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  • 401.
    Rosén, Tomas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. SUNY Stony Brook.
    Brouzet, Christophe
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. DESY.
    Lundell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Söderberg, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Three-Dimensional Orientation of Nanofibrils in Axially Symmetric Systems Using Small-Angle X-ray Scattering2018Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, nr 12, s. 6889-6899Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increased availability and brilliance of new X-ray facilities have in the recent years opened up the possibility to characterize the alignment of dispersed anisotropic nanoparticles in various microfluidic applications, from hydrodynamic self-assemblies to flows in complex geometries. In such applications, it is vital to study the alignment of the nanoparticles in the flow, as this in turn affects the final properties of the self-assembled superstructures or those of the flow itself. Small-angle X-ray scattering (SAXS) is a well-suited characterization technique for this but typically provides the alignment in a projected plane perpendicular to the beam direction. In this work, we demonstrate a simple method to reconstruct the full three-dimensional orientation distribution function from a SAXS experiment through the assumption that the azimuthal angle of the nanoparticles around the flow direction is distributed uniformly, an assumption that is valid for a large range of nanoparticle flow processes. For demonstration purposes, the experimental results from previous works on hydrodynamic self-assembly of cellulose nanofibrils (CNFs) into filaments have been revised, resulting in a small correction to the presented order parameters. The results are then directly compared with simple numerical models to describe the increased alignment of CNFs both in the flowing system and during the drying of the filament. The proposed reconstruction method will allow for further improvements of theoretical or numerical simulations and consequently open up new possibilities for optimizing assembly processes, which include flow alignment of elongated nanoparticles.

  • 402.
    Rovera, Cesare
    et al.
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy..
    Ghaani, Masoud
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy..
    Santo, Nadia
    Univ Milan, Dept Biosci, Via Celoria 26, I-20133 Milan, Italy..
    Trabattoni, Silvia
    Univ Milano Bicocca, Dept Mat Sci, Via R Cozzi 55, I-20125 Milan, Italy..
    Olsson, Richard
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Romano, Diego
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy.;Univ Milan, Local Unit, Natl Consortium Mat Sci & Technol, INSTM, Via Celoria 2, I-20133 Milan, Italy..
    Farris, Stefano
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy.;Univ Milan, Local Unit, Natl Consortium Mat Sci & Technol, INSTM, Via Celoria 2, I-20133 Milan, Italy..
    Enzymatic Hydrolysis in the Green Production of Bacterial Cellulose Nanocrystals2018Ingår i: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, nr 6, s. 7725-7734Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we extensively describe experimental models, with correlating experimental conditions, which were used to investigate the enzymatic hydrolysis of bacterial cellulose (BC) to obtain nanocrystals. Cellulase from Trichoderma reesei was used in five enzyme/BC ratios over a period of 74 h. The turbidity data was modeled using both logistic regression and empirical regression to determine the fractal kinetics, resulting in unique kinetic patterns for the mixtures that were richest in BC and in enzymes. The evolution of the yield was inversely related to the turbidity, as confirmed through a semiempirical approach that was adopted to model the experimental data. The yield values after 74 h of hydrolysis were higher for the substrate-rich mixtures (similar to 20%) than for the enzyme rich mixtures (similar to 5%), as corroborated by cellobiose and glucose quantification. Transmission electron microscopy and atomic force microscopy analyses revealed a shift from a fibril network to a needle-like morphology (i.e., aggregated nanocrystals or individual nanocrystals similar to 6 nm width and 200-800 nm in length) as the enzyme/BC ratios went from lower to higher. These results were explained in terms of the heterogeneous substrate model and the erosion model. This work initiated a promising, environmentally friendly method that could serve as an alternative to the commonly used chemical hydrolysis routes.

  • 403.
    Rozenbaum, Rene T.
    et al.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Andrén, Oliver C. J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    van der Mei, Henny C.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Woudstra, Willem
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Busscher, Henk J.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sharma, Prashant K.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Penetration and Accumulation of Dendrons with Different Peripheral Composition in Pseudomonas aeruginosa Biofilms2019Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, nr 7, s. 4327-4333Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multidrug resistant bacterial infections threaten to become the number one cause of death by the year 2050. Development of antimicrobial dendritic polymers is considered promising as an alternative infection control strategy. For antimicrobial dendritic polymers to effectively kill bacteria residing in infectious biofilms, they have to penetrate and accumulate deep into biofilms. Biofilms are often recalcitrant to antimicrobial penetration and accumulation. Therefore, this work aims to determine the role of compact dendrons with different peripheral composition in their penetration into Pseudomonas aeruginosa biofilms. Red fluorescently labeled dendrons with pH-responsive NH3+ peripheral groups initially penetrated faster from a buffer suspension at pH 7.0 into the acidic environment of P. aeruginosa biofilms than dendrons with OH or COO- groups at their periphery. In addition, dendrons with NH3+ peripheral groups accumulated near the top of the biofilm due to electrostatic double-layer attraction with negatively charged biofilm components. However, accumulation of dendrons with OH and COO- peripheral groups was more evenly distributed across the depth of the biofilms than NH3+ composed dendrons and exceeded accumulation of NH3+ composed dendrons after 10 min of exposure. Unlike dendrons with NH3+ groups at their periphery, dendrons with OH or COO- peripheral groups, lacking strong electrostatic double-layer attraction with biofilm components, were largely washed-out during exposure to PBS without dendrons. Thus, penetration and accumulation of dendrons into biofilms is controlled by their peripheral composition through electrostatic double-layer interactions, which is an important finding for the further development of new antimicrobial or antimicrobial-carrying dendritic polymers.

  • 404.
    Sanchez, Carmen
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wåhlander, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Karlsson, Mattias E.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Quintero, Diana C. Marin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hillborg, Henrik
    ABB Power Technol, SE-72178 Vasteras, Sweden..
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Nilsson, Fritjof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Characterization of Reduced and Surface-Modified Graphene Oxide in Poly(Ethylene-co-Butyl Acrylate) Composites for Electrical Applications2019Ingår i: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, nr 4, artikel-id 740Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Promising electrical field grading materials (FGMs) for high-voltage direct-current (HVDC) applications have been designed by dispersing reduced graphene oxide (rGO) grafted with relatively short chains of poly (n-butyl methacrylate) (PBMA) in a poly(ethylene-co-butyl acrylate) (EBA) matrix. All rGO-PBMA composites with a filler fraction above 3 vol.% exhibited a distinct non-linear resistivity with increasing electric field; and it was confirmed that the resistivity could be tailored by changing the PBMA graft length or the rGO filler fraction. A combined image analysis- and Monte-Carlo simulation strategy revealed that the addition of PBMA grafts improved the enthalpic solubility of rGO in EBA; resulting in improved particle dispersion and more controlled flake-to-flake distances. The addition of rGO and rGO-PBMAs increased the modulus of the materials up to 200% and the strain did not vary significantly as compared to that of the reference matrix for the rGO-PBMA-2 vol.% composites; indicating that the interphase between the rGO and EBA was subsequently improved. The new composites have comparable electrical properties as today's commercial FGMs; but are lighter and less brittle due to a lower filler fraction of semi-conductive particles (3 vol.% instead of 30-40 vol.%).

  • 405. Scaffaro, R.
    et al.
    Maio, A.
    Lo Re, Giada
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer.
    Parisi, A.
    Busacca, A.
    Advanced piezoresistive sensor achieved by amphiphilic nanointerfaces of graphene oxide and biodegradable polymer blends2018Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 156, s. 166-176Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work focuses on the preparation of a piezoresistive sensor device, by exploiting an amphiphilic sample of graphene oxide (GO) as a compatibilizer for poly (lactic acid) (PLA)-Poly (ethylene-glycol) (PEG) blends. The presence of GO determined a high stiffening and strengthening effect, without affecting toughness, and allowed a good stability of mechanical properties up to 40 days. Moreover, GO endowed the materials with electrical properties highly sensitive to pressure and strain variations: the biodegradable pressure sensor showed a responsivity of 35 μA/MPa from 0.6 to 8.5 MPa, a responsivity around 19 μA/MPa from 8.5 to 25 MPa. For lower pressure values (around 0.16–0.45 MPa), instead, the responsivity increases up to 220 μA/MPa in terms of ΔI/ΔP (i.e. (ΔI/ΔI0)/P close to 1 kPa−1). Furthermore, this novel sensor is able to monitor submicrometric displacements with an impressive sensitivity (up to 25 μA/μm in terms of ΔI/ΔL, or 70 in terms of (ΔI/I0)/ε). We implemented a model able to predict pressure changes up to 25 MPa, by monitoring and measuring variations in electrical conductivity, thus paving the road to use these biodegradable, ecofriendly materials as low-cost sensors for a large pressure range.

  • 406.
    Schneider, Lynn M.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Ihrner, Niklas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Zenkert, Dan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bicontinuous electrolytes via thermally initiated polymerization for structural lithium ion batteries.Manuskript (preprint) (Övrigt vetenskapligt)
  • 407.
    Schneider, Lynn M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    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.
    Bicontinuous Electrolytes via Thermally Initiated Polymerization for Structural Lithium Ion Batteries2019Ingår i: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 2, nr 6, s. 4362-4369Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Structural batteries (SBs) are a growing research subject worldwide. The idea is to provide massless energy by using a multifunctional material. This technology can provide a new pathway in electrification and offer different design opportunities and significant weight savings in vehicle applications. The type of SB discussed here is a multifunctional material that can carry mechanical loads and simultaneously provide an energy storage function. It is a composite material that utilizes carbon fibers (CFs) as electrodes and structural reinforcement which are embedded in a multifunctional polymer matrix (i.e., structural battery electrolyte). A feasible composite manufacturing method still needs to be developed to realize a full-cell SB. UV initiated polymerization induced phase separation (PIPS) has previously been used to make bicontinuous structural battery electrolytes (SBE) with good ionic conductivity and mechanical performance. However, UV-curing cannot be used for fabrication of a full cell SB since a full-cell is made of multiple layers of nontransparent CFs. The present paper investigates thermally initiated PIPS to prepare a bicontinuous SBE and an SB half-cell. In addition, the effect of curing temperature was examined with respect to curing performance, morphology, ionic conductivity, and mechanical and electrochemical performance. The study revealed that thermally initiated PIPS provides a robust and scalable process route to fabricate SBs. The results of this study are an important milestone in the development of SB technology as they allow for the SB fabrication for an actual application. However, other challenges still remain to be solved before this technology can be introduced into an application.

  • 408.
    Schuurmans, C. C. L.
    et al.
    Netherlands.
    Abbadessa, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bengtson, M. A.
    Netherlands.
    Pletikapic, G.
    Netherlands.
    Eral, H. B.
    Netherlands.
    Koenderink, G.
    Netherlands.
    Masereeuw, R.
    Netherlands.
    Hennink, W. E.
    Netherlands.
    Vermonden, T.
    Netherlands.
    Complex coacervation-based loading and tunable release of a cationic protein from monodisperse glycosaminoglycan microgels2018Ingår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 14, nr 30, s. 6327-6341Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Glycosaminoglycans (GAGs) are of interest for biomedical applications because of their ability to retain proteins (e.g. growth factors) involved in cell-to-cell signaling processes. In this study, the potential of GAG-based microgels for protein delivery and their protein release kinetics upon encapsulation in hydrogel scaffolds were investigated. Monodisperse hyaluronic acid methacrylate (HAMA) and chondroitin sulfate methacrylate (CSMA) micro-hydrogel spheres (diameters 500-700 μm), were used to study the absorption of a cationic model protein (lysozyme), microgel (de)swelling, intra-gel lysozyme distribution and its diffusion coefficient in the microgels dispersed in buffers (pH 7.4) of varying ionic strengths. Upon incubation in 20 mM buffer, lysozyme was absorbed up to 3 and 4 mg mg−1 dry microspheres for HAMA and CSMA microgels respectively, with loading efficiencies up to 100%. Binding stoichiometries of disaccharide : lysozyme (10.2 : 1 and 7.5 : 1 for HAMA and CSMA, respectively) were similar to those for GAG-lysozyme complex coacervates based on soluble GAGs found in literature. Complex coacervates inside GAG microgels were also formed in buffers of higher ionic strengths as opposed to GAG-lysozyme systems based on soluble GAGs, likely due to increased local anionic charge density in the GAG networks. Binding of cationic lysozyme to the negatively charged microgel networks resulted in deswelling up to a factor 2 in diameter. Lysozyme release from the microgels was dependent on the ionic strength of the buffer and on the number of anionic groups per disaccharide, (1 for HAMA versus 2 for CSMA). Lysozyme diffusion coefficients of 0.027 in HAMA and <0.006 μm2 s−1 in CSMA microgels were found in 170 mM buffer (duration of release 14 and 28 days respectively). Fluorescence Recovery After Photobleaching (FRAP) measurements yielded similar trends, although lysozyme diffusion was likely altered due to the negative charges introduced to the protein through the FITC-labeling resulting in weaker protein-matrix interactions. Finally, lysozyme-loaded CSMA microgels were embedded into a thermosensitive hydrogel scaffold. These composite systems showed complete lysozyme release in ∼58 days as opposed to only 3 days for GAG-free scaffolds. In conclusion, covalently crosslinked methacrylated GAG hydrogels have potential as controlled release depots for cationic proteins in tissue engineering applications.

  • 409. Senf, Deborah
    et al.
    Ruprecht, Colin
    Farahani, Saina Kishani
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Matic, Aleksandar
    Toriz, Guillermo
    Gatenholm, Paul
    Wågberg, Lars
    KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi.
    Pfrengle, Fabian
    Tailormade Polysaccharides with Defined Branching Patterns:Enzymatic Polymerization of Arabinoxylan Oligosaccharides2018Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, s. 12163-12168Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The heterogeneous nature of non-cellulosic polysaccharides,such as arabinoxylan, makes it difficult tocorrelate molecular structure with macroscopic properties. Tostudy the impact of specific structural features of the polysaccharideson crystallinity or affinity to other cell wall components,collections of polysaccharides with defined repeatingunits are required. Herein, a chemoenzymatic approach toartificial arabinoxylan polysaccharides with systematicallyaltered branching patterns is described. The polysaccharideswere obtained by glycosynthase-catalyzed polymerization ofglycosyl fluorides derived from arabinoxylan oligosaccharides.X-ray diffraction and adsorption experiments on cellulosicsurfaces revealed that the physicochemical properties of thesynthetic polysaccharides strongly depend on the specificnature of their substitution patterns. The artificial polysaccharidesallow structure–property relationship studies that are notaccessible by other means.

  • 410.
    Senf, Deborah
    et al.
    Max Planck Inst Colloids & Interfaces, Biomol Syst, Potsdam, Germany..
    Ruprecht, Colin
    Max Planck Inst Colloids & Interfaces, Biomol Syst, Potsdam, Germany..
    Farahani, Saina Kishani
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi. KTH Fibre Polymer Tech, Stockholm, Sweden..
    Pfrengle, Fabian
    Max Planck Inst Colloids & Interfaces, Biomol Syst, Potsdam, Germany..
    Chemoenzymatic synthesis of artificial xylan polysaccharides with defined substitution patterns2019Ingår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Artikel i tidskrift (Övrigt vetenskapligt)
  • 411.
    Senf, Deborah
    et al.
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany.;Free Univ Berlin, Inst Chem & Biochem, Arnimallee 22, D-14195 Berlin, Germany..
    Ruprecht, Colin
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany..
    Kishani, Saina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Matic, Aleksandar
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany.;Univ Potsdam, Dept Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Toriz, Guillermo
    Chalmers Univ Technol, Dept Chem & Chem Engn, Wallenberg Wood Sci Ctr & Biopolymer Technol, S-41296 Gothenburg, Sweden..
    Gatenholm, Paul
    Chalmers Univ Technol, Dept Chem & Chem Engn, Wallenberg Wood Sci Ctr & Biopolymer Technol, S-41296 Gothenburg, Sweden..
    Wågberg, 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.
    Pfrengle, Fabian
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany.;Free Univ Berlin, Inst Chem & Biochem, Arnimallee 22, D-14195 Berlin, Germany..
    Tailormade Polysaccharides with Defined Branching Patterns: Enzymatic Polymerization of Arabinoxylan Oligosaccharides2018Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 57, nr 37, s. 11987-11992Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The heterogeneous nature of non-cellulosic polysaccharides, such as arabinoxylan, makes it difficult to correlate molecular structure with macroscopic properties. To study the impact of specific structural features of the polysaccharides on crystallinity or affinity to other cell wall components, collections of polysaccharides with defined repeating units are required. Herein, a chemoenzymatic approach to artificial arabinoxylan polysaccharides with systematically altered branching patterns is described. The polysaccharides were obtained by glycosynthase-catalyzed polymerization of glycosyl fluorides derived from arabinoxylan oligosaccharides. X-ray diffraction and adsorption experiments on cellulosic surfaces revealed that the physicochemical properties of the synthetic polysaccharides strongly depend on the specific nature of their substitution patterns. The artificial polysaccharides allow structure-property relationship studies that are not accessible by other means.

  • 412. Sharma, Sunita
    et al.
    Sapkota, Dipak
    Xue, Ying
    Rajthala, Saroj
    Yassin, Mohammed A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Wistrand, Anna Finne
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Mustafa, Kamal
    Delivery of VEGFA in bone marrow stromal cells seeded in copolymer scaffold enhances angiogenesis, but is inadequate for osteogenesis as compared with the dual delivery of VEGFA and BMP2 in a subcutaneous mouse model2018Ingår i: Stem Cell Research & Therapy, E-ISSN 1757-6512, Vol. 9, artikel-id 23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: In bone tissue engineering (BTE), extensive research into vascular endothelial growth factor A (VEGFA)-mediated angiogenesis has yielded inconsistent results. The aim of this study was to investigate the influence on angio-and osteogenesis of adenoviral-mediated delivery of VEGFA alone or in combination with bone morphogenetic protein 2 (BMP2) in bone marrow stromal cells (BMSC) seeded onto a recently developed poly(LLA-co-CL) scaffold. Methods: Human BMSC were engineered to express VEGFA alone or in combination with BMP2 and seeded onto poly(LLA-co-CL) scaffolds. Changes in angiogenic and osteogenic gene and protein levels were examined by quantitative reverse-transcription polymerase chain reaction (RT-PCR), PCR array, and alkaline phosphatase assay. An in vivo subcutaneous mouse model was used to investigate the effect on angio-and osteogenesis of VEGFA alone or in combination with BMP2, using microcomputed tomography (mu CT), histology, immunohistochemistry, and immunofluorescence. Results: Combined delivery of a lower ratio (1: 3) of VEGFA and BMP2 (ad-BMP2 + VEGFA) led to upregulation of osteogenic and angiogenic genes in vitro at 3 and 14 days, compared with mono-delivery of VEGFA (ad-VEGFA) and other controls. In vivo, in a subcutaneous mouse model, both ad-VEGFA and ad-BMP2 + VEGFA scaffold explants exhibited increased angiogenesis at 2 weeks. Enhanced angiogenesis was largely related to the recruitment and differentiation of mouse progenitor cells to the endothelial lineage and, to a lesser extent, to endothelial differentiation of the implanted BMSC. mu CT and histological analyses revealed enhanced de novo bone formation only in the ad-BMP2 + VEGFA group, corresponding at the molecular level to the upregulation of genes related to osteogenesis, such as ALPL, RUNX2, and SPP1. Conclusions: Although BMSC expressing VEGFA alone or in combination with BMP2 significantly induced angiogenesis, VEGFA alone failed to demonstrate osteogenic activity both in vitro and in vivo. These results not only call into question the use of VEGFA alone in bone regeneration, but also highlight the importance in BTE of appropriately formulated combined delivery of VEGFA and BMP2.

  • 413.
    Shin, Sung-Ho
    et al.
    Korea Res Inst Chem Technol, Res Ctr Biobased Chem, Ulsan 44429, South Korea..
    Lee, Woojoo
    Korea Res Inst Chem Technol, Res Ctr Biobased Chem, Ulsan 44429, South Korea..
    Kim, Seon-Mi
    Korea Res Inst Chem Technol, Res Ctr Biobased Chem, Ulsan 44429, South Korea..
    Lee, Minkyung
    Korea Res Inst Chem Technol, Res Ctr Biobased Chem, Ulsan 44429, South Korea..
    Koo, Jun Mo
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hwang, Sung Yeon
    Korea Res Inst Chem Technol, Res Ctr Biobased Chem, Ulsan 44429, South Korea.;Univ Sci & Technol, Adv Mat & Chem Engn, Daejeon 34113, South Korea..
    Oh, Dongyeop X.
    Korea Res Inst Chem Technol, Res Ctr Biobased Chem, Ulsan 44429, South Korea.;Univ Sci & Technol, Adv Mat & Chem Engn, Daejeon 34113, South Korea..
    Park, Jeyoung
    Korea Res Inst Chem Technol, Res Ctr Biobased Chem, Ulsan 44429, South Korea.;Univ Sci & Technol, Adv Mat & Chem Engn, Daejeon 34113, South Korea..
    Ion-conductive self-healing hydrogels based on an interpenetrating polymer network for a multimodal sensor2019Ingår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 371, s. 452-460Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Conductive self-healing polymer hydrogel and related soft sensor devices are receiving considerable attention from academia to industry because of their impacts on the lifetime and ergonomic design of soft robotics, prosthesis, and health monitoring systems. However, the development of such a material has thus far been limited considering performances and accessibility. Herein, robustness, self-healing, and conductivity for soft electronic skin are realized by an interpenetrating polymer network (IPN) system based on chemical/ionic cross-inked poly(acrylic acid) containing ferric ions, intercalated with physically cross-linked poly(vinyl alcohol). This IPN hydrogel successfully satisfies all three aforementioned capabilities; elongation at break greater than 1400%; recovery to original mechanical properties greater than 80% after 24 h; and 0.14 Sm-1 of ionic conductivity, which is electrically healable. Such ionic conductivity of hydrogels enables multimodal sensing capabilities, i.e., for strain, pressure, and temperature. Particularly, a uniquely designed dual sensor attached to a finger simultaneously detects mechanical folding and pressure changes independently and can undergo large deformation 1000 times repeated and heating up to 90 degrees C.

  • 414. Sjödahl, Ragnar
    et al.
    Keyoumu, Ayiguli
    Axelsson, Patrik
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Dissolved wood components in the kraft pulping liquor: Effect on the rate of delignification and bleachability2003Konferensbidrag (Refereegranskat)
  • 415.
    Soeta, Hiroto
    et al.
    Univ Tokyo, Dept Biomat Sci, Grad Sch Agr & Life Sci, Tokyo 1138657, Japan..
    Lo Re, Giada
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Masuda, Akihiro
    Toray Res Ctr Ltd, Morphol Res Labs, Morphol Res Lab 3, Otsu, Shiga 5208567, Japan..
    Fujisawa, Shuji
    Univ Tokyo, Dept Biomat Sci, Grad Sch Agr & Life Sci, Tokyo 1138657, Japan..
    Saito, Tsuguyuki
    Univ Tokyo, Dept Biomat Sci, Grad Sch Agr & Life Sci, Tokyo 1138657, Japan..
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Isogai, Akira
    Univ Tokyo, Dept Biomat Sci, Grad Sch Agr & Life Sci, Tokyo 1138657, Japan..
    Tailoring Nanocellulose-Cellulose Triacetate Interfaces by Varying the Surface Grafting Density of Poly(ethylene glycol)2018Ingår i: ACS OMEGA, ISSN 2470-1343, Vol. 3, nr 9, s. 11883-11889Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Careful design of the structures of interfaces between nanofillers and polymer matrices can significantly improve the mechanical and'thermal' properties of the overall nanocomposites. Here, we investigate]how the grafting density on the surface of nanocelluloses influences the properties of nanocellulose/cellulose triacetate (CTA) composites. 2,2,6,6 The surface of nanocellulose, which was preparedby tetramethylpiperidine-l-oxyl oxidation, was modified with long poly(ethylene glycol) (PEG) chains at different grafting_ densities. The PEG -grafted nanocelluloses were h omogene ously embedded in CTA matrices. The mechanical and thermal properties of the nanocomposites were characterized. Increasing the grafting density caused the soft PEG chains to form denser and thicker layers around the rigid nanocelluloses. The PEG layers were not completely miscible with the CTA matrix. This structure consfderably enhanced the energy dissipation by allowing sliding at the interface, which increased the toughness of the nanocomposites. The thermal and mechanical properties of the composites could be tailored by controlling the grafting density. These findings provide a deeper understanding about interfacial design for nanocellulose-based composite materials.

  • 416.
    Soeta, Hiroto
    et al.
    Univ Tokyo, Tokyo, Japan..
    Saito, Tsuguyuki
    Univ Tokyo, Dept Biomat Sci, Tokyo, Japan..
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Isogati, Akira
    Univ Tokyo, Tokyo, Japan..
    Grafting density design of surface-modified nanocellulose for polymer composites2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 417.
    Song, Lin
    et al.
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Wang, Weijia
    Northwestern Polytech Univ, Sch Mat Sci & Engn, State Key Lab Solidificat Proc, Youyixilu 127, Xian 710072, Shaanxi, Peoples R China..
    Barabino, Edoardo
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Yang, Dan
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Koerstgens, Volker
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Zhang, Peng
    Deutsch Elektronen Synchrotron DESY, Photon Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Deutsch Elektronen Synchrotron DESY, Photon Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Mueller-Buschbaum, Peter
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany.;Tech Univ Munich, Heinz Maier Leibnitz Zentrum MLZ, Lichtenbergstr 1, D-85748 Garching, Germany..
    Composition Morphology Correlation in PTB7-Th/PC71 BM Blend Films for Organic Solar Cells2019Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 3, s. 3125-3135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    From a morphological perspective, the understanding of the influence of the [6,6]-phenyl C-71-butyric acid methyl ester (PC71BM) content on the morphology of the active layer is not complete in organic solar cells (OSCs) with bulk heterojunction (BHJ) configuration based on the low-bandgap polymer poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo [1,2-b:4,5-b dithiophene-2,6-diyhalt-(4-(2-ethylhexyl)-3-fluorothieno [3,4-b]thiophene-)-2-carboxylate-2-6-diyl] (PTB7-Th). In this work, we obtain the highest power conversion efficiency (PCE) of 10.5% for BHJ organic solar cells (OSCs) with a PTB7-Th/PC71BM weight ratio of 1:1.5. To understand the differences in PCEs caused by the PC71BM content, we investigate the morphology of PTB7-Th/PC71BM blend films in detail by determining the domain sizes, the polymer crystal structure, optical properties, and vertical composition as a function of the PC71BM concentration. The surface morphology is examined with atomic force microscopy, and the inner film morphology is probed with grazing incidence small angle X-ray scattering. The PTB7-Th crystal structure is characterized with grazing incidence wide-angle X-ray scattering and UV/vis spectroscopy. X-ray reflectivity is employed to yield information about the film vertical composition. The results show that in PTB7-Th/PC71BM blend films, the increase of PC71BM content leads to an enhanced microphase separation and a decreased polymer crystallinity. Moreover, a high PC71BM concentration is found to decrease the polymer domain sizes and crystal sizes and to promote polymer conjugation length and formation of fullerene-rich and/or polymer-rich layers. The differences in photovoltaic performance are well explained by these findings.

  • 418.
    Sorrentino, Andrea
    et al.
    Natl Res Council Italy, IPCB, I-23900 Lecce, Italy..
    Gorrasi, Giuliana
    Univ Salerno, Dipartimento Ingn Ind, Via Giovanni Paolo II 132, I-84084 Fisciano, SA, Italy..
    Bugatti, Valeria
    Univ Salerno, Dipartimento Ingn Ind, Via Giovanni Paolo II 132, I-84084 Fisciano, SA, Italy..
    Fuoco, Tiziana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Univ Salerno, Dipartimento Chim & Biol A Zambelli, Via Giovanni Paolo II 132, I-84084 Fisciano, SA, Italy.;KTH Royal Inst Technol, Dept Fibre & Polymer Technol, S-11428 Stockholm, Sweden..
    Pappalardo, Daniela
    Univ Sannio, Dipartimento Sci & Tecnol, Via Mulini, I-82100 Benevento, Italy..
    Polyethylene-like macrolactone-based polyesters: Rheological, thermal and barrier properties2018Ingår i: Materials Today Communications, ISSN 2352-4928, Vol. 17, s. 380-390Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Linear aliphatic poly(ester)s are receiving increasing interest due to their properties comparable to that of common polyethylene. In this work, unsaturated macrolactone omega-6-hexadecenlactone (6HDL) is used for the preparation of long-methylene chain aliphatic polyesters by metal-catalyzed ring-opening polymerization (ROP). Block and random copolymer of e-caprolactone (CL) are then synthetized. The microstructures of these polyesters are characterized by H-1 and C-13 NMR. Their rheological, thermal and barrier properties are evaluated and discussed. For comparison purposes, the properties of the relative homopolymers are also determined. Results show that the properties of these polymers differ depending on the main chain structure. In particular, the viscoelastic behavior of the copolymer sample shows an order-disorder transition in the temperature range of 75-85 degrees C. Thermogravimetric analysis and barrier properties show that the copolymers have a resistance to the diffusion of gases and vapors intermediate between that of the parent homopolymers.

  • 419.
    Stamm, Arne
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Biundo, Antonino
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Schmidt, Björn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Brücher, Jörg
    Holmen AB, Dev, S-89180 Östersund, Sweden.
    Lundmark, Stefan
    Perstorp AB, Innovat, Perstorp Ind Pk, S-28480 Perstorp, Sweden.
    Olsén, Peter
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Fogelström, Linda
    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.
    Malmström, Eva
    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.
    Bornscheuer, Uwe T
    Ernst Moritz Arndt Univ Greifswald, Inst Biochem, Dept Biotechnol & Enzyme Catalysis, Felix Hausdorff Str 4, D-17487 Greifswald, Germany.
    Syrén, Per-Olof
    KTH, Centra, Science for Life Laboratory, SciLifeLab. 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. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    A retrobiosynthesis-based route to generate pinene-derived polyesters2019Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 20, s. 1664-1671Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Significantly increased production of biobased polymers is aprerequisite to replace petroleum-based materials towardsreaching a circular bioeconomy. However, many renewablebuilding blocks from wood and other plant material are notdirectly amenable for polymerization, due to their inert backbonesand/or lack of functional group compatibility with thedesired polymerization type. Based on a retro-biosyntheticanalysis of polyesters, a chemoenzymatic route from (@)-apinenetowards a verbanone-based lactone, which is furtherused in ring-opening polymerization, is presented. Generatedpinene-derived polyesters showed elevated degradation andglass transition temperatures, compared with poly(e-decalactone),which lacks a ring structure in its backbone. Semirationalenzyme engineering of the cyclohexanone monooxygenasefrom Acinetobacter calcoaceticus enabled the biosynthesis ofthe key lactone intermediate for the targeted polyester. As aproof of principle, one enzyme variant identified from screeningin a microtiter plate was used in biocatalytic upscaling,which afforded the bicyclic lactone in 39% conversion in shakeflask scale reactions.

  • 420.
    Stamm, Arne
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Tengdelius, Mattias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Schmidt, Björn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Engström, Joakim
    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.
    Syrén, Per-Olof
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Fogelström, Linda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Malmström, Eva
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation.
    Chemo- enzymatic pathways toward pinene- based renewable materials2019Ingår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 21, nr 10, s. 2720-2731Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sobrerol methacrylate (SobMA) was synthesized and subsequently polymerized using different chemical and enzymatic routes. Sobrerol was enzymatically converted from -pinene in a small model scale by a Cytochrome P450 mutant from Bacillus megaterium. Conversion of sobrerol into SobMA was performed using both classical ester synthesis, i.e., acid chloride-reactions in organic solvents, and a more green approach, the benign lipase catalysis. Sobrerol was successfully esterified, leaving the tertiary alcohol and ene to be used for further chemistry. SobMA was polymerized into PSobMA using different radical polymerization techniques, including free radical (FR), controlled procedures (Reversible Addition Fragmentation chain-Transfer polymerization, (RAFT) and Atom Transfer Radical Polymerization (ATRP)) as well as by enzyme catalysis (horseradish peroxidase-mediated free radical polymerization). The resulting polymers showed high glass-transition temperatures (T-g) around 150 degrees C, and a thermal degradation onset above 200 degrees C. It was demonstrated that the T-g could be tailored by copolymerizing SobMa with appropriate methacrylate monomers and that the Flory-Fox equation could be used to predict the T-g. The versatility of PSobMA was further demonstrated by forming crosslinked thin films, either using the ene'-functionality for photochemically initiated thiol-ene'-chemistry, or reacting the tertiary hydroxyl-group with hexamethoxymethylmelamine, as readily used for thermally curing coatings systems.

  • 421.
    Stenström, Patrik
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Manzanares, D.
    Zhang, Yuning
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ceña, V.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Evaluation of amino-functional polyester dendrimers based on Bis-MPA as nonviral vectors for siRNA delivery2018Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 23, nr 8, artikel-id 2028Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein, we present the first evaluation of cationic dendrimers based on 2,2-bis(methylol)propionic acid (bis-MPA) as nonviral vectors for transfection of short interfering RNA (siRNA) in cell cultures. The study encompassed dendrimers of generation one to four (G1-G4), modified to bear 6-48 amino end-groups, where the G2-G4 proved to be capable of siRNA complexation and protection against RNase-mediated degradation. The dendrimers were nontoxic to astrocytes, glioma (C6), and glioblastoma (U87), while G3 and G4 exhibited concentration dependent toxicity towards primary neurons. The G2 showed no toxicity to primary neurons at any of the tested concentrations. Fluorescence microscopy experiments suggested that the dendrimers are highly efficient at endo-lysosomal escape since fluorescently labeled dendrimers were localized specifically in mitochondria, and diffuse cytosolic distribution of fluorescent siRNA complexed by dendrimers was observed. This is a desired feature for intracellular drug delivery, since the endocytic pathway otherwise transfers the drugs into lysosomes where they can be degraded without reaching their intended target. siRNA-transfection was successful in C6 and U87 cell lines using the G3 and G4 dendrimers followed by a decrease of approximately 20% of target protein p42-MAPK expression.

  • 422.
    Sterner, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    POLYMER EXTRACTION AND UTILIZATION OF BROWN ALGAL BIOMASS2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Akvakultur har världsförändringspotential. Havets vidder är enorma och akvatiska odlingar påverkar miljön och den lokala ekologin långt mindre än jordbruket på land. I algernas domäner finns det rikligt med näring, vatten och tillgängligt solljus, men det är en konstant brist på fria ytor att växa på. När en algfarm förser algerna med utrymmet på ett helt rep och de får växa ostört, då växer det så det knakar. I det svenska forskningsprojektet Seafarm, som finansierat detta arbete, ger ett 4500 m långt rep 15 kg/m Saccharina latissima brunalger, vid varje skörd. Den här avhandlingen är en studie i algbiomassabearbetning och hur nya material av biomassan kan framställas. Alginat, som är en av algens beståndsdelar, och en naturlig laddad polymer, är den röda tråden genom hela avhandlingen, både i början, där fokus låg på extraktion och i slutet där olika alginatmaterial preparerades.

    I en inledande studie undersöktes effekten av kelatering vid extraktionerna. Salter med olika jonkelateringsförmåga användes i extraktioner, och användningen av natriumcitrat visade sig vara mest fördelaktigt i extraktionslösningar för att utvinna alginat.

    Med utgångspunkt i den inledande extraktionsprocessen utvecklades en ny cyklisk process då natriumcitratlösningen regenererades och återanvändes. Den nya processen utvärderades och en intressant effekt var att den möjliggjorde utvinning av alginat i flera olika fraktioner med olika uronsyrasammansättning (de två byggstenarna i alginat). Denna fraktionering skalades upp för att renframställa tillräckligt med alginat för att kunna testa fraktionerna in en materialstudie.

    I materialstudien gjordes geltrådar genom att extrudera alginat ner i en kalciumkloridlösning, där de gelade. Några geler exponerades också för aluminiumklorid. Trådarna dragprovades och resultaten visade ett intressant samband mellan gelstyrka och uronsyrasammansättning vilket inspirerade oss till att göra en teoretisk studie för att klarlägga ursprunget till trenden.

    Geltrådar gjordes också till tunna fibrer i en process där de först extruderades, sedan drogs ut i olika saltlösningar och slutligen torkades. När fibrerna dragprovades visade det sig att de hade hög elasticitetsmodul och hög dragstyrka. Dragstyrkan var i samma storleksordning som t.ex. hampafiber eller bomullsfiber.

    En kompatibilisator utvecklades för att anpassa ytenergin hos alginatfibrerna och i en riktning att för att likna plaster som brukar fiberförstärkas. Kompatibilisatorn framställdes av linolja som ympades med maleinsyraanhydrid för att fästa laddade grupper på den. Denna nya komponent inkorporerades i fibrer tillsammans med alginat och fibrerna dragprovades.

    Publikationen är tillgänglig i fulltext från 2019-12-26 13:37
  • 423.
    Sterner, Martin
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Alginate with maleic anhydride grafted linseed oil as compatibilizerManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Linseed oil was graft modified with maleic anhydride and introduced into alginate by coextrusion,producing filaments which are targeted to work as interphase compatibilizersbetween alginate and hydrophobic matrices. Modified oil was produced by a straightforwardair catalyzed radical chemistry based grafting of maleic anhydride onto the oil backbone.Additional esterification with dodecanol was also investigated. The structures of the modifiedoils were verified with 2D-NMR. Modified oil was blended with alginate and extruded intoCaCl2 forming thin filaments with diameters in the 130 - 260 m range. The impact of oilintegration into the alginate filaments and the effects of various modification chemistries onthe filament tensile properties were assessed with special emphasis on stress-at-break andcompared to values predicted by an empirical model relating the ‘stress to alginateconcentration’-ratio to prevailing conditions during filament drawing. Analogous alginatefilaments were prepared with chloric-, oxalic- and phytic acid calcium salts for comparisonwith alginate-oil hybrids to reveal the induced impact, with respect to composition andcharge, on the tensile performance.

  • 424.
    Sterner, Martin
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    High-Performance Filaments from Fractionated Alginate by Polyvalent Cross-Linking: A Theoretical and Practical Approach2018Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, nr 8, s. 3311-3330Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of alginate fractions with significant differences in molecular weight and uronic acid compositions were produced by consecutive fractionation and converted to thin and strong cross-linked polymer filaments via extrusion into calcium, aluminum, or polyaluminum (PolyAl) polyvalent solutions followed by drawing and drying. Models were elaborated to relate the alginate uronic acid composition to the tensile performance in both the wet gel filament and the dry filament states. The wet gel model was compared to the theory of the unidirectional elongation of charged polyelectrolyte gels based on the classical rubber elasticity of dilated polymer networks, extended to include the contributions of non-Gaussian chain extensions and the effect of electrostatic interactions. The theory of equilibrium swelling pressure was applied to describe the observed shrinkage of the alginate gels following immersion in a polyvalent solution. Congruent with the theoretical model of charged gels, the tensile performance of the gel filaments prepared from CaCl2 depended on the compositional ratio of guluronic acid dyads in the alginate fraction multiplied by the alginate concentration, while the tensile behavior of wet gel filaments prepared by AlCl3 instead resembled that of elastic solid materials and depended only on the alginate concentration. The dry filament tensile properties were greatly dependent on the preparation conditions, particularly the ratio of stress to alginate concentration and the nature of the ions present during filament drawing. The PolyAl solution effectively caused shrinkage of alginate to a strong extent, and the resulting filaments behaved as highly stiff materials able to withstand stresses of approximately 500 MPa and having elastic moduli as high as 28 GPa.

  • 425.
    Sterner, Martin
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Multicomponent fractionation of Saccharina latissima brown algae using chelating salt solutions2016Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 28, nr 4, s. 2561-2574Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A fractionation strategy for Saccharina latissima algal biomass was developed utilizing chelating extraction salt solutions to mediate the liberation of algal components. Alginate, cellulose, laminarin, mannitol, protein, and inorganic salts were quantified in the fractions to reveal their individual dissolution patterns. Chelation power was identified as a key parameter for liberating alginate and increasing the yield of extracted components. The most efficient fractionation was achieved using aqueous sodium citrate as the extraction solution, producing an alginate-rich soluble fraction and a salt-poor insoluble fraction rich in cellulose and protein. Extractions at decreased pH were shown to be beneficial because they decreased the M/G ratio of the extracted alginate and concentrated the protein in the insoluble fraction from which it can easily be recovered; these effects could be achieved by switching the traditional sodium carbonate extraction solution with salts that have chelation capacity at lower pH. A cyclic extraction demonstrated that the sodium citrate solution can be reused for multiple alginate extractions with the buildup of the concentrations of other valuable components in the solution.

  • 426.
    Sterner, Martin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ribeiro, Mauricio Sodre
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Gröndahl, Fredrik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Cyclic fractionation process for Saccharina latissima using aqueous chelator and ion exchange resin2017Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 29, nr 6, s. 3175-3189Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new approach to process Saccharina latissima algal biomass was developed using sodium citrate and a polyvalent cation-specific resin to sequentially extract the alginate into several usable fractions. The fractionation was performed in a cyclic manner, utilizing a stepwise removal of the native polyvalent ions present in the algae to isolate fractions of alginate with different solubility in the presence of these ions. Sodium citrate was used in different concentrations in the extraction solution to remove polyvalent cations to adjust the alginate liberation while AMBERLITE IRC718 resin was added to further remove these ions and regenerate the extraction solution. Alginate was recovered by acid precipitation and analyzed for its uronic acid composition and molecular weight, and the carbohydrate compositions of the insoluble and soluble parts of the algal biomass residue were determined. Finally, the fractionation method was assessed with a life cycle analysis to determine the energy and water efficiency as well as the greenhouse gas emissions and the results were compared to conventional alkaline extraction. The results indicate that the energy and water use as well as the emissions are considerably lower for the cyclic extraction in comparison with the conventional methods.

  • 427.
    Sthoer, Adrien
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Adams, Ellen
    Ohio State University.
    Sengupta, Sanghamitra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Corkery, Robert
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Allen, Heather
    Tyrode, Eric
    KTH.
    La3+ and Y3+ interactions with the carboxylic acid moiety at theliquid/vapor interface: identification of binding complexes, chargereversal, and detection limits.Manuskript (preprint) (Övrigt vetenskapligt)
  • 428.
    Svärd, Antonia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Biopolymers and materials from rapeseed straw biorefining2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Rapeseed straw was fractionated through a hydrothermal process into its hemicellulose, lignin and cellulose components. In the first step, hemicellulose-rich fractions were extracted. Xylan-rich fractions with high molecular weight, 30,000 – 50,000 g/mol, were obtained at 110 °C and 1.5 M NaOH. Neutral and acidic conditions yielded extract rich in glucomannan with co-extracted xylan and lignin.After hemicellulose extraction, the straw was subjected to a soda cooking step where the straw was delignified and lignin solubilized. Two cooking times were evaluated in this step. A longer cooking time resulted in a lignin-rich precipitate and a cellulose pulp with a lower content of lignin compared with the shorter cooking time. Analysis showed rapeseed straw lignin consists of syringyl and guaiacyl aromatic structures. Peroxide bleaching of the pulp decreased the lignin content in the cellulose pulp further. Cellulose nanoparticles (CNF and CNC) were isolated from the bleached pulp. The CNF fraction was heterogenous in size while the CNC fraction was more homogenous in size with rod like aspects. Both were highly crystalline, with good thermal stability and high aspect ratio.Thin free-standing films of xylan were cast from water solution with mechanical integrity and very high strain-at-break > 80% even without added plasticizer.A surface modification process was developed where xylan was first pre-activated in alkali. This was followed by an etherification coupling reaction with glycidyl methacrylate and subsequently grafted by interfacial free radical graft polymerization with octadecyl acrylate chains. The resulting grafted xylan became hydrophobic and gained a thermoplastic behavior. It was blended with PCL matrix via melt-extrusion. The grafted xylan was homogeneously distributed within the biocomposite and the PCL matrix was reinforced while at the same time preserving the ability to elongate to tensile strains > 500%. Analogous biocomposites with unmodified xylan in a PCL matrix resulted in heterogenous mixtures and brittle tensile properties.

  • 429.
    Svärd, Antonia
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Brännvall, E.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Modified and thermoplastic rapeseed straw xylan: A renewable additive in PCL biocomposites2018Ingår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 119, s. 73-82Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Xylan extracted from rapeseed straw was chemically modified to gain hydrophobic and thermoplastic properties via macroinitiator formation followed by a free radical grafting-from polymerization with octadecyl acrylate. Biocomposites were then prepared by incorporation of 5 or 20% (w/w) rapeseed straw xylan into a poly(epsilon-caprolactone) (PCL) matrix by melt extrusion. The grafted xylan was homogeneously distributed within the biocomposite and reinforced the PCL matrix while at the same time preserving the ability to elongate to tensile strains > 500%. Analogous biocomposites made from unmodified xylan in a PCL matrix resulted in heterogeneous mixtures and brittle tensile properties.

  • 430.
    Svärd, Antonia
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Moriana, Rosana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. School of Engineering Science, HIS-University Skövde, Högskolevägen, Skövde.
    Brannvall, Elisabet
    RISE Bioecon, Box 5604, SE-11486 Stockholm, Sweden..
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Rapeseed Straw Biorefinery Process2019Ingår i: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 7, nr 1, s. 790-801Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A rapeseed straw biorefinery process was demonstrated with more than 50% of the straw recovered as products. Xylan with a weight-average molecular weight of 56 760 g/mol was extracted in an alkaline step. The straw residue was subjected to soda pulping, resulting in cellulose-rich fibers and a lignin-rich liquid fraction. The lignin contained syringyl and guaiacyl aromatic structural units in a 1/0.75 ratio. The cellulose pulp was bleached, resulting in a cellulose fraction of 85% purity and a crystallinity index (CI) of 83%. Two grades of nanocellulose, CNF and CNC, were isolated from the bleached pulp. The CNF was very heterogeneous in size with an average diameter of 4 nm and an average length of 1177 nm. The CNC had an average diameter of 6 nm and an average particle length of 193 nm. CNF and CNC had good thermal stability and an aspect ratio of 294 and 32, respectively.

  • 431.
    Svärd, Antonia
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sterner, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bioplastics and composites from plant heteropolysaccharides2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 432.
    Swensson, Beatrice
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gray, Derek G.
    McGill Univ, Dept Chem, Pulp & Paper Bldg,3420 Univ St, Montreal, PQ H3A 2A7, Canada..
    In Situ Preparation of Silver Nanoparticles in Paper by Reduction with Alkaline Glucose Solutions2018Ingår i: ACS OMEGA, ISSN 2470-1343, Vol. 3, nr 8, s. 9449-9452Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Percolation of contaminated water through paper sheets containing silver nanoparticles is a promising way to provide emergency drinking water. The silver nanoparticles are deposited by the in situ reduction of silver nitrate on the cellulose fibers of an absorbent blotting paper sheet. Sodium borohydride has been used as the reductant but is toxic and expensive. Glucose is a benign alternative but is much less reactive. In this note, we demonstrate an improved way to produce silver nanoparticles in paper sheets by adding sodium hydroxide to the glucose reductant. The silver content of the sheets, measured by diffuse reflectance spectroscopy, was around 2-3 mg of silver per gram of dry paper. This was sufficient to reduce the concentration of a model Escherichia coli suspension after percolation through the sheet.

  • 433.
    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.
    Enzymatic Hydrolysis of Tertiary Amide Bonds by anti Nucleophilic Attack and Protonation2018Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 83, nr 21, s. 13543-13548Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The molecular mechanisms conferring high resistance of planar tertiary amide bonds to hydrolysis by most enzymes have remained elusive. To provide a chemical explanation to this unresolved puzzle, UB3LYP calculations were performed on an active site model of Xaa-Pro peptidases. The calculated reaction mechanism demonstrates that biocatalysts capable of tertiary amide bond hydrolysis capitalize on anti nucleophilic attack and protonation of the amide nitrogen, in contrast to the traditional syn displayed by amidases and proteases acting on secondary amide bonds.

  • 434.
    Söderberg, Daniel
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Hedhammar, My
    KTH, Skolan för bioteknologi (BIO), Centra, Centrum för Bioprocessteknik, CBioPT. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinteknologi.
    Mittal, Nitesh
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Jansson, Ronnie
    Spiber AB, Stockholm, Sweden..
    Widhe, Mona
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Benselfelt, Tobias
    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.
    Håkansson, Karl
    RISE Bioecon, Stockholm, Sweden..
    Lundell, Fredrik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Bioactive composites of cellulose nanofibrils and recombinant silk proteins2019Ingår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Artikel i tidskrift (Övrigt vetenskapligt)
  • 435. Tabbara, A.
    et al.
    Grigorescu, D.
    Yassin, Mohammed A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Fristad, I.
    Evaluation of apical dimension, canal taper and maintenance of root canal morphology using XP-endo shaper2019Ingår i: Journal of Contemporary Dental Practice, Vol. 20, nr 2, s. 136-144Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To evaluate the shaping ability of the XP-endo shaper file system in maxillary molars, representing root canals with variation in morphology. Materials and methods: Twenty maxillary molars were instrumented according to recommended protocols. Pre- and postoperative microcomputed tomography (CT) scans were performed and the root canals classified according to canal type and curvature. The volume change, number of strokes needed to prepare the canals and the size of the 0.04-tapered gutta-percha cone that was adapted in the canal were recorded. Results: XP-endo shapercreated a significant change in volume after instrumentation in all the canals, with the biggest change found in the DB canals, followed by the MB1 and the P canals, both at full length and in the apical 4 mm. The number of strokes needed to achieve working length and final shape did not differ between the various root canals. Although not significant, the number of strokes needed to prepare the root canal increased with severity of the curvature, but the severity of the curvature did not result in increased removal of dentin in the apical 4 mm. It was possible to achieve a final root canal size where a 0.04-tapered gutta-percha cone could be adapted. Conclusion: The XP-endo shaper was a safe and effective instrument to achieve a root canal preparation of at least size 30 and a 0.04 taper. Clinical significance: The clinical performance of XP-endo shaper was to some extent dependent on preoperative volume and curvature of the root canal.

  • 436.
    Tagami, Ayumu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. Nippon Paper Industries Co., Ltd. .
    Towards molecular weight-dependent uses of kraft lignin2018Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    There is growing demand for a more efficient use of polymers that originate from renewable feedstocks due to the depleting supply of fossil fuels, based on economic and environmental reasons. As a result, lignin has attracted renewed interest as a resource for various bioproducts. Lignin is a natural biopolymer with a high carbon content and is composed of aromatic moieties, with a high level of polar functionalities. This makes it a unique precursor for certain high-value applications, such as in biofuels, bioplastics, composite materials, carbon fibers and activated carbons and as a source of phenolic monomers and fine chemicals.

    Industrial lignins are formed as byproducts of pulping processes (such as kraft, sulfite or alkaline pulping) or result from the biorefining process, where carbohydrates are used for sugar production. Lignin’s intrinsic structure is significantly modified during the processing of lignocellulose, resulting in the formation of more diverse, condensed and less reactive raw materials. Since molecular mass and polydispersity are the most important parameters affecting the chemical reactivity and thermal properties of lignin, additional process steps to improve the quality of crude technical lignins, including kraft lignin, are needed. Solvent extraction is a potentially useful technique for further improving the polydispersity of technical lignins.

    This work summarizes the impact of solvent fractionation on the chemical structure, antioxidant activity, heating value, and thermal and sorption properties of industrial hardwood and softwood kraft lignins. The purpose was to understand the correlation between certain structural features in the lignin fractions and their properties to select the appropriate solvent combinations for specific applications of lignin raw materials.

    Four common industrial solvents, namely, ethyl acetate, ethanol, methanol and acetone, in various combinations were used to separate both spruce and eucalyptus kraft lignins into fractions with lower polydispersities. Gel-permeation chromatography analysis was used to evaluate the efficiency of the chosen solvent combination for lignin fractionation. The composition and structure of the lignin material were characterized by elemental analysis, analytical pyrolysis (Py-GC/MS/FID) and 31P NMR spectroscopy. The thermal properties of the lignin samples were studied by thermogravimetric analysis. Proximate analysis data (ash, volatile components, organic matter and fixed carbon) were obtained through the direct measurement of weight changes during the analysis, while the high heating values (in MJ/kg) were calculated according to equations suggested in the literature. The sorption properties of fractionated kraft lignins were studied with respect to methylene blue dye.

    Additionally, lignin fractions with different molecular weights (and therefore various chemical structures) that were isolated from both softwood and hardwood kraft lignins were incorporated into a tunicate cellulose nanofiber (CNF)-starch mixture to prepare 100% bio-based composite films. The aim was to investigate the correlation between lignin diversity and film performance. The transmittance, density and thermal properties of the films were investigated, as were their mechanical properties, including the tensile stress and Young’s modulus.

    This part of the study addressed the importance of lignin diversity on composite film performance, which could be helpful for tailoring lignin applications in bio-based composite materials based on the material’s specific requirements.

  • 437.
    Tagami, Ayumu
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gioia, Claudio
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Lauberts, Maris
    Latvian State Inst Wood Chem, 27 Dzerbenes Str, LV-1006 Riga, Latvia..
    Budnyak, Tetyana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Moriana, Rosana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Solvent fractionation of softwood and hardwood kraft lignins for more efficient uses: Compositional, structural, thermal, antioxidant and adsorption properties2019Ingår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 129, s. 123-134Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work summarizes the impact of solvent fractionation on the chemical structure, antioxidant activity, heating values, and thermal and adsorption properties of industrial hardwood and softwood kraft lignins. The aim of the research was to develop a simple approach for obtaining lignin fractions with tailored properties for applications in certain materials. Four common industrial solvents, namely, ethyl acetate, ethanol, methanol and acetone, in various combinations, were found to be efficient for separating spruce and eucalyptus kraft lignins into fractions with low polydispersities. The ethanol fraction of spruce and the ethyl acetate fraction of eucalyptus afforded the highest yields. Gel-permeation chromatography analysis was used to evaluate the efficiency of the chosen solvent combination for lignin fractionation. The composition and structure of the lignin material was characterized by elemental analysis, analytical pyrolysis (Py-GC/MS/FID) and P-31 NMR spectro-scopy. The thermal properties of the lignin samples were studied using thermogravimetric analysis. Proximate analysis data (ash, volatile components, organic matter and fixed carbon) was obtained through the direct measurement of weight changes in each experimental curve, and the high heating values (in MJ/kg) were calculated according to equations suggested in the literature. The adsorption properties of fractionated kraft lignins were studied using methylene blue dye. The correlations observed between molecular weight, composition and functionality and the thermal, radical scavenging and adsorption properties of the lignin fractions provides useful information for selecting the appropriate solvent combinations for specific applications of lignin raw materials (including their use as antioxidants, biofuels or sorbents in water treatment processes).

  • 438.
    Tagami, Ayumu
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. Nippon paper Industries Co., Ltd..
    Gioia, Claudio
    University of Bologna.
    Lauberts, Maris
    Latvian State Institute of Wood Chemistry.
    Budnyak, Tetyana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Moriana, Rosana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. HIS-University of Skövde.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Solvent fractionation of softwood and hardwood kraft lignins for more efficient uses: compositional, structural, thermal, antioxidant and sorption propertiesManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    This work summarizes the impact of solvent fractionation on the chemical structure, antioxidant activity, heating values, and thermal and sorption properties of industrial hardwood and softwood kraft lignins. The aim was to develop a simple approach for the obtaining of lignin fractions with a tailored properties for the certain material applications.  Four common industrial solvents, namely, ethyl acetate, ethanol, methanol and acetone, in various combinations efficiently separated both spruce and eucalyptus kraft lignins into fractions with low polydispersities. The ethanol fraction of spruce and the ethyl acetate fraction of eucalyptus afforded the highest yields. Gel-permeation chromatography analysis was used to evaluate the efficiency of the chosen solvent combination for lignin fractionation. The composition and structure of the lignin material was characterized by elemental analysis, analytical pyrolysis (Py-GC/MS/FID) and 31P NMR spectroscopy. The thermal properties of the lignin samples were studied by thermogravimetric analysis. Proximate analysis data (ash, volatile components, organic matter and fixed carbon) were obtained through the direct measurement of weight changes in each experimental curve, and the high heating values (in MJ/kg) were calculated according to equations suggested in the literature. The sorption properties of fractionated kraft lignins were studied with respect to methylene blue dye. The clear correlation between certain structural features in the lignin fractions and the properties of the lignin provides useful information for selecting the appropriate solvent combinations for specific applications of lignin raw materials, including as antioxidants, biofuels or sorbents in water treatment processes.

  • 439.
    Tagami, Ayumu
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. Nippon paper Industries Co., Ltd. .
    Zhao, Yadong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Dobele, Galina
    Latvian State Institute of Wood Chemistry.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi. KTH, Tidigare Institutioner (före 2005), Pappers- och massateknik.
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lignin-modified tunicate cellulose nanofiber (CNF)-starch composites: impact of lignin diversity on film performanceManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Lignin fractions having different molecular weights and varied chemical structures isolated from kraft lignins of both softwood and hardwood via a sequential solvent fractionation technique were incorporated into a tunicate cellulose nanofibers (CNF) - starch mixture to prepare 100% bio-based composite films. The aim was to investigate the correlation between lignin diversity and film performance. It was confirmed that lignin’s distribution in the films was dependent on the solvents used for fractionation (acetone > methanol > ethanol > ethyl acetate) and influenced the optical properties of the films. The -OH group content and molecular weight of lignin were positively related to film density. In general, the addition of lignin fractions led to the thermal stability decrease and the Young's modulus increase of the composite films. The modulus of the films was found to decrease as the molecular weight of lignin increased, and a higher amount of carboxyl and phenolic -OH groups in the lignin fraction resulted in films with higher stiffness. The thermal analysis showed higher char content formation for lignin-containing films in a nitrogen atmosphere with increased molecular weight. In an oxygen atmosphere, the phenol contents, saturated side chains and short chain structures of lignin had impacts on the maximum decomposition temperature of the films, confirming the positive relationship between the antioxidant ability of lignin and thermo-oxidative stability of the corresponding film. This study addresses the importance of lignin diversities on composite film performance, which could be helpful for tailoring lignin’s applications in bio-based materials based on their specific characteristics.

  • 440.
    Tian, Weiqian
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Vahid Mohammadi, Armin
    Auburn Univ, Dept Mech & Mat Engn, Auburn, AL 36849 USA..
    Wang, Zhen
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ouyang, Liangqi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Beidaghi, Majid
    Auburn Univ, Dept Mech & Mat Engn, Auburn, AL 36849 USA..
    Hamedi, Mahiar M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Layer-by-layer self-assembly of pillared two-dimensional multilayers2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 2558Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report Layer-by-Layer (LbL) self-assembly of pillared two-dimensional (2D) multilayers, from water, onto a wide range of substrates. This LbL method uses a small molecule, tris(2-aminoethyl) amine (TAEA), and a colloidal dispersion of Ti3C2Tx MXene to LbL self-assemble (MXene/TAEA)(n )multilayers, where n denotes the number of bilayers. Assembly with TAEA results in highly ordered (MXene/TAEA)(n) multilayers where the TAEA expands the interlayer spacing of MXene flakes by only similar to 1 angstrom and reinforces the interconnection between them. The TAEA-pillared MXene multilayers show the highest electronic conductivity of 7.3 x10(4) S m(-1) compared with all reported MXene multilayers fabricated by LbL technique. The (MXene/ TAEA)(n) multilayers could be used as electrodes for flexible all-solid-state supercapacitors delivering a high volumetric capacitance of 583 F cm(-3) and high energy and power densities of 3.0 Wh L-1 and 4400 W L-1, respectively. This strategy enables large-scale fabrication of highly conductive pillared MXene multilayers, and potentially fabrication of other 2D heterostructures.

  • 441.
    Tian, Weiqian
    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.
    VahidMohammadi, Armin
    Auburn Univ, Dept Mech & Mat Engn, Auburn, AL 36849 USA..
    Reid, Michael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wang, Zhen
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi. KTH Royal Inst Technol, Dept Fibre & Polymer Technol, Tekn Ringen 56, S-10044 Stockholm, Sweden..
    Ouyang, Liangqi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Erlandsson, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Pettersson, Torbjörn
    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. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Beidaghi, Majid
    Auburn Univ, Dept Mech & Mat Engn, Auburn, AL 36849 USA..
    Hamedi, Mahiar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Multifunctional Nanocomposites with High Strength and Capacitance Using 2D MXene and 1D Nanocellulose2019Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, artikel-id 1902977Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The family of two-dimensional (2D) metal carbides and nitrides, known as MXenes, are among the most promising electrode materials for supercapacitors thanks to their high metal-like electrical conductivity and surface-functional-group-enabled pseudocapacitance. A major drawback of these materials is, however, the low mechanical strength, which prevents their applications in lightweight, flexible electronics. A strategy of assembling freestanding and mechanically robust MXene (Ti3C2Tx) nanocomposites with one-dimensional (1D) cellulose nanofibrils (CNFs) from their stable colloidal dispersions is reported. The high aspect ratio of CNF (width of approximate to 3.5 nm and length reaching tens of micrometers) and their special interactions with MXene enable nanocomposites with high mechanical strength without sacrificing electrochemical performance. CNF loading up to 20%, for example, shows a remarkably high mechanical strength of 341 MPa (an order of magnitude higher than pristine MXene films of 29 MPa) while still maintaining a high capacitance of 298 F g(-1) and a high conductivity of 295 S cm(-1). It is also demonstrated that MXene/CNF hybrid dispersions can be used as inks to print flexible micro-supercapacitors with precise dimensions. This work paves the way for fabrication of robust multifunctional MXene nanocomposites for printed and lightweight structural devices.

  • 442.
    Tian, Weiqian
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    VahidMohammadi, Armin
    Auburn Univ, Dept Mech & Mat Engn, Auburn, AL 36849 USA..
    Wang, Zhen
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Ouyang, Liangqi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Beidaghi, Majid
    Auburn Univ, Dept Mech & Mat Engn, Auburn, AL 36849 USA..
    Hamedi, Mahiar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Layer-by-layer assembly of pillared MXene multilayers for high volumetric energy storage and beyond2019Ingår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Artikel i tidskrift (Övrigt vetenskapligt)
  • 443.
    Torron, Susana
    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.
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Fogelström, Linda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hult, Karl
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi.
    Martinelle, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi.
    Telechelic polyesters and polycarbonates prepared by enzymatic catalysis2017Ingår i: Handbook of Telechelic Polyesters, Polycarbonates, and Polyethers, Pan Stanford Publishing Pte. Ltd. , 2017, s. 29-64Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    The majority of polyesters and polycarbonates are traditionally synthesized through conventional metal-based catalysis. Although effective, due to environmental concerns, their substitution for other more environmentally friendly alternatives has received increasing interest during the last decades. The search for catalytic systems that also allow milder reaction conditions has been intensified, owing to 30the unwanted side reactions, for example, backbone scissoring, that the metal-based catalysts may cause [1]. In this context, enzymes are anticipated as suitable alternatives [2,3,4,5,6,7,-8]. 

  • 444.
    Träger, Andrea
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Carlmark, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wågberg, 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.
    Interpenetrated Networks of Nanocellulose and Polyacrylamide with Excellent Mechanical and Absorptive Properties2018Ingår i: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 303, nr 5, artikel-id 1700594Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Composites based on interpenetrating networks (IPNs) of cellulose nanofibril (CNF) aerogels and polyacrylamide are prepared and exhibit robust mechanical, water retaining, and re-swelling capacities. Furthermore, their swelling behavior is not affected by an increased ionic strength of the aqueous phase. These unprecedented IPNs combine the water retaining capacity of the polyacrylamide with the mechanical strength provided by the CNF aerogel template. The CNF aerogel/polyacrylamide composites exhibit a compressive stress at break greater than 250% compared with a neat polyacrylamide hydrogel. Furthermore, the composites retain their wet compression properties after drying and re-swelling, whereas the neat polyacrylamide hydrogels fail at a significantly lower stress and strain after drying and re-swelling. These composite materials highlight the potential of CNF aerogels to strengthen the mechanical properties and reduce the number of fracture defects during the drying and re-swelling of a hydrogel. These composites show the potential of being optimized for a plethora of applications, especially in the hygiene field and for biomedical devices.

  • 445.
    Träger, Andrea
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Klein, Gregor
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Carrick, Christopher
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Pettersson, Torbjörn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Pendergraph, Samuel A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Carlmark, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. RISE Research Institutes of SwedenStockholmSweden.
    Macroscopic cellulose probes for the measurement of polymer grafted surfaces2019Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, nr 3, s. 1467-1477Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A synthesis protocol was identified to produce covalent grafting of poly(dimethyl siloxane) from cellulose, based on prior studies of analogous ring opening polymerizations. Following this polymer modification of cellulose, the contact adhesion was anticipated to be modified and varied as a function of the polymer molecular mass. The synthetic details were optimized for a filter paper surface before grafting the polymer from bulk cellulose spheres. The adhesion of the unmodified and grafted, bulk cellulose spheres were evaluated using the Johnson-Kendall-Roberts (JKR) theory with a custom build contact adhesion testing setup. We report the first example of grafting poly(dimethyl siloxane) directly from bulk cellulose using ring opening polymerization. For short grafting lengths, both the JKR work of adhesion and the adhesion energy at the critical energy release rate (G(c)) were comparable to unmodified cellulose beads. When polymer grafting lengths were extended sufficiently where chain entanglements occur, both the JKR work of adhesion and G(c) were increased by as much as 190%. Given the multitude of options available to graft polymers from cellulose, this study shows the potential to use this type of cellulose spheres to study the interaction between different polymer surfaces in a controlled manner. [GRAPHICS] .

  • 446. Turner, C.
    et al.
    Werner, Oskar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Superhydrophobic surfaces produced by supercritical fluid technology2011Ingår i: Environmental Division - Core Programming Topic at the 2011 AIChE Annual Meeting, AIChE , 2011, s. 556-560Konferensbidrag (Refereegranskat)
  • 447. Turner, C.
    et al.
    Werner, Oskar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Superhydrophobic surfaces produced by supercritical fluid technology2011Ingår i: 1st Annual World Congress on Sustainable Engineering 2011 - Topical Conference at the 2011 AIChE Annual Meeting, AIChE , 2011, s. 427-431Konferensbidrag (Refereegranskat)
  • 448.
    Unge, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. ABB Corporate Research .
    Identification of structural criteria for valence state localization in linear alkanes2018Ingår i: 2018 IEEE 2nd International Conference on Dielectrics, ICD 2018, Institute of Electrical and Electronics Engineers Inc. , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electronic charge transport in polyethylene is via a hopping mechanism. Theoretically hopping transport in polymers can be studied using kinetic Monte Carlo and Marcus Theory. An essential input to the charge transport simulation is to describe how the electronic states localize. Holes in polyethylene localized along the polymer backbone. In the amorphous phase the electronic states are localized to segments of the polymers. No structural criteria is available that determine how electronic states will distribute along the polymer backbone. Here we have applied quantum chemistry to study conformations of linear alkanes in order to identify structural criteria for valence states localization. Two subsequent gauche formations is identified as one localization criterion.

  • 449. Vanderfleet, O. M.
    et al.
    Reid, Michael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bras, J.
    Heux, L.
    Godoy-Vargas, J.
    Panga, M. K. R.
    Cranston, E. D.
    Insight into thermal stability of cellulose nanocrystals from new hydrolysis methods with acid blends2019Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, nr 1, s. 507-528Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract: This study provides insight into the thermal degradation of cotton cellulose nanocrystals (CNCs) by tuning their physico-chemical properties through acid hydrolysis using blends of phosphoric and sulfuric acid. CNCs isolated by sulfuric acid hydrolysis are known to degrade at lower temperatures than CNCs hydrolyzed with phosphoric acid; however, the reason for this change is unclear. Although all CNCs are inherently relatively thermally stable, their application in polymer composites and liquid formulations designed to function at high temperatures could be extended if thermal stability was improved. Herein, thermogravimetric analysis was carried out on six types of CNCs (in both acid and sodium form) with different surface chemistry, surface charge density, dimensions, crystallinity and degree of polymerization (DP) to identify the key properties that influence thermal stability of nanocellulose. In acid form, CNC surface charge density was found to be the determining factor in thermal stability due to de-esterification and acid-catalyzed degradation. Conversely, in sodium form, surface chemistry and charge density had a negligible effect on the onset of thermal degradation, however, the DP of the cellulose polymer chains highly influenced stability. The presence of more reducing ends in lower DP nanocrystals is inferred to facilitate thermally-induced depolymerization and degradation. Degree of crystallinity did not significantly affect CNC thermal stability. Studying CNCs produced from single or blends of acids (and changing the counterion) elucidated the thermal behavior of cellulose and furthermore demonstrated new routes to tailor CNCs thermal and colloidal stability. Graphical abstract: [Figure not available: see fulltext.].

  • 450.
    Vanderfleet, Oriana
    et al.
    McMaster Univ, Chem Engn, Mississauga, ON, Canada..
    Reid, Michael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bras, Julien
    CNRS, Grenoble INP Pagora, St Martin Dheres, France..
    Heux, Laurent
    CNRS, CERMAV, Grenoble 09, France..
    Godoy, Jazmin
    Schlumberger Technol Corp, Sugar Land, TX USA..
    Panga, Mohan
    Schlumberger Technol Corp, Sugar Land, TX USA..
    Cranston, Emily
    McMaster Univ, Chem Engn, Mississauga, ON, Canada..
    Effects of degree of polymerization, surface chemistry, and surface charge density on cellulose nanocrystal thermal stability2019Ingår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Artikel i tidskrift (Övrigt vetenskapligt)
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