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  • 1.
    Abidnejad, Roozbeh
    et al.
    Aalto University, Finland.
    Robertson, Daria
    Aalto University, Finland.
    Khakalo, Alexey
    VTT, Finland.
    Gholami Haghighi Fard, Morteza
    Aalto University, Finland.
    Seppälä, Ari
    Aalto University, Finland.
    Pasquier, Eva
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Tardy, Blaise L.
    Khalifa University, United Arab Emirates.
    Mattos, Bruno D.
    Aalto University, Finland.
    Rojas, Orlando J.
    Aalto University, Finland; University of British Columbia, Canada.
    Gas evolution in self-extinguishing and insulative nanopolysaccharide-based hybrid foams2024In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 346, article id 122646Article in journal (Refereed)
    Abstract [en]

    Lightweight, energy-efficient materials in building construction typically include polymeric and composite foams. However, these materials pose significant fire hazards due to their high combustibility and toxic gas emissions, including carbon monoxide and hydrogen cyanide. This study delves into the latter aspects by comparing hybrid systems based on nanofiber-reinforced silica-based Pickering foams with a synthetic reference (polyurethane foams). The extent and dynamics of fire retardancy and toxic gas evolution were assessed, and the results revealed the benefits of combining the thermal insulation of silica with the structural strength of biobased nanofibers, the latter of which included anionic and phosphorylated cellulose as well as chitin nanofibers. We demonstrate that the nanofiber-reinforced silica-based Pickering foams are thermal insulative and provide both fire safety and energy efficiency. The results set the basis for the practical design of hybrid foams to advance environmental sustainability goals by reducing energy consumption in built environments. 

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  • 2.
    Abitbol, Tiffany
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Mijlkovic, Ana
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Malafronte, Loredana
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Stevanic Srndovic, Jasna
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Larsson, Per Tomas
    RISE Research Institutes of Sweden.
    Lopez-Sanchez, Patricia
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Cellulose nanocrystal/low methoxyl pectin gels produced by internal ionotropic gelation.2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 260, article id 117345Article in journal (Refereed)
    Abstract [en]

    The biotechnological applications of cellulose nanocrystals (CNCs) continue to grow due to their sustainable nature, impressive mechanical, rheological, and emulsifying properties, upscaled production capacity, and compatibility with other materials, such as protein and polysaccharides. In this study, hydrogels from CNCs and pectin, a plant cell wall polysaccharide broadly used in food and pharma, were produced by calcium ion-mediated internal ionotropic gelation (IG). In the absence of pectin, a minimum of 4 wt% CNC was needed to produce self-supporting gels by internal IG, whereas the addition of pectin at 0.5 wt% enabled hydrogel formation at CNC contents as low as 0.5 wt%. Experimental data indicate that CNCs and pectin interact to give robust and self-supporting hydrogels at solid contents below 2.5 %. Potential applications of these gels could be as carriers for controlled release, scaffolds for cell growth, or wherever else distinct and porous network morphologies are required.

  • 3.
    Albornoz-Palma, Gregory
    et al.
    Universidad de Concepción, Chile.
    Betancourt, Fernando
    Universidad de Concepción, Chile.
    Mendonça, Regis
    Universidad de Concepción, Chile.
    Chinga-Carrasco, Gary
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Pereira, Miguel
    RISE - Research Institutes of Sweden, Bioeconomy, PFI. Universidad de Concepción, Chile.
    Relationship between rheological and morphological characteristics of cellulose nanofibrils in dilute dispersions2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, article id 115588Article in journal (Refereed)
    Abstract [en]

    The morphology of cellulose nanofibrils (CNFs), the rheological characteristics of their dispersions, and the corresponding relationships, are fundamental for understanding the properties of the material. This work aims at understanding how the morphological characteristics of the CNFs affect the rheology of the dispersions in the dilute region and to establish a relationship between both properties. A strong relationship was observed between the intrinsic viscosity of the CNF dispersions and their aspect ratio, which can be correlated through the expression ρ[η]=0.051p1.85. When comparing the model obtained in this work to the wormlike chain model, it was possible to verify that these models are independent of the flexibility of the CNFs. Regarding the fibrillation process, the dynamic viscosity only reflects part of the behavior of the morphological properties of the CNFs and does not provide reliable data that would allow these characteristics to be inferred, while the intrinsic viscosity does allow this relationship. 

  • 4.
    Altskär, Annika
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Andersson, R.
    Boldizar, A.
    Koch, K.
    Stading, Mats
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Rigdahl, M.
    Some effects of processing on the molecular structure and morphology of thermoplastic starch2008In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 71, no 4, p. 591-597Article in journal (Refereed)
    Abstract [en]

    Hydroxypropylated and oxidised potato starch (HONPS) was used together with glycerol and water to produce thermoplastic starch. The amount of glycerol was kept constant at 22 parts by weight per 100 parts of dry starch. The thermoplastic starch was converted into films/sheets using three different processing techniques; casting, compression moulding and film blowing. The last two methods represent typical thermoplastic conversion techniques requiring elevated processing temperatures. By means of size-exclusion chromatography, it was found that compression moulding and film blowing led to some degradation of high-molecular weight amylopectin as well as of high-molecular weight amylose-like molecules. The degradation was significantly less pronounced for the cast films. The morphology of the specimens was quite complex and phase separations on different levels were identified. In the cast films and, to a lesser extent, in the compression-moulded specimens, a fine network structure could be distinguished. Such a structure could however not be ascertained in the film-blown material and this is discussed in terms of the thermo-mechanical treatment of the starch materials. © 2007 Elsevier Ltd. All rights reserved.

  • 5. Anthonsen, M.W.
    et al.
    Varum, K.M.
    Hermansson, Ann-Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedelsforskning.
    Smidsrod, O.
    Brant, D.A.
    Aggregates in acidic solutions of chitosans detected by static laser light scattering1994In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 25, no 1, p. 13-23Article in journal (Refereed)
    Abstract [en]

    Chitosans having degrees of N-acetylation, FA, ranging from 0 to 0·6, were randomly degraded to different molecular weights and studied by multi angle static laser light scattering (LLS). Under the given experimental conditions, negative second virial coefficients of the solutions, A?2, revealed the presence of concentration dependent aggregates. Attempts to remove the aggregates, or to influence the aggregation behavior, were made by ultracentrifugation and extensive filtering of the solutions. Modification of the solvent conditions such as pH, ionic strength and temperature were carried out, and chitosan solutions were digested with an acidic proteinase. Non-degraded samples and chitosans prepared by both heterogeneous and homogeneous N-deacetylation of chitin were also studied. In all cases, the negative A?2 remained. However, it was observed that ultracentrifugation and filtering of the solutions decreased the measured molecular weights and radii of gyration, indicating that some of the material of high molecular weight and size could be removed by ultracentrifugation and filtration. The chemical nature of the physical basis of the molecular association was not revealed. Nevertheless, by the use of gel permeation chromatography coupled to an on-line low angle laser light scattering instrument and a differential refractive index concentration detector (HPSEC-LALLS-RI), a bimodal molecular weight distribution was observed in which about 5% of the sample had a very high molecular weight. These results coupled with the positive virial coefficients obtained earlier from osmotic pressure measurements suggest that a small fraction of the chitosan is aggregated to high molecular weight material, probably following a closed association model. Electron microscopy revealed the presence of some supramolecular structures. The positive second virial coefficients obtained earlier from osmometry are in harmony with these findings. The results demonstrate the occurrence of reversible aggregation in chitosan solutions. Static laser light scattering therefore cannot readily be used to determine molecular weights and sizes of chitosans under these conditions. It was not possible to correlate the extent of aggregation with the chemical composition of the chitosans. © 1994.

  • 6.
    Basu, Alex
    et al.
    Uppsala University, Sweden.
    Lindh, Jonas
    Uppsala university, Sweden.
    Ålander, Eva
    RISE - Research Institutes of Sweden, Bioeconomy.
    Strömme, Maria
    Uppsala university, Sweden.
    Ferraz, Natalia
    Uppsala university, Sweden.
    On the use of ion-crosslinked nanocellulose hydrogels for wound healing solutions: Physicochemical properties and application-oriented biocompatibility studies2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, p. 299-308Article in journal (Refereed)
    Abstract [en]

    Calcium ion-crosslinked nanofibrillated cellulose (NFC) hydrogels were investigated as potential materials for wound healing dressings. The physicochemical properties of the hydrogels were examined by rheology and water retention tests. Skin cells and monocytes were selected for application-oriented biocompatibility studies. The NFC hydrogels presented entangled fibrous networks and solid-like behavior. Water retention tests showed the materialÂŽs potential to maintain a suitable moist environment for different type of wounds. The hydrogels did not affect dermal fibroblasts monolayer cultures upon direct contact, as cell monolayers remained intact after application, incubation and removal of the materials. Inflammatory response studies with blood-derived mononuclear cells revealed the inert nature of the hydrogels in terms of cytokine secretion and reactive oxygen species production. Results highlight the great potential of ion-crosslinked NFC hydrogels for the development of advanced wound dressings, where further functionalization of the material could lead to improved properties towards the healing of specific wound types.

  • 7.
    Baş, Yağmur
    et al.
    Luleå University of Technology, Sweden.
    Berglund, Linn
    Luleå University of Technology, Sweden.
    Stevanic, Jasna S
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Scheepers, Gerhard
    RISE Research Institutes of Sweden, Built Environment, Building and Real Estate.
    Niittylä, Totte
    Swedish University of Agricultural Sciences, Sweden.
    Oksman, Kristiina
    Luleå University of Technology, Sweden; University of Toronto, Canada.
    Influence of TEMPO on preparation of softwood nanofibrils and their hydrogel network properties2025In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 348, article id 122812Article in journal (Refereed)
    Abstract [en]

    From an economic and environmental perspective, the use of less chemicals in the production of cellulose nanofibrils (CNFs) is advantageous. In this study, we investigated the oxidation (TEMPO/NaClO2/NaClO, pH 6.8) of softwood (SW) particles with varying amounts of TEMPO (16, 8 or 0 mg g−1 of wood). Following, TEMPO-oxidized SW nanofibrils (TO-SWNFs) were obtained by nanofibrillation and their size, morphology, and crystallite size were assessed. Hydrogel networks of TO-SWNFs were prepared and mechanical properties were measured in dH2O and phosphate buffered saline (PBS) to compare their performance for possible biomedical applications such as wound dressings. The results reveal that the presence of TEMPO is of importance for TO-SWNF network properties, presenting higher eq. H2O absorption (≈2500 %) and elongation at break (≈10 %) with good wet strength (≈180 kPa). In addition, a decrease in use of TEMPO catalyst from 16 to 8 mg g−1 of wood is possible, without detrimental effects on hydrogel network properties (dH2O absorption ≈ 2000 %, elongation at break ≈ 13 %, wet strength ≈ 190 kPa) related to applications as wound dressings. 

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  • 8. Bergstrm, E.M.
    et al.
    Salmen, L.
    RISE, Innventia.
    Kochumalayil, J.
    Berglund, L.
    Plasticized xyloglucan for improved toughness: Thermal and mechanical behaviour2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, no 4, p. 2532-2537Article in journal (Refereed)
  • 9.
    Borrega, Marc
    et al.
    Aalto university, Finland ; VTT Technical Research Centre of Finland Ltd, Finland.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Ahvenainen, Patrik
    University of Helsinki, Finland.
    Ceccherini, Sara
    Aalto university, Finland.
    Maloney, Thaddeus
    Aalto university, Finland.
    Rautkari, Lauri
    Aalto university, Finland.
    Sixta, Herbert
    Aalto university, Finland.
    Birch wood pre-hydrolysis vs pulp post-hydrolysis for the production of xylan-based compounds and cellulose for viscose application2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 190, p. 212-221Article in journal (Refereed)
    Abstract [en]

    Hydrothermal treatments of birch wood and kraft pulp were compared for their ability to extract the xylan and produce viscose-grade pulp. Water post-hydrolysis of kraft pulp produced a high-purity cellulosic pulp with lower viscosity but higher cellulose yield than traditional pre-hydrolysis kraft pulping of wood. Post-hydrolysis of pulp also increased the crystallite dimensions and degree of crystallinity in cellulose, and promoted a higher extent of fibril aggregation. The lower specific surface area in post-hydrolyzed pulps, derived from their larger fibril aggregates, decreased the accessibility of –OH groups. However, this lower accessibility did not seem to decrease the pulp reactivity to derivatizing chemicals. In the aqueous side-stream, the xylose yield was similar in both pre- and post-hydrolysates, although conducting post-hydrolysis of pulp in a flow-through system enabled the recovery of high purity and molar mass (∌10 kDa) xylan for high-value applications.

  • 10.
    Breijaert, T. C.
    et al.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Daniel, G.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Hedlund, D.
    Uppsala University, Sweden.
    Svedlindh, P.
    Uppsala University, Sweden.
    Kessler, V. G.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Granberg, Hjalmar
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Håkansson, Karl
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Seisenbaeva, G. A.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Self-assembly of ferria – nanocellulose composite fibres2022In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 291, article id 119560Article in journal (Refereed)
    Abstract [en]

    An environmentally benign synthesis of a magnetically responsive carboxymethylated cellulose nanofibril-based material is reported. Applied experimental conditions lead to the in-situ formation of magnetite nanoparticles with primary particle sizes of 2.0–4.0 nm or secondary particles of 3.6–16.4 nm depending on whether nucleation occurred between individual carboxymethylated cellulose nanofibrils, or on exposed fibril surfaces. The increase in magnetite particle size on the cellulose fibril surfaces was attributed to Ostwald ripening, while the small particles formed within the carboxymethyl cellulose aggregates were presumably due to steric interactions. The magnetite nanoparticles were capable of coordinating to carboxymethylated cellulose nanofibrils to form large “fibre-like” assemblies. The confinement of small particles within aggregates of reductive cellulose molecules was most likely responsible for excellent conservation of magnetic characteristics on storage of this material. The possibility for using the material in drug delivery applications with release rate controlled by daylight illumination is presented. © 2022 The Author(s)

  • 11.
    Cernencu, Alexandra
    et al.
    University Politehnica of Bucharest, Romania.
    Lungu, Adriana
    University Politehnica of Bucharest, Romania.
    Stancu, Izabela
    University Politehnica of Bucharest, Romania.
    Serafim, Andrada
    University Politehnica of Bucharest, Romania.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Iovu, Horia
    University Politehnica of Bucharest, Romania; Academy of Romanian Scientists, Romania.
    Bioinspired 3D printable pectin-nanocellulose ink formulations2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 220, p. 12-21Article in journal (Refereed)
    Abstract [en]

    The assessment of several ink formulations for 3D printing based on two natural macromolecular compounds is presented. In the current research we have exploited the fast crosslinking potential of pectin and the remarkable shear-thinning properties of carboxylated cellulose nanofibrils, which is known to induce a desired viscoelastic behavior. Prior to 3D printing, the viscoelastic properties of the polysaccharide inks were evaluated by rheological measurements and injectability tests. The reliance of the printing parameters on the ink composition was established through one-dimensional lines printing, the base units of 3D-structures. The performance of the 3D-printed structures after ionic cross-linking was evaluated in terms of mechanical properties and rehydration behavior. MicroCT was also used to evaluate the morphology of the 3D-printed objects regarding the effect of pectin/nanocellulose ratio on the geometrical features of scaffolds. The proportionality between the two polymers proved to be the determining factor for the firmness and strength of the printed objects. © 2019

  • 12.
    Chen, Fei
    et al.
    KTH Royal Institute of Technology, Sweden.
    Gällstedt, Mikael
    RISE, Innventia.
    Olsson, Richard T.
    KTH Royal Institute of Technology, Sweden.
    Gedde, Ulf W.
    KTH Royal Institute of Technology, Sweden.
    Hedenqvist, Mikael S.
    KTH Royal Institute of Technology, Sweden.
    Unusual effects of monocarboxylic acids on the structure and on the transport and mechanical properties of chitosan films2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 132, p. 419-429, article id 10041Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to study the transport of monocarboxylic acids in chitosan films, since this is important for understanding and predicting the drying kinetics of chitosan from aqueous solutions. Despite the wealth of data on chitosan films prepared from aqueous monocarboxylic acid solutions, this transport has not been reported. Chitosan films were exposed to formic, acetic, propionic and butyric acid vapours, it was found that the rate of uptake decreased with increasing molecular size. The equilibration time was unexpectedly long, especially for propionic and butyric acid, nine months. A clear two-stage uptake curve was observed for propionic acid. Evidently, the rate of uptake was determined by acid-induced changes in the material. X-ray diffraction and infrared spectroscopy indicated that the structure of the chitosan acetate and buffered chitosan films changed during exposure to acid and during the subsequent drying. The dried films previously exposed to the acid showed less crystalline features than the original material and a novel repeating structure possibly involving acid molecules. The molar mass of the chitosan decreased on exposure to acid but tensile tests revealed that the films were always ductile. The films exposed to acid vapour (propionic and butyric acid) for the longest period of time were insoluble in the size-exclusion chromatography eluent, and they were also the most ductile/extensible of all samples studied.

  • 13.
    Chinga Carrasco, Gary
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Pasquier, Eva
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Solberg, Amalie
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Leirset, Ingebjørg
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Stevanic Srndovic, Jasna
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Rosendahl, Jennifer
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology.
    Håkansson, Joakim
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology. University of Gothenburg, Sweden.
    Carboxylated nanocellulose for wound healing applications – Increase of washing efficiency after chemical pre-treatment and stability of homogenized gels over 10 months2023In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 314, article id 120923Article in journal (Refereed)
    Abstract [en]

    To commercialize a biomedical product as a medical device, reproducibility of production and time-stability are important parameters. Studies of reproducibility are lacking in the literature. Additionally, chemical pre-treatments of wood fibres to produce highly fibrillated cellulose nanofibrils (CNF) seem to be demanding in terms of production efficiency, being a bottleneck for industrial upscaling. In this study, we evaluated the effect of pH on the dewatering time and washing steps of 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO)-mediated oxidized wood fibres when applying 3.8 mmol NaClO/g cellulose. The results indicate that the method does not affect the carboxylation of the nanocelluloses, and levels of approximately 1390 μmol/g were obtained with good reproducibility. The washing time of a Low-pH sample was reduced to 1/5 of the time required for washing a Control sample. Additionally, the stability of the CNF samples was assessed over 10 months and changes were quantified, the most pronounced were the increase of potential residual fibre aggregates, reduction of viscosity and increase of carboxylic acid content. The cytotoxicity and skin irritation potential were not affected by the detected differences between the Control and Low-pH samples. Importantly, the antibacterial effect of the carboxylated CNFs against S. aureus and P. aeruginosa was confirmed. © 2023 The Authors

  • 14.
    Cortes Ruiz, Maria F.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Garemark, Jonas
    ETH Zurich, Switzerland.
    Ritter, Maximilian
    ETH Zurich, Switzerland.
    Brusentsev, Yury
    Åbo Akademi, Finland.
    Larsson, Per Tomas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. KTH Royal Institute of Technology, Sweden.
    Olsén, Peter
    KTH Royal Institute of Technology, Sweden.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden .
    Structure-properties relationships of defined CNF single-networks crosslinked by telechelic PEGs2024In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 339, article id 122245Article in journal (Refereed)
    Abstract [en]

    The high structural anisotropy and colloidal stability of cellulose nanofibrils’ enable the creation of self-standing fibrillar hydrogel networks at very low solid contents. Adding methacrylate moieties on the surface of TEMPO oxidized CNFs allows the formation of more robust covalently crosslinked networks by free radical polymerization of acrylic monomers, exploiting the mechanical properties of these networks more efficiently. This technique yields strong and elastic networks but with an undefined network structure. In this work, we use acrylate-capped telechelic polymers derived from the step-growth polymerization of PEG diacrylate and dithiothreitol to crosslink methacrylated TEMPO-oxidized cellulose nanofibrils (MATO CNF). This combination resulted in flexible and strong hydrogels, as observed through rheological studies, compression and tensile loading. The structure and mechanical properties of these hydrogel networks were found to depend on the dimensions of the CNFs and polymer crosslinkers. The structure of the networks and the role of individual components were evaluated with SAXS (Small-Angle X-ray Scattering) and photo-rheology. A thorough understanding of hybrid CNF/polymer networks and how to best exploit the capacity of these networks enable further advancement of cellulose-based materials for applications in packaging, soft robotics, and biomedical engineering.

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  • 15.
    Djafari Petroudy, Seyed Rahman
    et al.
    NTNU Norwegian University of Science and Technology, Norway; Gorgan University of Agricultural Sciences and Natural Resources, Iran.
    Syverud, Kristin
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Chinga-Carrasco, Gary
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Ghasemain, Ali
    Gorgan University of Agricultural Sciences and Natural Resources, Iran.
    Resalati, Hossein
    Gorgan University of Agricultural Sciences and Natural Resources, Iran.
    Effects of bagasse microfibrillated cellulose and cationic polyacrylamide on key properties of bagasse paper2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 99, p. 311-318Article in journal (Refereed)
    Abstract [en]

    This study explores the benefits of using bagasse microfibrillated cellulose (MFC) in bagasse paper. Two different types of MFC were produced from DED bleached soda bagasse pulp. The MFC was added to soda bagasse pulp furnishes in different amounts. Cationic polyacrylamide (C-PAM) was selected as retention aid. The results show that addition of MFC increased the strength of paper as expected. Interestingly, 1% MFC in combination with 0.1% C-PAM yielded similar drainage time as the reference pulp, which did not contain MFC. In addition, the samples containing 1% MFC and 0.1% C-PAM yielded (i) a significant increment of the tensile index, (ii) a minor decrease of opacity and (iii) preserved Gurley porosity. Hence, this study proves that small fractions of MFC in combination with adequate retention aids can have positive effects with respect to paper properties, which is most interesting from an industrial point of view.

  • 16. Fernandes, S.C.M.
    et al.
    Freire, C.S.R.
    Silvestre, A.J.D.
    Pascoal Neto, C.
    Gandini, A.
    Berglund, Lars A.
    Salmen, Lennart
    RISE, Innventia.
    Transparent chitosan films reinforced with a high content of nanofibrillated cellulose2010In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 81, no 2, p. 394-401Article in journal (Refereed)
    Abstract [en]

    This paper reports the preparation and characterization of nanocomposite films based on different chitosan matrices and nanofibrillated cellulose (NFC) for the purpose of improving strength properties. The nanocomposite films were prepared by a simple procedure of casting a water-based suspension of chitosan and NFC, and were characterized by several techniques: namely SEM, X-ray diffraction, visible spectrophotometry, TGA, tensile and dynamic-mechanical analysis. The films obtained were shown to be highly transparent (transmittance varying between 90 and 20% depending on the type of chitosan and NFC content), flexible, displayed better mechanical properties, with a maximum increment on the Young’s modulus of 78% and 150% for high molecular weight (HCH) and water-soluble high molecular weight (WSHCH) filled chitosans, respectively; and of 200% and 320% for low molecular weight (LCH) and water-soluble filled (WSLCH) chitosans, respectively. The filled films also showed increased thermal stability, with, for example, an increase in the initial degradation temperature (Tdi) from 227 °C in the unfilled LCH film up to 271 °C in filled LCHNFC50% nanocomposite films, and a maximum degradation temperature (Td1) raising from 304 °C to 313 °C for the same materials.

  • 17.
    Fontes-Candia, Cynthia
    et al.
    IATA-CSIC, Spain.
    Lopez-Sanchez, Patricia
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Ström, Anna
    Chalmers University of Technology, Sweden.
    Martínez, Juan
    ALBA Synchrotron Light Facility, Spain.
    Salvador, Ana
    IATA-CSIC, Spain.
    Sanz, Teresa
    IATA-CSIC, Spain.
    Trefna, Hana
    Chalmers University of Technology, Sweden.
    López-Rubio, Amparo
    IATA-CSIC, Spain.
    Martínez-Sanz, Marta
    IATA-CSIC, Spain.
    Maximizing the oil content in polysaccharide-based emulsion gels for the development of tissue mimicking phantoms2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 256, article id 117496Article in journal (Refereed)
    Abstract [en]

    Formulations based on agar and κ-carrageenan were investigated for the production of emulsion gels applicable as tissue mimicking phantoms. The effects of the polysaccharide matrix, the oil content and the presence of surfactants on the micro-/nanostructure, rheology, and mechanical and dielectric properties were investigated. Results showed a high capacity of the agar to stabilize oil droplets, producing gels with smaller (10−21 μm) and more uniform oil droplets. The addition of surfactants allowed increasing the oil content and reduced the gel strength and stiffness down to 57 % and 34 %, respectively. The permittivity and conductivity of the gels were reduced by increasing the oil content, especially in the agar gels (18.8 and 0.05 S/m, respectively), producing materials with dielectric properties similar to those of low-water content tissues. These results evidence the suitability of these polysaccharides to design a variety of tissue mimicking phantoms with a broad range of mechanical and dielectric properties. 

  • 18.
    From, Malin
    et al.
    Mid Sweden University, Sweden; Nouryon Pulp and Performance Chemicals AB, Sweden.
    Larsson, Per Tomas
    RISE Research Institutes of Sweden, Bioeconomy and Health.
    Andreasson, Bo
    Nouryon Pulp and Performance Chemicals AB, Sweden.
    Medronho, Bruno
    Mid Sweden University, Sweden; University of Algarve, Portugal.
    Svanedal, Ida
    Mid Sweden University, Sweden.
    Edlund, Håkan
    Mid Sweden University, Sweden.
    Norgren, Magnus
    Mid Sweden University, Sweden.
    Tuning the properties of regenerated cellulose: Effects of polarity and water solubility of the coagulation medium2020In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 236, article id 116068Article in journal (Refereed)
    Abstract [en]

    In this study, the effect of different alcohols and esters as a coagulation medium in the regeneration of cellulose dissolved in an aqueous LiOH-urea-based solvent was thoroughly investigated using various methods such as solid state NMR, X-ray diffraction, water contact angle, oxygen gas permeability, mechanical testing, and scanning electron microscopy. It was observed that several material properties of the regenerated cellulose films follow trends that correlate to the degree of cellulose II crystallinity, which is determined to be set by the miscibility of the coagulant medium (nonsolvent) and the aqueous alkali cellulose solvent rather than the nonsolvents’ polarity. This article provides an insight, thus creating a possibility to carefully tune and control the cellulose material properties when tailor-made for different applications.

  • 19.
    Gillgren, Thomas
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Blennow, A.
    Pettersson, Anders
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Stading, Mats
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Modulating rheo-kinetics of native starch films towards improved wet-strength2011In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 83, no 2, p. 383-391Article in journal (Refereed)
    Abstract [en]

    Starch directly functionalised in the plant by modulation of its biosynthesis by mutagenesis and transgene technology was exploited for its extended functionality beyond the normal variation. In this study we investigated the rheological and mechanical properties of films from such structurally highly different starch types derived from potato and cereal sources of normal and mutant and transgenic backgrounds. A new improved technique was developed to permit the dynamic mechanical analysis of films in the presence of water. It was found that the amylose content was decisive for the mechanical properties of the films - an increase in the amylose content resulted in both a higher stress and strain at break. Interestingly, there was no correlation between the speed of hydration and mechanical water resistance of the films. Generally, the films were clear and transparent, even after wetting. Transgenic potato starch with a low content of phosphate displayed an extraordinary combination of high robustness, transparency, mechanical strength and extensibility even in a wet condition. The combination of optimal phosphate and amylose concentrations in this sample probably favoured hydration and amorphisation without compromising the inter-chain interactions of the polysaccharide network. © 2010 Elsevier Ltd. All rights reserved.

  • 20.
    Guo, Juan
    et al.
    Chinese Academy of Forestry, China.
    Song, Kunlin
    Chinese Academy of Forestry, China.
    Salmen, Lennart
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Yin, Yafang
    Chinese Academy of Forestry, China; KTH Royal Institute of Technology, Sweden.
    Changes of wood cell walls in response to hygro-mechanical steam treatment2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 115, p. 207-214Article in journal (Refereed)
    Abstract [en]

    The effects of compression combined with steam treatment (CS-treatment), i.e. a hygro-mechanical steam treatment on Spruce wood were studied on a cell-structure level to understand the chemical and physical changes of the secondary cell wall occurring under such conditions. Specially, imaging FT-IR microscopy, nanoindentation and dynamic vapour absorption were used to track changes in the chemical structure, in micromechanical and hygroscopic properties. It was shown that CS-treatment resulted in different changes in morphological, chemical and physical properties of the cell wall, in comparison with those under pure steam treatment. After CS-treatment, the cellular structure displayed significant deformations, and the biopolymer components, e.g. hemicellulose and lignin, were degraded, resulting in decreased hygroscopicity and increased mechanical properties of the wood compared to both untreated and steam treated wood. Moreover, CS-treatment resulted in a higher degree of degradation especially in earlywood compared to a more uniform behaviour of wood treated only by steam.

  • 21.
    Hashemifesharaki, Reza
    et al.
    Mute Hammer LLC, USA.
    Xanthakis, Epameinondas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Altintas, Zeznep
    Technical University of Berlin, Germany.
    Guo, Ya
    Jiangnan University, China.
    Gharibzahedi, Seyed
    Islamic Azad University, Iran.
    Microwave-assisted extraction of polysaccharides from the marshmallow roots: Optimization, purification, structure, and bioactivity2020In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 240, article id 116301Article in journal (Refereed)
    Abstract [en]

    The process optimization and biological characterization of marshmallow root polysaccharides (MRPs) obtained from the microwave-assisted extraction (MAE) were studied. The highest MAE-yield (14.47%) was optimized at 457.32 W and 75 °C for 26 min. The extracted crude polysaccharides were purified using ion-exchange and gel-filtration chromatographies and eluted a single symmetrical narrow peak, showing a homogenous fraction (MRP-P1) with a molecular weight of 4.87 × 104 Da. The surface morphology of polysaccharides and functional groups of MRP-P1 were determined by employing scanning electron microscopy and Fourier-transform infrared spectroscopy, respectively. The major monosaccharide composition of MRPs were the three monomers of rhamnose, galactose, and glucose. The antioxidant, antimicrobial, and antitumor activities were increased in a concentration-dependent manner (1.0-10.0 mg/mL). MRP-P1 exhibited a strong in vitro antiproliferative activity against lung (A549), liver (HepG2), and breast (MCF-7) cancer cells. The anticancer activity of polysaccharides extracted under optimal MAE conditions was highly associated with their antioxidant and antibacterial functions. 

  • 22.
    Heggset, Ellinor B
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Chinga-Carrasco, Gary
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI. NTNU Norwegian University of Science and Technology, Norway.
    Temperature stability of nanocellulose dispersions2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 157, p. 114-121Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibrils (CNF) have potential as rheology modifiers of water based fluids, e.g. drilling fluids for use in oil wells or as additives in injection water for enhanced oil recovery (EOR). The temperature in oil wells can be high (>100 °C), and the retention time long; days for drilling fluids and months for EOR fluids. Hence, it is important to assess the temperature stability over time of nanocellulose dispersions to clarify their suitability as rheology modifiers of water based fluids at such harsh conditions. Dispersions of CNF produced mechanically, by using TEMPO mediated oxidation and by using carboxymethylation as pretreatment, in addition to cellulose nanocrystals (CNC), have been subjected to heat aging. Temperature stability was best for CNC and for mechanically produced CNF that were stable after heating to 140 °C for three days. The effect of additives was evaluated; cesium formate and sodium formate increased the temperature stability of the dispersions, while there was no effect of using phosphate buffer.

  • 23.
    Hermansson, Ann-Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Svenska livmedelsinstitutet.
    Rheological and microstructural evidence for transient states during gelation of kappa-carrageenan in the presence of potassium1989In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 10, no 3, p. 163-181Article in journal (Refereed)
    Abstract [en]

    Kappa-carrageenan gelation was studied by a combination of electron microscopy and dynamic viscoelastic measurements. There was an initial maximum in the storage modulus during cooling and gel formation of 1% kappa-carrageenan in the presence of potassium. The structure of the transient state was found to consist of a fine network structure, where the junction zones were believed to be double helices. The structure had the characteristics of a true gel but was unstable. When the temperature was lowered aggregation took place and the fine network structure was partly broken down. Ordered superstrands formed which aligned themselves in parallel or were densely packed together. The degree of aggregation depended on the potassium ion concentration. In the weakest gel formed in 0·01 m KCl, the superstrands did not form a network but were rather dispersed in the fine network structure. In 0·1 and 0·2 m KCl the superstrands formed a three-dimensional network, where aligned superstrands formed the junction zones and branching occurred when superstrands deviated from each other and aligned with new superstrands. In 0·1 m KCl the supermolecular network dominated but in 0·2 m KCl a mixed gel was formed of the fine network and the coarse supermolecular network. The mixed gel gave rise to the firmest gel. © 1989.

  • 24.
    Hermansson, Ann-Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Svenska livmedelsinstitutet.
    Shear induced changes in the viscoelastic behaviour of heat treated potato starch dispersions1990In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 13, no 1, p. 29-45Article in journal (Refereed)
    Abstract [en]

    The viscoelastic behaviour of native potato starch dispersions was studied using dynamic viscoelastic measurements. The influence of various shear and heat treatments of gelatinized starch pastes were compared in the concentration range 4-10%. Heating had a minor effect compared to the effect of shear treatment. The complex modulus (G*) decreased to about 5% of its maximum value when the starch pastes were sheared during the heating cycle, whereas heating alone resulted in a decrease to about 60% of the maximum G* value. Shear also caused an increase in the phase angle and characteristic changes were observed with regard to frequency and strain dependencies. When samples were prepared in a Brabender viscograph, the shear induced changes took place early in the pasting cycle. The characteristics of the concentration dependence differed due to the shear history of the sample. Peculiar concentration dependencies, some even negative, could be obtained from samples with different shear histories. The results imply that even moderate shear treatment gives rise to structure changes which are reflected by a transition in the type of the viscoelastic behaviour. © 1990.

  • 25.
    Hermansson, Elin
    et al.
    Chalmers University of Technology, Sweden.
    Schuster, Erich
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience, Structure Design. Chalmers University of Technology, Sweden.
    Lindgren, Lars
    Chalmers University of Technology, Sweden; Mölnlycke Health Care, Sweden.
    Altskär, Annika
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience, Structure Design. Chalmers University of Technology, Sweden.
    Ström, Anna
    Chalmers University of Technology, Sweden.
    Impact of solvent quality on the network strength and structure of alginate gels2016In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 144, p. 289-296Article in journal (Refereed)
    Abstract [en]

    The influence of the mixture of water and alcohols on the solubility and properties of alginate and its calcium-induced gels is of interest for the food, wound care and pharmaceutical industries. The solvent quality of water with increasing amounts of ethanol (0-20%) on alginate was studied using intrinsic viscosity. The effect of ethanol addition on the rheological and mechanical properties of calcium alginate gels was determined. Small-angle X-ray scattering and transmission electron microscopy were used to study the network structure. It is shown that the addition of ethanol up to 15% (wt) increases the extension of the alginate chain, which correlates with increased moduli and stress being required to fracture the gels. The extension of the polymer chain is reduced at 20% (wt) ethanol, which is followed by reduced moduli and stress at breakage of the gels. The network structure of gels at high ethanol concentrations (24%) is characterized by thick and poorly connected network strands.

  • 26.
    Jack, Alison A.
    et al.
    Cardiff University School of Dentistry, UK.
    Nordli, Henriette R.
    NTNU, Norway.
    Powell, Lydia C.
    Cardiff University School of Dentistry, UK.
    Powell, Kate A.
    Cardiff University School of Dentistry, UK.
    Kishnani, Himanshu
    Cardiff University School of Dentistry, UK.
    Johnsen, Per Olav
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Pukstad, Brita
    Trondheim University Hospital, Norway.
    Thomas, David W.
    Cardiff University School of Dentistry, UK.
    Chinga-Carrasco, Gary
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Hill, Katja E.
    Cardiff University School of Dentistry, UK.
    The interaction of wood nanocellulose dressings and the wound pathogen P. aeruginosa2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 157, p. 1955-1962Article in journal (Refereed)
    Abstract [en]

    Chronic wounds pose an increasingly significant worldwide economic burden (over £1 billion per annum in the UK alone). With the escalation in global obesity and diabetes, chronic wounds will increasingly be a significant cause of morbidity and mortality. Cellulose nanofibrils (CNF) are highly versatile and can be tailored with specific physical properties to produce an assortment of three-dimensional structures (hydrogels, aerogels or films), for subsequent utilization as wound dressing materials. Growth curves using CNF (diameter <20 nm) in suspension demonstrated an interesting dose-dependent inhibition of bacterial growth. In addition, analysis of biofilm formation (Pseudomonas aeruginosa PAO1) on nanocellulose aerogels (20 g/m2) revealed significantly less biofilm biomass with decreasing aerogel porosity and surface roughness. Importantly, virulence factor production by P. aeruginosa in the presence of nanocellulose materials, quantified for the first time, was unaffected (p > 0.05) over 24 h. These data demonstrate the potential of nanocellulose materials in the development of novel dressings that may afford significant clinical potential.

  • 27.
    Kaschuk, J. J.
    et al.
    Aalto University, Finland; University of British Columbia, Canada.
    Al Haj, Y.
    Aalto University, Finland.
    Valdez Garcia, J.
    University of Turku, Finland.
    Kamppinen, A.
    University of Turku, Finland.
    Rojas, O. J.
    Aalto University, Finland; University of British Columbia, Canada.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden. EPFL Institute of Materials, School of Engineering, Switzerland.
    Miettunen, K.
    University of Turku, Finland.
    Vapaavuori, J.
    Aalto University, Finland.
    Processing factors affecting roughness, optical and mechanical properties of nanocellulose films for optoelectronics2024In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 332, article id 121877Article in journal (Refereed)
    Abstract [en]

    This work aims to understand how nanocellulose (NC) processing can modify the key characteristics of NC films to align with the main requirements for high-performance optoelectronics. The performance of these devices relies heavily on the light transmittance of the substrate, which serves as a mechanical support and optimizes light interactions with the photoactive component. Critical variables that determine the optical and mechanical properties of the films include the morphology of cellulose nanofibrils (CNF), as well as the concentration and turbidity of the respective aqueous suspensions. This study demonstrates that achieving high transparency was possible by reducing the grammage and adjusting the drying temperature through hot pressing. Furthermore, the use of modified CNF, specifically carboxylated CNF, resulted in more transparent films due to a higher nanosized fraction and lower turbidity. The mechanical properties of the films depended on their structure, homogeneity (spatial uniformity of local grammage), and electrokinetic factors, such as the presence of electrostatic charges on CNF. Additionally, we investigated the angle-dependent transmittance of the CNF films, since solar devices usually operate under indirect light. This work demonstrates the importance of a systematic approach to the optimization of cellulose films, providing valuable insight into the optoelectronic field. 

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  • 28.
    Kotov, N.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Larsson, P. A.
    KTH Royal Institute of Technology, Sweden.
    Jain, K.
    KTH Royal Institute of Technology, Sweden.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Cernescu, A.
    Attocube systems AG, Germany.
    Wågberg, L.
    KTH Royal Institute of Technology, Sweden.
    Johnson, C. M.
    KTH Royal Institute of Technology, Sweden.
    Elucidating the fine-scale structural morphology of nanocellulose by nano infrared spectroscopy2023In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 302, article id 120320Article in journal (Refereed)
    Abstract [en]

    Nanoscale infrared (IR) spectroscopy and microscopy, enabling the acquisition of IR spectra and images with a lateral resolution of 20 nm, is employed to chemically characterize individual cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) to elucidate if the CNCs and CNFs consist of alternating crystalline and amorphous domains along the CNF/CNC. The high lateral resolution enables studies of the nanoscale morphology at different domains of the CNFs/CNCs: flat segments, kinks, twisted areas, and end points. The types of nanocellulose investigated are CNFs from tunicate, CNCs from cotton, and anionic and cationic wood-derived CNFs. All nano-FTIR spectra acquired from the different samples and different domains of the individual nanocellulose particles resemble a spectrum of crystalline cellulose, suggesting that the non-crystalline cellulose signal observed in macroscopic measurements of nanocellulose most likely originate from cellulose chains present at the surface of the nanocellulose particles. 

  • 29. Larsson, M.
    et al.
    Viriden, A.
    Stading, Mats
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Larsson, A.
    The influence of HPMC substitution pattern on solid-state properties2010In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 82, no 4, p. 1074-1081Article in journal (Refereed)
    Abstract [en]

    The solid-state properties were studied for different batches of hydroxypropyl methylcellulose (HPMC). The batches had similar chemical composition, but different degree of heterogeneity with regard to the distribution of the substituents along the polymer chains. The glass transition temperature, Tg, was analysed using a new developed method where dynamic mechanic analysis, DMA, was performed in compression mode on compacts, utilizing a wedge-shaped probe. The method was verified by conventional DMA on films. Molecular interactions were studied using FT-IR. In addition, the water vapour sorption was determined by gravimetric measurements and the plasticization by water vapour was studied on film samples using DMA. The results revealed a linear relationship between increasing Tg and increasing percent glucose liberated after enzyme hydrolysis. The percent glucose liberated can in turn be considered to account for both the heterogeneity of the substituents and the total degree of substitution. The results indicated that more heterogeneously substituted cellulose derivatives and derivates with a lower degree of substitution had stronger interactions between polymer chains. As expected from these results, some small difference in the plasticization by water vapour could be detected. However, no significant differences were found in molecular interactions using FT-IR or in the sorption of water vapour. The correlation between heterogeneity in the distribution of the substituents and Tg is of much interest as heterogeneously substituted batches of HPMC have been previously shown to exhibit very different behaviour in solution and in gelling tablets. © 2010 Elsevier Ltd.

  • 30.
    Lundin, Leif
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedelsforskning.
    Hermansson, Ann-Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedelsforskning.
    Influence of locust bean gum on the rheological behaviour and microstructure of K-?-carrageenan1995In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 28, no 2, p. 91-99Article in journal (Refereed)
    Abstract [en]

    Mixtures of ?-carrageenan-locust bean gum (LBG) were analysed by transmission electron microscopy and dynamic viscoelastic measurements. The effect of two different mannose:galactose (M:G) ratios of LBG on the rheology and microstructure of ?-carrageenan in KCl was studied. The rheological differences observed in the mixed gel as LBGs were added were found to be dependent on M:G ratio, salt concentration and LBG content. Monolayers of dilute samples of ?-carrageenan mixed with LBGs in varying ratios in 0.10 M KCl were visualised by low-angle rotary metal shadowing for transmission electron microscopy. The results obtained showed that LBG hindered the self-association of ?-carrageenan, and that the effect was enhanced at a higher M:G ratio and as the LBG contents were increased. Small deformation viscoelastic measurements were performed on ?-carrageenan-LBG mixtures in 0.050 and 0.10 M KCl at constant temperatures of 38 and 48 °C, respectively. Increased rheological stability was observed for mixtures containing a relatively high LBG content. Mixtures with a relatively low LBG content showed a maximum in storage modulus and an increase in phase angle. The stabilising effect of LBG on the rheology of the blends was more effective for the LBG with high M:G and as the LBG content was increased. © 1996.

  • 31.
    Lundin, Leif
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Hermansson, Ann-Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Rheology and microstructure of Ca- and Na-?-carrageenan and locust bean gum gels1998In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 34, no 4, p. 365-375Article in journal (Refereed)
    Abstract [en]

    The viscoelastic and microstructural influences of 0.1-0.6% locust bean gum on 0.5 or 1.0% ?-carrageenan gels, in different ionic environments, have been studied using small deformation oscillatory measurements and transmission electron microscopy (TEM). The results from the rheological measurements showed synergistic effects in the storage modulus, G?, as locust bean gum, of two different mannose to galactose ratios (3 and 5), was mixed with ion-exchanged Na-and Ca-?-carrageenan, in 0.25 M NaCl and 0.030 M CaCl2, respectively. The increase in G? was dependent on the mannose to galactose ratio, polymer concentrations, and ionic environment. At the supermolecular level, the microstructure of dilute samples has been visualised using low angle rotary metal shadowing for TEM. In the presence of sodium and calcium ions, the self-association of ?-carrageenan helices is moderate to low. Locust bean gum did not influence the supermolecular structure of ?-carrageenan to any large extent. The microstructure of the gels at the network level was studied using plastic embedding and thin sectioning for TEM. In both sodium and calcium ionic environments, the mixed gels showed a more homogeneous and connective network structure. © 1998 Elsevier Science Ltd. All rights reserved.

  • 32.
    Lundin, Leif
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedelsforskning.
    Hermansson, Ann-Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedelsforskning.
    Supermolecular aspects of xanthan-locust bean gum gels based on rheology and electron microscopy1995In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 26, no 2, p. 129-140Article in journal (Refereed)
    Abstract [en]

    The viscoelastic properties and supermolecular structure of synergistic gels, formed by xanthan and locust bean gum (LBG) of two different mannose:galactose ratios (M:G), have been investigated by small deformation viscoelastic measurements and by low angle rotary-shadowing for transmission electron microscopy. The rheological properties at 20 °C for mixtures subjected to heating and cooling cycles in the temperature range 30-80 °C were found to be dependent on the M:G ratio. Mixtures of xanthan and LBG mixed at temperatures ?40 °C were found to form true gels with low phase angles. Blends of xanthan and LBG with a low M:G ratio did not show any increase in synergistic effects as the temperature was increased, whilst the mixture of xanthan and LBG with a high M:G ratio showed a strong increase in synergistic effects as the temperature was raised above 60 °C. A difference in gelation temperature (Tg) of ~13 °C was observed between the mixtures of xanthan and the two LBG fractions. The Tg for xanthan with a high M:G ratio was ~53 °C, whilst the Tg for mixtures of xanthan and LBG with a low M:G ratio was ~40 °C. Results obtained using electron microscopy showed that the xanthan-LBG network was formed from xanthan supermolecular strands, and addition of LBG did not influence the xanthan structure. The observed structural features of the gels were independent of heat treatment and LBG fraction. The structural similarities and rheological differences observed between xanthan and the LBG fractions are discussed in comparison with existing interaction models at the molecular level. Based on these results, a speculative network model at the supermolecular level is presented. © 1995.

  • 33.
    Lundqvist, Jon
    et al.
    Lund university, Sweden.
    Jacobs, Anna
    STFI.
    Palm, Magnus
    Lund university, Sweden.
    Zacchi, Guido
    Lund university, Sweden.
    Dahlman, Olof
    STFI.
    Stålbrand, Henrik
    Lund university, Sweden.
    Characterization of galactoglucomannan extracted from spruce (Picea abies) by heat-fractionation at different conditions2003In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 51, no 2, p. 203-211Article in journal (Refereed)
  • 34. López-Rubio, A.
    et al.
    Lagaron, J. M.
    Ankerfors, Mikael
    RISE, STFI-Packforsk.
    Lindström, Tom
    RISE, STFI-Packforsk.
    Nordqvist, D.
    Mattozzi, A.
    Hedenqvist, M. S.
    Erratum to "Enhanced film forming and film properties of amylopectin using micro-fibrillated cellulose" [Carbohydr. Polym. 68 (2007) 718-727] (DOI:10.1016/j.carbpol.2006.08.008)2008In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 71, no 3, p. 482-Article in journal (Refereed)
  • 35.
    Martinez-Sanz, Marta
    et al.
    IATA-CSIC, Spain.
    Ström, Anna K.
    Chalmers University of Technology, Sweden.
    Lopez-Sanchez, Patricia
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Agrifood and Bioscience.
    Knutsen, Svein Halvor
    Nofima AS, Norway.
    Ballance, Simon
    Nofima AS, Norway.
    Zobel, Hanne Kristine
    Nofima AS, Norway.
    Sokolova, Anna
    Australian Nuclear Science and Technology Organisation, Australia.
    Gilbert, Elliot
    Australian Nuclear Science and Technology Organisation, Australia; University of Queensland, Australia.
    Lopez-Rubio, Amparo
    IATA-CSIC, Spain.
    Advanced structural characterisation of agar-based hydrogels: Rheological and small angle scattering studies2020In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 236, article id 115655Article in journal (Refereed)
    Abstract [en]

    Agar-based extracts from Gelidium sesquipedale were generated by heat and combined heat-sonication, with and without the application of alkali pre-treatment. Pre-treatment yielded extracts with greater agar contents; however, it produced partial degradation of the agar, reducing its molecular weight. Sonication produced extracts with lower agar contents and decreased molecular weights. A gelation mechanism is proposed based on the rheological and small angle scattering characterization of the extracts. The formation of strong hydrogels upon cooling was caused by the association of agarose chains into double helices and bundles, the sizes of which depended on the agar purity and molecular weight. These different arrangements at the molecular scale consequently affected the mechanical performance of the obtained hydrogels. Heating of the hydrogels produced a gradual disruption of the bundles; weaker or smaller bundles were formed upon subsequent cooling, suggesting that the process was not completely reversible.

  • 36.
    Martín-Alfonso, Jose
    et al.
    University of Huelva, Spain.
    Cuadri, Antonio
    University of Huelva, Spain.
    Berta, Marco
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Agrifood and Bioscience.
    Stading, Mats
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Agrifood and Bioscience. Chalmers University of Technology, Sweden.
    Relation between concentration and shear-extensional rheology properties of xanthan and guar gum solutions2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, p. 63-70Article in journal (Refereed)
    Abstract [en]

    The influence of concentration on the shear and extensional rheology properties of aqueous solutions of xanthan and guar gums was studied in this work. Shear rheology involved small amplitude oscillatory shear (SAOS), flow curves and transient flow, while the extensional rheology was analyzed using hyperbolic contraction flow. In addition, the mechanical properties during solutions manufacture were monitored in situ through the evolution of torque with processing time by mixing rheometry. The results showed that the hydrocolloids exert a great influence on the process rheokinetics and on the resulting rheological response. SAOS tests showed that the xanthan gum solutions behaved as weak gels, whereas guar gum solutions suggest the presence of entanglement and the formation of a viscoelastic, gel-like structure. All the systems exhibited shear-thinning behaviour. Guar gum solutions obeyed the Cox-Merz rule, with some divergence at high rates for the more concentrated solutions, while the Cox-Merz rule was not followed for xanthan gum in the range of concentration studied. The extensional viscosity exhibited an extensional-thinning behaviour within the strain range used and all solutions were characterized by a high Trouton ratio.

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  • 37. Medronho, Bruno
    et al.
    Andrade, Raquel
    Vivod, Vera
    Östlund, Åsa
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Material och produkter (TRm).
    Miguel, Maria Graca
    Lindman, Björn
    Voncina, Bojana
    Valente, Artur
    Cyclodextrin-Grafted Cellulose: Physico-Chemical Characterization2013In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 93, no 1, p. 324-330Article in journal (Refereed)
  • 38.
    Menzel, Carolin
    et al.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Andersson, Mariette
    SLU Swedish University of Agricultural Sciences, Sweden.
    Andersson, Roger
    SLU Swedish University of Agricultural Sciences, Sweden.
    Vazquez-Gutirrez, José L.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Daniel, Geoffrey
    SLU Swedish University of Agricultural Sciences, Sweden.
    Langton, Maud
    SLU Swedish University of Agricultural Sciences, Sweden; CSIRO Commonwealth Scientific and Industrial Research Organisation, Australia.
    Gällstedt, Mikael
    RISE, Innventia.
    Koch, Kristine
    SLU Swedish University of Agricultural Sciences, Sweden.
    Improved material properties of solution-cast starch films: Effect of varying amylopectin structure and amylose content of starch from genetically modified potatoes2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 130, p. 388-397Article in journal (Refereed)
    Abstract [en]

    High-amylose potato starches were produced through genetic modification resulting in changed granule morphology and composition, with higher amylose content and increased chain length of amylopectin. The increased amylose content and structural changes in amylopectin enhanced film-forming behavior and improved barrier and tensile properties in starch films. The molecular structure in these starches was related to film-forming properties. Solution-cast films of high-amylose starch revealed a homogeneous structure with increasing surface roughness at higher amylose content, possibly due to amylose aggregation. Films exhibited significantly higher stress and strain at break compared with films of wild-type starch, which could be attributable to the longer chains of amylopectin being involved in the interconnected network and more interaction between chains, as shown using transmission electron microscopy. The oxygen permeability of high-amylose starch films was significantly decreased compared with wild-type starch. The nature of the modified starches makes them an interesting candidate for replacement of non-renewable oxygen and grease barrier polymers used today.

  • 39.
    Mericer, Caglar
    et al.
    University of Bologna, Italy.
    Minelli, Matteo
    University of Bologna, Italy.
    Giacinti Baschetti, Marco
    University of Bologna, Italy.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioeconomy.
    Water sorption in microfibrillated cellulose (MFC): The effect of temperature and pretreatment2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, p. 1201-1212Article in journal (Refereed)
    Abstract [en]

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

  • 40.
    Mira, I
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Persson, K
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Villwock, VK
    On the effect of surface active agents and their structure on the temperature-induced changes of normal and waxy wheat starch in aqueous suspension. Part I. Pasting and calorimetric studies2007In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 68, p. 665-678Article in journal (Refereed)
    Abstract [en]

    Pasting and calorimetric studies of normal and waxy wheat starch were performed in the presence of a series of ionic (sulphates, trimethyl ammonium bromides) and non-ionic (monoglycerides, maltosides) short (12 carbon atoms) and long (16 carbon atoms) n-alkyl chain surfactants. With the exception of the alkyl ammonium bromides, all of the short chain surfactants lower the pasting temperature (PT) in normal wheat starch, while the long chain surfactants have the opposite effect. Contrary, regardless of their chain length, all ionic surfactants lower the PT in waxy wheat starch while the non-ionic surfactants induce small, sometimes almost negligible changes in the PT. Calorimetric studies revealed the absence of a direct connection between the effect of surfactants on the onset of the starch gelatinisation transition and the PT. However, in the presence of all surfactants, except the alkyl ammonium bromides, the PT of normal wheat starch was found to lie within or very close the temperature range within which the dissociation of the amylose-surfactant complexes takes place. Waxy wheat starch, in contrast, pasted at temperatures that fell within the temperature range of the starch gelatinisation transition. This is taken as evidence of the existence of a correlation between the PT and the dissociation of the amylose-surfactant complexes.

  • 41.
    Mira, I
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Villwock, VK
    Persson, K
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    On the effect of surface active agents and their structure on the temperature-induced changes of normal and waxy wheat starch in aqueous suspension. Part II. A confocal laser scanning microscopy study2007In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 68, p. 637-646Article in journal (Refereed)
    Abstract [en]

    The location and penetration patterns of two fluorescently-labelled, surface active molecules into normal and waxy wheat starch granules prior, during and after the temperature-induced gelatinisation were studied by means of confocal laser scanning microscopy (CLSM). Amphiphilic dyes were found to have a tendency to penetrate wheat starch granules in aqueous suspension. The penetration patterns were however found to be dependent on the contact time, type of starch and the chain length of the amphiphilic dye. The penetration of amphiphilic dyes through the starch granule matrix proved to be less restricted in waxy than in normal wheat starch. For a given type of starch, the penetration of the longer chain dye was more constrained than that of the shorter chain one. The extent to which the dye diffuses into the granule matrix as it gelatinizes is also affected by the chain length of the dye, diffusion of the shorter chain dye occurring more profusely and at lower temperatures than for the longer chain one. These differences are suggested to be related to the dissociation temperature of the AM-amphiphilic dye complexes.

  • 42.
    Moberg, Tobias
    et al.
    Chalmers University of Technology, Sweden.
    Rigdahl, Mikael
    Chalmers University of Technology, Sweden.
    Stading, Mats
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik. Chalmers University of Technology, Sweden.
    Levenstam Bragd, Emma
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Extensional viscosity of microfibrillated cellulose suspensions2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 102, no 1, p. 409-412Article in journal (Refereed)
    Abstract [en]

    The extensional properties of micro fibrillated cellulose (MFC)-suspensions at different fibril concentrations and with different amounts of added sodium chloride were evaluated. The MFC-suspensions were obtained by diluting a stock solution consisting of 0.95 wt.% cellulose with either deionized water or sodium chloride solution, giving a series of different concentrations and sodium chloride contents. The extensional viscosities of the suspensions were measured utilizing contraction flow geometry. Here the specimens were forced through a hyperbolic nozzle and the required pressure drop over the nozzle was measured. The extensional viscosity exhibited an extensional-thinning behaviour over the extensional strain rates used. Furthermore the extensional viscosity decreased with decreasing concentration of the suspensions, in similarities with the shear properties of the specimens. For the suspensions containing sodium chloride, the extensional viscosity appeared to increase when the concentration of sodium chloride was increased. But excessive amounts of added sodium chloride promoted an agglomeration of the suspensions.

  • 43.
    Mølgaard, Susanne
    et al.
    University of Copenhagen, Denmark.
    Henriksson, Marielle
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Hållbar Samhällsbyggnad.
    Cárdenas, Marité
    University of Copenhagen, Denmark; Malmö University, Sweden.
    Svagan, Anna
    University of Copenhagen, Denmark.
    Cellulose-nanofiber/polygalacturonic acid coatings with high oxygen barrier and targeted release properties2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 114, p. 179-182Article in journal (Refereed)
    Abstract [en]

    A bio-inspired coating consisting of pectin (polygalacturonic acid) and cationic cellulose nanofibers were successfully produced by the layer-by-layer method. The build-up and the morphology of the resulting coatings were studied with spectroscopic ellipsometry and atomic force microscopy, respectively. The coating was able to survive the exposure of a simulated gastric fluid, but was partially degraded upon exposure to pectinase enzyme, which simulate the action of the microbial symbionts present in the human colon. Prior to exposure, the oxygen permeability coefficient of the coating (0.033 ml (STP) mm m-2 day-1 atm-1 at 23 °C and 20% RH) was in the same order of magnitude as for ethylene vinyl alcohol films (0.001-0.01 ml (STP) mm m-2 day-1 atm-1). However, after exposure to the mimicked gastrointestinal (GI) tract conditions, the contribution of coating to the overall barrier properties was not measurable.

  • 44.
    Naderi, Ali
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy. RISE, Innventia. BillerudKorsnäs, Sweden.
    Koschella, Andreas
    Friedrich Schiller University of Jena, Germany.
    Heinze, Thomas
    Friedrich Schiller University of Jena, Germany.
    Shih, Kuo-Chih
    University of Connecticut, USA; National Taiwan University, Taiwan.
    Nieh, Mu-Ping
    University of Connecticut, USA.
    Pfeifer, Annett
    Friedrich Schiller University of Jena, Germany.
    Chang, Chung-Chueh
    Stony Brook University, USA.
    Erlandsson, Johan
    KTH Royal Institute of Technology, Sweden.
    Sulfoethylated nanofibrillated cellulose: Production and properties2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 169, p. 515-523Article in journal (Refereed)
    Abstract [en]

    Sulfoethylated nanofibrillated cellulose (NFCSulf) was produced by an industrially relevant process. The properties of the NFCSulf were compared with those of carboxymethylated nanofibrillated cellulose (NFCCarb), which has been identified as an attractive NFC for several industrial applications. The investigations revealed that NFCSulf is characterized by a higher degree of fibrillation and has superior redispersion properties. Furthermore, NFCSulf displays higher stability in varying pH values as compared to NFCCarb. Hence, NFCSulf may be a more attractive alternative than NFCCarb in applications such as rheological modifiers or adsorbing components in personal care products, in which the performance of NFC must remain unaffected in varying ambient conditions. The superior properties of NFCSulf compared to NFCCarb were proposed to be due to the combination of the unique chemical characteristics of the sulfoethylated reagent, and the larger size of the sulfonate group compared to the carboxymethyl group.

  • 45.
    Nechyporchuk, Oleksandr
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Hanna, Ulmefors
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Teleman, Anita
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Silica-rich regenerated cellulose fibers enabled by delayed dissolution of silica nanoparticles in strong alkali using zinc oxide2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 264, article id 118032Article in journal (Refereed)
    Abstract [en]

    Silica nanoparticles (SNPs) dissolve in alkaline media, which limits their use in certain applications. Here, we report a delayed dissolution of SNPs in strong alkali induced by zinc oxide (ZnO), an additive which also limits gelation of alkaline cellulose solutions. This allows incorporating high solid content of silica (30 wt%) in cellulose solutions with retention of their predominant viscous behavior long enough (ca. 180 min) to enable fiber wet spinning. We show that without addition of ZnO, silica dissolves completely, resulting in strong gelation of cellulose solutions that become unsuitable for wet spinning. With an increase of silica concentration, gelation of the solutions occurs faster. Employing ZnO, silica-rich regenerated cellulose fibers were successfully spun, possessing uniform cross sections and smooth surface structure without defects. These findings are useful in advancing the development of functional man-made cellulose fibers with incorporated silica, e.g., fibers with flame retardant or self-cleaning properties. © 2021 The Author(s)

  • 46.
    Nechyporchuk, Oleksandr
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, IVF. Chalmers University of Technology, Sweden.
    Kolman, Krzysztof
    Chalmers University of Technology, Sweden; University of Gothenburg, Sweden.
    Bridarolli, Alexandra
    University of London, UK .
    Odlyha, Marianne
    University of London, UK.
    Bozec, L.
    University of London, UK.
    Oriola, Marta
    University of Barcelona, Spain.
    Campo-Francés, Gema
    University of Barcelona, Spain.
    Persson, Michael E
    AkzoNobel, Sweden.
    Holmberg, Krister
    Chalmers University of Technology, Sweden.
    Bordes, Romain
    Chalmers University of Technology, Sweden.
    On the potential of using nanocellulose for consolidation of painting canvases2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 194, p. 161-169Article in journal (Refereed)
    Abstract [en]

    Nanocellulose has been recently proposed as a novel consolidant for historical papers. Its use for painting canvas consolidation, however, remains unexplored. Here, we show for the first time how different nanocelluloses, namely mechanically isolated cellulose nanofibrils (CNF), carboxymethylated cellulose nanofibrils (CCNF) and cellulose nanocrystals (CNC), act as a bio-based alternative to synthetic resins and other conventional canvas consolidants. Importantly, we demonstrate that compared to some traditional consolidants, all tested nanocelluloses provided reinforcement in the adequate elongation regime. CCNF showed the best consolidation per added weight; however, it had to be handled at very low solids content compared to other nanocelluloses, exposing canvases to larger water volumes. CNC reinforced the least per added weight but could be used in more concentrated suspensions, giving the strongest consolidation after an equivalent number of coatings. CNF performed between CNC and CCNF. All nanocelluloses showed better consolidation than lining with synthetic adhesive (Beva 371) and linen canvas in the elongation region of interest. 

  • 47. Popescu, C.-M.
    et al.
    Larsson, P.T.
    RISE, Innventia.
    Olaru, N.
    Vasile, C.
    Spectroscopic study of acetylated kraft pulp fibers2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, no 2, p. 530-536Article in journal (Refereed)
  • 48. Popescu, C.-M.
    et al.
    Larsson, P.T.
    RISE, Innventia.
    Vasile, C.
    Carbon-13 CP/MAS solid state NMR and X-ray diffraction spectroscopy studies on lime wood decayed by Chaetomium globosum2011In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, no 2, p. 808-812Article in journal (Refereed)
  • 49.
    Powell, Lydia C.
    et al.
    Cardiff University, UK; Swansea University, UK.
    Khan, Saira
    Cardiff University, UK.
    Chinga-Carrasco, Gary
    RISE, Innventia, PFI – Paper and Fiber Research Institute.
    Wright, Chris J.
    Swansea University, UK.
    Hill, Katja E.
    Cardiff University, UK.
    Thomas, David W.
    Cardiff University, UK.
    An investigation of Pseudomonas aeruginosa biofilm growth on novel nanocellulose fibre dressings2016In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 137, p. 191-197Article in journal (Refereed)
    Abstract [en]

    Nanocellulose from wood is a novel biomaterial, which is highly fibrillated at the nanoscale. This affords the material a number of advantages, including self-assembly, biodegradability and the ability to absorb and retain moisture, which highlights its potential usefulness in clinical wound-dressing applications. In these in vitro studies, the wound pathogen Pseudomonas aeruginosa PAO1 was used to assess the ability of two nanocellulose materials to impair bacterial growth (<48 h). The two nanocelluloses had a relatively small fraction of residual fibres (<4%) and thus a large fraction of nanofibrils (widths <20 nm). Scanning electron microscopy and confocal laser scanning microscopy imaging demonstrated impaired biofilm growth on the nanocellulose films and increased cell death when compared to a commercial control wound dressing, Aquacel®. Nanocellulose suspensions inhibited bacterial growth, whilst UV-vis spectrophotometry and laser profilometry also revealed the ability of nanocellulose to form smooth, translucent films. Atomic force microscopy studies of the surface properties of nanocellulose demonstrated that PAO1 exhibited markedly contrasting morphology when grown on the nanocellulose film surfaces compared to an Aquacel® control dressing (p < 0.05). This study highlights the potential utility of these biodegradable materials, from a renewable source, for wound dressing applications in the prevention and treatment of biofilm development.

  • 50.
    Reid, Michael
    et al.
    KTH Royal Institute of Technology, Sweden.
    Karlsson, Maria
    RISE Research Institutes of Sweden. Linköping University, Sweden.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Fluorescently labeled cellulose nanofibrils for detection and loss analysis2020In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 250, article id 116943Article in journal (Refereed)
    Abstract [en]

    Fluorescently labeled cellulose nanofibrils (CNFs) were used to evaluate CNF leaching from paper according to standard safety assays for food contact materials. Enzymatically pretreated pulp was first labeled with 5-([4,6-Dichlorotriazin-2-yl]amino)fluorescein hydrochloride (DTAF), followed by homogenization to produce fluorescent CNFs of varying degrees of fibrillation. Labeling at the μmolar DTAF/g cellulose level imparted quantitative ppb fluorescence detection of CNFs (LOD of approximately 20 ppb), without significantly altering other material properties, suggesting that DTAF-labeled CNFs are an appropriate mimic for native CNFs and that this approach can be used to detect low CNF concentrations. Cold and hot-water extractions of laboratory papers (100 % CNFs and CNF-fiber blended papers) showed loss values below 3 wt% CNFs, with the finest CNF quality showing the least loss overall and with greater loss experienced under hot water conditions compared with cold water. DTAF-labeled CNFs can be used to address questions related to CNF distribution, localization, and loss. 

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