper2013Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 57Artikel i tidskrift (Refereegranskat)
  • 48.
    Gonzalez, Israel
    et al.
    University of Girona, Sweden.
    Alcalá, Manel
    University of Girona, Sweden.
    Chinga-Carrasco, Gary
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Vilaseca, Fabiola
    University of Girona, Sweden.
    Boufi, Sami
    Université de Sfax, Tunisia.
    Mutjé, Peré
    University of Girona, Sweden.
    From paper to nanopaper: evolution of mechanical and physical properties2014Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, nr 4, s. 2599-2609Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work the evolution of physical and mechanical properties of papers and nanopapers is studied. Handsheets made of eucalyptus fibres reinforced with 0, 25, 50, 75 and 100 wt% of nanofibrillated cellulose (NFC) content were fabricated using a Rapid Köthen-like equipment. The obtained papers and nanopapers were physical- and mechanically-characterized. The results showed a significant increase in density and a reduction of porosity in the samples during their transition from paper to nanopaper; besides, nanopapers were more transparent and smoother than normal papers. These physical changes where more evident with increasing amounts of NFC. Regarding mechanical properties, nanopapers with a 100 wt% content of NFC improved their strength and rigidity in 228 and 317 %, respectively, in comparison with normal papers. The evolution of strength and rigidity from paper to nanopaper was linear in relation to the amount of NFC, which means that the ultimate tensile strength was mainly dependant on nanofibril failure.

  • 49. Gorski, D.
    et al.
    Kure, K-A.
    Mörseburg, Kathrin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    On the relationship between improved energy efficiency in high-consistency refining, fibre and fines properties and critical paper properties2011Konferensbidrag (Refereegranskat)
  • 50. Gorski, D.
    et al.
    Mörseburg, Kathrin
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Axelsson, P.
    Engstrand, P.
    Peroxide-based ATMP refining of Spruce: Energy efficiency, fibre properties and pulp quality2011Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, s. 47-63Artikel i tidskrift (Refereegranskat)
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