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  • 1. Trovatti, E.
    et al.
    Tang, Hu
    KTH, School of Biotechnology (BIO).
    Hajian, Alireza
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Meng, Qijun
    KTH, School of Biotechnology (BIO).
    Gandini, A.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Enhancing strength and toughness of cellulose nanofibril network structures with an adhesive peptide2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, 256-263 p.Article in journal (Refereed)
    Abstract [en]

    The mechanical properties of cellulose nanofibrils network structure are essential for their applications in functional materials. In this work, an adhesive peptide consisting of just 11 amino acid residues with a hydrophobic core sequence of FLIVI (F – phenylalanine, L – leucine, I – isoleucine, V – valine) flanked by three lysine (K) residues was adsorbed to 2,2,6,6-Tetramethyl-1-piperidinyloxy radical (TEMPO) oxidized cellulose nanofibrils (TO-CNF). Composite films were prepared by solution casting from water suspensions of TO-CNF adsorbed with the adhesive peptide. The nanofibrils network structure of the composite was characterized by atomic force microscopy (AFM). The structure of the peptide in the composites and the interactions between TO-CNF and the peptide were studied by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The mechanical properties of the composites were characterized by tensile tests and dynamic mechanical analysis (DMA). With 6.3 wt.% adhesive peptide adsorbed onto TO-CNF, the composite showed a modulus of 12.5 ± 1.4 GPa, a tensile strength of 344.5 ± (15.3) MPa, and a strain to failure of 7.8 ± 0.4%, which are 34.4%, 48.8%, and 23.8% higher than those for neat TO-CNF, respectively. This resulted in significantly improved toughness (work to fracture) for the composite, 77% higher than that for the neat TO-CNF.

  • 2.
    Kaldéus, Tahani
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Nordenström, Malin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Insights into the EDC-mediated PEGylation of cellulose nanofibrils and their colloidal stability2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, 871-878 p.Article in journal (Refereed)
    Abstract [en]

    EDC-mediated coupling has frequently been utilized to poly(ethylene glycol) functionalize (PEGylate) cellulose-based materials, but no work has previously been reported on the direct N-(3-dimethylaminopropyl)-N-ethylcarbodiimide (EDC)-mediated PEGylation of cellulose nanofibrils (CNF). Herein, we report the first study where CNF has been directly sterically stabilized with amine-terminated PEG employing N-hydroxysuccinimide (NHS)-assisted EDC-coupling. This work has shown that this coupling reaction is highly sensitive to the reaction conditions and purification procedures, and hence an optimized coupling protocol was developed in order to achieve a reaction yield. Elemental analysis of the nitrogen content also showed the successful PEGylation. It was also shown that a surprisingly low PEGylation (1%) is sufficient to significantly improve the colloidal stability of the PEGylated samples, which reached dispersion-arrested-state-transitions at higher concentrations than neat CNF. The colloidal stability was preserved with increasing ionic strength, when comparably long polymer chains were grafted, targeting only 1% PEGylation.

  • 3.
    Aminzadeh, Selda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lauberts, M.
    Dobele, G.
    Ponomarenko, J.
    Mattsson, T.
    Lindström, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Sevastyanova, Olena
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Membrane filtration of kraft lignin: Structural charactristics and antioxidant activity of the low-molecular-weight fraction2018In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 112, 200-209 p.Article in journal (Refereed)
    Abstract [en]

    Lignin, which is the second most abundant biomass component and has carbon-rich phenolic content, is a promising renewable raw material for multiple applications, such as carbon fibers, adhesives, and emulsifiers. To use lignin efficiently, it is important to ensure its purity and homogeneity. As a result, the separation of lignin into fractions with high purity and narrow molecular-weight distributions is likely a prerequisite for several applications. Ultrafiltration using ceramic membranes has many advantages, including enabling direct lignin extraction from Kraft pulp cooking liquors without pH and temperature adjustment. One challenge with membrane filtration using such a system is the potential for reduced membrane performance over time, which is associated with fouling. In this study, LignoBoost Kraft lignin was fractionated using a ceramic membrane with a molecular weight cut-off of 1 kDa. The separation behavior during ultrafiltration fractionation was investigated and the antioxidant properties of the recovered low-molecular-weight (low-MW) lignin samples were evaluated. Using this model system, the permeate fluxes were unstable during the 100 h of membrane operation. However, a decrease in the average MW in the permeate over time was observed. The shift in MW was most pronounced for virgin membranes, while a more stable MW distribution was evident for membranes subjected to multiple cleaning cycles. According to 2D NMR analysis, low-MW lignin that was recovered after 100 h of operation, consisted of smaller lignin fragments, such as dimers and oligomers, with a high content of methoxy-groups. This was confirmed using the size exclusion chromatography method, which indicated an weigh average molecular weight in the range of 450–500 Da. 31P NMR spectroscopy showed that, despite the lower total content of phenolic OH groups, the low-MW sample had a higher proportion of non-condensed phenolic OH groups. The results of the antioxidant tests demonstrated the strong potential of lignin and its low-MW fraction as a natural antioxidant, particularly for lipid-containing systems. The low-MW lignin fraction showed better antioxidant activity than the non-fractionated LignoBoost lignin in the kinetic oxygen radical absorbance capacity (ORAC) test and demonstrated three-fold stronger inhibition of the substrate (fluorescein) than the reference antioxidant Trolox (a water-soluble derivative of vitamin E).

  • 4.
    Li, Yuanyuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Fu, Qiliang
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Yang, Xuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Transparent wood for functional and structural applications2018In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 376, no 2112, 20170182Article, review/survey (Refereed)
    Abstract [en]

    Optically transparent wood combines mechanical performance with optical functionalities is an emerging candidate for applications in smart buildings and structural optics and photonics. The present review summarizes transparent wood preparation methods, optical and mechanical performance, and functionalization routes, and discusses potential applications. The various challenges are discussed for the purpose of improved performance, scaled-up production and realization of advanced applications. This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.

  • 5. Li, M.
    et al.
    Chen, Pan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Xu, M.
    Xu, X.
    A novel self-assembly Lentinan-tetraphenylethylene​ composite with strong blue​ fluorescence in water and its properties2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, 13-24 p.Article in journal (Refereed)
    Abstract [en]

    We report a unique self-assembly of lentinan, a triple helical β-(1→3)-glucan (t-LNT), in water. By molecular dynamics simulation, it was found that t-LNT aggregated preferentially along the chain direction to form long chains, accompanied by side-direction linkage to form branches. Transmission electron microscopy images demonstrated that t-LNT formed dendrite-like fibers, which further formed fishnet-like porous/mesoporous aggregates with increasing concentration. The meshes in the fishnet were ascribed to the intersection of branches. The major driving force for aggregation was expected to be hydrogen bonding between hydroxyl groups in t-LNT chains. Based on this self-assembly behavior, a novel composite was prepared from t-LNT and tetraphenylethylene (TPE) by entrapping TPE aggregates into the meshes of t-LNT fishnets. The as-prepared t-LNT/TPE composite largely enhanced the blue fluorescence of TPE in water, exhibiting stable optical property and good biocompatibility, and t-LNT is expected to show great potential as a carrier of hydrophobic molecules for biomedical application.

  • 6.
    Cheng, Ming
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Li, Yuanyuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Liu, Peng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Zhang, Fuguo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Hajian, Alireza
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Wang, Haoxin
    State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Li, Jiajia
    State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Wang, Linqin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Yang, Xichuan
    State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    A Perylenediimide Tetramer-Based 3D Electron Transport Material for Efficient Planar Perovskite Solar Cell2017In: Solar RRL, ISSN 2367-198X, Vol. 1, no 5, 1700046- p.Article in journal (Refereed)
    Abstract [en]

    A perylenediimide (PDI) tetramer-based three dimensional (3D) molecular material, termed SFX-PDI4, has been designed, synthesized, and characterized. The low-lying HOMO and LUMO energy levels, high electron mobility and good film-formation property make it a promising electron transport material (ETM) in inverted planar perovskite solar cells (PSCs). The device exhibits a high power conversion efficiency (PCE) of 15.3% with negligible hysteresis, which can rival that of device based on PC61BM. These results demonstrate that three dimensional PDI-based molecular materials could serve as high performance ETMs in PSCs.

  • 7.
    Aminzadeh, Selda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Zhang, Liming
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    A possible explanation for the structural inhomogeneity of lignin in LCC networks2017In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 51, no 6, 1365-1376 p.Article in journal (Refereed)
    Abstract [en]

    Lignin has a very complex structure, and this is partly due to the monomers being connected by many different types of covalent bonds. Furthermore, there are multiple covalent bonds between lignin and polysaccharides in wood, and it is known that the structure of lignin covalently bound to the hemicellulose xylan is different to lignin bound to the hemicellulose glucomannan. Here, synthetic lignin (DHP) is synthesized at different pH and it is shown that lignin made at lower pH has a structure more similar to the lignin bound to xylan, i.e., having higher relative content of beta-O-4 ethers. It is hypothesized that xylan due to its carboxylic acids forms a locally lower pH and thus "direct" the lignin structure to have more beta-O-4 ethers. The biological significance of these results is discussed.

  • 8. Mattsson, Cecilia
    et al.
    Hasani, Merima
    Dang, Binh
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Mayzel, Maxim
    Theliander, Hans
    About structural changes of lignin during kraft cooking and the kinetics of delignification2017In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 71, no 7-8, 545-553 p.Article in journal (Refereed)
    Abstract [en]

    Wood meal was submitted to kraft cooking in a small-scale flow-through reactor and the structural changes of lignin have been investigated. The rate determining steps in kraft cooking were in focus. Based on two-dimensional nuclear magnetic resonance (2D-NMR) measurements on lignin fractions extracted at different cooking times from the black liquor, it was observed that the main lignin reactions occur within 10-20 min and thus the kinetics of the chemical reaction cannot be the rate-determining step. On the other hand, the molecular weight (MW) of lignin is shifted towards larger fragments in the course of cooking time but the MW decreases with increasing ionic strength. Obviously, the kinetics of the delignification are strongly dependent on solubility and/or mass transport at the cell wall level. At chip size level, the mass transport of cooking chemicals into the wood chip may influence the overall kinetics in the initial part of the cooking. At longer cooking times the concentration of chemicals becomes sufficiently high in the wood chips, and the delignification is progressively governed by solubility and/or mass transport of lignin molecules occurring at the cell wall level.

  • 9. Escudero, Viviana
    et al.
    Jorda, Lucia
    Sopena-Torres, Sara
    Melida, Hugo
    Miedes, Eva
    Munoz-Barrios, Antonio
    Swami, Sanjay
    Alexander, Danny
    McKee, Lauren S.
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Sanchez-Vallet, Andrea
    Bulone, Vincent
    KTH, School of Biotechnology (BIO), Glycoscience.
    Jones, Alan M.
    Molina, Antonio
    Alteration of cell wall xylan acetylation triggers defense responses that counterbalance the immune deficiencies of plants impaired in the beta-subunit of the heterotrimeric G-protein2017In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 92, no 3, 386-399 p.Article in journal (Refereed)
    Abstract [en]

    Arabidopsis heterotrimeric G-protein complex modulates pathogen-associated molecular pattern-triggered immunity (PTI) and disease resistance responses to different types of pathogens. It also plays a role in plant cell wall integrity as mutants impaired in the G- (agb1-2) or G-subunits have an altered wall composition compared with wild-type plants. Here we performed a mutant screen to identify suppressors of agb1-2 (sgb) that restore susceptibility to pathogens to wild-type levels. Out of the four sgb mutants (sgb10-sgb13) identified, sgb11 is a new mutant allele of ESKIMO1 (ESK1), which encodes a plant-specific polysaccharide O-acetyltransferase involved in xylan acetylation. Null alleles (sgb11/esk1-7) of ESK1 restore to wild-type levels the enhanced susceptibility of agb1-2 to the necrotrophic fungus Plectosphaerella cucumerina BMM (PcBMM), but not to the bacterium Pseudomonas syringae pv. tomato DC3000 or to the oomycete Hyaloperonospora arabidopsidis. The enhanced resistance to PcBMM of the agb1-2 esk1-7 double mutant was not the result of the re-activation of deficient PTI responses in agb1-2. Alteration of cell wall xylan acetylation caused by ESK1 impairment was accompanied by an enhanced accumulation of abscisic acid, the constitutive expression of genes encoding antibiotic peptides and enzymes involved in the biosynthesis of tryptophan-derived metabolites, and the accumulation of disease resistance-related secondary metabolites and different osmolites. These esk1-mediated responses counterbalance the defective PTI and PcBMM susceptibility of agb1-2 plants, and explain the enhanced drought resistance of esk1 plants. These results suggest that a deficient PTI-mediated resistance is partially compensated by the activation of specific cell-wall-triggered immune responses. Significance Statement The plant heterotrimeric G protein complex is an essential component of Pathogen Associated Molecular Pattern-triggered immunity (PTI) and of plant disease resistance to several types of pathogens. We found that modification of the degree of xylan acetylation in plant cell walls activates PTI-independent resistance responses that counterbalance the hypersusceptibility to particular pathogens of plants lacking the heterotrimeric G subunit. These data demonstrate that immune deficient response can be partially compensated by the activation of cell wall-triggered immunity that confers specific disease resistance.

  • 10.
    Yao, Kun
    et al.
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Huang, Shu
    KTH, School of Biotechnology (BIO).
    Tang, Hu
    KTH, School of Biotechnology (BIO).
    Xu, Y.
    Buntkowsky, G.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Bioinspired Interface Engineering for Moisture Resistance in Nacre-Mimetic Cellulose Nanofibrils/Clay Nanocomposites2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 23, 20169-20178 p.Article in journal (Refereed)
    Abstract [en]

    The interfacial adhesion design between "mortar" and "bricks" is essential for mechanical and barrier performance of nanocellulose-based nacre-mimetic nanocomposites, especially at high moisture conditions. To address this fundamental challenge, dopamine (DA) has been conjugated to cellulose nanofibrils (CNFs) and subsequently assembled with montmorillonite (MTM) to generate layered nanocomposite films inspired by the strong adhesion of mussel adhesive proteins to inorganic surfaces under water. The selective formation of catechol/metal ion chelation and hydrogen bonding at the interface between MTM platelets and CNFs bearing DA renders transparent films with strong mechanical properties, particularly at high humidity and in wet state. Increasing the amount of conjugated DA on CNFs results in nanocomposites with increased tensile strength and modulus, up to 57.4 MPa and 1.1 GPa, respectively, after the films are swollen in water. The nanocomposites also show excellent gas barrier properties at high relative humidity (95%), complementing the multifunctional property profile.

  • 11.
    Hatton, Fiona
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. University of Sheffield, United Kingdom.
    Engström, Joakim
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Forsling, Josefine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Biomimetic adsorption of zwitterionic-xyloglucan block copolymers to CNF: towards tailored super-absorbing cellulose materials2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 24, 14947-14958 p.Article in journal (Refereed)
    Abstract [en]

    A biomimetic, facile approach to cellulose modification is the utilisation of self-adsorbing, naturally occurring biopolymers, such as the hemicellulose xyloglucan (XG). Herein, XG-block-poly(sulfobetaine methacrylate) (XG-b-PSBMA) zwitterionic block copolymers have been prepared and assessed for their ability to adsorb to cellulose, specifically cellulose nanofibrils (CNF). The polymers were synthesised using reversible addition-fragmentation chain-transfer (RAFT) polymerisation, employing an XG macromolecular RAFT agent (XG-RAFT), polymerising a sulfobetaine methacrylate (SBMA) under aqueous conditions. The incorporation of the XG block shifted the upper critical solution temperature (UCST) values to higher temperatures (20 and 30 °C) compared with the PSBMA homopolymers (17 and 22 °C) and the transition was also broadened. The adsorption of the polymers to a CNF surface was monitored using quartz crystal microbalance with dissipation monitoring (QCM-D), showing that the XG block enhanced the adsorption of the zwitterionic polymer. The formation of CNF-composite films was achieved utilising a facile vacuum filtration methodology, and the targeted compositions were confirmed by FT-IR and TGA analyses. The films exhibited high degrees of swelling in water, which were investigated at two different temperatures, 5 and 60 °C (below and above the polymer USCT values). These results highlight the advantage of using an XG block for the biomimetic modification of cellulose to form new cellulose-composite materials such as super-absorbing films.

  • 12.
    Li, Yuanyuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Yu, Shun
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Chen, Pan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Rojas, Ramiro
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Hajian, Alireza
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Cellulose nanofibers enable paraffin encapsulation and the formation of stable thermal regulation nanocomposites2017In: Nano Energy, ISSN 2211-2855, Vol. 34, 541-548 p.Article in journal (Refereed)
    Abstract [en]

    Non-leaking, green materials with high content of phase change materials (PCM) can conserve solar energy and contribute to a sustainable society. Here, paraffin was encapsulated by nanocellulose (CNF) through a pickering emulsion method, while simultaneously forming a composite material. The thermodynamic drive for phase separation was confirmed by molecular modeling. Particle formation was characterized by dynamic light scattering and they were processed into stable PCM/CNF composites in the form of PCM paper structures with favorable mechanical properties. The PCM composite was lightweight and showed a solid content of paraffin of more than 72 wt%. Morphology was characterized using FE-SEM. The thermal regulation function of the PCM composite was demonstrated in the form of a model roof under simulated sunlight. No obvious leakage was observed during heating/cooling cycles, as supported by DSC and SAXS data. The PCM composite can be extended to panels used in energy-efficient smart buildings with thermal regulation integrated in load-bearing structures.

  • 13. Löbmann, Korbinian
    et al.
    Wohlert, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Müllertz, Anette
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Svagan, Anna J.
    Cellulose Nanopaper and Nanofoam for Patient-Tailored Drug Delivery2017In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 4, no 9, 1600655Article in journal (Refereed)
    Abstract [en]

    The development of drug delivery systems with tailored drug release can be very challenging especially in the case of problematic drugs. To address this problem, pharmaceutical scientists frequently use different formulation approaches and excipients, often involving a complex and multistep preparation. In this study, new cellulose nanofiber (CNF) based drug formulations are developed that allow controlled drug release in a facile and fast way, i.e., by simply casting drug/CNF dispersions. Altering the processing conditions and utilizing the unique inherent chemicophysical properties of cationic CNF at interfaces, it is possible to produce either drug-loaded CNF nanopapers (containing 21 or 51 wt% drug) or nanofoams (containing 21 wt% drug). The different formulations exhibit tailored release kinetics of the poorly watersoluble model drug indomethacin from immediate (nanopapers, 10-20 min) to slow release (nanofoams, approximate to 24 h). The fast release, from the nanopapers, is a result of the interplay of the molecular and supramolecular structure of indomethacin in addition to observed enhanced intrinsic dissolution of drug in the presence of CNF. The slower drug release is achieved by changing the hierarchical structure, i.e., creating a CNF based foam (porosity 99.2 wt%), and the prolonged release is mainly due to an extended drug diffusion path.

  • 14.
    Rosén, Tomas
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Chaotic rotation of a spheroidal particle in simple shear flow2017In: Chaos, ISSN 1054-1500, E-ISSN 1089-7682, Vol. 27, no 6, 063112Article in journal (Refereed)
    Abstract [en]

    The angular motion of a neutrally buoyant prolate spheroidal particle in simple shear flow has previously been found to follow two-dimensional dynamics similar to a Duffing-van der Pol oscillator as a consequence of inertia of the surrounding fluid. This behavior was however only present if the aspect ratio is large enough. When decreasing the particle aspect ratio, the particle could be found to perform period-doubled or chaotic orbits as effects of particle inertia also influence the dynamics. In this work, it is demonstrated that the onset of complex dynamics is through a Shilnikov bifurcation as the log-rolling state (particle is rotating around its symmetry axis, which is parallel to the vorticity direction) is transformed from a regular saddle node into a saddle focus when particle inertia is increased. Furthermore, it is shown that the same also applies for the two dimensional Duffing-van der Pol oscillator when including inertial terms. These results open up the possibility of developing a reduced model to mimic the influence of both fluid and particle inertia on the angular dynamics of spheroidal particles in simple shear flow, which can be used in fluid simulations with Lagrangian particles.

  • 15. Gunnarsson, Maria
    et al.
    Theliander, Hans
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Hasani, Merima
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Chemisorption of air CO2 on cellulose: an overlooked feature of the cellulose/NaOH(aq) dissolution system2017In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 6, 2427-2436 p.Article in journal (Refereed)
    Abstract [en]

    A natural abundance of the air CO2 in NaOH(aq) at low temperature was investigated in terms of cellulose-CO2 interactions upon cellulose dissolution in this system. An organic superbase, namely 1,8-diazabicyclo[5.4.0]undec-7-ene, DBU, known for its ability to incorporate CO2 in carbohydrates, was employed in order to shed light on this previously overlooked feature of NaOH(aq) at low temperature. The chemisorption of CO2 onto cellulose was investigated using spectroscopic methods in combination with suitable regeneration procedures. ATR-IR and NMR characterisation of regenerated celluloses showed that chemisorption of CO2 onto cellulose during its dissolution in NaOH(aq) takes place both with and without employment of the CO2-capturing superbase. The chemisorption was also observed to be reversible upon addition of water: CO2 desorbed when water was used as regenerating agent but could be preserved when instead ethanol was used. This finding could be an important parameter to take into consideration when developing processes for dissolution of cellulose based on this system.

  • 16. Mao, Rui
    et al.
    Goutianos, Stergios
    Tu, Wei
    Meng, Nan
    Yang, Guang
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Peijs, Ton
    Comparison of fracture properties of cellulose nanopaper, printing paper and buckypaper2017In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 52, no 16, 9508-9519 p.Article in journal (Refereed)
    Abstract [en]

    Cellulose nanopaper consists of a dense fibrous self-binding network composed of cellulose nanofibres connected by physical entanglements, hydrogen bonding, etc. Compared with conventional printing paper, cellulose nanopaper has higher strength and modulus because of stronger fibres and inter-fibre bonding. The aim of this paper is to investigate the fracture properties of cellulose nanopaper using double edge notch tensile tests on samples with different notch lengths. It was found that strength is insensitive to notch length. A cohesive zone model was used to describe the fracture behaviour of notched cellulose nanopaper. Fracture energy was extracted from the cohesive zone model and divided into an energy component consumed by damage in the material and a component related to pull-out or bridging of nanofibres between crack surfaces which was not facilitated due to the limited fibre lengths for the case of nanopapers. For comparison, printing paper which has longer fibres than nanopaper was tested and modelled to demonstrate the importance of fibre length. Buckypaper, a fibrous network made of carbon nanotubes connected through van der Waals forces and physical entanglements, was also investigated to elaborate on the influence of inter-fibre connections.

  • 17.
    Sandin, Staffan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Cheritat, Alicia
    Backström, Joakim
    Cornell, Ann M.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Deposition efficiency in the preparation of ozone-producing nickel and antimony doped tin oxide anodes2017In: Journal of Electrochemical Science and Engineering, ISSN 1847-9286, Vol. 7, no 1, 51-64 p.Article in journal (Refereed)
    Abstract [en]

    The influence of precursor salts in the synthesis of nickel and antimony doped tin oxide (NATO) electrodes using thermal decomposition from dissolved chloride salts was investigated. The salts investigated were SnCl4 center dot 5H(2)O, SnCl2 center dot 2H(2)O, SbCl3 and NiCl2 center dot 6H(2)O. It was shown that the use of SnCl4 center dot 5H(2)0 in the preparation process leads to a tin loss of more than 85 %. The loss of Sb can be as high as 90 % while no indications of Ni loss was observed. As a consequence, the concentration of Ni in the NATO coating will be much higher than in the precursor solution. This high and uncontrolled loss of precursors during the preparation process will lead to an unpredictable composition in the NATO coating and will have negative economic and environmental effects. It was found that using SnCl2 center dot 2H(2)0 instead of SnCl4 center dot 5H(2)O can reduce the tin loss to less than 50 %. This tin loss occurs at higher temperatures than when using SnCl4 center dot 5H(2)O where the tin loss occurs from 56 - 147 degrees C causing the composition to change both during the drying (80 - 110 degrees C) and calcination (460 - 550 degrees C) steps of the preparation process. Electrodes coated with NATO based on the two different tin salts were investigated for morphology, composition, structure, and ozone electrocatalytic properties.

  • 18.
    Elwinger, Fredrik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Pourmand, Payam
    KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Furo, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Diffusive Transport in Pores. Tortuosity and Molecular Interaction with the Pore Wall2017In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 25, 13757-13764 p.Article in journal (Refereed)
    Abstract [en]

    The self-diffusion of neat water, dimethyl sulfoxide (DMSO), octanol, and the molecular components in a water-DMSO solution was measured by H-1 and H-2 NMR diffusion experiments for those fluids imbibed into controlled pore glasses (CPG). Their highly interconnected structure is scaled by pore size and shows invariant pore topology independent of the size. The nominal pore diameter of the explored CPGs varied from 7.5 to 72.9 nm. Hence, the about micrometer mean-square diffusional displacement during the explored diffusion tithes was much larger than the individual pore size, and the experiment yielded the average diffusion coefficient Great care was taken to establish the actual pore: volumes of the CPGs. Transverse relaxation experiments processed by inverse Laplace transformation were performed to verify that the liquids explored filled exactly the available pore volume. Relative to the respective diffusion coefficients obtained in bulk phases, we observe a reduction in the diffusion coefficient that is independent of pore size for the larger pores and becomes stronger toward the smaller pores. Geometric tortuosity governs the behavior at larger pore sizes, while the interaction with pore walls becomes the dominant factor at our smallest pore diameter. Deviation from the trends predicted by the Renkin equation indicates that the interaction with the pore wall is not a just simple steric one but is in part dependent on the specific features of the molecules explored here.

  • 19.
    Lu, Huiran
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Guccini, Valentina
    KTH.
    Kim, Hyeyun
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Salazar-Alvarez, German
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Cornell, Ann M.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Effects of Different Manufacturing Processes on TEMPO-Oxidized Carboxylated Cellulose Nanofiber Performance as Binder for Flexible Lithium-Ion Batteries2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 43, 37712-37720 p.Article in journal (Refereed)
    Abstract [en]

    Carboxylated cellulose nanofibers (CNF) prepared using the TEMPO-route are good binders of electrode components in flexible lithium-ion batteries (LIB). However, the different parameters employed for the defibrillation of CNF such as charge density and degree of homogenization affect its properties when used as binder. This work presents a systematic study of CNF prepared with different surface charge densities and varying degrees of homogenization and their performance as binder for flexible LiFePO4 electrodes. The results show that the CNF with high charge density had shorter fiber lengths compared with those of CNF with low charge density, as observed with atomic force microscopy. Also, CNF processed with a large number of passes in the homogenizer showed a better fiber dispersibility, as observed from rheological measurements. The electrodes fabricated with highly charged CNF exhibited the best mechanical and electrochemical properties. The CNF at the highest charge density (ISSO mu mol g(-1)) and lowest degree of homogenization (3 + 3 passes in the homogenizer) achieved the overall best performance, including a high Young's modulus of approximately 311 MPa and a good rate capability with a stable specific capacity of 116 mAh g(-1) even up to 1 C. This work allows a better understanding of the influence of the processing parameters of CNF on their performance as binder for flexible electrodes. The results also contribute to the understanding of the optimal processing parameters of CNF to fabricate other materials, e.g., membranes or separators.

  • 20.
    Cheng, Ming
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Li, Yuanyuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Safdari, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Chen, Cheng
    Liu, Peng
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Efficient Perovskite Solar Cells Based on a Solution Processable Nickel(II) Phthalocyanine and Vanadium Oxide Integrated Hole Transport Layer2017In: Advanced Energy Materials, ISSN 1614-6832, Vol. 7, no 14, 1602556Article in journal (Refereed)
    Abstract [en]

    An organic-inorganic integrated hole transport layer (HTL) composed of the solution-processable nickel phthalocyanine (NiPc) abbreviated NiPc-(OBu)(8) and vanadium(V) oxide (V2O5) is successfully incorporated into structured mesoporous perovskite solar cells (PSCs). The optimized PSCs show the highest stabilized power conversion efficiency of up to 16.8% and good stability under dark ambient conditions. These results highlight the potential application of organic-inorganic integrated HTLs in PSCs.

  • 21. Bamba, Yu
    et al.
    Ogawa, Yu
    Saito, Tsuguyuki
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Isogai, Akira
    Estimating the Strength of Single Chitin Nanofibrils via Sonication-Induced Fragmentation2017In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 18, no 12, 4405-4410 p.Article in journal (Refereed)
    Abstract [en]

    We report the mechanical strength of native chitin nanofibrils. Highly crystalline alpha-chitiri nanofibrils Were purified from filaments produced by a microalgae Phaeocystis globosa, and two types of beta-chitin nariofibrils were purified from pens of a squid Loligo bleekeri and tubes of a tubeworm Lamellibrachia satsuma, with relatively low and high crystallinity, respectively. These chitin nanofibrils were fully dispersed in water. The strength of individualized nanofibrils was estimated using cavitation induced tensile fracture of nanoscale filaments in a liquid medium. Both types of beta-chitin nanofibrils exhibited similar strength values of approximately 3 GP; in contrast, the alpha-chitin nanofibrils exhibited a much lower strength value of 1.6 GPa. These strength estimates suggest that the tensile strength of chitin nanofibrils is governed by the molecular packing modes of chitin rather than their crystallinity.

  • 22. Durruty, Julie
    et al.
    Sewring, Tor
    Schneider, Helen
    Schneider, Lynn
    Mattsson, Tuve
    Theliander, Hans
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Filtration properties of kraft lignin: The influence of xylan and precipitation conditions2017In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 4, 508-526 p.Article in journal (Refereed)
    Abstract [en]

    LignoBoost lignin powder was dissolved together with xylan and re-precipitated. The influence of the (i) precipitation temperature, (ii) rate of acidification and (iii) final pH of the slurries on the resulting material and its filtration properties was investigated. In the case of slow acidification, larger agglomerates were obtained for slurries with higher precipitation temperatures as well as with higher ionic strengths. Fast acidification led to a more heterogeneous formation of particles, having a broader particle size distribution, compared to slow acidification. Chemical analysis of different layers of the filter cakes formed revealed that xylan was distributed evenly on the solid lignin, reinforcing the hypothesis that xylan is sorbed onto the lignin agglomerates when precipitated together with lignin. Furthermore, the resulting lignin-xylan mixtures were found to be more difficult to filter in the case of a higher final pH of the slurry (pH 4), close to the pKa values of the carboxylic acid groups of xylan, compared to lower pH values (pH 1-3). This is likely the result of an increase in electrostatic repulsive interactions between the particles/agglomerates at higher pH: a locally more porous solid structure is formed, leading to a larger solid/liquid surface area during filtration.

  • 23.
    Yao, Kun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Biotechnology (BIO), Glycoscience.
    Meng, Qijun
    Bulone, Vincent
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Flexible and Responsive Chiral Nematic Cellulose Nanocrystal/Poly(ethylene glycol) Composite Films with Uniform and Tunable Structural Color2017In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 29, no 28, 1701323Article in journal (Refereed)
    Abstract [en]

    The fabrication of responsive photonic structures from cellulose nanocrystals (CNCs) that can operate in the entire visible spectrum is challenging due to the requirements of precise periodic modulation of the pitch size of the self-assembled multilayer structures at the length scale within the wavelength of the visible light. The surface charge density of CNCs is an important factor in controlling the pitch size of the chiral nematic structure of the dried solid CNC films. The assembly of poly(ethylene glycol) (PEG) together with CNCs into smaller chiral nematic domains results in solid films with uniform helical structure upon slow drying. Large, flexible, and flat photonic composite films with uniform structure colors from blue to red are prepared by changing the composition of CNCs and PEG. The CNC/PEG(80/20) composite film demonstrates a reversible and smooth structural color change between green and transparent in response to an increase and decrease of relative humidity between 50% and 100% owing to the reversible swelling and dehydration of the chiral nematic structure. The composite also shows excellent mechanical and thermal properties, complementing the multifunctional property profile.

  • 24.
    Kamada, Ayaka
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Mittal, Nitesh
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Söderberg, L. Daniel
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Ingverud, Tobias
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ohm, Wiebke
    Roth, Stephan V.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Photon Science, Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg, Germany.
    Lundell, Fredrik
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics.
    Lendel, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Flow-assisted assembly of nanostructured protein microfibers2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 6, 1232-1237 p.Article in journal (Refereed)
    Abstract [en]

    Some of the most remarkable materials in nature are made from proteins. The properties of these materials are closely connected to the hierarchical assembly of the protein building blocks. In this perspective, amyloid-like protein nanofibrils (PNFs) have emerged as a promising foundation for the synthesis of novel bio-based materials for a variety of applications. Whereas recent advances have revealed the molecular structure of PNFs, the mechanisms associated with fibril-fibril interactions and their assembly into macroscale structures remain largely unexplored. Here, we show that whey PNFs can be assembled into microfibers using a flow-focusing approach and without the addition of plasticizers or cross-linkers. Microfocus small-angle X-ray scattering allows us to monitor the fibril orientation in the microchannel and compare the assembly processes of PNFs of distinct morphologies. We find that the strongest fiber is obtained with a sufficient balance between ordered nanostructure and fibril entanglement. The results provide insights in the behavior of protein nanostructures under laminar flow conditions and their assembly mechanism into hierarchical macroscopic structures.

  • 25. Lauberts, Maris
    et al.
    Sevastyanova, Olena
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Ponomarenko, Jevgenija
    Dizhbite, Tatjana
    Dobele, Galina
    Volperts, Alexandr
    Lauberte, Liga
    Telysheva, Galina
    Fractionation of technical lignin with ionic liquids as a method for improving purity and antioxidant activity2017In: INDUSTRIAL CROPS AND PRODUCTS, ISSN 0926-6690, Vol. 95, 512-520 p.Article in journal (Refereed)
    Abstract [en]

    Alder soda lignin, a by-product of the chemical processing of black alder wood, was fractionated using ionic liquids (ILs) based on the 1-buthyl-3-methylimidazolium [Bmim] cation and the following anions: chloride ([Bmim]Cl), dimethylphosphate ([Bmim]Me2PO4), acetate ([Brhim]OAc) and tosylate ([Bmim]OTs). The aim was to obtain lignin fractions of improved purity for further application as antioxidants. The purity and properties of the IL lignin fractions were compared with those of other lignin fractions obtained using sequential extraction with organic solvents. The original lignin and the lignin fractions were characterized by analytical pyrolysis (Py-GC/MS/FID), size-permeation chromatography (GPC), electron paramagnetic resonance (EPR) spectroscopy and wet chemistry methods. The lignin treatment with [Bmim]DMP, [Bmim]OAc and [Bmim]OTs produced fractions with a lignin content of 98-99%. These fractions along with the n-propanol and methanol fractions obtained using sequential organic solvent extraction were enriched with certain structural features that had a positive impact on lignin antioxidant activity, according to the results from DPPH center dot and ORAC assays.

  • 26. Trovatti, E.
    et al.
    Cunha, A. Gisela
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Carvalho, A. J. F.
    Gandini, A.
    Furan-modified natural rubber: A substrate for its reversible crosslinking and for clicking it onto nanocellulose2017In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 95, 762-768 p.Article in journal (Refereed)
    Abstract [en]

    The conventional vulcanization process applied to elastomers is irreversible and hinders therefore their useful recycling. We demonstrate here that natural rubber can be reversibly crosslinked via the Diels-Alder coupling of furan and maleimide moieties. The furan-modified natural rubber used in this strategy was also exploited to bind it to maleimide-modified nanocellulose, thus generating a covalently crosslinked composite of these two renewable polymers.

  • 27. Wojtasz-Mucha, J.
    et al.
    Hasani, Merima
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Theliander, Hans
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Hydrothermal pretreatment of wood by mild steam explosion and hot water extraction2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 241, 120-126 p.Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to compare the two most common hydrothermal pre-treatments for wood – mild steam explosion and hot water extraction – both with the prospect of enabling extraction of hemicelluloses and facilitating further processing. Although both involve autohydrolysis of the lignocellulosic tissue, they are performed under different conditions: the most prominent difference is the rapid, disintegrating, discharge employed in the steam explosion opening up the structure. In this comparative study, the emphasis was placed on local composition of the pre-treated wood chips (of industrially relevant size). The results show that short hot water extraction treatments lead to significant variations in the local composition within the wood chips, while steam explosion accomplishes a comparably more even removal of hemicelluloses due to the advective mass transport during the explosion step.

  • 28. Galysh, V.
    et al.
    Sevastyanova, Olena
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Deartel, M.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Gornikov, Yu.
    Impact of ferrocyanide salts on the thermo-oxidative degradation of lignocellulosic sorbents2017In: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 128, no 2, 1019-1025 p.Article in journal (Refereed)
    Abstract [en]

    The catalytic effect of ferrocyanide salts of d-metals on the thermo-oxidative degradation of lignocellulose-inorganic sorbents derived from apricot seed shells was investigated by differential thermal analysis. A comparative analysis of the thermal characteristics of the apricot seed shells and the lignocellulose matrix obtained from the shells by alkali-acid pretreatment was performed. It was shown that acid-alkali pretreatment of the apricot seed shells increases the thermal stability of the lignocellulosic material, due to the removal of low molecular weight carbohydrates and other components. The thermal degradation process of the lignocellulose-inorganic samples containing different ferrocyanides occurred at lower temperatures than the initial lignocellulose matrix, indicating the catalytic activity of modifiers. It was demonstrated that for the sorbents containing mixed salts of potassium cobalt and potassium nickel ferrocyanide, thermal destruction ends at temperatures that are 60 A degrees C lower than those for the initial lignocellulose matrix. The obtained results also show that the thermal destruction of composite lignocellulose-inorganic sorbents can be a suitable method for their disposal.

  • 29.
    Benselfelt, Tobias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Influence of Surface Charge Density and Morphology on the Formation of Polyelectrolyte Multilayers on Smooth Charged Cellulose Surfaces2017In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 33, no 4, 968-979 p.Article in journal (Refereed)
    Abstract [en]

    To clarify the importance of the surface charge for the formation of polyelectrolyte multilayers, layer-by-layer (LbL) assemblies of polydiallyldimethylammonium chloride (pDADMAC) and polystyrenesulfonate (PSS) have been investigated on cellulose films with different carboxylic acid contents (20, 350, 870, and 1200 μmol/g) regenerated from oxidized cellulose. The wet cellulose films were thoroughly characterized prior to multilayer deposition using quantitative nanomechanical mapping (QNM), which showed that the mechanical properties were greatly affected by the degree of oxidation of the cellulose. Atomic force microscopy (AFM) force measurements were used to determine the surface potential of the cellulose films by fitting the force data to the DLVO theory. With the exception of the 1200 μmol/g film, the force measurements showed a second-order polynomial increase in surface potential with increasing degree of oxidation. The low surface potential for the 1200 μmol/g film was attributed to the low degree of regeneration of the cellulose film in aqueous media due to increasing solubility with increasing charge. The multilayer formation was characterized using a quartz crystal microbalance with dissipation (QCM-D) and stagnation-point adsorption reflectometry (SPAR). Extensive deswelling was observed for the charged films when pDADMAC was adsorbed due to the reduced osmotic pressure when ions inside the film were released, and the 1:1 charge compensation showed that all the charges in the films were reached by the pDADMAC. The multilayer formation was not significantly affected by the charge density above 350 μmol/g due to interlayer repulsions, but it was strongly affected by the salt concentration during the layer build-up.

  • 30.
    Larsson, Per Tomas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Innventia AB, Sweden.
    Karlsson, Rose-Marie Pernilla
    Westlund, Per-Olof
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Internal Structure of Isolated Cellulose I Fibril Aggregates in the Water Swollen State2017In: Nanocelluloses: Their Preparation, Properties, and Applications / [ed] Agarwal, UP Atalla, RH Isogai, A, American Chemical Society (ACS), 2017, Vol. 1251, 91-112 p.Conference paper (Refereed)
    Abstract [en]

    By combining H-2-NMRD and CP/MAS C-13-NMR measurements of water-based cellulose gels and of water swollen pulps it was possible to estimate the nature of the interior structure of cellulose fibril aggregates. A set of samples with high cellulose purity and low charge was used. The interpretation of data was based on a relaxation model describing the exchange dynamics for deuterium exchange between water molecules and cellulose hydroxyl groups. The theoretical model used made it possible to calculate cellulose surface-to-volume ratios (q-values) from both H-2-NMRD and CP/MAS C-13-NMR data. Good consistency between H-2-NMRD and CP/MAS C-13-NMR data was found. In all investigated samples the cellulose fibril aggregates showed a different degree of "openness" interpreted as the presence of interstitial water inside fibril aggregates. One result also showed that an increased degree of fibril aggregate openness results from the TEMPO-oxidation. Common to all samples was that in the water swollen state water molecules could access part of the fibril aggregate interior.

  • 31. Lewis, William J. T.
    et al.
    Mattsson, Tuve
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Chew, Y. M. John
    Bird, Michael R.
    Investigation of cake fouling and pore blocking phenomena using fluid dynamic gauging and critical flux models2017In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 533, 38-47 p.Article in journal (Refereed)
    Abstract [en]

    Cake growth during a low pressure cross-flow microfiltration (MF) of a Kraft lignin suspension was studied using fluid dynamic gauging (FDG). This is the first paper to discuss the identification of fouling mechanisms and their transition points based on simultaneous, in situ and in real-time FDG measurements of cake layer thickness and flux. The FDG results were used to quantify the significance of membrane pore-level fouling phenomena which occur at an early stage of the filtration. A flux decline of approximately 75% was attributed to membrane pore fouling i.e. deposition on the surface of the membrane which caused direct blocking of the membrane pores. We present here a novel toolset for quick and achievable diagnosis of membrane fouling mechanisms, which can accelerate innovations in membrane technology and process optimisation. Furthermore, this innovative approach showed good agreement with a mathematical approach, based on a critical flux model, which was applied to raw flux data. In addition to cake thickness measurements, destructive strength testing of the fouling layer showed an increase in cohesive strength over time. The results showed that filter cakes formed by Kraft lignin become harder to remove by shear stress as they become thicker during the course of the filtration. A removal mechanism for lignin layer under stress is also proposed. The methodology described here can be applied to rapidly predict and assess routes to performance improvements in cross-flow MF.

  • 32.
    Zhang, Wei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Liu, Peng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Sadollahkhani, Azar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Li, Yuanyuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Zhang, Biaobiao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Fuguo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Safdari, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hao, Yan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hua, Yong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Investigation of Triphenylamine (TPA)-Based Metal Complexes and Their Application in Perovskite Solar Cells2017In: ACS OMEGA, ISSN 2470-1343, Vol. 2, no 12, 9231-9240 p.Article in journal (Refereed)
    Abstract [en]

    Triphenylamine-based metal complexes were designed and synthesized via coordination to Ni(II), Cu(II), and Zn(II) using their respective acetate salts as the starting materials. The resulting metal complexes exhibit more negative energy levels (vs vacuum) as compared to 2,2', 7,7'-tetrakis(N, N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD), high hole extraction efficiency, but low hole mobilities and conductivities. Application of dopants typically used for Spiro-OMeTAD was not successful, indicating a more complicated mechanism of partial oxidation besides the redox potential. However, utilization as hole-transport material was successful, giving a highest efficiency of 11.1% under AM 1.5G solar illumination.

  • 33.
    Xing, Xiaohui
    et al.
    KTH, School of Biotechnology (BIO), Glycoscience. University of Adelaide, Australia.
    Hsieh, Yves S.Y.
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Yap, Kuok
    Ang, Main E.
    Lahnstein, Jelle
    Tucker, Matthew R.
    Burton, Rachel A.
    Bulone, Vincent
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. University of Adelaide, Australia.
    Isolation and structural elucidation by 2D NMR of planteose, a major oligosaccharide in the mucilage of chia (Salvia hispanica L.) seeds2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 175, 231-240 p.Article in journal (Refereed)
    Abstract [en]

    An oligosaccharide was isolated in high purity and excellent yield from the water-extractable mucilage of chia (Salvia hispanica L.) seeds using an optimized solid-phase extraction method. LC–MS analysis showed that the compound presents a molecular mass of 504 Da and trifluoroacetic acid hydrolysis revealed that it consists of galactose, glucose and fructose. Glycosidic linkage analysis showed that the oligosaccharide contains two non-reducing ends corresponding to terminal glucopyranose and terminal galactopyranose, respectively. The oligosaccharide was identified as planteose by the complete assignment of a series of 2D NMR spectra (COSY, TOCSY, ROESY, HSQC, and HMBC). The significance of the presence of planteose in chia seeds is discussed in the context of nutrition and food applications.

  • 34.
    Vasileva, Elena
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Li, Yuanyuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Sychugov, Ilya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Mensi, Mounir
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Lasing from Organic Dye Molecules Embedded in Transparent Wood2017In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 5, no 10, 1700057Article in journal (Refereed)
    Abstract [en]

    The report on a study of laser emission from a conceptually new organic material based on transparent wood (TW) with embedded dye Rhodamine 6G molecules is presented in this paper. The lasing performance is compared to a reference organic material containing dye in a poly-methyl-methacrylate matrix. From experimental results, one can conclude that the optical feedback in dye-TW material is realized within cellulose fibers, which play the role of tiny optical resonators. Therefore, the output emission is a collective contribution of individual resonators. Due to this fact, as well as low Q-factor of the resonators/fibers and their length variation, the spectral line of laser emission is broadened up to several nanometers.

  • 35.
    Lu, Huiran
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Hagberg, Johan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Cornell, Ann
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Li4Ti5O12 flexible, lightweight electrodes based on cellulose nanofibrils as binder and carbon fibers as current collectors for Li-ion batteries2017In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 39, 140-150 p.Article in journal (Refereed)
    Abstract [en]

    TEMPO oxidized cellulose nanofibrils (TOCNF) were used as binder material to prepare bendable Li4Ti5O12 (LTO) electrodes. Carbon fiber (CF) layers were integrated as current collectors to enhance the mechanical properties and to increase the specific energy of the electrodes. These electrodes combined with CF current collectors (LTO/CF) show good electrochemical properties and are flexible, sustainable, mechanical and chemical stable, lightweight and produced by a water-based easy filtration process. An increase of the active material weight (LTO) from around 19% to 71% of the electrode and current collector combined weight is demonstrated with CF compared with a copper current collector. Additionally, preparation of the current collector material is non-expensive, quick and easy compared to that of carbon nanotube or graphene. To test the flexible battery application, 4000 times repeated bending was carried out on both the LTO electrodes and the LTO/CF electrodes. This had no significant effect on the morphology, mechanical and electrochemical properties of neither the LTO nor the LTO/CF electrodes. Addition of the CF layer improves the mechanical properties and specific capacity of the LTO-electrode. A thicker LTO electrode with only 2 wt% TOCNF is demonstrated which is promising for thicker electrodes with high energy density. A full cell was assembled with the LTO/CF as negative electrode and LiFePO4 (LFP)/CF as positive, which exhibited a stable cycling performance and good energy density.

  • 36.
    Li, Yuanyuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Fu, Qiliang
    Rojas, Ramiro
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Yan, Min
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Lawoko, Martin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Lignin-Retaining Transparent Wood2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 17, 3445-3451 p.Article in journal (Refereed)
    Abstract [en]

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80wt% of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83%, haze of 75%, thermal conductivity of 0.23WmK(-1), and work-tofracture of 1.2MJm(-3) (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings.

  • 37. Durruty, J.
    et al.
    Mattsson, T.
    Theliander, Hans
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Local filtration properties of Kraft lignin: The influence of residual xylan2017In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 179, 455-466 p.Article in journal (Refereed)
    Abstract [en]

    The influence of lignin and xylan interactions on the filtration properties of precipitated LignoBoost lignin was investigated. LignoBoost lignin was (i) suspended in acid water with xylan added and (ii) dissolved together with xylan and then re-precipitated. The resulting lignin-xylan mixtures were more difficult to filter than the original LignoBoost lignin, although the formed filter cake was also found more porous in the case of re-precipitated solids. Furthermore, the pressure dependency of the filtration properties was shown to increase after the addition of xylan. One possible explanation based on the findings presented in this paper is that xylan is sorbed at the surface of the lignin agglomerates: it increases the contact area between solid and liquid, thus making the particle structure more porous. The influence of ionic strength was also investigated through the addition of sodium sulphate: it was found that increasing the ionic strength of the slurries made the solids easier to separate, possibly due to a decrease in electrostatic repulsive interactions between the solids and the formation of a denser solid structure.

  • 38.
    Li, Yuanyuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Yu, Shun
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Veinot, J. G. C.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Sychugov, Ilya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Luminescent Transparent Wood2017In: Advanced Optical Materials, ISSN 2195-1071, Vol. 5, no 1, 1600834Article in journal (Refereed)
    Abstract [en]

    Luminescent transparent wood is prepared by combining the complementary properties of naturally grown anisotropic porous wood and luminescent quantum dots. The wood structure introduces strong diffused luminescence and waveguiding, which can potentially be exploited for optoelectronic and photovoltaic applications, such as for planar illumination sources and luminescent buildings/furniture. Images below show the transparency, haze, and luminescence of quantum dot wood.

  • 39.
    Soares, Rúdi
    et al.
    KTH.
    Bessman, Alexander
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Wallmark, Oskar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Electrical Engineering (EES), Centres, Swedish Centre of Excellence in Electric Power Engineering, EKC2. KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Svens, P.
    Measurements and analysis of battery harmonic currents in a commercial hybrid vehicle2017In: 2017 IEEE Transportation and Electrification Conference and Expo, ITEC 2017, Institute of Electrical and Electronics Engineers Inc. , 2017, 45-50 p.Conference paper (Refereed)
    Abstract [en]

    In this paper, the harmonic content of the battery current in a commercial hybrid vehicle (bus) is measured and analyzed for a number of different driving situations. It is found that the most prominent harmonic reaches peak magnitudes that can be higher than 10% of the maximum dc-current level with a maximum frequency less than 150 Hz. Further, it is found that this harmonic can be approximated using a fitted, simple analytical expression with reasonable agreement for all driving situations considered.

  • 40.
    Hellwig, Johannes
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Karlsson, R. -MP.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Wagberg, L.
    Pettersson, T.
    Measuring elasticity of wet cellulose beads with an AFM colloidal probe using a linearized DMT model2017In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 9, no 27, 4019-4022 p.Article in journal (Refereed)
    Abstract [en]

    The mechanical properties of wet cellulose are investigated using an atomic force microscope AFM and calculated using a linearized DMT model. Measurements were performed using a model system of gel beads made of cellulose with different charge densities, which show a high impact on the mechanical properties of the cellulose in wet state.

  • 41.
    Wetterling, John
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Mattsson, Tuve
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Theliander, Hans
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Modelling filtration processes from local filtration properties: The effect of surface properties on microcrystalline cellulose2017In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 165, 14-24 p.Article in journal (Refereed)
    Abstract [en]

    The influence of structure and charge of particles surfaces on the cake filtration behaviour of microcrystalline cellulose was investigated. The local filtration properties were evaluated experimentally and used to model the overall filtration behaviour. At suspension conditions where the microcrystalline cellulose particles are charged, a large pressure drop was observed close to the filter medium, thereby indicating that a rate-limiting skin layer was formed. Measurements of the local solidosity of the filter cake indicated that a secondary filter cake, with a negligible filtration resistance, formed above the rate-limiting skin layer. This behaviour was not observed when the surface roughness of the particles was increased or when the surface charge of the particles was neutralised by making a change to the pH of the suspension. The filtration behaviour of particles with these surface properties was instead dominated by the formation of a compressible filter cake. Local filtration properties of compressible filter cakes determined experimentally were used to successfully model the overall filtration behaviour. The filtration model used an empirical relationship to describe the pressure dependence of the local solidosity of the filter cake along with a cell model to describe the relationship between the solidosity and the permeability of the filter cake.

  • 42. Mishra, G.
    et al.
    Mittal, Nitesh
    KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Sharma, A.
    Multifunctional Mesoporous Carbon Capsules and their Robust Coatings for Encapsulation of Actives: Antimicrobial and Anti-bioadhesion Functions2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 23, 19371-19379 p.Article, review/survey (Refereed)
    Abstract [en]

    We present the synthesis and applications of multifunctional hollow porous carbon spheres with well-ordered pore architecture and ability to encapsulate functional nanoparticles. In the present work, the applications of hollow mesoporous carbon capsules (HMCCs) are illustrated in two different contexts. In the first approach, the hollow capsule core is used to encapsulate silver nanoparticles to impart antimicrobial characteristics. It is shown that silver-loaded HMCCs (concentration ?100 μg/mL) inhibit the growth and multiplication of bacterial colonies of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) up to 96% and 83%, respectively. In the second part, the fabrication of hierarchical micro- and nanostructured superhydrophobic coatings of HMCCs (without encapsulation with silver nanoparticles) is evaluated for anti-bioadhesion properties. Studies of protein adsorption and microorganism and platelet adhesion have shown a significant reduction (up to 100%) for the HMCC-based superhydrophobic surfaces compared with the control surfaces. Therefore, this unique architecture of HMCCs and their coatings with the ability to encapsulate functional materials make them a promising candidate for a variety of applications.

  • 43.
    Fu, Qiliang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Medina, Lilian
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Li, Yuanyuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Carosio, Federico
    Hajian, Alireza
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 41, 36154-36163 p.Article in journal (Refereed)
    Abstract [en]

    Eco-friendly materials need "green" fire-retardancy treatments, which offer opportunity for new wood nanotechnologies. Balsa wood (Ochroma pyramidale) was delignified to form a hierarchically structured and nanoporous scaffold mainly composed of cellulose nanofibrils. This nanocellulosic wood scaffold was impregnated with colloidal montmorillonite clay to form a nanostructured wood hybrid with high flame-retardancy. The nanoporous scaffold was characterized by scanning electron microscopy and gas adsorption. Flame-retardancy was evaluated by cone calorimetry, whereas thermal and thermo-oxidative stabilities were assessed by thermogravimetry. The location of well-distributed clay nanoplatelets inside the cell walls was confirmed by energy-dispersive X-ray analysis. This unique nanostructure dramatically increased the thermal stability because of thermal insulation, oxygen depletion, and catalytic charring effects. A coherent organic/inorganic charred residue was formed during combustion, leading to a strongly reduced heat release rate peak and reduced smoke generation.

  • 44.
    Giummarella, Nicola
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Salmén, Lennart
    Lawoko, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    On the effect of hemicellulose removal on cellulose-lignin interactions2017In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 4, 542-549 p.Article in journal (Refereed)
    Abstract [en]

    In a recent study, it was suggested that there could be direct associations between cellulose and lignin in mild alkaline cooked pulps. The observation was based on studies showing that the molecular straining of lignin was similar to that of cellulose. This finding has serious ramifications for technical production of pulps as it could expand on what is known about recalcitrant lignin removal during pulping. Herein, we investigate the possible interaction between cellulose and lignin discussing possible mechanisms involved at the nano-and molecular-scales, and present support for that the removal of hemicellulose by hot water extraction or mild kraft pulping causes strong interactions between lignin and cellulose.

  • 45.
    Rosén, Tomas
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Kotsubo, Yusuke
    Aidun, Cyrus K.
    Do-Quang, Minh
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Orientational dynamics of a triaxial ellipsoid in simple shear flow: Influence of inertia2017In: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 96, no 1, 013109Article in journal (Refereed)
    Abstract [en]

    The motion of a single ellipsoidal particle in simple shear flow can provide valuable insights toward understanding suspension flows with nonspherical particles. Previously, extensive studies have been performed on the ellipsoidal particle with rotational symmetry, a so-called spheroid. The nearly prolate ellipsoid (one major and two minor axes of almost equal size) is known to perform quasiperiodic or even chaotic orbits in the absence of inertia. With small particle inertia, the particle is a