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  • 101.
    Ankerfors, Caroline
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Gimåker, Magnus
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Östlund, Ida
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Polyelectrolyte Multilayers and Other Dosage Strategies: Effects on Properties of Paper Sheets Produced in Pilot Scale Using MillProcess Waters2018In: Paper Conference and Trade Show, PaperCon 2018: Shaping the future through innovation, TAPPI , 2018, Vol. 2, p. 658-669, article id PA3.3Conference paper (Other academic)
  • 102.
    Ankerfors, Mikael
    et al.
    RISE, Innventia.
    Aulin, Christian
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Nanocellulose research and developments at Innventia2011Conference paper (Refereed)
  • 103.
    Ankerfors, Mikael
    et al.
    RISE, Innventia.
    Duker, Elisabeth
    BillerudKorsnäs AB, Sweden.
    Lindström, Tom
    RISE, Innventia.
    Topo-chemical modification of fibres by grafting of carboxymethyl cellulose in pilot scale2013In: Nordic Pulp and Paper Research Journal, ISSN 0283-2631 , no 1, p. 6-14Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to graft carboxymethyl cellulose (CMC) on to bleached softwood kraft pulp at temperatures below 100°C and to do a pilot paper machine trial in order to examine the influence of the CMC on dewatering, sheet formation and mechanical properties. During the pilot trial, one CMC grafted pulp was compared to a pulp with 3 different refining degrees. It was shown that CMC-grafting improves the mechanical properties of paper with only a minor effect on the sheet density. It was also shown that the CMC grafting is less detrimental to dewatering than refining and at a certain tensile index a higher dry content after pressing could be reached. The formation number of the paper produced in the FEX trial was not significantly affected by the addition of CMC.

  • 104.
    Ankerfors, Mikael
    et al.
    BillerudKorsnäs AB, Sweden.
    Lindström, Tom
    RISE, Innventia.
    Glad Nordmark, Gunborg
    RISE, Innventia.
    Multilayer assembly onto pulp fibres using oppositely charged microfibrillated celluloses, starches, and wetstrength resins: Effect on mechanical properties of CTMP-sheets2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 1, p. 135-141Article in journal (Refereed)
    Abstract [en]

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

  • 105.
    Ankerfors, Mikael
    et al.
    ÅF Industry, Sweden.
    Lindström, Tom
    RISE - Research Institutes of Sweden, Bioeconomy.
    Glad Nordmark, Gunborg
    RISE - Research Institutes of Sweden, Bioeconomy.
    The effects of different types of wet-end added microfibrillated celluloses on the properties of paper made from bleached kraft pulp2017In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 3, p. 336-345Article in journal (Refereed)
    Abstract [en]

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

  • 106.
    Ankerfors, Mikael
    et al.
    BillerudKorsnäs AB, Sweden.
    Lindström, Tom
    RISE, Innventia.
    Söderberg, L. Daniel
    KTH Royal Institute of Technology, Sweden.
    The use of microfibrillated cellulose in fine paper manufacturing: Results from a pilot scale papermaking trial2014In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 3, p. 476-483Article in journal (Refereed)
    Abstract [en]

    In this work the strength enhancing capabilities of microfibrillated cellulose (MFC) in highly filled papers was studied. Both the MFC production and the paper making were done in pilot scale under realistic industrial conditions. The results clearly show that MFC (2.5-5.0 wt-%) could improve the mechanical properties of highly filled papers (20-35 wt-% filler contents). All studied dry mechanical properties were improved and the improvements were most pronounced for Z-strength and fracture toughness. By combining the MFC with a C-starch dosage further improvements in mechanical properties could be achieved. The improvements in mechanical properties enabled increased filler content with retained properties. The filler increase could be achieved at the same time as the sheet formation and the dry content after pressing were improved.

  • 107.
    Ankerfors, Mikael
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Söderberg, L. Daniel
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    The use of microfibrillated cellulose in high filler fine papers2013Conference paper (Refereed)
    Abstract [en]

    The field of communication, printing and writing papers has become an increasingly competitive field during the latest years as the market demand of printing and writing papers and newsprint has finally started to decline in the developed economies. One obvious approach to stay competitive is to increase the filler content of such papers. High filler paper is not a new idea and numerous approaches have been tested over the years to produce such papers. In order to reach industrial implementation, pilot-scale research and development under industrial conditions is necessary as a step after laboratory studies. Therefore an environment has been developed in order to perform projects targeting existing technologies for high filler applications as well as the new possibilities incurred by e.g. microfibrillated cellulose.

  • 108.
    Ansari, Farhan
    et al.
    KTH Royal Institute of Technology, Sweden.
    Lindh, Erik L.
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Furo, Istvan
    KTH Royal Institute of Technology, Sweden.
    Johansson, Mats K. G.
    KTH Royal Institute of Technology, Sweden.
    Berglund, Lars A.
    KTH Royal Institute of Technology, Sweden.
    Interface tailoring through covalent hydroxyl-epoxy bonds improves hygromechanical stability in nanocellulose materials2016In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 134, p. 175-183Article in journal (Refereed)
    Abstract [en]

    Wide-spread use of cellulose nanofibril (CNF) biocomposites and nanomaterials is limited by CNF moisture sensitivity due to surface hydration. We report on a versatile and scalable interface tailoring route for CNF to address this, based on technically important epoxide chemistry. Bulk impregnation of epoxide-amine containing liquids is used to show that CNF hydroxyls can react with epoxides at high rates and high degree of conversion to form covalent bonds. Reactions take place inside nanostructured CNF networks under benign conditions, and are verified by solid state NMR. Epoxide modified CNF nanopaper shows significantly improved mechanical properties under moist and wet conditions. High resolution microscopy is used in fractography studies to relate the property differences to structural change. The cellulose-epoxide interface tailoring concept is versatile in that the functionality of molecules with epoxide end-groups can be varied over a wide range. Furthermore, epoxide reactions with nanocellulose can be readily implemented for processing of moisture-stable, tailored interface biocomposites in the form of coatings, adhesives and molded composites.

  • 109.
    Ansari, Farhan
    et al.
    KTH Royal Institute of Technology, Sweden.
    Sjöstedt, Anna
    KTH Royal Institute of Technology, Sweden.
    Larsson, Per Tomas
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Berglund, Lars A.
    KTH Royal Institute of Technology, Sweden.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Hierarchical wood cellulose fiber/epoxy biocomposites: Materials design of fiber porosity and nanostructure2015In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 74, p. 60-68Article in journal (Refereed)
    Abstract [en]

    Delignified chemical wood pulp fibers can be designed to have a controlled structure of cellulose fibril aggregates to serve as porous templates in biocomposites with unique properties. The potential of these fibers as reinforcement for an epoxy matrix (EP) was investigated in this work. Networks of porous wood fibers were impregnated with monomeric epoxy and cured. Microscopy images from ultramicrotomed cross sections and tensile fractured surfaces were used to study the distribution of matrix inside and around the fibers - at two different length scales. Mechanical characterization at different relative humidity showed much improved mechanical properties of biocomposites based on epoxy-impregnated fibers and they were rather insensitive to surrounding humidity. Furthermore, the mechanical properties of cellulose-fiber biocomposites were compared with those of cellulose-nanofibril (CNF) composites; strong similarities were found between the two materials. The reasons for this, some limitations and the role of specific surface area of the fiber are discussed.

  • 110. Antonsson, S.
    et al.
    Mäkelä, Petri
    RISE, Innventia.
    Fellers, Christer
    RISE, Innventia.
    Lindström, M. E.
    Comparison of the physical properties of hardwood and softwood pulps2009In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 24, no 4, p. 409-414Article in journal (Refereed)
    Abstract [en]

    High mechano-sorptive creep resistance, i.e., good creep resistance in environments with changing relative humidity, is one of the key requirements for linerboards. The aim of this study was to investigate the influence of pulp types and pulp properties on the mechano-sorptive creep of kraftliner. A high-yield softwood, kraftliner pulp, and four different hardwood pulps were investigated. The physical properties of laboratory sheets were evaluated, with emphasis on the mechanosorptive creep properties. The results showed that the density increase due to increased beating significantly improved the tensile stiffness of all pulps, while its effect on the isocyclic creep stiffness was less pronounced. The hardwood pulps showed higher tensile stiffness, better mechano-sorptive creep properties, and lower hygroexpansion than the softwood pulp at a given density. However, the softwood pulp did exhibit better tensile strength and fracture toughness properties than the hardwood pulps. The results imply that hardwood pulps can be competitive with softwood pulps in kraftliners, provided that their tensile strength and fracture toughness properties can be improved by, for example, chemical means. Furthermore, the isocyclic creep stiffness correlates with the ratio of tensile stiffness to hygroexpansion, indicating that this ratio can be used for engineering estimates of the mechano-sorptive creep performance of paper materials.

  • 111. Antonsson, S.
    et al.
    Pulkkinen, I.
    Fiskari, J.
    Karlström, Katarina
    RISE, Innventia.
    Lindström, M.E
    The relationship between hygroexpansion, tensile stiffness, and mechano-sorptive creep in bleached hardwood kraft pulps2010In: Appita journal, ISSN 1038-6807, Vol. 63, no 3, p. 231-234Article in journal (Refereed)
    Abstract [en]

    Hygroexpansion coefficient and tensile stiffness are important parameters in many paper applications. This study compares several bleached industrial hardwood kraft pulps, comprising five eucalypt pulps from South America, Europe, and Africa as well as an acacia pulp from Asia and a birch pulp from Scandinavia. Refined and unrefined pulps are compared. The results indicate significant differences in hygroexpansion but smaller differences in tensile stiffness index at comparable densities. No single factor offering a reasonable explanation of these differences in hygroexpansion coefficient, such as carbohydrate composition, fibre dimensions, or fibre form, was found. However, correlation between hygroexpansion coefficient and the mechano-sorptive creep stiffness was observed. We suggest that the hygroexpansion coefficient at a given tensile stiffness level can be used to rank pulps in terms of their mechano-sorptive creep properties.

  • 112.
    Appelquist, Karin
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Eliasson, Thomas
    Karaktärisering av Bohusgranit i samband med utbyggnad av E6, norra Bohuslän2011Report (Refereed)
    Abstract [sv]

    Tunnslipsundersökningar samt Los Angeles (LA)-analys har utförts på fem olika typer av Bohusgraniter, provtagna längs utbyggnad av väg E6 mellan Strömstad och Tanumshede. Undersökningen har utförts som ett led i utvecklingen av nya, alternativa provningsmetoder för vägmaterial som bättre återspeglar funktionsegenskaperna hos berget. Huvudsyftet med undersökningen är att undersöka hur mekaniska egenskaper (i det här fallet LA-värde) kan kopplas till bergarternas petrografiska egenskaper. Resultaten visar att bergarternas motstånd mot fragmentering (LA-värde) är beroende av en kombination av dess omvandlingsgrad, mikrosprickor och kornstorlek. LA-värdet i de undersökta proverna är främst beroende av provets omvandlingsgrad av plagioklas. Andelen mikrosprickor är i sin tur ofta kopplat till omvandlingsgraden. Ju högre andel sericit-omvandlad plagioklas desto färre mikrosprickor och mindre sprickpropagering, vilket ökar provets motstånd mot fragmentering (lägre LA-värde). Även kornstorleken har betydelse för provets motstånd mot fragmentering, vilket är särskilt tydligt för provet med minst kornstorlek.

  • 113.
    Appelquist, Karin
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Mueller, Urs
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Utveckling av ett nytt funktionstest för ASR i betong2014In: CBI-nytt, ISSN 0349-2060, no 2, p. 10-11Article in journal (Other academic)
  • 114.
    Appelquist, Karin
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Trägårdh, Jan
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Korrelation mellan tre provningsmetoder för alkalisilikareaktivitet av svensk krossballast för betong2013In: Svensk Bergs & Brukstidning, ISSN 0039-6435, Vol. 92, no 3Article in journal (Other academic)
  • 115.
    Apruzzese, P.
    et al.
    Imperial College London.
    Falzon, B.G.
    Monash University.
    Olsson, R.
    RISE, Swerea, Swerea SICOMP.
    Modelling the postbuckling behaviour of impacted composite aerostructures2009In: ICCM International Conferences on Composite MaterialsConference paper (Refereed)
    Abstract [en]

    Two approaches to modelling the effects of embedded defects and impact damage in composite aerostructures are presented. These differ in the manner n which the damage is represented; one as an equivalent delamination and the other as a soft inclusion with non-linear homogenized material properties. These techniques are applied to study the effects of defects and impact damage on the performance of composite panels.

  • 116.
    Argyropoulos, Dimitris
    et al.
    North Carolina State University, USA.
    Crestini, Claudia
    Ca’ Foscari University of Venice, Italy.
    Dahlstrand, Christian
    Ren FuelK2B AB, Sweden.
    Furusjö, Erik
    RISE Research Institutes of Sweden, Bioeconomy and Health, Biorefinery and Energy. Luleå University of Technology, Sweden.
    Gioia, Claudio
    Universityof Trento, Italy.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Henriksson, Gunnar
    KTH Royal Institute of Technology, Sweden.
    Hulteberg, Christian
    Lund University, Sweden.
    Lawoko, Martin
    KTH Royal Institute of Technology, Sweden.
    Pierrou, Clara
    RenFuel Materials AB, Sweden.
    Samec, Joseph
    RenFuel Materials AB, Sweden; Stockholm University, Sweden; Chulalongkorn University, Thailand; Ren FuelK2B AB, Sweden.
    Subbotina, Elena
    Yale University, USA.
    Wallmo, Henrik
    Valmet AB, Sweden.
    Wimby, Martin
    Valmet AB, Sweden.
    Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges.2023In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, article id e202300492Article in journal (Refereed)
    Abstract [en]

    Kraft lignin, a by-product from the production of pulp, is currently incinerated in the recovery boiler during the chemical recovery cycle, generating valuable bioenergy and recycling inorganic chemicals to the pulping process operation. Removing lignin from the black liquor or its gasification lowers the recovery boiler load enabling increased pulp production. During the past ten years, lignin separation technologies have emerged and the interest of the research community to valorize this underutilized resource has been invigorated. The aim of this review is to give (1) a dedicated overview of the kraft process with a focus on the lignin, (2) an overview of applications that are being developed, and (3) a techno-economic and life cycle asseeements of value chains from black liquor to different products. Overall, it is anticipated that this effort will inspire further work for developing and using kraft lignin as a commodity raw material for new applications undeniably promoting pivotal global sustainability concerns.

  • 117.
    Arm, Maria
    et al.
    SGI Swedish Geotechnical Institute, Sweden.
    Pascal, Suer
    SGI Swedish Geotechnical Institute, Sweden.
    Arvidsson, Håkan
    VTI Swedish National Road and Transport Research Institute, Sweden.
    Lindqvist, Jan-Erik
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Technical environmental long-term properties of industrial residues: summary of field and laboratory investigations2011In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 31, no 1, p. 101-107Article in journal (Refereed)
    Abstract [en]

    In Sweden, use of industrial residues is still hindered by concern for their long-term properties. A three-year research project was therefore initiated aiming to (1) identify the crucial processes of ageing related to the usefulness of residues in roads; (2) investigate the consequences of these processes for technical and environmental properties of the residues, and (3) propose a method for accelerated ageing to predict the long-term properties. This paper gives an overview of the project methodology, a summary of the test results and references to papers where further details are given. The project, running through 2006-2008, compared naturally aged samples of two residues used as sub-bases in existing asphalt paved roads with samples of fresh residues from producers' piles. Steel slag of electric arc furnace (EAF) type and municipal solid waste incinerator (MSWI) bottom ash were chosen. The samples were thoroughly characterised in order to identify which ageing processes had been crucial. The results showed that: - Bottom ash from the pavement edge was more aged than bottom ash from the road centre. However, no difference in pH was found, instead the differences were caused by differences in water exposure. - Steel slag from the pavement edge showed traces of carbonation and leaching processes, whereas slag from the road centre was identical to fresh slag. - Water exposure to the subbase materials after ten years in an asphalt paved road was calculated to less than 0.1–0.5 litres per kg. - Ageing reactions in steel slag and MSWI bottom ash, ready for use, were too small to be verified by laboratory measurement of deformation properties under loaded conditions. An accelerated ageing test for steel slag was set up to achieve the carbonation (decrease in pH) and leaching that was observed in the pavement edge material. An accelerated ageing test for bottom ash was set up to achieve the pozzolan reactions that were observed in SEM analyses of in situ specimens. It is recommended to use uncrushed particles when properties of aged material are studied, in order to preserve the original particle surfaces.

  • 118.
    Arne, B.
    et al.
    RISE, Swerea, Swerea KIMAB.
    Björk, Thomas
    RISE, Swerea, Swerea KIMAB.
    Laser ablation breakdown spectroscopy technique for simultaneous analysis of steel and slags in metallurgical samples2009In: Yejin Fenxi/Metallurgical Analysis, ISSN 10007571, Vol. 29, no 2, p. s.8-13Article in journal (Refereed)
    Abstract [zh]

    The original purpose of this research was to develop a method for fast, simultaneous analysis of both the steel and slag content of heterogeneous metallurgical samples for process control. The method is based on Laser Induced Breakdown Spectroscopy (LIBS). The reason for choosing LIBS is that it can be employed for both conductive and non-conductive materials, and is relatively insensitive to sample shape and surface finish. The heterogeneous samples produced contain large numbers of sub-millimetre slag particles that cannot be completely separated from the surrounding steel in a LIBS analysis. A method has therefore been developed to perform a line scan analysis with approximately 0.5 mm resolution and 10 mm length along the sample. The laser pulse rate is 20 Hz and the scan speed is 1 mm/s. Slag particles appear in the line scan as "polluted areas" of the steel with very high concentrations of e. g. Ca, Al and Si. A mathematical model was developed to evaluate the data in steps, based on a single calibration. Firstly, "clean steel" areas are identified and the steel composition determined. In the second step, the average composition across the entire length of the scan is determined. In the final step, the average slag composition is determined by means of a difference calculation. The method was tested on several samples from the development of the heterogeneous sampler. It was found that the elements C, Si, Mn, P, S and Al can be determined in the steel with an RSD of a few percent. In the slag, the RSD's are higher, around10% for several important elements. It is expected that the method can be further developed for rapid analysis of smaller non-metallic inclusions.

  • 119.
    Aronsson Rindby, Anna Cornelia
    et al.
    Chalmers University of Technology.
    Sahlin, Augusta
    Chalmers University of Technology.
    Troell, Eva
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Kristoffersen, Hans
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Compilation and validation of heat transfer coefficients of quenching oils2012In: Proceedings of the 6th International Quenching and Control of Distortion Conference Including the 4th International Distortion Engineering Conference, 2012Conference paper (Other academic)
  • 120.
    Aronsson, Rune
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, CBI - Cement- och betonginstitutet.
    Fagerlund, Göran
    Betongs slagseghet i pålar1977Report (Refereed)
  • 121.
    Arya, Mina
    et al.
    University of Borås, Sweden.
    Malmek, Else-Marie
    Juteborg AB, Sweden.
    Ecoist, Thomas Koch
    Ecoist AB, Sweden.
    Pettersson, Jocke
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Skrifvars, Mikael
    University of Borås, Sweden.
    Khalili, Pooria
    University of Borås, Sweden.
    Enhancing Sustainability: Jute Fiber-Reinforced Bio-Based Sandwich Composites for Use in Battery Boxes2023In: Polymers, E-ISSN 2073-4360, Vol. 15, no 18, article id 3842Article in journal (Refereed)
    Abstract [en]

    The rising industrial demand for environmentally friendly and sustainable materials has shifted the attention from synthetic to natural fibers. Natural fibers provide advantages like affordability, lightweight nature, and renewability. Jute fibers’ substantial production potential and cost-efficiency have propelled current research in this field. In this study, the mechanical behavior (tensile, flexural, and interlaminar shear properties) of plasma-treated jute composite laminates and the flexural behavior of jute fabric-reinforced sandwich composites were investigated. Non-woven mat fiber (MFC), jute fiber (JFC), dried jute fiber (DJFC), and plasma-treated jute fiber (TJFC) composite laminates, as well as sandwich composites consisting of jute fabric bio-based unsaturated polyester (UPE) composite as facing material and polyethylene terephthalate (PET70 and PET100) and polyvinyl chloride (PVC) as core materials were fabricated to compare their functional properties. Plasma treatment of jute composite laminate had a positive effect on some of the mechanical properties, which led to an improvement in Young’s modulus (7.17 GPa) and tensile strength (53.61 MPa) of 14% and 8.5%, respectively, as well as, in flexural strength (93.71 MPa) and flexural modulus (5.20 GPa) of 24% and 35%, respectively, compared to those of JFC. In addition, the results demonstrated that the flexural properties of jute sandwich composites can be significantly enhanced by incorporating PET100 foams as core materials. © 2023 by the authors.

  • 122.
    Asp, Leif
    RISE, Swerea, Swerea SICOMP.
    Local models for NCF composite materials mechanical performance prediction2007In: ICCM International Conferences on Composite MaterialsConference paper (Refereed)
    Abstract [en]

    This paper presents models for NCF reinforced composite materials performance prediction developed within the European research project FALCOM. The research project was conducted during the years 2002 and 2005 and was led by QinetiQ, UK. In total nine European countries were represented in FALCOM. The models consider material heterogeneity on three scales. On the micro-scale homogenization of the fibre bundle is performed. On the meso-scale formulations of Representative Volume Elements with different degrees of sophistication are defined. Finally on the macro-scale models span from straightforward employment of laminate theory to full through-thickness 3D-representation of the meso-scale features. The paper illustrates the diversity of local performance models for NCF composite analysis presenting a selection of models developed in the FALCOM project.

  • 123.
    Asp, Leif
    RISE, Swerea, Swerea SICOMP.
    Multifunctional composite materials for energy storage in structural load paths2013In: Plastics, rubber and composites, ISSN 1465-8011, E-ISSN 1743-2898, Vol. 42, no 4, p. 144-149Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of the research performed to date by a Swedish interdisciplinary team of scientists striving to develop multifunctional composite materials for storage of electric energy in mechanical load paths. To realise structural batteries from polymer composites, research pursued on carbon fibres for use as negative electrode in the battery as well as on polymer electrolytes for use as polymer matrix in the composite is reported. The work on carbon fibres comprises characterisation of the electrochemical capacity of commercial carbon fibre grades and how this is affected by mechanical load. Co-polymers are studied for their multifunctional performance with respect to lithium ion conductivity and stiffness. Also, rational processing of these polymer electrolytes and the effect of processing on their properties are addressed. © 2013 Institute of Materials, Minerals and Mining.

  • 124.
    Asp, Leif
    RISE, Swerea, Swerea SICOMP.
    Structural battery materials2012In: ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite MaterialsConference paper (Refereed)
    Abstract [en]

    Since four years Swerea SICOMP has been leading a team of Swedish researchers developing structural battery materials from polymer composites. The research performed in the Swedish project KOMBATT (Lightweight structural energy storage materials) is funded by the Swedish foundation for strategic research (SSF). The research addresses two technical challenges in particular. Firstly, solid polymer electrolytes that efficiently transfer loads in the composite and simultaneously transports lithium ions, while being electrically insulating, must be developed. Secondly, the ability of the reinforcement, i.e. The carbon fibres, to intercalate lithium ions as part of the chemical redox reactions, while maintaining its mechanical properties must be assured. This paper is the first in a series of papers at this conference from the KOMBATT project team and presents background and overview of the project.

  • 125.
    Asp, Leif
    et al.
    RISE, Swerea, Swerea SICOMP.
    Juntikka, Rickard
    RISE, Swerea, Swerea SICOMP.
    High velocity impact on NCF reinforced composites2009In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 69, no 9, p. 1478-1482Article in journal (Refereed)
    Abstract [en]

    In the current paper, a series of high velocity impact tests using φ{symbol}50 and φ{symbol}25 mm ice spheres and 0.32 g granite stones on non-crimp fabric (NCF) composite plates are reported. The impact tests were performed using an air gun and velocities between 100 m/s and 199 m/s. The impact events were monitored using a high-speed camera, with a 20 million frames per second capacity, as well as by a displacement transducer for out-of-plane displacement measurements of the impacted plates. NCF composite plates of two different thicknesses were impacted. The composites were manufactured from carbon fibre and epoxy resin by vacuum infusion. Engineering type models were employed to predict impact response and impact damage formation. Comparison between predicted and resulting damage for the impact test validates the application of a semi-empirical model for predicting impact velocity thresholds for damage formation. Analytical models relying on the assumption of solid impact bodies cannot be employed for these types of impact. © 2008 Elsevier Ltd. All rights reserved.

  • 126.
    Asp, Leif
    et al.
    RISE, Swerea, Swerea SICOMP.
    Juntikka, Rickard
    RISE, Swerea, Swerea SICOMP.
    High velocity impact on NCF reinforced composites2008In: Special Issue on the 12th European Conference on Composite Materials, ECCM 2006, Vol. 69, no 9, p. 1478-1482Conference paper (Refereed)
    Abstract [en]

    In the current paper, a series of high velocity impact tests using /50 and /25 mm ice spheres and 0.32 g granite stones on non-crimp fabric (NCF) composite plates are reported. The impact tests were performed using an air gun and velocities between 100 m/s and 199 m/s. The impact events were monitored using a high-speed camera, with a 20 million frames per second capacity, as well as by a displacement transducer for out-of-plane displacement measurements of the impacted plates. NCF composite plates of two different thicknesses were impacted. The composites were manufactured from carbon fibre and epoxy resin by vacuum infusion. Engineering type models were employed to predict impact response and impact damage formation. Comparison between predicted and resulting damage for the impact test validates the application of a semi-empirical model for predicting impact velocity thresholds for damage formation. Analytical models relying on the assumption of solid impact bodies cannot be employed for these types of impact. © 2008 Elsevier Ltd.

  • 127.
    Asp, Leif
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP.
    Marklund, Erik
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP.
    Varna, Janis
    Luleå University of Technology, Sweden.
    Olsson, Robin
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP.
    Multiscale modelling of non-crimp fabric composites2012Conference paper (Refereed)
    Abstract [en]

    Damage initiation and evolution in NCF composites leading to final failure includes a multitude of mechanisms and phenomena on several length scales. From an engineering point-of-view a computational scheme where all mechanisms would be explicitly addressed is too complex and time consuming. Hence, methods for macroscopic performance prediction of NCF composites, with limited input regarding micro- And mesoscale details, are requested. In this paper, multi-scale modelling approaches for in-plane transverse strength of NCF composites are outlined and discussed. In addition a simplistic method to predict transverse tensile and compressive strength for textile composites featuring low or no fibre waviness is presented.

  • 128.
    Asp, Leif
    et al.
    RISE, Swerea, Swerea SICOMP.
    Nilsson, S.
    Aeronautical Research Institute of Sweden, FFA.
    Singh, S.
    DERA Farnborough.
    An experimental investigation of the influence of delamination growth on the residual strength of impacted laminates2001In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 32, no 9, p. 1229-1235Article in journal (Refereed)
    Abstract [en]

    This study concerns an experimental investigation to establish data for validation of residual strength models for impacted composite panels. The work focuses on compression tests of panels with embedded artificial delaminations at various depths. Accompanying tests on undamaged and impact-damaged panels are reported and the relevance of the tests on artificially delaminated panels is assessed. In the experiments both the artificially delaminated and the impacted plates failed by delamination growth. Consequently, the same mechanism governed failure in the two cases. Hence, the artificially delaminated plate test is reliable for validation of methods developed for analysis of the residual strength of impact-damaged panels. However, for impacted plates, the load at global plate buckling was consistently 10% lower than that of the artificially delaminated plates and 20% lower than that of the undamaged plates. Hence, conservative prediction of the global buckling load of an impacted composite panel require s methods that consider influence of stiffness reduction of the damaged zone. © 2001 Elsevier Science Ltd. All rights reserved.

  • 129.
    Asp, Leif
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP.
    Sjögren, A.
    Aero Research Institute of Sweden, Sweden.
    Greenhalgh, E.S.
    DERA, UK.
    Delamination Growth and Thresholds in a Carbon/Epoxy Composite under Fatigue Loading2001In: Journal of composites technology & research, ISSN 0884-6804, E-ISSN 1945-7537, Vol. 23, no 2, p. 55-68Article in journal (Refereed)
    Abstract [en]

    This paper presents a study on delamination growth in Mode I, Mode II and mixed mode under fatigue loading in an HTA/6376C composite. The computed slopes of the modified Paris plots were high. Therefore, threshold values of the strain energy release rate for delamination growth were determined. Low fatigue threshold values revealed a significant effect of fatigue loading. The largest effect was found for the ENF test (Mode II) for which the fatigue threshold value was only 10% of the critical strain energy release rate in static tests. Threshold values for MMB (mixed mode) and DCB (Mode I) tests were 15% and 23% of the static values, respectively. Fractographic evaluation revealed identical initial failure mechanisms in fatigue and static loading conditions for the ENF specimen. The ENF specimen failed by formation and coalescence of microcracks. The low fatigue threshold for the ENF specimen was explained by microscopical observations on the specimen edge. It was also shown that the fracture surfaces generated in static and fatigue DCB and MMB tests were similar.

  • 130.
    Asta, Nadia
    et al.
    KTH Royal institute of Technology, Sweden.
    Reid, Michael S.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. KTH Royal institute of Technology, Sweden.
    Pettersson, Torbjörn
    KTH Royal institute of Technology, Sweden.
    Wågberg, Lars
    KTH Royal institute of Technology, Sweden.
    The Use of Model Cellulose Materials for Studying Molecular Interactions at Cellulose Interfaces2023In: ACS Macro Letters, E-ISSN 2161-1653, Vol. 12, p. 1530-1535Article in journal (Refereed)
    Abstract [en]

    Despite extensive research on biobased and fiber-based materials, fundamental questions regarding the molecular processes governing fiber-fiber interactions remain unanswered. In this study, we introduce a method to examine and clarify molecular interactions within fiber-fiber joints using precisely characterized model materials, i.e., regenerated cellulose gel beads with nanometer-smooth surfaces. By physically modifying these materials and drying them together to create model joints, we can investigate the mechanisms responsible for joining cellulose surfaces and how this affects adhesion in both dry and wet states through precise separation measurements. The findings reveal a subtle balance in the joint formation, influencing the development of nanometer-sized structures at the contact zone and likely inducing built-in stresses in the interphase. This research illustrates how model materials can be tailored to control interactions between cellulose-rich surfaces, laying the groundwork for future high-resolution studies aimed at creating stiff, ductile, and/or tough joints between cellulose surfaces and to allow for the design of high-performance biobased materials. 

  • 131.
    Athley, Karin
    et al.
    RISE, Innventia.
    Granlöf, Lars
    RISE, Innventia.
    Söderberg, Daniel
    RISE, Innventia.
    Ström, Göran
    RISE, Innventia.
    Optimizing the benefit of retention chemicals2014Conference paper (Refereed)
    Abstract [en]

    Pre-flocculation of filler has been tested as a concept for improving the retention of filler and the strength properties of the sheet. The impact of the size of the filler floes on the mechanical retentionin a fibre network was investigated using a modified laboratory hand sheet former. The mechanical retention was found to increase linearly with both particle size and grammage of the fibre web. These results were confirmed in a full scale production trial on the FEX pilot paper machine at Innventia. Here different filler floe sizes were created through different chemical pre-flocculation strategies. The particle size in the flow to the headbox was measured with FBRM, and a linear relation between particle size and filler retention was found. Corresponding linear relation was seen in a pilot trial when adding filler and retention aid conventionally. This implies that mechanical retention constitute an important part of the filler retention not only upon pre-flocculation but also with conventional addition of filler and retention aid. Thus, the particle size before the headbox can be a good indicator of the retention level. For the conventional application of a two component retention aid system, the increased filler retention correlated to impaired formation and decreased sheet strength. On the contrary, pre-flocculation led to an increase in both sheet strength and filler retention, demonstrating the advantage of pre-flocculating filler.

  • 132.
    Athley, Karin
    et al.
    RISE, Innventia.
    Granlöf, Lars
    RISE, Innventia.
    Söderberg, L. Daniel
    RISE, Innventia.
    Ankerfors, Mikael
    RISE, Innventia.
    Ström, Göran R.
    RISE, Innventia.
    Mechanical retention - Influence of filler floc size and grammage of the fibre web2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 2, p. 202-207Article in journal (Refereed)
    Abstract [en]

    An investigation of the impact of particle size on the mechanical retention of particles in a fibre network has been conducted. The particles used were five sets of quartz particle fractions having fairly narrow particle size distributions with average particle size ranging from a few μm to around 100 μm. The particles were used to model flocculated filler aggregates as part of a larger study of the effect of pre-flocculation on mechanical retention. Pre-flocculation of the filler is a possible strategy to increase the filler content of paper without deterioration of strength properties. A modified laboratory hand sheet former, known as the Rapid Drainage Device (RDD) was used. The major modification consisted of a long pipe that acted as a suction leg, which provides a dewatering vacuum at the same level as on a paper machine. The experimental results showed that mechanical filler retention increased linearly with particle size and grammage of the fibre layer above a critical grammage which depended on particle size. The linear relation was also seen in a pilot scale trial on the FEX pilot-paper machine at Innventia. During this trial fine paper was produced using pre-flocculated filler where the mean particle size of the flocs and fibres was measured in the flow to the headbox. The results from this pilot trial show that mechanical retention is an important part of the total filler retention. Drainage time and therefore drainage resistance increased with the grammage of the fibre layer and amount of quartz particle added. Drainage time, compared at total grammage (i.e. the sum of fibre and quartz particle grammage) was lowest for a fraction of medium-sized particles, with a median size of 35 μm. There was no obvious effect on retention or drainage resistance of a change in the dewatering pressure from 27.5 to 41.5 kPa.

  • 133.
    Atwell, D.L.
    et al.
    Deakin University.
    Barnett, M.R.
    Deakin University.
    Hutchinson, Bevis
    RISE, Swerea, Swerea KIMAB.
    The effect of initial grain size and temperature on the tensile properties of magnesium alloy AZ31 sheet2012In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 549, p. s.1-6Article in journal (Refereed)
    Abstract [en]

    This research aimed to assemble and review data that are relevant to sheet metal formability of the magnesium alloy AZ31. Rolled sheets were processed to give four different grain sizes in the range from 2.9 to 47.1 μm. Similar basal textures were present in all these conditions. Tensile tests were carried out at various temperatures between 25 °C and 240 °C, with some additional tests also made below room temperature in dry ice. Results are presented and discussed relating to strength, ductility, strain rate sensitivity and anisotropy. An optimum grain size of about 7 μm applies for ductility over most of the temperature interval. Uniform elongation decreases steadily with increasing temperature whereas the post-necking and total elongation values increase markedly. Measurements of strength, anisotropy and strain rate sensitivity all indicate a significant role of grain boundary mediated deformation above room temperature. The plastic strain ratio, r, is high at room temperature but decreases considerably, especially for the fine grained conditions, at higher temperatures. Modifications to the active slip modes also occur over the same temperature interval but their effect on plasticity is probably less important than was previously believed. © 2012 Elsevier B.V.

  • 134. Aulin, C.
    et al.
    Shchukarev, A.
    Lindqvist, J.
    Malmström, E.
    Wågberg, L.
    Lindström, Tom
    RISE, STFI-Packforsk.
    Wetting kinetics of oil mixtures on fluorinated model cellulose surfaces2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 317, no 2, p. 556-567Article in journal (Refereed)
    Abstract [en]

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

  • 135. Aulin, C.
    et al.
    Varga, I.
    Claesson, P. M.
    Wågberg, L.
    Lindström, Tom
    RISE, STFI-Packforsk.
    Buildup of polyelectrolyte multilayers of polyethyleneimine and microfibrillated cellulose studied by in situ dual-polarization interferometry and quartz crystal microbalance with dissipation2008In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, no 6, p. 2509-2518Article in journal (Refereed)
    Abstract [en]

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

  • 136. Aulin, C.
    et al.
    Yun, S. H.
    Wåberg, L.
    Lindström, Tom
    RISE, STFI-Packforsk.
    Design of highly oleophobic cellulose surfaces from structured silicon templates2009In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 1, no 11, p. 2443-2452Article in journal (Refereed)
    Abstract [en]

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

  • 137. Aulin, Christian
    et al.
    Gällstedt, Mikael
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Oxygen and oil barrier properties of microfibrillated cellulose films and coatings2010In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 17, no 3, p. 559-574Article in journal (Refereed)
    Abstract [en]

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

  • 138.
    Aulin, Christian
    et al.
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Karabulut, Erdem
    KTH Royal Institute of Technology, Sweden.
    Tran, Amy
    KTH Royal Institute of Technology, Sweden.
    Waisgberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Lindström, Tom
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Transparent nanocellulosic multilayer thin films on polylactic acid with tunable gas barrier properties2013In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, no 15, p. 7352-7359Article in journal (Refereed)
    Abstract [en]

    The layer-by-layer (LbL) deposition method was used for the build-up of alternating layers of nanofibrillated cellulose (NFC) or carboxymethyl cellulose (CMC) with a branched, cationic polyelectrolyte, polyethyleneimine (PEI) on flexible poly (lactic acid) (PLA) substrates. With this procedure, optically transparent nanocellulosic films with tunable gas barrier properties were formed. 50 layer pairs of PEI/NFC and PEI/CMC deposited on PLA have oxygen permeabilities of 0.34 and 0.71 cm3·μm/m 2·day·kPa at 23 C and 50% relative humidity, respectively, which is in the same range as polyvinyl alcohol and ethylene vinyl alcohol. The oxygen permeability of these multilayer nanocomposites outperforms those of pure NFC films prepared by solvent-casting. The nanocellulosic LbL assemblies on PLA substrates was in detailed characterized using a quartz crystal microbalance with dissipation (QCM-D). Atomic force microscopy (AFM) reveals large structural differences between the PEI/NFC and the PEI/CMC assemblies, with the PEI/NFC assembly showing a highly entangled network of nanofibrils, whereas the PEI/CMC surfaces lacked structural features. Scanning electron microscopy images showed a nearly perfect uniformity of the nanocellulosic coatings on PLA, and light transmittance results revealed remarkable transparency of the LbL-coated PLA films. The present work demonstrates the first ever LbL films based on high aspect ratio, water-dispersible nanofibrillated cellulose, and water-soluble carboxymethyl cellulose polymers that can be used as multifunctional films and coatings with tailorable properties, such as gas barriers and transparency. Owing to its flexibility, transparency and high-performance gas barrier properties, these thin film assemblies are promising candidates for several large-scale applications, including flexible electronics and renewable packaging.

  • 139.
    Aulin, Christian
    et al.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Biopolymer Coatings for Paper and Paperboard2011In: Biopolymers: New Materials for Sustainable Films and Coatings / [ed] Plackett David, John Wiley & Sons, 2011, p. 255-276Chapter in book (Other academic)
  • 140.
    Aulin, Christian
    et al.
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Salazar-Alvarez, German
    KTH Royal Institute of Technology, Sweden; Stockholm University, Sweden.
    Lindström, Tom
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    High strength flexible and transparent nanofibrillated cellulose-nanoclay biohybrid films with tunable oxygen and water vapor permeability2012In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 4, no 20, p. 6622-6628Article in journal (Refereed)
    Abstract [en]

    A novel, technically and economically benign procedure to combine vermiculite nanoplatelets with nanocellulose fibre dispersions into functional biohybrid films is presented. Nanocellulose fibres of 20 nm diameters and several micrometers in length are mixed with high aspect ratio exfoliated vermiculite nanoplatelets through high-pressure homogenization. The resulting hybrid films obtained after solvent evaporation are stiff (tensile modulus of 17.3 GPa), strong (strength up to 257 MPa), and transparent. Scanning electron microscopy (SEM) shows that the hybrid films consist of stratified nacre-like layers with a homogenous distribution of nanoplatelets within the nanocellulose matrix. The oxygen barrier properties of the biohybrid films outperform commercial packaging materials and pure nanocellulose films showing an oxygen permeability of 0.07 cm3 μm m-2 d-1 kPa -1 at 50% relative humidity. The oxygen permeability of the hybrid films can be tuned by adjusting the composition of the films. Furthermore, the water vapor barrier properties of the biohybrid films were also significantly improved by the addition of nanoclay. The unique combination of excellent oxygen barrier behavior and optical transparency suggests the potential of these biohybrid materials as an alternative in flexible packaging of oxygen sensitive devices such as thin-film transistors or organic light-emitting diode displays, gas storage applications and as barrier coatings/laminations in large volume packaging applications.

  • 141.
    Aulin, Christian
    et al.
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Ström, Göran R.
    RISE, Innventia.
    Multilayered alkyd resin/nanocellulose coatings for use in renewable packaging solutions with a high level of moisture resistance2013In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, no 7, p. 2582-2589Article in journal (Refereed)
    Abstract [en]

    A surprisingly simple and rapid methodology for large-area, lightweight, and thin laminate coatings with remarkable moisture barrier properties is introduced. Commercially available paperboards are coated with thin layers of nanocellulose. The nanocellulose coating induces a surface smoothening effect on the coated sheets as characterized by environmental scanning electron microscopy and white light interferometry. A moisture-protective layer of renewable alkyd resins is deposited on the nanocellulose precoated sheets using a water-borne dispersion coating process or lithographic printing. Through an auto-oxidation process, the applied alkyd resins are transformed into moisture sealant layers. The moisture barrier properties are characterized in detail by water vapor permeability measurements at different levels of relative humidity. The water vapor barrier properties of the nanocellulose precoated substrates were significantly improved by thin layers of renewable alkyd resins. The effect of the alkyd resin properties, coating technologies, and base paper substrates on the final barrier performance of the sheets were studied. It was found that the nanocellulose coating had a notable effect on the homogeneity and barrier performance of the alkyd resin layers and in particular those alkyd resin layers that were applied by printing. The concept is environmentally friendly, energy-efficient, and economic and is ready for scaling-up via continuous roll-to-roll processes. Large-scale renewable coatings applicable for sustainable packaging solutions are foreseen.

  • 142.
    Axegard, P.
    et al.
    RISE, Innventia.
    Bergnor, E.
    RISE, Innventia.
    Environmental performance of modern ECF bleaching2011Conference paper (Refereed)
  • 143.
    Axegård, Peter
    RISE - Research Institutes of Sweden, Bioeconomy.
    The biorefinery pulp mill2017In: Biofor International, February 13-17, 2017, Montreal, Canada, 2017Conference paper (Other academic)
    Download (pdf)
    presentationsbild
  • 144.
    Axegård, Peter
    RISE, Innventia.
    The kraft pulp mill bio-refinery2013Conference paper (Refereed)
  • 145.
    Axegård, Peter
    et al.
    RISE, Innventia.
    Berglin, Niklas
    RISE, Innventia.
    Lindgren, Karin
    RISE, Innventia.
    Tomani, Per
    RISE, Innventia.
    Öhman, Fredrik
    RISE, Innventia.
    The kraft pulp mill biorefinery platform2011Conference paper (Refereed)
  • 146.
    Babaahmadi, Arezou
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Tang, Luping
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB. Chalmers University of Technology, Sweden.
    Abbas, Zareen
    University of Gothenburg, Sweden.
    Zack, Thomas
    University of Gothenburg, Sweden.
    Mårtensson, Per
    Swedish Nuclear Fuel and Waste Management Company, Sweden.
    Development of an electro-chemical accelerated ageing method for leaching of calcium from cementitious materials2015In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 49, no 1-2, p. 705-718Article in journal (Refereed)
    Abstract [en]

    To facilitate the long term durability predictions of nuclear waste repositories, acceleration methods enhancing calcium leaching process from cementitious materials are needed, even though mechanisms not necessarily comparable to those predominant in a natural leaching process may be developed. In the previously published acceleration methods the samples are very small, which limits further physical or mechanical tests. In this paper, a new acceleration method based on electro-chemical migration is presented. The method although not driven with the same kinetics as in natural leaching, was designed in such a way that unnecessarily destructive by-effects could be minimized while promoting a higher leaching rate for a sample size suitable for further testing the mechanical and physical properties. It is shown that approximately 1 × 106C of electrical charge per paste specimen of size Ø50 × 75 mm (approximately 230 g) is required to leach out the total amount of Portlandite. The chemical and mineralogical properties of leached samples are characterized by various techniques. It is concluded that aged samples are comparable to those leached in a natural leaching process as both are characterized by a layered system comprising an unaltered core delineated by total dissolution of Portlandite followed by a progressive decalcification of the calcium silicate hydrate gel.

  • 147.
    Babi, Mouhanad
    et al.
    McMaster University, USA.
    Fatona, Ayodele
    McMaster University, USA.
    Li, Xiang
    McMaster University, USA.
    Cerson, Christine
    McMaster University, USA.
    Jarvis, Victoria M.
    McMaster University, USA.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden.
    Moran-Mirabal, Jose M.
    McMaster University, USA.
    Efficient Labeling of Nanocellulose for High-Resolution Fluorescence Microscopy Applications2022In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 23, no 5, p. 1981-1994Article in journal (Refereed)
    Abstract [en]

    The visualization of naturally derived cellulose nanofibrils (CNFs) and nanocrystals (CNCs) within nanocomposite materials is key to the development of packaging materials, tissue culture scaffolds, and emulsifying agents, among many other applications. In this work, we develop a versatile and efficient two-step approach based on triazine and azide-alkyne click-chem. to fluorescently label nanocelluloses with a variety of com. available dyes. We show that this method can be used to label bacterial cellulose fibrils, plant-derived CNFs, carboxymethylated CNFs, and CNCs with Cy5 and fluorescein derivatives to high degrees of labeling using minimal amounts of dye while preserving their native morphol. and crystalline structure. The ability to tune the labeling d. with this method allowed us to prepare optimized samples that were used to visualize nanostructural features of cellulose through super-resolution microscopy. The efficiency, cost-effectiveness, and versatility of this method make it ideal for labeling nanocelluloses and imaging them through advanced microscopy techniques for a broad range of applications.

  • 148.
    Bachinger, Angelika
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP.
    Marklund, Erik
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP. Luleå University of Technology, Sweden.
    Rössler, Joraine
    Hellström, Peter
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP.
    Asp, Leif
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, SICOMP. Chalmers University of Technology, Sweden.
    Stiffness-modifiable composite for pedestrian protection2014Conference paper (Refereed)
    Abstract [en]

    A novel functional material allowing stiffness-reduction upon external stimulation was developed. Implementation of such technology in the design of a car front has high potential to result in increased protection of vulnerable road users (VRUs). The composite material is obtained by coating carbon fibres with a thermoplastic polymer in a continuous process, followed by infusion with an epoxy resin. The process is scalable for industrial use. The coating process was optimized regarding coating efficiency, energy consumption, risks involved for operating personnel and environment, and tailored to gain the optimal coating thickness obtained from numerical calculations. A drastic decrease in transversal stiffness could be detected for the composite material by dynamic mechanical thermal analysis (DMTA), when the temperature was increased above the glass transition temperature of the thermoplastic interphase. The ability of the material to achieve such temperature and associated reduction in stiffness by the application of current was verified using a special 3-point bending setup developed for this task.

  • 149.
    Bachinger, Angelika
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Sandinge, Anna
    RISE Research Institutes of Sweden, Safety and Transport, Fire and Safety.
    Lindqvist, Karin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Strid, Anna
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Gong, Guan
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Systematic evaluation of bromine-free flame-retardant systems in acrylonitrile-butadiene-styrene2022In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 139, no 13, article id 51861Article in journal (Refereed)
    Abstract [en]

    A systematic investigation of phosphorus-based flame-retardant (PFR) systems in acrylonitrile-butadiene-styrene (ABS) is presented. The effect of various PFRs, combinations thereof and influence of different synergists is studied in terms of fire and mechanical performance, as well as toxicity of resulting ABS. Sustainable flame-retardant systems with a promising effect on the fire-retardant properties of ABS are identified: A combination of aluminum diethylphosphinate and ammonium polyphosphate is shown to exhibit superior flame-retardant properties in ABS compared to other studied PFRs and PFR combinations. Among a variety of studied potential synergists for this system, a grade of expandable graphite with a high-initiation temperature and a molybdenum-based smoke suppressant show the most promising effect, leading to a significant reduction of the peak heat release rate as well as the smoke production rate. Compared to current state-of-the-art brominated flame-retardant for ABS, the identified flame-retardant systems reduce the maximum smoke production rate by 70% and the peak heat release rate by 40%. However, a significant reduction of the impact performance of the resulting ABS is identified, which requires further investigation.

  • 150.
    Backlund, Birgit
    RISE, Innventia.
    Nya produkter från skogsråvara2014Conference paper (Refereed)
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