Change search
Refine search result
1 - 15 of 15
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Buasiri, Thanyarat
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Habermehl-Cwirzen, Karin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Krzeminski, Lukasz
    Silesian University of Technology, The Institute of Engineering Materials and Biomaterials, Poland.
    Cwirzen, Andrzej
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Piezoresistive Load Sensing and Percolation Phenomena in Portland Cement Composite Modified with In-Situ Synthesized Carbon Nanofibers2019In: Nanomaterials, E-ISSN 2079-4991, Vol. 9, no 4, article id 594Article in journal (Refereed)
    Abstract [en]

    Carbon nanofibers (CNFs) were directly synthesized on Portland cement particles by chemical vapor deposition. The so-produced cements contained between 2.51–2.71 wt% of CNFs; depending on the production batch. Several mortar mixes containing between 0 and 10 wt% of the modified cement were produced and the electrical properties at various ages and the load sensing capabilities determined. The percolation threshold related to the electrical conductivity was detected and corresponded to the amount of the present CNFs, 0.271, 0.189, 0.135 and 0.108 wt%. The observed threshold depended on the degree of hydration of the Portland cement. The studied mortars showed a strong piezoresistive response to the applied compressive load reaching a 17% change of the electrical resistivity at an applied load of 3.5 MPa and 90% at 26 MPa. This initial study showed that the studied material is potentially suitable for future development of novel fully integrated monitoring systems for concrete structures.

    Download full text (pdf)
    fulltext
  • 2.
    Campalani, Carlotta
    et al.
    Department of Molecular Sciences and Nanosystems, Università Ca’ Foscari di Venezia, Via Torino 155, 30172 Venezia Mestre, Italy.
    Cattaruzza, Elti
    Department of Molecular Sciences and Nanosystems, Università Ca’ Foscari di Venezia, Via Torino 155, 30172 Venezia Mestre, Italy.
    Zorzi, Sandro
    Department of Molecular Sciences and Nanosystems, Università Ca’ Foscari di Venezia, Via Torino 155, 30172 Venezia Mestre, Italy.
    Vomiero, Alberto
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Molecular Sciences and Nanosystems, Università Ca’ Foscari di Venezia, Via Torino 155, 30172 Venezia Mestre, Italy.
    You, Shujie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Matthews, Lauren
    The European Synchrotron Radiation Facility, 38043 Grenoble CEDEX 9, France.
    Capron, Marie
    The European Synchrotron Radiation Facility, 38043 Grenoble CEDEX 9, France; Partnership for Soft Condensed Matter PSCM, ESRF The European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043 Grenoble CEDEX 9, France.
    Mondelli, Claudia
    CNR-IOM, Institut Laue Langevin, 71, Avenue des Martyrs, 38042 Grenoble CEDEX 9, France.
    Selva, Maurizio
    Department of Molecular Sciences and Nanosystems, Università Ca’ Foscari di Venezia, Via Torino 155, 30172 Venezia Mestre, Italy.
    Perosa, Alvise
    Department of Molecular Sciences and Nanosystems, Università Ca’ Foscari di Venezia, Via Torino 155, 30172 Venezia Mestre, Italy.
    Biobased Carbon Dots: From Fish Scales to Photocatalysis2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 2, article id 524Article in journal (Refereed)
    Abstract [en]

    The synthesis, characterization and photoreduction ability of a new class of carbon dots made from fish scales is here described. Fish scales are a waste material that contains mainly chitin, one of the most abundant natural biopolymers, and collagen. These components make the scales rich, not only in carbon, hydrogen and oxygen, but also in nitrogen. These self-nitrogen-doped carbonaceous nanostructured photocatalyst were synthesized from fish scales by a hydrothermal method in the absence of any other reagents. The morphology, structure and optical properties of these materials were investigated. Their photocatalytic activity was compared with the one of conventional nitrogen-doped carbon dots made from citric acid and diethylenetriamine in the photoreduction reaction of methyl viologen.

  • 3.
    Hamawandi, Bejan
    et al.
    Department of Applied Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
    Ballikaya, Sedat
    Department of Physics, University of Istanbul, Fatih, Istanbul, 34135, Turkey.
    Råsander, Mikael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Halim, Joseph
    Department of Physics, Chemistry and Biology (IFM), SE-581 83 Linköping, Sweden.
    Vinciguerra, Lorenzo
    Department of Applied Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
    Rosen, Johanna
    Department of Physics, Chemistry and Biology (IFM), SE-581 83 Linköping, Sweden.
    Johnsson, Mats
    Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
    Toprak, Muhammet
    Department of Applied Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
    Composition Tuning of Nanostructured Binary Copper Selenides through Rapid Chemical Synthesis and their Thermoelectric Property Evaluation2020In: Nanomaterials, E-ISSN 2079-4991, Vol. 10, no 5, article id 854Article in journal (Refereed)
    Abstract [en]

    Reduced energy consumption and environmentally friendly, abundant constituents are gaining more attention for the synthesis of energy materials. A rapid, highly scalable, and process-temperature-sensitive solution synthesis route is demonstrated for the fabrication of thermoelectric Cu2xSe. The process relies on readily available precursors and microwave-assisted thermolysis, which is sensitive to reaction conditions; yielding Cu1.8Se at 200 °C and Cu2Se at 250 °C within 6–8 min reaction time. Transmission electron microscopy (TEM) revealed crystalline nature of as-made particles with irregular truncated morphology, which exhibit a high phase purity as identified by X-ray powder diffraction (XRPD) analysis. Temperature-dependent transport properties were characterized via electrical conductivity, Seebeck coefficient, and thermal diffusivity measurements. Subsequent to spark plasma sintering, pure Cu1.8Se exhibited highly compacted and oriented grains that were similar in size in comparison to Cu2Se, which led to its high electrical and low thermal conductivity, reaching a very high power-factor (24 µW/K−2cm−1). Density-of-states (DOS) calculations confirm the observed trends in electronic properties of the material, where Cu-deficient phase exhibits metallic character. The TE figure of merit (ZT) was estimated for the materials, demonstrating an unprecedentedly high ZT at 875 K of 2.1 for Cu1.8Se sample, followed by 1.9 for Cu2Se. Synthetic and processing methods presented in this work enable large-scale production of TE materials and components for niche applications.

  • 4.
    Han, Zhenyao
    et al.
    School of Chemistry and Chemical Engineering, College of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
    Kurokawa, Hiromi
    Algae Biomass Energy System R&D Center (ABES), University of Tsukuba, Tsukuba 305-8572, Japan.
    Matsui, Hirofumi
    Faculty of Medicine, University of Tsukuba, Tsukuba 305-8575, Japan.
    He, Chunlin
    School of Chemistry and Chemical Engineering, College of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
    Wang, Kaituo
    School of Chemistry and Chemical Engineering, College of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
    Wei, Yuezou
    School of Nuclear Science and Technology, University of South China, Hengyang City 421001, China.
    Dodbiba, Gjergj
    Graduate School of Engineering, The University of Tokyo, Bunkyo 113-8656, Japan.
    Otsuki, Akira
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. Ecole Nationale Supérieure de Géologie, Geo Ressources UMR 7359 CNRS, University of Lorraine, 2 Rue du Doyen Marcel Roubault, BP 10162, 54505 Vandoeuvre-lès-Nancy, France.
    Fujita, Toyohisa
    School of Chemistry and Chemical Engineering, College of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
    Stability and Free Radical Production for CO2 and H2 in Air Nanobubbles in Ethanol Aqueous Solution2022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 2, article id 237Article in journal (Refereed)
    Abstract [en]

    In this study, 8% hydrogen (H2) in argon (Ar) and carbon dioxide (CO2) gas nanobubbles was produced at 10, 30, and 50 vol.% of ethanol aqueous solution by the high-speed agitation method with gas. They became stable for a long period (for instance, 20 days), having a high negative zeta potential (−40 to −50 mV) at alkaline near pH 9, especially for 10 vol.% of ethanol aqueous solution. The extended Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory was used to evaluate the nanobubble stability. When the nanobubble in ethanol alkaline aqueous solution changed to an acidic pH of around 5, the zeta potential of nanobubbles was almost zero and the decrease in the number of nanobubbles was identified by the particle trajectory method (Nano site). The collapsed nanobubbles at zero charge were detected thanks to the presence of few free radicals using G-CYPMPO spin trap reagent in electron spin resonance (ESR) spectroscopy. The free radicals produced were superoxide anions at collapsed 8%H2 in Ar nanobubbles and hydroxyl radicals at collapsed CO2 nanobubbles. On the other hand, the collapse of mixed CO2 and H2 in Ar nanobubble showed no free radicals. The possible presence of long-term stable nanobubbles and the absence of free radicals for mixed H2 and CO2 nanobubble would be useful to understand the beverage quality.

  • 5.
    Jonasson, Simon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Bünder, Anne
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE 90187 Umeå, Sweden.
    Berglund, Linn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hertzberg, Magnus
    SweTree Technologies AB, SE 90403 Umeå, Sweden.
    Niittylä, Totte
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE 90187 Umeå, Sweden.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada.
    The Effect of High Lignin Content on Oxidative Nanofibrillation of Wood Cell Wall2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 5, article id 1179Article in journal (Refereed)
    Abstract [en]

    Wood from field-grown poplars with different genotypes and varying lignin content (17.4 wt % to 30.0 wt %) were subjected to one-pot 2,2,6,6-Tetramethylpiperidin-1-yl)oxyl catalyzed oxidation and high-pressure homogenization in order to investigate nanofibrillation following simultaneous delignification and cellulose oxidation. When comparing low and high lignin wood it was found that the high lignin wood was more easily fibrillated as indicated by a higher nanofibril yield (68% and 45%) and suspension viscosity (27 and 15 mPa·s). The nanofibrils were monodisperse with diameter ranging between 1.2 and 2.0 nm as measured using atomic force microscopy. Slightly less cellulose oxidation (0.44 and 0.68 mmol·g−1) together with a reduced process yield (36% and 44%) was also found which showed that the removal of a larger amount of lignin increased the efficiency of the homogenization step despite slightly reduced oxidation of the nanofibril surfaces. The surface area of oxidized high lignin wood was also higher than low lignin wood (114 m2·g−1 and 76 m2·g−1) which implicates porosity as a factor that can influence cellulose nanofibril isolation from wood in a beneficial manner.

  • 6.
    Jonasson, Simon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Bünder, Anne
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden.
    Berglund, Linn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Niittylä, Totte
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada; Wallenberg Wood Science Centre (WWSC), Luleå University of Technology, 97187 Luleå, Sweden.
    Characteristics of Cellulose Nanofibrils from Transgenic Trees with Reduced Expression of Cellulose Synthase Interacting 12022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 19, article id 3448Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibrils can be derived from the native load-bearing cellulose microfibrils in wood. These microfibrils are synthesized by a cellulose synthase enzyme complex that resides in the plasma membrane of developing wood cells. It was previously shown that transgenic hybrid aspen trees with reduced expression of CSI1 have different wood mechanics and cellulose microfibril properties. We hypothesized that these changes in the native cellulose may affect the quality of the corresponding nanofibrils. To test this hypothesis, wood from wild-type and transgenic trees with reduced expression of CSI1 was subjected to oxidative nanofibril isolation. The transgenic wood-extracted nanofibrils exhibited a significantly lower suspension viscosity and estimated surface area than the wild-type nanofibrils. Furthermore, the nanofibril networks manufactured from the transgenics exhibited high stiffness, as well as reduced water uptake, tensile strength, strain-to-break, and degree of polymerization. Presumably, the difference in wood properties caused by the decreased expression of CSI1 resulted in nanofibrils with distinctive qualities. The observed changes in the physicochemical properties suggest that the differences were caused by changes in the apparent nanofibril aspect ratio and surface accessibility. This study demonstrates the possibility of influencing wood-derived nanofibril quality through the genetic engineering of trees.

  • 7.
    López-Rubio, Amparo
    et al.
    Preservation and Food Safety Technologies, IATA-CSIC, Avda. Agustin Escardino 7, 46980 Paterna, Spain.
    Blanco-Padilla, Adriana
    Departmento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro 76010, Mexico.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mendoza, Sandra
    Departmento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro 76010, Mexico.
    Strategies to Improve the Properties of Amaranth Protein Isolate-Based Thin Films for Food Packaging Applications: Nano-Layering through Spin-Coating and Incorporation of Cellulose Nanocrystals2020In: Nanomaterials, E-ISSN 2079-4991, Vol. 10, no 12, article id 2564Article in journal (Refereed)
    Abstract [en]

    In this work, two different strategies for the development of amaranth protein isolate (API)-based films were evaluated. In the first strategy, ultrathin films were produced through spin-coating nanolayering, and the effects of protein concentration in the spin coating solution, rotational speed, and number of layers deposited on the properties of the films were evaluated. In the second strategy, cellulose nanocrystals (CNCs) were incorporated through a casting methodology. The morphology, optical properties, and moisture affinity of the films (water contact angle, solubility, water content) were characterized. Both strategies resulted in homogeneous films with good optical properties, decreased hydrophilic character (as deduced from the contact angle measurements and solubility), and improved mechanical properties when compared with the neat API-films. However, both the processing method and film thickness influenced the final properties of the films, being the ones processed through spin coating more transparent, less hydrophilic, and less water-soluble. Incorporation of CNCs above 10% increased hydrophobicity, decreasing the water solubility of the API films and significantly enhancing material toughness.

  • 8.
    Neumueller, Daniela
    et al.
    Department of Materials Science, Montanuniversität Leoben, 8700 Leoben, Austria.
    Rafailović, Lidija D.
    Department of Materials Science, Montanuniversität Leoben, 8700 Leoben, Austria.
    Jovanović, Aleksandar Z.
    University of Belgrade-Faculty of Physical Chemistry, 11158 Belgrade, Serbia.
    Skorodumova, Natalia V.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Materials Science and Engineering, School of Industrial Engineering and Management, KTH–Royal Institute of Technology, 100 44 Stockholm, Sweden.
    Pasti, Igor A.
    University of Belgrade-Faculty of Physical Chemistry, 11158 Belgrade, Serbia.
    Lassnig, Alice
    Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, 8700 Leoben, Austria.
    Griesser, Thomas
    Institute of Chemistry of Polymeric Materials, Department of Polymer Engineering and Science, Montanuniversität Leoben, 8700 Leoben, Austria.
    Gammer, Christoph
    Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, 8700 Leoben, Austria.
    Eckert, Juergen
    Department of Materials Science, Montanuniversität Leoben, 8700 Leoben, Austria; Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, 8700 Leoben, Austria.
    Hydrogen Evolution Reaction on Ultra-Smooth Sputtered Nanocrystalline Ni Thin Films in Alkaline Media-From Intrinsic Activity to the Effects of Surface Oxidation2023In: Nanomaterials, E-ISSN 2079-4991, Vol. 13, no 14, article id 2085Article in journal (Refereed)
    Abstract [en]

    Highly effective yet affordable non-noble metal catalysts are a key component for advances in hydrogen generation via electrolysis. The synthesis of catalytic heterostructures containing established Ni in combination with surface NiO, Ni(OH)(2), and NiOOH domains gives rise to a synergistic effect between the surface components and is highly beneficial for water splitting and the hydrogen evolution reaction (HER). Herein, the intrinsic catalytic activity of pure Ni and the effect of partial electrochemical oxidation of ultra-smooth magnetron sputter-deposited Ni surfaces are analyzed by combining electrochemical measurements with transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy. The experimental investigations are supplemented by Density Functional Theory and Kinetic Monte Carlo simulations. Kinetic parameters for the HER are evaluated while surface roughening is carefully monitored during different Ni film treatment and operation stages. Surface oxidation results in the dominant formation of Ni(OH)(2), practically negligible surface roughening, and 3-5 times increased HER exchange current densities. Higher levels of surface roughening are observed during prolonged cycling to deep negative potentials, while surface oxidation slows down the HER activity losses compared to as-deposited films. Thus, surface oxidation increases the intrinsic HER activity of nickel and is also a viable strategy to improve catalyst durability.

    Download full text (pdf)
    fulltext
  • 9.
    Nissilä, Tuukka
    et al.
    Fibre and Particle Engineering Research Unit, Faculty of Technology, University of Oulu, FI-90014 Oulu, Finland.
    Wei, Jiayuan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Geng, Shiyu
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Teleman, Anita
    RISE Research Institutes of Sweden, SE-11428 Stockholm, Sweden.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, ON M5S 3G8, Canada.
    Ice-Templated Cellulose Nanofiber Filaments as a Reinforcement Material in Epoxy Composites2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 2, article id 490Article in journal (Refereed)
    Abstract [en]

    Finding renewable alternatives to the commonly used reinforcement materials in composites is attracting a significant amount of research interest. Nanocellulose is a promising candidate owing to its wide availability and favorable properties such as high Young’s modulus. This study addressed the major problems inherent to cellulose nanocomposites, namely, controlling the fiber structure and obtaining a sufficient interfacial adhesion between nanocellulose and a non-hydrophilic matrix. Unidirectionally aligned cellulose nanofiber filament mats were obtained via ice-templating, and chemical vapor deposition was used to cover the filament surfaces with an aminosilane before impregnating the mats with a bio-epoxy resin. The process resulted in cellulose nanocomposites with an oriented structure and a strong fiber–matrix interface. Diffuse reflectance infrared Fourier transform and X-ray photoelectron spectroscopy studies revealed the presence of silane on the filaments. The improved interface, resulting from the surface treatment, was observable in electron microscopy images and was further confirmed by the significant increase in the tan delta peak temperature. The storage modulus of the matrix could be improved up to 2.5-fold with 18 wt% filament content and was significantly higher in the filament direction. Wide-angle X-ray scattering was used to study the orientation of cellulose nanofibers in the filament mats and the composites, and the corresponding orientation indices were 0.6 and 0.53, respectively, indicating a significant level of alignment.

    Download full text (pdf)
    fulltext
  • 10.
    Rosenstock Völtz, Luísa
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Wallenberg Wood Science Center (WWSC), Luleå, Sweden.
    Geng, Shiyu
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Wallenberg Wood Science Center (WWSC), Luleå, Sweden.
    Teleman, Anita
    RISE Research Institutes of Sweden, Stockholm, Sweden.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Wallenberg Wood Science Center (WWSC), Luleå University of Technology, SE-97187 Luleå, Sweden; Department of Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, ON M5S 3G8, Canada.
    Influence of Dispersion and Orientation on Polyamide-6 Cellulose Nanocomposites Manufactured through Liquid-Assisted Extrusion2022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 5, article id 818Article in journal (Refereed)
    Abstract [en]

    In this study, the possibility of adding nanocellulose and its dispersion to polyamide 6 (PA6), a polymer with a high melting temperature, is investigated using melt extrusion. The main challenges of the extrusion of these materials are achieving a homogeneous dispersion and avoiding the thermal degradation of nanocellulose. These challenges are overcome by using an aqueous suspension of never-dried nanocellulose, which is pumped into the molten polymer without any chemical modification or drying. Furthermore, polyethylene glycol is tested as a dispersant for nanocellulose. The dispersion, thermal degradation, and mechanical and viscoelastic properties of the nanocomposites are studied. The results show that the dispersant has a positive impact on the dispersion of nanocellulose and that the liquid-assisted melt compounding does not cause the degradation of nanocellulose. The addition of only 0.5 wt.% nanocellulose increases the stiffness of the neat polyamide 6 from 2 to 2.3 GPa and shifts the tan δ peak toward higher temperatures, indicating an interaction between PA6 and nanocellulose. The addition of the dispersant decreases the strength and modulus but has a significant effect on the elongation and toughness. To further enhance the mechanical properties of the nanocomposites, solid-state drawing is used to create an oriented structure in the polymer and nanocomposites. The orientation greatly improves its mechanical properties, and the oriented nanocomposite with polyethylene glycol as dispersant exhibits the best alignment and properties: with orientation, the strength increases from 52 to 221 MPa, modulus from 1.4 to 2.8 GPa, and toughness 30 to 33 MJ m−3 in a draw ratio of 2.5. This study shows that nanocellulose can be added to PA6 by liquid-assisted extrusion with good dispersion and without degradation and that the orientation of the structure is a highly-effective method for producing thermoplastic nanocomposites with excellent mechanical properties.

  • 11.
    Singh, Shikha
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Centre Català del Plàstic (CCP)—Universitat Politècnica de Catalunya Barcelona Tech (EEBE-UPC)-ePLASCOM, 08019 Barcelona, Spain.
    Patel, Mitul Kumar
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Geng, Shiyu
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Teleman, Anita
    RISE (Research Institutes of Sweden), SE-114 28 Stockholm, Sweden.
    Herrera, Natalia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Schwendemann, Daniel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Maspoch, Maria Lluisa
    Centre Català del Plàstic (CCP)—Universitat Politècnica de Catalunya Barcelona Tech (EEBE-UPC)-ePLASCOM, 08019 Barcelona, Spain.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering, University of Toronto, Toronto, ON M5S 3BS, Canada; Wallenberg Wood Science Center (WWSC), Luleå University of Technology, SE-971 87 Luleå, Sweden.
    Orientation of Polylactic Acid–Chitin Nanocomposite Films via Combined Calendering and Uniaxial Drawing: Effect on Structure, Mechanical, and Thermal Properties2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 12, article id 3308Article in journal (Refereed)
    Abstract [en]

    The orientation of polymer composites is one way to increase the mechanical properties of the material in a desired direction. In this study, the aim was to orient chitin nanocrystal (ChNC)-reinforced poly(lactic acid) (PLA) nanocomposites by combining two techniques: calendering and solid-state drawing. The effect of orientation on thermal properties, crystallinity, degree of orientation, mechanical properties and microstructure was studied. The orientation affected the thermal and structural behavior of the nanocomposites. The degree of crystallinity increased from 8% for the isotropic compression-molded films to 53% for the nanocomposites drawn with the highest draw ratio. The wide-angle X-ray scattering results confirmed an orientation factor of 0.9 for the solid-state drawn nanocomposites. The mechanical properties of the oriented nanocomposite films were significantly improved by the orientation, and the pre-orientation achieved by film calendering showed very positive effects on solid-state drawn nanocomposites: The highest mechanical properties were achieved for pre-oriented nanocomposites. The stiffness increased from 2.3 to 4 GPa, the strength from 37 to 170 MPa, the elongation at break from 3 to 75%, and the work of fracture from 1 to 96 MJ/m3. This study demonstrates that the pre-orientation has positive effect on the orientation of the nanocomposites structure and that it is an extremely efficient means to produce films with high strength and toughness.

  • 12.
    Thomas, Bony
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Geng, Shiyu
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Sain, Mohini
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, ON M5S 3G8, Canada.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, ON M5S 3G8, Canada.
    Hetero-Porous, High-Surface Area Green Carbon Aerogels for the Next-Generation Energy Storage Applications2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 3, article id 653Article in journal (Refereed)
    Abstract [en]

    Various carbon materials have been developed for energy storage applications to address the increasing energy demand in the world. However, the environmentally friendly, renewable, and nontoxic bio-based carbon resources have not been extensively investigated towards high-performance energy storage materials. Here, we report an anisotropic, hetero-porous, high-surface area carbon aerogel prepared from renewable resources achieving an excellent electrical double-layer capacitance. Two different green, abundant, and carbon-rich lignins which can be extracted from various biomasses, have been selected as raw materials, i.e., kraft and soda lignins, resulting in clearly distinct physical, structural as well as electrochemical characteristics of the carbon aerogels after carbonization. The obtained green carbon aerogel based on kraft lignin not only demonstrates a competitive specific capacitance as high as 163 F g−1 and energy density of 5.67 Wh kg−1 at a power density of 50 W kg−1 when assembled as a two-electrode symmetric supercapacitor, but also shows outstanding compressive mechanical properties. This reveals the great potential of the carbon aerogels developed in this study for the next-generation energy storage applications requiring green and renewable resources, lightweight, robust storage ability, and reliable mechanical integrity.

  • 13.
    Thomas, Bony
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Sain, Mohini
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, ON M5S 3G8, Canada.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, ON M5S 3G8, Canada; Wallenberg Wood Science Center (WWSC), Luleå University of Technology, SE-97187 Luleå, Sweden.
    Sustainable Carbon Derived from Sulfur-Free Lignins for Functional Electrical and Electrochemical Devices2022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 20, article id 3630Article in journal (Refereed)
    Abstract [en]

    Technical lignins, kraft, soda, lignoboost, and hydrolysis lignins were used for the production of carbon particles at different carbonization temperatures, 1000 °C and 1400 °C. The results showed that the lignin source and carbonization temperature significantly influenced the carbon quality and microstructure of the carbon particles. Soda lignin carbonized up to 1400 °C showed higher degree of graphitization and exhibited the highest electrical conductivity of 335 S·m−1, which makes it suitable for applications, such as electromagnetic interference shielding and conductive composite based structural energy storage devices. The obtained carbon particles also showed high surface area and hierarchical pore structure. Kraft lignin carbonized up to 1400 °C gives the highest BET surface area of 646 m2 g−1, which makes it a good candidate for electrode materials in energy storage applications. The energy storage application has been validated in a three-electrode set up device, and a specific capacitance of 97.2 F g−1 was obtained at a current density of 0.1 A g−1 while an energy density of 1.1 Wh kg−1 was observed at a power density of 50 W kg−1. These unique characteristics demonstrated the potential of kraft lignin-based carbon particles for electrochemical energy storage applications. 

    Download full text (pdf)
    fulltext
  • 14.
    Zairov, Rustem R.
    et al.
    Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzov Str., 8, 420088 Kazan, Russia.
    Dovzhenko, Alexey P.
    Department of Physical Chemistry, Kazan (Volga Region) Federal University, Kremlyovskaya Str., 18, 420008 Kazan, Russia.
    Sarkanich, Kirill A.
    Department of Physical Chemistry, Kazan (Volga Region) Federal University, Kremlyovskaya Str., 18, 420008 Kazan, Russia.
    Nizameev, Irek R.
    Department of Nanotechnologies in Electronics, Kazan National Research Technical University Named after A.N. Tupolev-KAI, 10, K. Marx Str., 420111 Kazan, Russia.
    Luzhetskiy, Andrey V.
    Federal State Autonomous Educational Institution of Higher Education “Gubkin Russian State University of Oil and Gas” (National Research University), Leninsky Prospect, 65, 119991 Moscow, Russia.
    Sudakova, Svetlana N.
    Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzov Str., 8, 420088 Kazan, Russia.
    Podyachev, Sergey N.
    Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzov Str., 8, 420088 Kazan, Russia.
    Burilov, Vladimir A.
    Department of Physical Chemistry, Kazan (Volga Region) Federal University, Kremlyovskaya Str., 18, 420008 Kazan, Russia.
    Vatsouro, Ivan M.
    Department of Chemistry, M. V. Lomonosov Moscow State University, Lenin’s Hills 1, 119991 Moscow, Russia.
    Vomiero, Alberto
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Molecular Sciences and Nanosystems, Ca’ Foscari University Venezia, Via Torino 155, 30172 Venezia-Mestre, Italy.
    Mustafina, Asiya R.
    Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzov Str., 8, 420088 Kazan, Russia.
    Single Excited Dual Band Luminescent Hybrid Carbon Dots-Terbium Chelate Nanothermometer2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 11, article id 3080Article in journal (Refereed)
    Abstract [en]

    The report introduces hybrid polyelectrolyte-stabilized colloids combining blue and green-emitting building blocks, which are citrate carbon dots (CDs) and [TbL]+ chelate complexes with 1,3-diketonate derivatives of calix[4]arene. The joint incorporation of green and blue-emitting blocks into the polysodium polystyrenesulfonate (PSS) aggregates is carried out through the solvent-exchange synthetic technique. The coordinative binding between Tb3+ centers and CD surface groups in initial DMF solutions both facilitates joint incorporation of [TbL]+ complexes and the CDs into the PSS-based nanobeads and affects fluorescence properties of [TbL]+ complexes and CDs, as well as their ability for temperature sensing. The variation of the synthetic conditions is represented herein as a tool for tuning the fluorescent response of the blue and green-emitting blocks upon heating and cooling. The revealed regularities enable developing either dual-band luminescent colloids for monitoring temperature changes within 25–50 °C through double color emission or transforming the colloids into ratiometric temperature sensors via simple concentration variation of [TbL]+ and CDs in the initial DMF solution. Novel hybrid carbon dots-terbium chelate PSS-based nanoplatform opens an avenue for a new generation of sensitive and customizable single excited dual-band nanothermometers.

  • 15.
    Zhao, Jun
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements. College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China; State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
    Gao, Tong
    College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
    Dang, Jie
    College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
    Cao, Weiyu
    State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
    Wang, Ziqi
    College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
    Li, Shuangxi
    College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
    Shi, Yijun
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Using Green, Economical, Efficient Two-Dimensional (2D) Talc Nanosheets as Lubricant Additives under Harsh Conditions2022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 10, article id 1666Article in journal (Refereed)
    Abstract [en]

    Two-dimensional (2D) nanomaterials have attracted much attention for lubrication enhancement of grease. It is difficult to disperse nanosheets in viscous grease and the lubrication performances of grease under harsh conditions urgently need to be improved. In this study, the 2D talc nanosheets are modified by a silane coupling agent with the assistance of high-energy ball milling, which can stably disperse in grease. The thickness and size of the talc nanosheet are about 20 nm and 2 µm. The silane coupling agent is successfully grafted on the surface of talc. Using the modified-talc nanosheet, the coefficient of friction and wear depth can be reduced by 40% and 66% under high temperature (150 °C) and high load (3.5 GPa), respectively. The enhancement of the lubrication and anti-wear performance is attributed to the boundary adsorbed tribofilm of talc achieving a repairing effect of the friction interfaces, the repairing effect of talc on the friction interfaces. This work provides green, economical guidance for developing natural lubricant additives and has great potential in sustainable lubrication.

1 - 15 of 15
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf