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  • 151.
    Guo, Yaxiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Yao, Zhaoyang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Timmer, Brian J. J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Sheng, Xia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Fan, Lizhou
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Zhang, Fuguo
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Inst Artificial Photosynth, Dalian 116024, Peoples R China..
    Boosting nitrogen reduction reaction by bio-inspired FeMoS containing hybrid electrocatalyst over a wide pH range2019Ingår i: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 62, s. 282-288Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A facile preparation of bio-inspired and morphology controllable catalytic electrode FeS@MoS2/CFC, featuring a carbon fiber cloth (CFC) covered with FeS dotted MoS2 nanosheets, has been established. Synergy between the CFC as a self-standing conductive substrate and the FeS nanoparticle dotted MoS2 nanosheets with abundant active sites makes the noble-metal-free catalytic electrode FeS@MoS2/CFC highly efficient in nitrogen reduction reaction (NRR), with an ammonia production rate of 8.45 mu g h(-1) cm(-2) and excellent long-term stability at -0.5 V in pH neutral electrolyte. Further electrolysis in acidic and alkaline electrolytes revealed the overall NRR catalytic activity of this electrode over a wide pH range.

  • 152.
    Gustafsson, Emil
    et al.
    KTH.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Pelton, Robert
    McMaster Univ, Dept Chem Engn, Hamilton, ON, Canada..
    Polyelectrolyteinterdigitation across interfaces and wet adhesion: Influence of polyvinylamine on wet adhesion between cellulose model surfaces modified with carboxymethylcellulose2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 153.
    Göthe, Viktoria
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Green Nanocomposites from Cereal Husk2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The aim of this master thesis study was to investigate the possibility to extract cellulose nanocrystals (CNC) from cereal husks and their capability to be used as reinforcement systems of hemicellulosic biopolymers. CNC were isolated from rye husk and used as reinforcement in nanocomposites. To obtain the isolated CNC the rye husk was processed through alkaline treatments, bleaching treatments and finally an acid hydrolysis. The cellulose extraction was optimized and optimal conditions were reached when 3wt% of rye husk were used for both alkaline and bleaching treatments. Acid hydrolysis was performed at 45°C for 30 minutes. The total yield from the rye husk to the CNCs was approximately 11wt%. The isolation process from macro to nano size was monitored via different chemico-physical characterization methods.

    Via Scanning Electron Microscopy (SEM) analysis, the isolation of the cellulose fibers from rye husk could be assessed. The chemical composition was evaluated via carbohydrate analysis, ash, extractives and lignin Klason determination. From these chemical data, it was verified that most of the amorphous components of the rye husk were removed reaching 73.17% of cellulose for the isolated cellulose fibers. Fourier transform infrared spectroscopy (FTIR) was used to follow the chemical structural changes through the CNC isolation process. From the FTIR spectra, it could be seen that the bleached husk and CNC materials were similar to a cellulose fiber compared to the rye husk and alkaline treated husk, which had FTIR spectra typical for lignocellulosic biomass. This fact indicates that most of the hemicellulose and lignin were removed due to the chemical treatments the rye husk was submitted to. Crystalline index of the samples was also determined with FTIR and an increasing crystallinity trend was observed through the isolation, from rye husk to CNC. The Thermogravimetric Analysis (TGA) was used to assess the thermal stability and it was observed that the bleached and CNC samples had an increased thermal stability with respect to the lignocellulosic and alkaline samples, indicating the most labile components of the rye husk were removed. The rye husk CNC exhibited a length of 335.4 nm, diameter of 2.86 nm and a zeta potential of -35.8 mV together with a high purity (>98% of cellulose) crystallinity and thermal stability.

    Green nanocomposites based on commercial arabinoxylan from rye and CNC isolated from rye husk were prepared. The method employed to produce the nanocomposite films was solvent casting. Different amounts of CNC were added to the arabinoxylan matrix: 0, 5, 10 and 20wt% of CNC. Mechanical and thermal properties of the nanocomposites were evaluated. The nanocomposite films exhibited an increase in the thermal stability, Young modulus and tensile strength due to the addition of the CNC indicating a good compatibility and interaction between the raw materials.

  • 154.
    Hajian, Alireza
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH Royal Institute of Technology.
    Cellulose–Assisted Dispersion of Carbon Nanotubes: From Colloids to Composites2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Det är en utmaning att dispergera nanopartiklar för nanostrukturerade kompositer. Avhandlingen beskriver en ny väg för att framställa kompositer från kolnanorör (CNT) och föreslår mekanismer för växelverkan mellan CNT och CNF. Den nya vägen baseras sig på dispergering av CNT i vatten med hjälp av CNF. CNT behöver inte modifieras kemiskt eller med ytaktiva ämnen. Mekaniska och elektriska egenskaper hos materialen kan därför förbättras.

    Cellulsosaderivat kan dispergera och stabilisera CNT i vatten. Nanocellulosa är en ny typ av derivat, i form av fibriller eller nanokristaller, som kan dispergera och stabilisera icke modifierade CNT i vatten. Dispersioner av CNF-CNT används för att framställa starka nanokompositer med hög CNT-halt och hög elektrisk ledningsförmåga. Dispergerings-mekanismen studeras och förklaras från experimentella data. Den dispergerande förmågan hos CNF leder till förbättrade egenskaper hos CNF-CNT-kompositer.

    Struktur-egenskaps relationer för fibrer och filmer rapporteras. Två typer av funktionella material studeras i detalj. Ett av materialen består av ledande mönster av CNF-CNT på substrat av nanocellulosa. Det andra exemplet är superelastiska aerogeler utan kemisk tvärbindning. Aerogelerna kan återvinnas och öppnar möjligheter för superelastiska aerogeler.

  • 155.
    Hajian, Alireza
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Fu, Qiliang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Recyclable and superelastic aerogels based on carbon nanotubes and carboxymethyl cellulose2018Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 159, s. 1-10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deformation mechanisms are largely unknown for superelastic carbon nanotube (CNT) aerogels, and this hampers materials design efforts. The CNT network in the cell walls is typically crosslinked or connected by a thermoset polymer phase. In order to create a recyclable superelastic aerogel, unmodified single or multi-walled CNTs were dispersed in water by adding to aqueous carboxymethyl cellulose (CMC) solution. Directional freeze-drying was used to form honeycombs with cell walls of random-in-the-plane CNTs in CMC matrix. Cell wall morphology and porosity were studied and related to CNT type and content, as well as elastic or plastic buckling of the cell walls under deformation. CMC acts as a physical crosslinker for the CNTs in a porous cell wall. Aerogel structure and properties were characterized before and after recycling. The conductivity of the composite aerogel with a density of 10 kg/m3, 99% porosity and 50 wt % single-walled CNT exceeds 0.5 S/cm. The potential of these superelastic and conductive aerogels for applications such as mechanoresponsive materials was examined in cyclic conductivity tests at different strains. This opens a new route for recyclable superelastic CNT composite aerogels, avoiding material loss, chemical treatment or addition of other components.

  • 156.
    Hajian, Alireza
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Wang, Zhen
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Berglund, Lars. A
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Hamedi, Mahiar M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Cellulose Nanopaper with Monolithically Integrated Conductive Micropatterns2019Ingår i: Advanced Electronic Materials, ISSN 2199-160X, Vol. 5, nr 3, artikel-id 1800924Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work presents a route to fabricate micropatterned conductive structures where the conductors are monolithically integrated with nanocellulose-based paper. To fabricate conductive features, microstructures are patterned on filter papers using wax-printing, followed by vacuum filtration of carbon nanotubes (CNTs) or silver nanowires (AgNWs) dispersed in aqueous cellulose nanofibrils (CNFs). These patterns are then laminated onto a pure CNF substrate (both in gel-state) and dried to form cellulose nanopapers with integrated conductive micropatterns. Resolutions of the conductive features are shown down to 400 µm wide, 250 nm thick, and with conductivity values of 115 ± 5 S cm −1 for the CNF–CNT and 3770 ± 230 S cm −1 for the CNF–AgNW micropatterns. The nanopaper and the conductive patterns both constitute random fibrous networks, and they display similar ductility and swelling behavior in water. Thus, the integrated conductive micropatterns can withstand folding, as well as wetting cycles. This stability of the micropatterns makes them useful in various devices based on nanocellulose substrates. As an example, an electroanalytical nanopaper device that operates in wet conditions is demonstrated.

  • 157.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Carbonized biopolymers as building blocks in renewable materials2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 158.
    Halysh, Vita
    et al.
    Igor Sikorsky Kyiv Polytech Inst, Fac Chem Engn, Dept Ecol & Technol Plant Polymers, Peremogy Avenu 37-4, UA-03056 Kiev, Ukraine.;Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Riazanova, Anastasia V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Pasalskiy, Bogdan
    Kyiv Natl Univ Trade & Econ, Kyoto Str 19, UA-02156 Kiev, Ukraine..
    Budnyak, Tetyana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Kartel, Mykola
    Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Walnut shells as a potential low-cost lignocellulosic sorbent for dyes and metal ions2018Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 8, s. 4729-4742Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Currently, it is necessary to develop new methods and materials for solving the problem of environmental pollution by various toxicants. For these purposes, vegetal materials can be used. In this study, efficient low-cost sorbents based on walnut shells, an agro-industrial by-product, were prepared by treatment with acetic acid or a mixture of acetic acid and hydrogen peroxide. It was shown that the treatments significantly affected the composition and structure of walnut shells and their sorption properties with respect to organic dyes (methylene blue, methyl violet, and murexide) and heavy metal ions. Methylene blue dye was used for additional studies on the effect of pH, contact time and kinetics of sorption. The maximum adsorption rate of the dye occurred within the first 30 min of contact, during which the concentration of methylene blue in the solution was reduced by more than half. Full sorption equilibrium was reached within 180-230 min for studied samples. The adsorption kinetics of methylene blue was found to best be described by pseudo-second-order kinetic model. It was shown that dyes adsorption processes were well described by Freundlich model, which takes into consideration the heterogeneity of the surface of the adsorbent. The obtained plant sorbents are characterized by a high sorption capacity for heavy metal ions (18-29 mg/g for Fe3+ and 33-44 mg/g for Cu-2). Due to their numerous advantages, such as the high sorption capacity, high availability and low cost of raw materials, simplicity of disposal and nontoxicity, the obtained natural sorbents may have a wide practical use in industrial wastewater treatment. [GRAPHICS] .

  • 159.
    Hamedi, Mahiar Max
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Herland, Anna
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik. Karolinska Inst, Dept Neurosci, Swedish Med Nanosci Ctr, S-17177 Stockholm, Sweden..
    Zhang, Fengling
    Linkoping Univ, Dept Phys Chem & Biol, SE-58183 Linkoping, Sweden..
    Pei, Qibing
    Univ Calif Los Angeles, Dept Mat Sci & Engn, Henry Samueli Sch Engn & Appl Sci, Los Angeles, CA 90095 USA..
    Organic Polymer Electronics - A Special Issue in Honor of Prof. Olle Inganas2019Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 31, nr 22, artikel-id 1901940Artikel i tidskrift (Refereegranskat)
  • 160.
    Hamedi, Mahiar
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Nyström, Gustav
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Marais, Andrew
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Karabulut, Erdem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Cui, Yi
    Stanford Univ, Stanford, CA 94305 USA..
    Soft, compressible and fully Interdigitated 3D energy storage devices built by layer-by-layer assembly inside aerogels2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 161.
    Han, Tong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Sophonrat, Nanta
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Tagami, Ayumu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Mellin, P.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem2019Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 235, s. 1061-1069Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Technical lignin particles melt under relatively low temperature. This results in the problem in the continuous feeding and fluidization during lignin pyrolysis, which in turn limits its utilization on a large scale. In this study, two most available types of lignin have been used to investigate the lignin melting problem, which are Kraft lignin (KL) from pulping process and hydrolysis lignin (HL) from bio-ethanol production process. Elemental composition, thermal property and thermally decomposed derivatives of each sample are tested by elemental analyzer, TGA, DSC, and Py-GC/MS. Morphology, structure and crystal change before and after heat treatment are tested by microscopy, FTIR and XRD. All results suggest that lignin structure determines its melting properties. Kraft lignin from pulping process contains a less cross-linked structure. It melts under heating. On the other hand, hydrolysis lignin from hydrolysis process contains a highly crossed-linked and condensed structure. It does not melt before decomposition under heat treatment. Modifying lignin structure is suggested for the resolution of technical lignin melting problem.

  • 162.
    Hatton, Fiona
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Fibre & Polymer Technol, Stockholm, Sweden..
    Ruda, Marcus
    CelluTech AB, Stockholm, Sweden..
    Lansalot, Muriel
    UCBL, CPE, CNRS, C2P2, CPE Lyon Bat 308F, Villeurbanne, France..
    DAgosto, Franck
    UCBL, CPE, CNRS, C2P2, CPE Lyon Bat 308F, Villeurbanne, France..
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Fibre & Polymer Technol, Stockholm, Sweden..
    Carlmark, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Fibre & Polymer Technol, Stockholm, Sweden..
    Xyloglucan-functional latex particles via RAFT-mediated emulsion polymerization for the modification of cellulose by physical adsorption2016Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Artikel i tidskrift (Övrigt vetenskapligt)
  • 163.
    Heckler, Ilona
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Arseneault, Mathieu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Granskog, Viktor
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Antunez, Pablo Mesa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Zhang, Yuning
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Triazine trione based adhesive as potential materials for bone fracture fixation2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 164.
    Hed, Yvonne
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Antoni, Per
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Montanez, Maria I.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hult, Anders
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bifunctional dendritic structures based on AB(2)C monomers2009Ingår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 238Artikel i tidskrift (Övrigt vetenskapligt)
  • 165.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Barrier packaging materials2018Ingår i: Handbook of Environmental Degradation Of Materials: Third Edition, Elsevier Inc. , 2018, s. 559-581Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 166.
    Hellwig, Johannes
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    López Durán, Vernica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Pettersson, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Measuring elasticity of wet cellulose fibres with AFM using indentation and a linearized Hertz model2018Ingår i: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 10, nr 31Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanical properties of different pulp fibres in liquid were measured using an atomic force microscope. Specifically a custom-made sample holder was used to indent the fibre surface, without causing any motion, and the Young's modulus was calculated from the indentation using a linearized Hertz model.

  • 167.
    Hendrikse, Natalie
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Centra, Science for Life Laboratory, SciLifeLab. Swedish Orphan Biovitrum AB, Stockholm, Sweden.
    Charpentier, Gwenaelle
    KTH, Centra, Science for Life Laboratory, SciLifeLab. ESCOM, 1 Allee Reseau Jean Marie Buckmaster, F-60200 Compiegne, France..
    Nordling, Erik
    Swedish Orphan Biovitrum AB, Stockholm, Sweden..
    Syrén, Per-Olof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. Swedish Orphan Biovitrum AB, Stockholm, Sweden.
    Ancestral diterpene cyclases show increased thermostability and substrate acceptance2018Ingår i: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 285, nr 24, s. 4660-4673Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bacterial diterpene cyclases are receiving increasing attention in biocatalysis and synthetic biology for the sustainable generation of complex multicyclic building blocks. Herein, we explore the potential of ancestral sequence reconstruction (ASR) to generate remodeled cyclases with enhanced stability, activity, and promiscuity. Putative ancestors of spiroviolene synthase, a bacterial class I diterpene cyclase, display an increased yield of soluble protein of up to fourfold upon expression in the model organism Escherichia coli. Two of the resurrected enzymes, with an estimated age of approximately 1.7 million years, display an upward shift in thermostability of 7-13 degrees C. Ancestral spiroviolene synthases catalyze cyclization of the natural C-20-substrate geranylgeranyl diphosphate (GGPP) and also accept C-15 farnesyl diphosphate (FPP), which is not converted by the extant enzyme. In contrast, the consensus sequence generated from the corresponding multiple sequence alignment was found to be inactive toward both substrates. Mutation of a nonconserved position within the aspartate-rich motif of the reconstructed ancestral cyclases was associated with modest effects on activity and relative substrate specificity (i.e., k(cat)/K-M for GGPP over k(cat)/K-M for FPP). Kinetic analyses performed at different temperatures reveal a loss of substrate saturation, when going from the ancestor with highest thermostability to the modern enzyme. The kinetics data also illustrate how an increase in temperature optimum of biocatalysis is reflected in altered entropy and enthalpy of activation. Our findings further highlight the potential and limitations of applying ASR to biosynthetic machineries in secondary metabolism.

  • 168.
    Henriksson, Gunnar
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Berglund, Jennie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wohlert, Jakob
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Aminzadeh, Selda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Vilaplana, Francisco
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Non-cellulose wood polysaccharides - a need for a stricter structural and functional classification?2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 169.
    Henschen, Jonatan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bio-based preparation of nanocellulose and functionalization using polyelectrolytes2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Nanocellulosa, som kan utvinnas från skogsråvara, har de senaste åren fått mycket uppmärksamhet för sina intressanta egenskaper och breda användningsområde. Studierna i denna avhandling syftar till att vidga möjligheterna att använda nanocellulosa i olika applikationer. Detta har skett genom att utveckla en ny metod för att tillverka nanocellulosa och genom att studera möjligheten att adsorbera polyelektrolyter på material av nanocellulosa för att ändra hur bakterier interagerar med dessa.

    Nanocellulosan tillverkades genom att förbehandla pappersmassa med smält oxalsyra dihydrat. Reaktionsblandningen tvättades med etanol, aceton eller tetrahydrofuran innan den torkades och fibrillerades. Den resulterande nanocellulosan erhölls med högt utbyte, hade hög ytladdning (upp till 1,4 mmol g-1) och innehöll partiklar som både liknande nanofibriller och nanokristaller. Materialet visades kunna användas både för att tillverka Pickering emulsioner och tunna filmer med en styrka upp till 197 MPa, töjning upp till 5 %, E-modul upp till 10,6 GPa och syrepermeabilitet ner till 0.31 cm3 µm m‑2 dag‑kPa‑1.

    Genom att adsorbera polyvinylamin och polyakrylsyra på material av nanocellulosa visades det vara möjligt att påverka mängden bakterier som fäster till materialet. Substraten bestod både av kompakta filmer och porösa aerogeler. Genom att variera ytladdningen på materialen, ytans struktur och antalet adsorberade lager av polymererna var det möjligt att tillverka material med både hög och låg bakterieadhesion. Detta gör det möjligt att anpassa material för användning antingen som kontaktaktivt- eller icke-adhesivt antibakteriellt material. Båda dessa kan vara miljövänliga alternativ till dagens antibakteriella material.

    Nanocellulosa är ett material som inom snar framtid sannolikt kommer användas inom en mängd olika applikationer. För att öka mängden applikationer där nanocellulosa tillför ett stort värde är det nödvändigt att utveckla alternativa tillverkningsmetoder till dagens välkända, exempelvis, genom att använda den beskrivna oxaleringen som förbehandling. Förmågan att styra bakterieadhesionen på material av nanocellulosa ger därtill möjlighet att hitta nya användningsområden inom t.ex. hälso- och sjukvårdsbranschen.

  • 170.
    Henschen, Jonatan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Illergård, Josefin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Larsson, Per
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Antibacterial surface modification of nanocellulosic materials2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 171.
    Henschen, Jonatan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Li, Dongfang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Preparation of cellulose nanomaterials via cellulose oxalates2019Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 213, s. 208-216Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanocellulose prepared from cellulose oxalate has been discussed as an alternative to other methods to prepare cellulose nanofibrils or crystals. The current work describes the use of a bulk reaction between pulp and oxalic acid dihydrate to prepare cellulose oxalate followed by homogenization to produce nanocellulose. The prepared nanocellulose is on average 350 nm long and 3–4 nm wide, with particles of size and shape similar to both cellulose nanofibrils and cellulose nanocrystals. Films prepared from this nanocellulose have a maximum tensile stress of 140–200 MPa, strain at break between 3% and 5%, and oxygen permeability in the range of 0.3–0.5 cm 3 μm m −2 day −1 kPa −1 at 50% relative humidity. The presented results illustrate that cellulose oxalates may be a low-cost method to prepare nanocellulose with properties reminiscent of those of both cellulose nanofibrils and cellulose nanocrystals, which may open up new application areas for cellulose nanomaterials.

  • 172.
    Herrera, Martha
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Thitiwutthisakul, Kasinee
    SCG Packaging Publ Co Ltd, Prod & Technol Dev Ctr, Ban Pong 70110, Ratchaburi, Thailand..
    Yang, Xuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Dept Fibre & Polymer Technol, S-10044 Stockholm, Sweden.;KTH Royal Inst Technol, Wallenberg Wood Sci Ctr, S-10044 Stockholm, Sweden..
    Rujitanaroj, Pim-on
    SCG Packaging Publ Co Ltd, Prod & Technol Dev Ctr, Ban Pong 70110, Ratchaburi, Thailand..
    Rojas, Ramiro
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer.
    Preparation and evaluation of high-lignin content cellulose nanofibrils from eucalyptus pulp2018Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 5, s. 3121-3133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High Klason lignin content (23 wt%) cellulose nanofibrils (LCNF) were successfully isolated from eucalyptus pulp through catalyzed chemical oxidation, followed by high-pressure homogenization. LCNFs had a diameter of ca. 13 nm according to AFM evaluation. Dense films were obtained through vacuum filtration (nanopaper) and subjected to different drying methods. When drying under heat and mild vacuum (93 degrees C, 95 kPa) a higher water contact angle, lower roughness and oxygen transmission rate were observed, compared to those drying at room temperature under compression conditions. DSC experiments showed difference in signals associated to T-g of LCNF compared to CNF produced from spruce bleached pulp through enzymatic pre-treatment. The LCNF-based nanopaper showed mechanical properties slightly lower than for those made from cellulose nanofibrils, yet with increased hydrophobicity. In summary, the high-lignin content cellulose nanofibrils proved to be a suitable material for the production of low oxygen permeability nanopaper, with chemical composition close to native wood.

  • 173. Hohn, N.
    et al.
    Schlosser, S. J.
    Bießmann, L.
    Grott, S.
    Xia, S.
    Wang, K.
    Schwartzkopf, M.
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer. Deutsches Elektronen-Synchrotron, Germany.
    Müller-Buschbaum, P.
    Readily available titania nanostructuring routines based on mobility and polarity controlled phase separation of an amphiphilic diblock copolymer2018Ingår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 10, nr 11, s. 5325-5334Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The amphiphilic diblock copolymer polystyrene-block-polyethylene oxide is combined with sol-gel chemistry to control the structure formation of blade-coated foam-like titania thin films. The influence of evaporation time before immersion into a poor solvent bath and polarity of the poor solvent bath are studied. Resulting morphological changes are quantified by scanning electron microscopy (SEM) and grazing incidence small angle X-ray scattering (GISAXS) measurements. SEM images surface structures while GISAXS accesses inner film structures. Due to the correlation of evaporation time and mobility of the polymer template during the phase separation process, a decrease in the distances of neighboring titania nanostructures from 50 nm to 22 nm is achieved. Furthermore, through an increase of polarity of an immersion bath the energetic incompatibility of the hydrophobic block and the solvent can be enhanced, leading to an increase of titania nanostructure distances from 35 nm to 55 nm. Thus, a simple approach is presented to control titania nanostructure in foam-like films prepared via blade coating, which enables an easy upscaling of film preparation.

  • 174.
    Hohn, Nuri
    et al.
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Hetzenecker, Andreas E.
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Giebel, Michael A.
    Tech Univ Munich, Dept Chem, Lehrstuhl Anorgan Chem Schwerpunkt Neue Mat, Lichtenbergstr 4, D-85747 Garching, Germany..
    Geier, Sebastian
    Tech Univ Munich, Dept Chem, Lehrstuhl Anorgan Chem Schwerpunkt Neue Mat, Lichtenbergstr 4, D-85747 Garching, Germany..
    Biessmann, Lorenz
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Koerstgens, Volker
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Saxena, Nitin
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Schlipf, Johannes
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Ohm, Wiebke
    Deutsch Elektronen Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Deimel, Peter S.
    Tech Univ Munich, Phys Dept, Lehrstuhl Mol Nanowissensch & Chem Phys Grenzflac, James Franck Str 1, D-85748 Garching, Germany..
    Allegretti, Francesco
    Tech Univ Munich, Phys Dept, Lehrstuhl Mol Nanowissensch & Chem Phys Grenzflac, James Franck Str 1, D-85748 Garching, Germany..
    Barth, Johannes V.
    Tech Univ Munich, Phys Dept, Lehrstuhl Mol Nanowissensch & Chem Phys Grenzflac, James Franck Str 1, D-85748 Garching, Germany..
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Faessler, Thomas F.
    Tech Univ Munich, Dept Chem, Lehrstuhl Anorgan Chem Schwerpunkt Neue Mat, Lichtenbergstr 4, D-85747 Garching, Germany..
    Mueller-Buschbaum, Peter
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany.;Tech Univ Munich, Heinz Maier Leibnitz Zentrum MLZ, Lichtenbergstr 1, D-85748 Garching, Germany..
    Amphiphilic diblock copolymer-mediated structure control in nanoporous germanium-based thin films2019Ingår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, nr 4, s. 2048-2055Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fabrication of porous, foam-like germanium-based (Ge-based) nanostructures is achieved with the use of the amphiphilic diblock copolymer polystyrene-b-polyethylene oxide as structure directing agent. Basic concepts of block copolymer assisted sol-gel synthesis are successfully realized based on the [Ge-9](4-) Zintl clusters as a precursor for Ge-based thin films. Material/elemental composition and crystalline Ge-based phases are investigated via X-ray photoelectron spectroscopy and X-ray diffraction measurements, respectively. Poor-good solvent pair induced phase separation leads to pore sizes in the Ge-based films up to 40 nm, which can be tuned through a change of the molar mixing ratio between polymer template and precursor as proven by grazing incidence small angle X-ray scattering and scanning electron microscopy.

  • 175.
    Hohn, Nuri
    et al.
    Tech Univ Munich, Lehrstuhl Funkt Mat, Dept Phys, James Franck Str 1, D-85748 Garching, Germany. chwartzkopf, Matthias; Roth, Stephan V..
    Shlosser, Steffen J.
    Biessmann, Lorenz
    Song, Lin
    Grott, Sebastian
    Xia, Senlin
    Wang, Kun
    Schwartzkopf, Matthias
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Mueller-Buschbaum, Peter
    Impact of Catalytic Additive on Spray Deposited and Nanoporous Titania in Films Observed via in Situ X-ray Scattering: Implications for hanced Photovoltaics2018Ingår i: ACS Applied Nano Materials, ISSN 2574-0970, Vol. 1, nr 8, s. 4227-4235Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the aim of obtaining nanostructured titania thin films for the tential use in hybrid or dye sensitized solar cells, the amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) is employed as a ructure directing template in combination with solgel chemistry. For sy upscaling, spraying is used as a deposition technique. In situ azing incidence small-angle X-ray scattering (GISAXS) measurements are rformed during spraying and show that most titania structures are ready formed within the solution prior to deposition. However, ructural rearrangement is enabled during the deposition period when all amounts of hydrochloric acid (HCl) are used as a catalytic ditive to the spray solution. This behavior is ascribed to an altering the reaction dynamics and phase separation in the presence of HCl, ich significantly improves the templating effect of the employed block copolymer. With HCl as an additive the final nanoscale rphologies exhibit smaller pore sizes and strongly enhanced order as mpared to thin films sprayed from solutions that do not contain HCl as antified with atomic force microscopy, scanning electron microscopy, d GISAXS.

  • 176.
    Holder, Shima
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Nilsson, Fritjof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Understanding and modelling the diffusion process of low molecular weight substances in polyethylene pipes2019Ingår i: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, s. 301-309Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Peroxides are widely used as crosslinkers in polyethylene (PE) drinking water pipes. Cross-linked polyethylene (PEX) has better mechanical properties than PE, but peroxide decomposition by-products can migrate from PEX water pipes into the drinking water unless sufficient preventive actions are undertaken. This work systematically examines the migration of tert-Butyl methyl ether (MTBE), a dominating crosslinking by-product from PEX water pipes, into tap water by utilizing both experimental techniques and finite element (FEM) diffusion modeling. The effects of pipe geometry, tap water temperature (23–80 °C), boundary conditions (air or water interface) and degasing (at 180 °C) were considered. The MTBE diffusivity increased strongly with increasing temperature and it was concluded that a desired water quality can be achieved with proper degasing of the PEX pipes. As the FEM simulations were in excellent agreement with the experimental results, the model can accurately predict the MTBE concentration as a function of time, water temperature and PEX pipe geometry, and enable the pipe manufacturers to aid in ensuring desirable drinking water quality.

  • 177.
    Hollertz, Rebecca
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    López Durán, Vernica
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation.
    Larsson, Per A.
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Wågberg, Lars
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Chemically modified cellulose micro- and nanofibrils as paper-strength additives2017Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 9, s. 3883-3899Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chemically modified cellulose micro- and nanofibrils were successfully used as paper strength additives. Three different kinds of cellulose nanofibrils (CNFs) were studied: carboxymethylated CNFs, periodate-oxidised carboxymethylated CNFs and dopamine-grafted carboxymethylated CNFs, all prepared from bleached chemical fibres of dissolving grade, and one microfibrillated cellulose from unbleached kraft fibres. In addition to mechanical characterization of the final paper sheets the fibril retention, sheet density and sheet morphology were also studied as a function of addition of the four different cellulose fibrils. In general, the cellulose fibrils, when used as additives, significantly increased the tensile strength, Young’s modulus and strain-at-break of the paper sheets. The effects of the different fibrils on these properties were compared and evaluated and used to analyse the underlying mechanisms behind the strengthening effect. The strength-enhancing effect was most pronounced for the periodate-oxidised CNFs when they were added together with polyvinyl amine (PVAm) or poly(dimethyldiallylammonium chloride) (pDADMAC). The addition of periodate-oxidised CNFs, with pDADMAC as retention aid, resulted in a 37% increase in tensile strength at a 2 wt% addition and an 89% increase at a 15 wt% addition (from 67 to 92 and 125 kNm/kg, respectively) compared to a reference with only pDADMAC. Wet-strong sheets with a wet tensile index of 30 kNm/kg were also obtained when periodate-oxidised CNFs and PVAm were combined. This significant increase in wet strength is suggested to be the result of a formation of cross-links between the aldehyde groups, introduced by the periodate oxidation, and hydroxyl groups on the lignocellulosic fibres and the primary amines of PVAm. Even though less significant, there was also an increase in wet tensile strength when pDADMAC was used together with periodate-oxidised fibrils which shows that the aldehyde groups are able to increase the wet strength without the presence of the primary amines of the PVAm. As an alternative method to strengthen the fibre network, carboxymethylated CNFs grafted with dopamine, by an ethyl dimethylaminopropyl carbodiimide coupling, were used as a strength additive. When used as an additive, these CNFs showed a strong propensity to form films on and around the fibres and significantly increased the mechanical properties of the sheets. Their addition resulted in an increase in the Young´s modulus by 41%, from 5.1 to 7.2 GPa, and an increase in the tensile strength index of 98% (from 53 to 105 kNm/kg) with 5 wt% retained dopamine-grafted CNFs.

  • 178.
    Hua, Geng
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Franzén, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Odelius, Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Phosphazene-Catalyzed Regioselective Ring-Opening Polymerization of rac-1-Methyl Trimethylene Carbonate: Colder and Less is Better2019Ingår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 52, nr 7, s. 2681-2690Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The regioselective organocatalytic ring-opening polymerization (ROP) of a 6-membered cyclic carbonate, rac-1-methyl trimethylene carbonate, was studied using phosphazene base (t-BuP2) as the principle catalyst. The influence on the reaction kinetics caused by the reaction temperature (-74-60 degrees C), catalyst loading (0.5-2.5%), and reaction solvent (toluene and tetrahydrofuran) was systematically tuned and followed by H-1 NMR. All studied reactions reached close to or above 90% monomer conversion in 3 h, and all exhibited typical equilibrium polymerization behavior that is inherent to 6-membered cyclic carbonates. Good control over the molecular weight and distribution of the polycarbonate product was obtained in most studied conditions, with M-n ranging from similar to 4k to similar to 20k and D < 1.2. The regioregularity (X-reg) of the resulting polycarbonate was thoroughly studied using various NMR techniques, with the highest X-reg obtained being.0.90. The major influence from the reaction conditions on both the ROP kinetics and X-reg are as follows: higher reaction temperature resulted in a decrease of both; higher catalyst loading resulted in a faster ROP reaction but a slight decrease in X-reg; and toluene being a better solvent resulted in both faster reaction and higher X-reg. Throughout this study, we have demonstrated the possibility to synthesize regioregular aliphatic polycarbonate using an organic base as the ROP catalyst, contrary to the existing studies on similar systems where only metal-base catalysts were in focus and our systems showed similar high X-reg of the product.

  • 179.
    Hua, Geng
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Olsen, Peter
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Franzen, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Odelius, Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Anionic polycondensation and equilibrium driven monomer formation of cyclic aliphatic carbonates2018Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, nr 68, s. 39022-39028Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current work explores the sodium hydride mediated polycondensation of aliphatic diols with diethyl carbonate to produce both aliphatic polycarbonates and cyclic carbonate monomers. The lengths of the diol dictate the outcome of the reaction; for ethylene glycol and seven other 1,3-diols with a wide array of substitution patterns, the corresponding 5-membered and 6-membered cyclic carbonates were synthesized in excellent yield (70-90%) on a 100 gram scale. Diols with longer alkyl chains, under the same conditions, yielded polycarbonates with an M-w ranging from 5000 to 16000. In all cases, the macromolecular architecture revealed that the formed polymer consisted purely of carbonate linkages, without decarboxylation as a side reaction. The synthetic design is completely solvent-free without any additional post purification steps and without the necessity of reactive ring-closing reagents. The results presented within provide a green and scalable approach to synthesize both cyclic carbonate monomers and polycarbonates with possible applications within the entire field of polymer technology.

  • 180.
    Hua, Geng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Ring-opening Approaches to Functional Renewable Polymers2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 181.
    Huang, Tianxiao
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Betulin-modified cellulosic textile fibers with improved water repellency, hydrophobicity and antibacterial properties2019Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Textiles made from natural sources, such as cotton and flax, have advantages over those made of synthetic fibers in terms of sustainability. Unlike major synthetic fibers that have a negative impact on the environment due to poor biodegradability, cotton cellulose is a renewable material.Cotton cellulose fibers exhibit various attractive characteristics such as softness and inexpensiveness. Cellulosic textiles can be easily wetted, since the structure contains a large amount of hydrophilic hydroxyl groups, and when water repellency is needed, this is a disadvantage. Currently, paraffin waxes or fluorinated silanes are used to achieve hydrophobicity, but this contradicts the concept of green chemistry since these chemicals are not biodegradable. The use of bio-based materials like forest residues or side-streams from forest product industries might be a good alternative, since this not only decreases the pressure on the environment but can also increase the value of these renewable resources.Betulin is a hydrophobic extractive present in the outer bark of birch trees (Betula verrucosa). Nowadays, the birch bark containing betulin generated in the paper industry is disposed of by incineration as a solid fuel to provide energy, but this application is not highly valuable and this motivates us to see whether betulin can be used as a hydrophobe to prepare waterproof cellulosic textiles. Methods of dip-coating, film compression molding and grafting were performed to build “betulin-cellulosic textile system” to render the textile with hydrophobicity and other functions. The textile impregnated in a solution of betulin-based copolymer exhibited a contact angle of 151°, which indicated that superhydrophobicity can be reached. AATCC water spray test results showed that cellulosic textile coated with betulin-based film had a water repellency of 80, which is the third highest class according to the rating standards. Betulin-grafted textiles were also prepared and showed a static water contact angle of 136°, and an antibacterial property with a bacterial removal of 99%.This thesis proposes that betulin can be used as a green alternative in functional material preparation. By developing betulin, a more value-added application rather than incineration can be achieved.

  • 182.
    Huang, Tianxiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Chen, Chao
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Li, Dongfang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hydrophobic and antibacterial textile fibres prepared by covalently attaching betulin to cellulose2019Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Betulin, a natural compound extractable from the outer bark of birch, can be used to improve the properties of cellulosic textile fibres. Herein, oxidation was performed to prepare carboxyl-functionalized cellulose, which was subsequently covalently attached by betulin through esterification. The surface-modified cellulosic textile fibres showed a substantially improved hydrophobicity, as indicated by a water contact angle of 136°. Moreover, the material showed excellent antibacterial properties, as indicated by over 99% bacterial removal and growth inhibition, in both Gram-positive and Gram-negative bacterial assays. The method of surface-modification of the cellulosic materials adapted in this study is simple and, to the best of our knowledge, has not been carried out before. The results of this study prove that betulin, a side-stream product produced by forest industry, could be used in value-added applications, such as for preparing functional materials. Additionally, this modification route can be envisaged to be applied to other cellulose sources (e.g., microfibrillated cellulose) to achieve the goal of functionalization.

  • 183.
    Huang, Tianxiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Li, Dongfang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Water repellency improvement of cellulosic textile fibers by betulin and a betulin-based copolymer2018Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 3, s. 2115-2128Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Betulin is a naturally abundant and hydrophobic compound in the outer bark of birch and can readily be obtained by solvent extraction. Here, solutions of betulin were used to treat cotton fabrics and improve their water repellency. Cotton fabric impregnated in a solution of betulin in ethanol showed a contact angle for water of approximately 153A degrees and reached a water repellency score of 70 according to a standard water repellency test method. A betulin-terephthaloyl chloride (TPC) copolymer was synthesized. Both betulin and betulin-TPC copolymer were characterized by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The copolymer was characterized by size exclusion chromatography and differential scanning calorimetry. When impregnated with a solution of betulin-TPC copolymer in tetrahydrofuran, a cotton fabric showed a water contact angle of 151A degrees and also reached a water repellency score of 70. Films based on betulin and betulin-TPC copolymer were prepared and coated onto the surface of the fabrics by compression molding. These coated fabrics showed water contact angles of 123A degrees and 104A degrees respectively and each reached a water repellency score of 80.

  • 184.
    Hult, Daniel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Versatile Synthetic Strategies to Highly Functional Polyesters and Polycarbonates2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Polymers have become ubiquitous in today’s society and are found in everything from household items to airplanes and automobiles. Synthetic polymeric materials are as diverse as their applications and their final properties are highly reliant on the building blocks and methods used to assemble them. In the field of biomedical materials, polyesters and polycarbonates have been hailed as excellent materials in large part due to their inherent hydrolytic degradability. With this in mind, careful choice of monomers can ensure that materials not only conform to the desired physical properties, but also elicit a favorable biological response. The utilization of post-polymerization modification of these promising materials has the capability of opening up further avenues to target even more advanced applications. Unfortunately, rigorous and difficult reaction conditions, including multi-step synthesis have to a certain extent held back the adoption of these complex functional materials in applied research. In a pragmatic approach, a sustainable framework was developed in this thesis to seek out more practical methods, limiting the amount of reaction steps and overtly hazardous chemicals.

    In a first study, we set out to simplify and scale-up the synthesis of cyclic carbonates with pendant functional groups, capable of undergoing controlled ring-opening polymerization. By avoiding the use of protective-group chemistry we were able two devise a two-step method to create a library of functional monomers. Results in this study show that reactive intermediates could be isolated on 100 g scales, which in a second step was functionalized with a desired alcohol.

    With this framework in mind, key practical decisions were made to drastically re-think the work up procedures for greater scalability of bis-MPA dendrimers. In this work, a more efficient, scalable and sustainable approach was devised. Elimination of traditional arduous purification steps led to the synthesis of monodisperse dendrimers up to the sixth generation, with 192 functional groups on 50 g scales. Further work included the omission of protective group-chemistry, using orthogonal functional groups to cut the number of synthetic steps by half.

    The know-how developed in the first two projects led us to pursue greater scalability of functional polycarbonates through a simpler polymerization technique. The method allowed the step-growth polymerization of functional materials from more easily accessible monomers isolated on 100 g scales. Subsequent polymerization afforded materials with glass transition temperatures in the range of -45 °C to 169 °C. The method served as a complement to cyclic carbonates, offering a wider range of functional monomers. Furthermore, by careful choice of assembly method, both alternating and scrambled compositions could be achieved.

    In a final study, we set out to take advantage of the scrambling mechanism. Control of the final composition of highly rigid degradable polycarbonates was pursued, using renewable building-blocks derived from sugar. In a proof of concept study, thermal and hydrolytic stability of these materials is shown to be dependent on both amount and configuration of each monomer in the final material.

  • 185.
    Hult, Daniel
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Garcia-Gallego, Sandra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Ingverud, Tobias
    Andrén, Oliver
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Degradable High Tg Sugar Derived Polycarbonates from Isosorbide and Dihydroxyacetone2018Ingår i: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polycarbonates from isosorbide and dihydroxyacetone (DHA) have been synthesised using organocatalytic step-growth polymerization of their corresponding diols and bis-carbonylimidazolides monomers. By choice of feed ratio and monomer activation, either isosorbide or ketal protected DHA, random and alternating poly(Iso-co-DHA) carbonates have been formed. Thermal properties by DSC and TGA were herein strongly correlated to monomer composition. Dilution studies using 1H-NMR of a model compound DHA-diethyl carbonate in acetonitrile and deuterated water highlighted the influence of α-substituents on the keto/hydrate equilibrium of DHA. Further kinetics studies of in the pH* range of 4.7 to 9.6 serve to show the hydrolytic pH-profile of DHA-carbonates. The Hydrolytic degradation of deprotected polymer pellets show an increased degradation with increasing DHA content. Pellets with a random or alternating configuration show different characteristics in terms of mass loss and molecular weight loss profile over time.

  • 186.
    Hult, Daniel
    et al.
    KTH. KTH Royal Inst Technol, Stockholm, Sweden..
    Olsson, Vilhelm
    KTH.
    Garcia-Gallego, Sandra
    KTH.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Versatile chemistries to highly functional polyesters and polycarbonates2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 187. Ibarra, David
    et al.
    Köpcke, Viviana
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Influence of a monocomponent endoglucanase on different fibre raw materials: Study of accessability and reactivity2008Konferensbidrag (Refereegranskat)
  • 188.
    Ihrner, Niklas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Structural Lithium Ion Battery Electrolytes2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    A major challenge in the electrification of vehicles in the transport industry is that batteries are heavy, which reduces their effectiveness in mobile applications. A solution to this is structural batteries, which are batteries that can carry mechanical load while simultaneously storing energy. This can potentially lead to large weight savings on a systems level, since they may allow replacement of load bearing structures with structural batteries. Carbon fibers are suitable for structural batteries because they have superb mechanical properties and readily intercalate lithium ions, i.e. they can be used as electrodes in a lithium ion battery. However, to utilize carbon fibers in structural batteries, a polymer (matrix) is needed to form a composite battery. The polymer is required to have high modulus and high ion transport properties, which are inversely related, to function as an electrolyte. This thesis focuses on the development and characterization of such polymer electrolytes.

    The first study was performed on a homogenous polymer electrolyte based on plasticized polyethylene glycol-methacrylate. The influence of crosslink density, salt concentration and plasticizer concentration on the mechanical and electrochemical properties were investigated. Increases in both ionic conductivity and storage modulus were obtained when, compared to non-plasticized systems. However, at high storage modulus (E’>500 MPa) the ionic conductivity (𝜎<10-7 S cm-1) is far from good enough for the realization of structural batteries.

    In a second study, phase separated systems were therefore investigated. Polymerization induced phase separation (PIPS) via UV-curing was utilized to the produce structural battery electrolytes (SBE), consisting of liquid electrolyte and a stiff vinyl ester thermoset. The effect of monomer structure and volume fraction of liquid electrolyte on the morphology, electrochemical and mechanical properties were investigated. High storage modulus (750 MPa) in combination with high ionic conductivity (1.5 x 10-4 S cm-1) were obtained at ambient temperature. A SBE carbon fiber lamina half-cell was prepared via vacuum infusion and electrochemically cycled vs lithium metal. The results showed that both ion transport and load transfer was enabled through the SBE matrix.

    In the third study the mechanical and electrochemical properties of the SBE-carbon fiber lamina were investigated and the multifunctional performance was evaluated. A new formulation of SBE, with a small addition of thiol monomer, were prepared with improved electrochemical and mechanical properties. The mechanical properties of the SBE carbon fiber lamina did not deteriorate after electrochemical cycling. The capacity of the SBE carbon fiber lamina half-cell was 232 ± 26 mAh g-1, at a C/20 charge rate. Furthermore, the lamina displayed multifunctional performance, compared to the monofunctional properties of its constituents.

    In the final study, a new curing method was investigated, since UV-curing cannot be used to prepare full-cell carbon fiber composite structural batteries. Thermal curing was investigated to prepare the SBE. The PIPS was not adversely affected by the change in curing method, and the length scale of the phase separation in the SBE was slightly larger compared to UV-cured SBEs. The thermally cured SBEs exhibited improved thermomechanical properties without a reduction in the electrochemical properties. Thermal curing did not affect the electrochemical properties of the SBE carbon fiber lamina, however the type of carbon fiber utilized was found to negatively affect the cycling performance.

    Publikationen är tillgänglig i fulltext från 2020-03-25 10:42
  • 189.
    Ingverud, Tobias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Exploring crosslinked networks of polymers and hybrid cellulose materials2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Polymerkemin har under de senaste decennierna haft en enorm utveckling, vilket har resulterat i nya funktionella material med banbrytande applikationer. Denna utveckling har drivits på av starka tvärvetenskapliga allianser mellan medicin, biologi, kemi och materialvetenskap. Termoresponsiva block-sampolymerer har bland annat tagits fram för sin förmåga att själv-organiseras, vilken möjliggör inkapsling och frisättning av medicin. Den dendritiska polymerfamiljen har visat sig vara ett utmärkt exempel på högreaktiva och interaktiva funktionella material, speciellt lämpliga för biomedicinska tillämpningar. Betydelsen av aminer är stor i allmänhet och speciellt inom polymerkemin, tack vare deras nukleofila egenskaper i reaktioner, men också för deras förmåga att interagera med andra fysikaliska konstellationer. Det finns också en ökad medvetenhet om vår ökande levnadsstandard, effekterna av klimatförändringar och jordens befolkningstillväxt. Dessa utmaningar, behöver vårt yttersta fokus och ökad kunskap, för att styra våra steg mot en mer biobaserad cirkulär ekonomi. I Sverige skulle vi kunna ta bättre hand om vår skog och utnyttja dess fina råmaterial och förädla den till nya material. Denna avhandling strävar efter spontan tvärbindning av olika funktionella polymerer, med fokus på hybridisering med nanocellulosa-material.

    Initialt framställdes interaktiva, permanent laddade, amin-funktionella termoresponsiva tri- och stjärnblocksampolymerer. Dessa utvärderades och användes som elektrostatisk makro-tvärbindare för cellulosa nanofibriller (CNF), vilket resulterade i hydrogeler med låg torrhalt och anmärkningsvärd termoresponsivitet och skjuvningsmodul.

    För det andra utvecklades och utvärderades reaktiva och interaktiva aminfunktionella dendritiska linjär-dendritiska (DLD)-polymerer in vitro och in vivo. DLD-polymererna användes som antibakteriella hydrogeler som var snabbnedbrytande och verkade hämmande för kirurgiskt påverkad sårinfekiton (SSI). Tvärbindning av poly(etylen glykol) (PEG) systemet optimerades för snabb applicering under fysiologiska förhållanden i from av tvåkomponentssystem samt för att kunna matcha olika vävnaders skjuvningsmodul.

    För det tredje introducerades och karakteriserades Helux, den hyperförgrenade kommersiella heterofunktionella poly(amidoamin) karboxylat polymeren. Aminreaktioner utfördes för att demonstrera lättillgängliga modifieringar av Helux. Hetero-funktionaliteten utvärderades genom att öka molekylvikten och sedan bilda självtvärbundna Heluxfilmer. Dessutom framställdes även tvåkomponents-hydrogeler baserat på Helux och PEG som visade temperaturhärdningsberoende skjuvningsmodul.

    Slutligen användes Helux i kombination med CNF för att visa potentialen i att blanda på nanonivå utan aggregering. CNF-Helux visade sig kunna bilda hydrogeler och våtstabila termo-tvärbundna CNF-Helux-kompositsammansättningar, såsom filmer och aerogeler, redo för ytmodifiering av kvarvarande amin-grupper i de bildade 3D-nätverken.

    Publikationen är tillgänglig i fulltext från 2020-04-16 12:13
  • 190.
    Ingverud, Tobias
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Erlandsson, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    The combination of a dendritic polyampholyte and cellulose nanofibrils – a new type of functional materialManuskript (preprint) (Övrigt vetenskapligt)
  • 191.
    Ingverud, Tobias
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Helux: A heterofunctional hyperbranched poly(amido amine) carboxylateManuskript (preprint) (Övrigt vetenskapligt)
  • 192.
    Jara, Rory
    et al.
    SI Grp, Proc Technol Grp, Morgantown, WV USA.;West Virginia Univ, Wood Sci & Technol Dept, Morgantown, WV 26506 USA..
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    van Heiningen, Adriaan
    Univ Maine, 537 Jenness Hall, Orono, ME 04469 USA..
    Intrinsic dissolution kinetics and topochemistry of xylan, mannan, and lignin during auto-hydrolysis of red maple wood meal2019Ingår i: Canadian Journal of Chemical Engineering, ISSN 0008-4034, E-ISSN 1939-019X, Vol. 97, nr 3, s. 649-661Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High temperature aqueous treatment of wood is the preferred technology for deconstructing lignocellulosics. Many studies have been carried out on the kinetics and mechanism of hot-water extraction. However, most were performed in batch or integral plug flow reactors, which are not optimal for measuring intrinsic dissolution kinetics of the lignocellulosic components. Therefore, we used a continuous mixed batch reactor (or Berty reactor) to determine the intrinsic dissolution kinetics of xylan, mannan, and lignin from milled hardwood (Acer rubrum) at three different temperatures (150, 160, and 170 degrees C) and four constant pH values: 2, 3, 4, and 5. During the initial phase of autohydrolysis (carbohydrate-free), lignin and (lignin-free) xylan dissolve starting at a high rate and then a slowly decreasing rate, respectively. This is followed by the dissolution of xylan-lignin complexes and finally cellulose xylan complexes when cellulose has been significantly hydrolysed. The kinetics and molecular weight distribution of the removed wood polymers are used to describe the topochemistry of autohydrolysis based on recent knowledge of the ultrastructure of hardwood fibres.

  • 193.
    Jawerth, Marcus
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lundmark, Stefan
    Perstorp AB, Perstorp, Sweden..
    Gioia, Claudio
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    A retrosynthesis perspective on new thermoset resin applications based on industrial Kraft lignin2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 194.
    Jawerth, Marcus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Royal Inst Technol, Wallenberg Wood Sci Ctr, Stockholm, Sweden..
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Royal Inst Technol, Wallenberg Wood Sci Ctr, Stockholm, Sweden..
    Lundmark, Stefan
    Perstorp AB, Perstorp, Sweden..
    Berumen, Catalina Perez
    Univ Autonoma Coahuila, Saltillo, Coahuila, Mexico..
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Royal Inst Technol, Stockholm, Sweden..
    Modification of low molecular weight lignin model compounds for thermoset resin applications2016Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Artikel i tidskrift (Övrigt vetenskapligt)
  • 195.
    Johannisson, Wilhelm
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Ihrner, Niklas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Zenkert, Dan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Carlstedt, D.
    Asp, L. E.
    Sieland, F.
    Multifunctional performance of a carbon fiber UD lamina electrode for structural batteries2018Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 168, s. 81-87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In electric transportation there is an inherent need to store electrical energy while maintaining a low vehicle weight. One way to decrease the weight of the structure is to use composite materials. However, the electrical energy storage in today's systems contributes to a large portion of the total weight of a vehicle. Structural batteries have been suggested as a possible route to reduce this weight. A structural battery is a material that carries mechanical loads and simultaneously stores electrical energy and can be realized using carbon fibers both as a primary load carrying material and as an active battery electrode. However, as yet, no proof of a system-wide improvement by using such structural batteries has been demonstrated. In this study we make a structural battery composite lamina from carbon fibers with a structural battery electrolyte matrix, and we show that this material provides system weight benefits. The results show that it is possible to make weight reductions in electric vehicles by using structural batteries. 

  • 196.
    Josefsson, Peter
    et al.
    KTH.
    Wågberg, Lars
    KTH.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    CELL 114-Mode of action of fungal cellulases studied using model cellulose films and a quartz crystal microbalance2007Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 233, s. 773-773Artikel i tidskrift (Övrigt vetenskapligt)
  • 197.
    Kaldéus, Tahani
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Surface modification approaches of cellulose nanofibrils and their effect on dispersibility2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In the strive to find and develop sustainable bio-based materials an increased interest for nanocellulosic materials as attractive alternatives has arisen during the past decades. This can be attributed to their abundant renewability, remarkable inherent mechanical properties and their capability to be chemically modified. Cellulose nanofibrils (CNFs) are commonly obtained from wood pulp fibres and prepared through mechanical, chemical and/or enzymatic treatments. However, due to their hydrophilic nature and tendency to self-aggregate, their surface chemistry need to be altered to fully utilise their inherent properties and enable their usage in conventional large-scale industrial processes.

    This thesis work focuses on elucidating the fundamental aspects of the colloidal stability of highly concentrated CNF dispersions and the redispersibility of dried CNFs. Small amounts of amine-terminated poly(ethylene glycol) (PEG) were used to sterically stabilise the CNFs at higher fibril concentrations and delay the dispersion-arrested state transition (Paper I). The redispersibility of dried CNFs was studied for differently charged CNFs as a function of redispersing agents such as carboxymethyl cellulose (CMC), PEG and lignin (Paper II).

    This thesis presents green, facile modification approaches as well as strategies for improved dispersibility and compatibility with polymer matrices. The commercially established carboxymethylation process was expanded with a subsequent functionality step, yielding a mild, versatile one-pot protocol for the preparation of bi-functional CNFs (Paper III). Further, reactive amphiphilic macromolecules with targeted side-chain functionalities were used to compatibilise the CNF surface by water-based approaches. In the first study, a macroinitiator was used for the development of a versatile, yet facile, protocol for the controlled polymerisation of both hydrophilic and hydrophobic monomers in water from the CNF surface (Paper IV). In the second study, a reactive macro-compatibiliser was used to molecularly engineer the interface between CNFs and a polymer matrix by reactive-melt processing, yielding nanocomposites with improved stiffness while maintaining the deformability (Paper V).

    Publikationen är tillgänglig i fulltext från 2020-02-22 11:00
  • 198.
    Kaldéus, Tahani
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Larsson, Per Tomas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. RISE Bioecon, Drottning Kristinas Väg 61, S-11486 Stockholm, Sweden..
    Boujemaoui, Assya
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    One-pot preparation of bi-functional cellulose nanofibrils2018Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 12, s. 7031-7042Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein, we present a route to obtain bi-functional cellulose nanofibrils (CNF) by a one-pot approach using an already established functionalisation route, carboxymethylation, to which a subsequent functionalisation step, allylation or alkynation, has been added in the same reaction pot, eliminating the need of solvent exchange procedures. The total charge of the fibres and the total surface charge of the nanofibrils were determined by conductometric and polyelectrolyte titration, respectively. Furthermore, the allyl and alkyne functionalised cellulose were reacted with methyl 3-mercaptopropionate and azide-functionalised disperse red, respectively, to estimate the degree of functionalisation. The samples were further assessed by XPS and FT-IR. Physical characteristics were evaluated by CP/MAS C-13-NMR, XRD, AFM and DLS. This new approach of obtaining bi-functionalised CNF allows for a facile and rapid functionalisation of CNF where chemical handles can easily be attached and used for further modification of the fibrils.

  • 199.
    Kaldéus, Tahani
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Leggieri, Maria Rosella Telaretti
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sanchez, Carmen
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    All-Aqueous SI-ARGET ATRP from Cellulose Nanofibrils Using Hydrophilic and Hydrophobic Monomers2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 5, s. 1937-1943Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An all-water-based procedure for "controlled" polymer grafting from cellulose nanofibrils is reported. Polymers and copolymers of poly(ethylene glycol) methyl ether methacrylate (POEGMA) and poly(methyl methacrylate) (PMMA) were synthesized by surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP) from the cellulose nanofibril (CNF) surface in water. A macroinitiator was electrostatically immobilized to the CNF surface, and its amphiphilic nature enabled polymerizations of both hydrophobic and hydrophilic monomers in water. The electrostatic interactions between the macroinitiator and the CNF surface were studied by quartz crystal microbalance with dissipation energy (QCM-D) and showed the formation of a rigid adsorbed layer, which did not desorb upon washing, corroborating the anticipated electrostatic interactions. Polymerizations were conducted from dispersed modified CNFs as well as from preformed modified CNF aerogels soaked in water. The polymerizations yielded matrix-free composite materials with a CNF content of approximately 1-2 and 3-6 wt % for dispersion-initiated and aerogel-initiated CNFs, respectively.

  • 200.
    Kaldéus, Tahani
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Nordenström, Malin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Erlandsson, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Redispersibility properties of dried cellulose nanofibrils - influence on structure and mechanical propertiesManuskript (preprint) (Övrigt vetenskapligt)
1234567 151 - 200 av 431
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