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  • 101.
    Karlsson, Josefin
    et al.
    KTH. Royal Inst Technol, S-10044 Stockholm, Sweden..
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Enarsson, Lars-Erik
    KTH.
    Wågberg, Lars
    KTH.
    CELL 283-Making biointeractive fibers: Buildup of antibacterial multilayers studied by QCM-D and SPAR2008Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 235Artikkel i tidsskrift (Annet vitenskapelig)
  • 102.
    Kasai, Wakako
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Morooka, Toshiro
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Fabrication and characterization of cellulosic material prepared by periodate oxidation from pulp2010Konferansepaper (Fagfellevurdert)
    Abstract [en]
    • Cellulose is the most abundant and sustainable natural resource on the earth, and biosynthesized as the major plant component. Main usage of Cellulose is structural materials such as pulp, paper and wood-based materials although cellulose has been used as the derivs. by chem. modifications. Recently, renewable resources are noted for their pos. aspects from an ecol. point of view. The aim of this research is to create high-value-added products from biomass based products such as pulp in order to develop the functional materials leading to new industrial applications. In this presentation, we try to prep. dialc. cellulose by periodate oxidn. from pulp and fabricate and characterize films from the deriv.

     

  • 103.
    Kasai, Wakako
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Morooka, Toshiro
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Mechanical properties of films made from dialcohol cellulose2011Inngår i: Proceedings of the 16th International Symposium on Wood, Fiber and Pulping Chemistry, ISWFPC: Vol. 1, 2011, s. 436-438Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Mechanicalpropertiesofdialcoholcellulosefilmsprepared by homogeneous periodate oxidation were studied. Dialdehydecellulosewith a high oxidation level (over 90%) was prepared by the oxidation for 12 hours in an aqueous solution of methylolcellulose. By reducing the dialdehydecellulosewith NaBR), water-solubledialcoholcellulosewhich has open ring structure at C2-C3 position was obtained. Thedialcoholcellulosewas characterized using NMR, FTIR and DSC. Thedialcoholcellulosegave a clear and transparentfilm, which was subjected both to tensile and DMA tests.

  • 104.
    Kasai, Wakako
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Morooka, Toshiro
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Mechanical properties of films made from dialcohol cellulose prepared by homogeneous periodate oxidation2014Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, nr 1, s. 769-776Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    2,3-Dialdehyde celluloses were prepared by homogeneous periodate oxidation in an aqueous solution of methylol cellulose. Since methylol cellulose stays dissolved in water for a certain time before decomposing gradually into regenerated cellulose, the oxidation reaction progressed homogeneously throughout the period. The resulting dialdehyde cellulose achieved an oxidation level of over 90 % in as little as 12 h. Reducing the dialdehyde celluloses with NaBH4 resulted in water-soluble dialcohol celluloses, which have an open-ring structure at the C2-C3 position. The dialcohol celluloses were characterized using nuclear magnetic resonance spectrometry, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The T-g of the products decreased with increasing oxidation levels. The products might be processable, and unique tensile properties were obtained by cutting the C2-C3 bonds in the glucopyranose rings. The dialcohol celluloses prepared using a cast method yielded clear and transparent films which showed unique mechanical properties by tensile tests depending on the values of oxidation level.

  • 105.
    Keyoumu, Ayiguli
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Sjödahl, Ragnar
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Henriksson, Gunnar
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Gellerstedt, Göran
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Continuous Nano- and Ultrafiltration of Kraft Pulping Black Liquor with Ceramic Filters: A method for lowering the load on the recovery boiler while generating valuable side-products2004Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 20, nr 2, s. 143-150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ceramic membranes coated with ZrO2 were used for the continuous separation of a well-defined low molecular weight lignin from softwood and hardwood kraft black liquors on a pilot scale. The membranes used had M-w cut-offs of 1000, 5000, and 15,000 Da, respectively. The flux (permeate flow) through the different membranes measured as L/(m(2 .)h) was studied by varying the inlet pressure and temperature. The black liquor lignins in the permeate from the filters were isolated and studied with GPC and UV spectroscopy. The low molecular weight lignin fraction was highly phenolic and could be polymerised by one-electron oxidation.

  • 106.
    Kittikorn, Thorsak
    et al.
    Prince Songkla Univ, Dept Mat Sci & Technol, Fac Sci, Hat Yai 90112, Thailand..
    Malakul, Raminatun
    Prince Songkla Univ, Dept Microbiol, Fac Sci, Hat Yai 90112, Thailand..
    Strömberg, Emma
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Enhancement of mechanical, thermal and antibacterial properties of sisal/polyhydroxybutyrate-co-valerate biodegradable composite2018Inngår i: JOURNAL OF METALS MATERIALS AND MINERALS, ISSN 0857-6149, Vol. 28, nr 1, s. 52-61Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lignocellulosic biocomposite is a promising biodegradable materials, though improvement of the interfacial adhesion between cellulose fibre and polymer matrix is still challenged. Therefore, this work investigated the effect of propionylation of sisal reinforced fibre in the sisal/polyhydroxybutyrate-co-valerate (PHBV) biocomposite. Propionylation involved esterification substitution of propionic anhydride to hydroxyl group of sisal fibre, where ester group (COOR) of propionylated fibre was successfully observed by Fourier transform Infrared spectroscopy (FTIR). Then mechanical and thermal properties were evaluated and biodegradation characteristics were assessed. The tensile strength and modulus of propionylated sisal/PHBV biocomposite were greater than unmodified sisal/PHBV, which revealed better compatibility at the interface. In addition, propionate moieties of sisal fibre could induce crystalline formation of PHBV, as determined by an increase of crystalline phase. The higher decomposition temperature (Td) and activation energy (Ea) of 155 kJ.mol(-1), determined by thermal gravimetric analyser (TGA), were strong confirmation of good thermal resistance of the propionylated sisal biocomposite. The storage modulus, as characterized by dynamic mechanical thermal analyser (DMTA), also revealed the improvement of stiffness. Bacterial growth tests evaluated the inhibition of bacterial growth on the PHBV biocomposites. It was clear that propionylation of sisal fibre decreased colonization of Staphylococcus aureus (SA) and Escherichia coli (E.coli).

  • 107.
    Kittikorn, Thorsak
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Chemical surface modification of empty fruit bunch oil palm fibre in PP biocomposites2009Konferansepaper (Annet vitenskapelig)
  • 108.
    Kittikorn, Thorsak
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Comparison of Water Uptake as Function of Surface Modification of Empty Fruit Bunch Oil Palm Fibres in PP Biocomposites2013Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, nr 2, s. 2998-3016Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Empty fruit bunch oil palm (EFBOP) fibres were surface modified by four different methods, propionylation, vinyltrimethoxy silanization, PPgMA dissolution modification, and PPgMA blending, and integrated into a polypropylene (PP) matrix. The designed biocomposites were subjected to an absorption process at different temperatures. Their water uptake behaviour was compared with the unmodified fibre biocomposites. An increased fibre content and temperature resulted in increased water uptake for all of the biocomposites. The biocomposites containing modified fibres showed a reduction in water uptake, rate of diffusion, sorption, and permeation in comparison with unmodified fibre composites. Comparing the 20 wt% fibre composites at ambient temperature, the performance in water absorption followed the sequence silanization < propionylation < PPgMA dissolution modification < PPgMA blending < no modification. Furthermore, the lowest water absorption was obtained from the silanized fibre/PP composite with 40% fibre content at ambient temperature. Dissolution or blending of PPgMA gave similar water uptake results. The reduction of diffusion, sorption, and permeation confirmed that the modification of fibres was potentially effective at resisting water penetration into the composites.

  • 109.
    Kittikorn, Thorsak
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Effect of surface modifications on microbial growth and biodegradation in sisal/PLA biocomposites2013Manuskript (preprint) (Annet vitenskapelig)
  • 110.
    Kittikorn, Thorsak
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Susceptibility to biodegradation by fungi for sisal/PLA and sisal/PHBV biocomposites2013Manuskript (preprint) (Annet vitenskapelig)
  • 111.
    Kittikorn, Thorsak
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    The effect of surface modifications on the mechanical and thermal properties of empty fruit bunch oil palm fibre PP biocomposites2012Inngår i: Polymers from Renewable Resources, ISSN 2041-2479, Vol. 3, nr 3, s. 79-100Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this work was to study the effect of chemical surface modifications on empty fruit bunch oil palm fibre/polypropylene composite properties. By FTIR spectra, propionylated fibre and PPgMA-modified fibre showed the presence of a carbonyl group of esters while vinyltrimethoxysilane-treated fibre showed a peak of silicate, confirming that the modifications were successful. PPgMAmodified fibre PP composite at fibre content 20% demonstrated the highest modulus of 0.71 GPa while the modulus of unmodified fibre PP composite was 0.56 GPa. By DSC analysis, PPgMA-modified fibre and vinyltrimethoxysilane-treated fibre PP composite at the same fibre content of 5% showed the highest crystallinity of 46% and 44% respectively whereas unmodified fibre PP composite showed a lower crystallinity of 38%. The DMTA analysis showed that after 60°C, the modified fibre PP composites exhibited a higher stiffness than pure polypropylene.

  • 112.
    Kittikorn, Thorsak
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material. Skövde University.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The mechanical properties of natural cellulosic fiber/biodegradable polymer biocomposites2011Inngår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC, 2011, s. 1330-1333Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim of this work was to investigate a methodology for the improvement of the mechanical properties of sustainable biodegradable biocomposites based on polylactide (PLA). Cellulosic fibre was incorporated as a reinforcing agent for improvement of the mechanical properties of the biocomposites. A coupling agent was synthesized and employed in order to enhance the interfacial adhesion of two components via a melt blending process. FT-IR spectra showed presences of specific functional groups of maleic anhydride on the backbone of the PLA after the grafting. The modulus of PLA was considerably raised after incorporation of the fibre. Furthermore, an addition of a coupling agent in PLA biocomposites was also able to remarkably increase the stiffness of the material.

  • 113.
    Kittikorn, Thorsak
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The mechanical properties of natural cellulosic fibre/biodegradable polymer biocomposites2011Inngår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC: Volume 2, 2011, s. 1330-1333Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Theaim of this work was to investigate a methodology fortheimprovement ofthemechanicalpropertiesof sustainablebiodegradablebiocompositesbased on polylactide (PLA).Cellulosicfibrewas incorporated as a reinforcing agent for improvement ofthemechanicalpropertiesofthebiocomposites. A coupling agent was synthesized and employed in order to enhancetheinterfacial adhesion of two components via a melt blending process. FT-IR spectra showed presences of specific functional groups of maleic anhydride onthebackbone ofthePLA afterthegrafting.Themodulus of PLA was considerably raised after incorporation ofthefibre. Furthermore, an addition of a coupling agent in PLAbiocompositeswas also able to remarkably increasethestiffness ofthematerial.

  • 114. Kopcke, Viviana
    et al.
    Ibarra, David
    Larsson, Per Tomas
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Optimization of enzymatic and chemical treatments to use Eucalyptus kraft pulp as dissolving pulp2010Inngår i: Polymers from Renewable Resources, ISSN 2041-2479, Vol. 1, nr 17, s. 34-Artikkel i tidsskrift (Fagfellevurdert)
  • 115.
    Köpcke, Viviana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ibarra, David
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Increasing accessibility and reactivity of paper grade pulp by enzymatic treatment for use as dissolving pulp2008Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, nr 4, s. 363-368Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

     In this study, the feasibility of using different kraft pulps as dissolving pulps for the viscose process was investigated. Two different bleached hardwood kraft pulps from eucalypt (Eucalyptus globulus) and birch (Betula pendula) were subjected to several enzymatic and chemical pretreatments in order to improve the accessibility and reactivity of the pulps and to reduce the hemicellulose content. Enzymatic treatments were carried out using a commercial monocomponent endoglucanase and a commercial xylanase. Chemical treatment consisted of an alkali extraction. The effects of these pretreatments on reactivity and viscosity were assayed. In both pulps, the endoglucanase enhanced the cellulose reactivity and reduced the viscosity. The sequential combination of xylanase and endoglucanase enhanced the positive effect of endoglucanase treatment alone for eucalypt but showed no major effect for birch. The addition of an alkali extraction step after the xylanase followed by endoglucanase treatment as a final step significantly reduced the hemicellulose content to 24% while the reactivity reached the value of a commercial dissolving pulp (65-70%). The viscosity, on the other hand, showed a considerably decrease.

  • 116.
    Köpcke, Viviana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ibarra, David
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Study on the feasibility of converting kraft pulps into dissolving pulps: accessibility and reactivity2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For the prodn. of cellulose derivs. raw material contg. high cellulose and low hemicellulose content is required and today's industrial state of the art is to use dissolving pulps produced by sulphite process or prehydrolisis kraft.  This work, in contrast, focuses on the study of two different paper-grade kraft pulps from hardwood - birch and eucalyptus -- and the possibility to use it as raw material for the prodn. of cellulose derivs.  There have been different studies that focus their investigations mainly on the decrease of the hemicellulose content.  The aspects of accessibility and reactivity of cellulose towards solvents and reagents, however, are investigated far less although being key parameters when a homogenous substitution is desired for the prodn. of cellulose derivs. of high quality.  In order to accomplish the requirements of a com. dissolving pulp, the kraft pulps were subjected to different enzymic treatments using com. enzymes, xylanase and monocomponent endoglucanase.  Reactivity (Fock) was notably improved and the hemicellulose content decreased down to com. typical dissolving pulp values.  Further on, the structural characteristics of the pulps will be studied by means of 13C-CP/MAS NMR and size exclusion chromatog. (SEC).

  • 117. Köpcke, Viviana
    et al.
    Ibarra, David
    Larsson, Per Tomas
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Feasibility study on converting paper-grade pulps to dissolving-grade pulps2010Konferansepaper (Fagfellevurdert)
  • 118.
    Köpcke, Viviana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ibarra, David
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Larsson, Per Tomas
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Optimization of treatment sequences for the production of dissolving pulp from birch kraft pulp2010Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 25, nr 1, s. 31-38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As a continuation of our work, the viability of converting paper-grade kraft pulps into dissolving-grade pulps, for several raw materials, has been presented. It has been demonstrated that a combination of an enzymatic treatment using a commercial xylanase followed by alkali extraction resulted in an efficient hemicellulose removal. Furthermore, the cellulose reactivity could be enhanced by an additional enzymatic treatment using a commercial monocomponent endoglucanase. As a result, pulps with the characteristics of those of a commercial dissolving pulp, in terms of hemicellulose content and cellulose reactivity, were obtained. The viscosity of the treated pulps, however, was significantly affected by the treatments; they present lower values than those suitable for the production of cellulose derivatives and regenerated cellulose. The pulps, on the other hand, contained mostly cellulose II, which may also affect the process. Therefore, as a continuation of this work, an optimization of the sequences of treatments as well as a study of the parameters involved was performed in order to overcome the low viscosity values and the presence of cellulose II. After the optimization, it was observed that the xylanase treatment could be replaced by an alkali extraction step, the reaction time for the alkali treatment could be shortened, the viscosity could be increased and pulps containing cellulose I could be obtained. ;  In addition, the hemicellulose content and cellulose reactivity values remained in the range of those of a commercial dissolving-grade pulp.

  • 119.
    Köpcke, Viviana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ibarra, David
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Larsson, Per Tomas
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Optimization of treatments for the conversion of eucalyptus kraft pulp to dissolving pulp2010Inngår i: Polymers from Renewable Resources, ISSN 2041-2479, Vol. 1, nr 1Artikkel i tidsskrift (Fagfellevurdert)
  • 120.
    Köpcke, Viviana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Nanko, Hiroki
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The effect of different monocomponent endoglucanases on cellulose accessibility in dissolving pulpsManuskript (Annet vitenskapelig)
  • 121.
    Le Normand, Myriam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Extraction and valorization of spruce bark hemicelluloses and pectins2011Inngår i: The third Nordic Wood Biorefinery Conference: 22-24 March, 2011 Stockholm, Sweden, 2011, s. 274-275Konferansepaper (Annet vitenskapelig)
  • 122.
    Le Normand, Myriam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    SPRUCE BARK HEMICELLULOSES AND PECTINS: EXTRACTION AND CHARACTERIZATION2011Inngår i: 16TH INTERNATIONAL SYMPOSIUM ON WOOD, FIBER AND PULPING CHEMISTRY, PROCEEDINGS, VOLS I & II / [ed] Wang, L Kuang, S Hou, Q Cao, C Si, CL Zhang, HJ, CHINA LIGHT INDUSTRY PRESS , 2011, s. 103-106Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In industrial spruce bark, up to 20 % of the dry mass consists of non-cellulosic polysaccharides. These polysaccharides can easily be extracted with pressurized hot water and have a large potential as a starting polymeric biomass for functional materials development. In this study, spruce bark was collected directly after the debarking process. The different steps of extraction were performed in an Accelerated Solvent Extractor (ASE). Bark was first extracted with acetone at 100 degrees C to remove extractives. Spruce bark polysaccharides could then be extracted with pressurized water at 100-460 degrees C with the highest yield at 140 degrees C. They were mainly composed of glucose, arabinose and galacturonic acid units which revealed the presence of pectic substances, starch and arabinose-rich hemicelluloses, e.g. arabinans. Molecular weight estimations showed the presence of rather large polysaccharides with a Mw varying between 10 to 30 kDa, depending of the extraction conditions.

  • 123.
    Le Normand, Myriam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Holmbom, Bjarne
    Åbo Akademi University, Finland.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Hot-water extraction and characterization of spruce bark non-cellulosic polysaccharides2012Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, nr 1, s. 18-23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Non-cellulosic polysaccharides (NCP) from bark offer large potential as a class of natural raw materials for functional materials development and production of biochemicals. We have elaborated a process for sequential extraction of NCP from industrial Norway spruce bark using an accelerated solvent extraction (ASE) with water at 100 to 160°C. Carbohydrates, Klason lignin and ash content as well as size-exclusion chromatography (SEC) analyses were performed for all hot-water extracts. NCP were mainly composed of glucose, arabinose and galacturonic acid units which revealed the presence of starch, arabinose-rich hemicelluloses and pectins. In total, the industrial bark of Norway spruce contained up to 20% of NCP which were extracted with pressurized hot water. NCP were mainly extractable at 140°C and started to undergo degradation at higher temperature.

  • 124.
    Le Normand, Myriam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Krogell, Jens
    Laboratory of Wood and Paper Chemistry, Process Chemistry Centre, Åbo Akademi University, Turku/Åbo, Finland.
    Holmbom, Bjarne
    Laboratory of Wood and Paper Chemistry, Process Chemistry Centre, Åbo Akademi University, Turku/Åbo, Finland.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    HOT-WATER EXTRACTION AND CHARACTERIZATIONOF HEMICELLULOSES AND PECTINS FROM BARK OF NORWAY SPRUCE (PICEA ABIES)2010Inngår i: 11th European Workshop on Lignocellulosics and Pulp: August 16-19, 2010 Hamburg/Germany, 2010, s. 243-246Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Bark of Norway spruce (Picea abies) contains 20 to 30% of hemicelluloses and pectins which could be extractedwith pressurized hot water. Hemicelluloses and pectins from the fresh inner bark were extracted with anAccelerated Solvent Extractor (ASE) with water at 100 °C, 140 °C and 160 °C. A large amount of arabinose andgalacturonic acid units in the water extract obtained at 140 °C revealed the presence of arabinans and pectins. Atthis temperature, the extraction of hemicelluloses and pectins was the most effective and generated high-molarmassnon-cellulosic polysaccharides with an average molar mass Mw around 40 kDa. Aromatic substancespresent in the hot-water extract at 140 °C could partly be removed by sorption on DAX-8 polyacrylate resin.

  • 125.
    Le Normand, Myriam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Moriana, Rosana
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Isolation and characterization of cellulose nanocrystals from spruce bark in a biorefinery perspective2014Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 111, s. 979-987Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present study reports for the first time the isolation of cellulose fibers and cellulose nanocrystals (CNCs) from the bark of Norway spruce. The upgrading of bark cellulose to value-added products, such as CNCs, is part of the "bark biorefinery" concept. The removal of non-cellulosic constituents was monitored throughout the isolation process by detailed chemical composition analyses. The morphological investigation of the CNCs was performed using AFM and showed the presence of nanocrystals with an average length of 175.3 nm and a diameter of 2.8 nm, giving an aspect ratio of around 63. X-ray diffraction (XRD) analyses showed that the crystallinity index increased with successive treatments to reach a final value greater than 80% for CNCs. The thermal degradation of the isolated bark CNCs started at 190 degrees C Spruce bark appeared to be a new promising industrial source of cellulose fibers and CNCs.

  • 126.
    Le Normand, Myriam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Moriana, Rosana
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The bark biorefinery: a side-stream of the forest industry converted into nanocomposites with high oxygen-barrier properties2014Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, nr 6, s. 4583-4594Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of the bark biorefinery concept is to upgrade the different constituents present in bark to multiple value-added bio-based products. Non-cellulosic polysaccharides (NCP) and cellulose nanocrystals (CNC) sequentially isolated from the inner bark of Norway spruce were used as raw materials for the formulation of renewable nanocomposites. The film formation abilities of NCP/CNC formulations prepared with different proportions of CNC were studied. Homogeneous transparent films with a glossy appearance were obtained when more than 30 wt% CNC was incorporated. The influence of the CNC content on the NCP/CNC films was assessed in terms of structural, thermal, mechanical and oxygen-barrier properties. All the films showed better performances with increasing CNC content, which was explained by the strong interactions between the two components. The effect on the film performances of adding sorbitol as a plasticizer was also evaluated. The presence of sorbitol decreased the thermal stability, the stiffness and the oxygen permeability of the films at 80 % RH. However, the addition of sorbitol enhanced the elongation of the films and further improved their oxygen-barrier properties at 50 % RH. The composite properties could thus be tailored by adding different amounts of sorbitol and CNC, resulting in all-carbohydrate materials with performances similar to or even better than the conventional barrier materials used in packaging.

  • 127.
    Le Normand, Myriam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Mélida, Hugo
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Holmbom, Bjarne
    Åbo Akademi.
    Michaelsen, Terje E.
    Unversity of Oslo.
    Inngjerdingen, Marit
    University of Oslo.
    Bulone, Vincent
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Paulsen, B.S.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Hot-water extracts from the inner bark of Norway spruce with immunomodulating activities2014Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 101, nr 1, s. 699-704Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The inner bark of Norway spruce (Picea abies) was sequentially extracted with hot water at 100 degrees C, 140 C and 160 degrees C. The hot-water extracts (IB 100 degrees C, IB 140 degrees C and IB 160 degrees C) contained pectic polysaccharides and showed immunostimulating activities. Structural analyses of their carbohydrate content, including glycosidic linkage analyses, revealed the presence of pectins with a large rhamnogalacturonan RG-I domain ramified with highly-branched arabinans. IB 100 degrees C also contained a large amount of terminal glucosyl residues, indicating the presence of highly substituted polymers. IB 160 degrees C was mainly composed of starch. The hot-water extracts were tested for two biological activities, namely complement fixation and macrophage stimulation. IB 100 degrees C exhibited the highest complement fixation activity, with a 1.7-times higher IC(H)50 than the control pectin, while IB 140 degrees C and IB 160 degrees C gave similar IC(H)50 values as the control. Macrophages were stimulated by IB 100 degrees C and IB 140 degrees C in a dose-dependent manner, but not by IB 160 degrees C. IB 100 degrees C presented the highest activity toward macrophages, comparable to the control pectin.

  • 128. Lennholm, Helena
    et al.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Rosenqvist, Marie
    Iversen, Tommy
    Photoyellowing of groundwood pulps. A study with spectroscopic and chemometric methods.1992Inngår i: Proc. Joint EC-Seminar, 1992, s. 72-97Konferansepaper (Fagfellevurdert)
  • 129. Lennholm, Helena
    et al.
    Rosenqvist, Marie
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Iversen, Tommy
    Photoyellowing of groundwood pulps1994Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 9, nr 1, s. 10-15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The photoyellowing of spruce groundwood pulps (GWP) has been studied by use of UV/VIS diffuse reflectance- and FTIR-transmission spectroscopy.  Brightness reversion was induced by exposing unbleached, hydrogen peroxide-bleached and sodium borohydride-reduced spruce GWP to simulate daylight for various exposure times.  Spectra were recorded and principal component anal. was used to evaluate the spectral data.  The information obtained indicates the presence of two alternative photo-induced processes proceeding in parallel during the irradn.  The first process, more pronounced during the initial phase of the photoyellowing was ascribed to redox reactions involving structures with absorption bands at 340 or 380 nm and 440 nm in the UV/VIS-spectra.  These absorption bands could results from photo-induced transformations involving quinonoid redox couples.  The second process, pronounced during both the initial and final phase of the photoyellowing, was interpreted as non-specific oxidns. of lignin causing major chromophore formation.

  • 130.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ibarra, David
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Köpcke, Viviana
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Production of Dissolving Grade Pulps from Wood and Non-Wood Paper-Grade Pulps by Enzymatic and Chemical Pretreatments2012Inngår i: Functional Materials from Renewable Sources / [ed] Liebner, F., Rosenau, T., American Chemical Society (ACS), 2012, s. 167-189Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    A raw material with high cellulose content and low content of hemicelluloses, residual lignin, extractives and minerals is required for many important applications in the pharmaceutical, textile, food and paint industries i.e. cotton and dissolving grade pulp are used. However, the high costs for the production of dissolving grade pulps has triggered interest in upgrading paper-grade pulps into dissolving pulps by selective removal of hemicelluloses and subsequent activation of the pulps. This study reports the feasibility to produce dissolving grade pulps from different wood and non-wood paper-grade pulps employing enzymatic and chemical pre-treatments. The results were compared to those of commercial bleached dissolving pulps.

  • 131.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ibarra, David
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Köpcke, Vivianna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Production of Dissolving Grade Pulps from Wood and Non-wood Paper Grade Pulps Using Enzymatic and Chemical Pre-treatmentsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Cellulose is the most abundant biorenewable material, constitutes an important polymer since it is used as raw material for several products, e.g. paper and board but also cellulose-based products which have many important applications in the pharmaceutical, textile, food and paint industries. A raw material with high cellulose content and low content of hemicelluloses, residual lignin, extractives and minerals is required for the production of these products, e.g. cotton and dissolving grade pulp are used. However, the high cost production of dissolving grade pulps has aroused the possibility of upgrading paper grade pulps into dissolving pulps by selective removal of hemicelluloses and subsequent activation of the pulps. This study reports the feasibility to produce dissolving grade pulps from different wood and non-wood paper grade pulps employing enzymatic and chemical pre-treatments. The results were compared to those of commercial bleached dissolving pulps.

  • 132.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Iversen, T.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Treatment of a cellulose fiber surface with a suberin monomer-derived polymer2015Inngår i: Polymers from Renewable Resources, ISSN 2041-2479, Vol. 6, nr 3, s. 75-90Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The biorefinery concept requires the development of value-added products, such as materials from biomass, including bark. Suberin is the most abundant component in birch (Betula verrucosa) outer bark and acts as a barrier against the penetration of water and external attacks from microorganisms. The aliphatic domain of suberin is rich in hydroxy fatty acids, such as cis-9,10-epoxy-18- hydroxyoctadecanoic acid. In this study, it was isolated from the outer bark of birch and polymerized to prepare polyepoxy acid (PEA), which was used to impregnate filter papers. After complete drying, PEA-loaded filter papers were placed under UV to crosslink the epoxides through cationic polymerization with a diaryliodonium salt as the photo-initiator. The crosslinking was evaluated using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The materials obtained after UV curing showed substantially increased hydrophobicity, decreased moisture absorption, increased tensile strength, and increased ductility. Field-emission scanning electron microscopy (FE-SEM) showed that the crosslinked PEA covered the surface of the cellulose fibers and filled the interstitial spaces.

  • 133.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Iversen, Tommy
    Innventia.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Biocomposites based on birch suberin2012Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Artikkel i tidsskrift (Annet vitenskapelig)
  • 134.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Iversen, Tommy
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Innventia AB, Drottning Kristinas väg 61, SE-114 86 Stockholm, Sweden.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Hydrophobic materials based on cotton linter cellulose and an epoxy-activated polyester derived from a suberin monomer2015Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434XArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Suberin is a natural hydrophobic material that could be used to improve the water repellency of cellulose surfaces. It is also abundant in the outer bark of birch (Betula verrucosa); birch bark is a side-stream product in Scandinavia from the forest industry, which is generally burned for energy production. A suberin monomer, cis-9,10-epoxy-18-hydroxyoctadecanoic acid, was isolated from birch outer bark and polymerized via lipase (immobilized Candida antarctica lipase B). The resulting epoxy-activated polyester was characterized by nuclear magnetic resonance (NMR) imaging, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, and size exclusion chromatography. Then the polyester was cured with tartaric or oxalic acid, and the crosslinked polyesters were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry. Hydrophobic materials were prepared by compression molding of polyester-impregnated cellulose sheets, and the final products were characterized by FTIR, cross-polarization magic angle spinning 13 C NMR, and field-emission scanning electron microscopy. The water contact angle was significantly increased from 0 ° for the original cellulose sheets to over 100 ° for the produced hydrophobic materials.

  • 135.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Moriana, Rosana
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    From forest residues to hydrophobic nanocomposites with high oxygen-barrier properties2016Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 2, s. 261-269Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A biorefinery of forest resources should be able to convert all components of trees, including the bark and other types of forest residues, into value-added products. Here, non-cellulosic polysaccharides (NCPs) isolated from Norway spruce bark and cellulose nanocrystals (CNCs) isolated from the logging residues of Norway spruce were mixed to prepare nanocomposites with competitive thermo-mechanical properties. Polyepoxy acid (PEA) derived from a monomer of suberin in birch bark was used as a coating on the nanocomposites to develop functional materials entirely based on forest resources. All of the PEA-coated nanocomposites were hydrophobic. At 50% and 80% relative humidity, they showed high oxygen-barrier properties that were comparable to or even better than those of some renewable materials such as xylan-, galactoglucomannan- and nanofibrillated cellulose-based films and synthetic materials such as polyvinylidene chloride and polyamide.

  • 136.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ionic Liquids pretreatment of cellulose fiber materials for improvement of reactivity and value added applications2011Inngår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC , 2011, s. 503-510Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cellulose is one of the most abundant biological and renewable materials in the world. The application of cellulose is widely distributed among various industries such as fiber, paper, pharmaceutical, membrane, polymer and paint. However, the utilization of cellulose or cellulosic materials has not been developed entirely because of its poor solubility in common organic solvents. Ionic liquids (ILs) are relatively new family of solvents for dissolution of cellulose. They are organic salts containing cations and anions with low melting temperature, which make them suitable for the solubilization of cellulose. Moreover, ILs are non-volatile, non-toxic, non-flammable and thermally and chemically stable. Cellulose dissolved in ILs can be regenerated with anti-solvents as water, ethanol and acetone. In this study, the pretreatment of both hardwood and softwood dissolving pulps with two ILs ([C4mim+]CH3COO- and [C4mim+]Cl-) were performed. Furthermore, the impact of treating cellulose with ILs was also evaluated by using different analytical techniques, such as size exclusion chromatography (SEC), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM).

  • 137.
    Li, Dongfang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Pretreatment of softwood dissolving pulp with ionic liquids2012Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, nr 8, s. 935-943Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Few Scandinavian pulp mills produce dissolving pulps; however, the demand on textile fibers is increasing. This study investigates the chemical interaction of dissolving pulp with ionic liquids (ILs), where softwood and hardwood industrial dissolving pulps were pretreated with ILs 1-butyl-3-methyl-imidazolium acetate ([C(4)mim(+)]CH3COO-) and 1-butyl-3-methyl-imdazolium chloride ([C(4)mim(+)]Cl-). Time and temperature dependence of the dissolution process as well as the impact of the pretreatment on the molecular weight properties, thermal stability, morphology, and crystallinity of the cellulose were evaluated by means of size exclusion chromatography (SEC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and solid state nuclear magnetic resonance (NMR). It was shown that the dissolution of cellulosic material in ILs is a temperature-dependent process; however, the viscosity of ILs affected the efficiency of dissolution at a given temperature. Molecular weight properties were affected negatively by increased dissolution temperature, while the type of antisolvent for the regeneration had no major impact on the degree of polymerization of cellulose. Water was more efficient than ethanol for the regeneration of cellulose when performed at an elevated temperature. The pretreatment decreased the crystallinity of cellulosic material. This might lead to the increased accessibility and reactivity of cellulose.

  • 138. Moliner, C.
    et al.
    Badia, J. D.
    Bosio, B.
    Arato, E.
    Kittikorn, T.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. e Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University, Songkhla, Thailand .
    Strömberg, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Teruel-Juanes, R.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ribes-Greus, A.
    Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites2018Inngår i: Chemical Engineering Communications, ISSN 0098-6445, E-ISSN 1563-5201, Vol. 205, nr 2, s. 226-237Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0–10–20–30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied to simulate the potential of thermal recovery technologies, such as pyrolysis and controlled combustion, to use these biocomposites after the end of their service life. The mathematical descriptions of both thermo-chemical reactions were helpful in the evaluation of the eventual optimal operational conditions to carry out a suitable energetic valorisation. A minimum of 240°C and 137 kJ/mol of activation energy in inert conditions and 236°C and 118 kJ/mol in oxidative conditions ensured the feasibility of the reactions regardless the composition of the PHBV/sisal biocomposites, which may ease the operability of further energy valorisation with the aim to turn biowaste into new fuels.

  • 139.
    Moliner, C.
    et al.
    Univ Genoa, DICCA, Via Opera Pia 15, I-16145 Genoa, Italy.;Univ Politecn Valencia, ITM, Camino Vera S-N, E-46022 Valencia, Spain..
    Badia, J. D.
    Univ Politecn Valencia, ITM, Camino Vera S-N, E-46022 Valencia, Spain.;Univ Valencia, Escola Tecn Super Engn, Dept Engn Quim, Av Univ S-N, E-46100 Burjassot, Spain..
    Bosio, B.
    Univ Genoa, DICCA, Via Opera Pia 15, I-16145 Genoa, Italy..
    Arato, E.
    Univ Genoa, DICCA, Via Opera Pia 15, I-16145 Genoa, Italy..
    Teruel-Juanes, R.
    Univ Politecn Valencia, ITM, Camino Vera S-N, E-46022 Valencia, Spain..
    Kittikorn, Thorsak
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Prince Songkla Univ, Fac Sci, Dept Mat Sci & Technol, Hat Yai 90112, Thailand..
    Strömberg, Emma
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ribes-Greus, A.
    Univ Politecn Valencia, ITM, Camino Vera S-N, E-46022 Valencia, Spain..
    Thermal kinetics for the energy valorisation of polylactide/sisal biocomposites2018Inngår i: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 670, s. 169-177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thermal stability and decomposition kinetics of PLA/sisal biocomposites was discussed to evaluate the suitability of their use in energy recovery processes such as pyrolysis and combustion. The influence of the addition of sisal up to 30%wt, the presence of coupling agent, and the atmosphere of operation, i.e. inert or oxidative was discussed by means of multi-rate linear non-isothermal thermogravimetric experiments. All biocomposites showed a mean high heating value of 15 MJ/kg indicating their suitability for energy recovery processes. The thermal requirements of PLA/sisal decomposition were assessed in terms of onset decomposition temperature and apparent activation energy. A minimum of 240 degrees C and 174 kJ mol(-1) in inert environment and 225 degrees C and 190 kJ mol(-1) in oxidative environment ensured the feasibility of the reactions regardless the composition of the PLA/sisal biocomposites. The atmosphere of work lead to a greater amount of residue in case of pyrolysis reactions that would need further treatment whereas an oxidative atmosphere resulted in nearly zero final waste stream. The similar kinetics obtained for all samples regardless the amount of sisal or use of coupling agent eases the operability of energy facilities aimed of turning these biowastes into new fuels.

  • 140.
    Monica, Ek
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Garegg, Per J
    Hultberg, Hans
    Oscarson, Stefan
    Reductive Ring Openings of Carbohydrate Benzylidene Acetals Using Borane-Trimethylamine and Aluminium Chloride. Regioselectivity and Solvent Dependance1983Inngår i: Journal of carbohydrate chemistry, ISSN 0732-8303, E-ISSN 1532-2327, Vol. 2, nr 3, s. 305-311Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Regioselective reductive ring openings of 4, 6-O-benzylidene acetals of hexopyranosides are described using borane trimethylamine-aluminium chloride. Using toluene as solvent, 4-O-benzyl ethers with the 6-OH free are obtained. Using tetrahydrofuran as solvent. 6-O-benzyl ethers with the 4-OH free are obtained.

  • 141.
    Monica, Ek
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lennholm, Helena
    Lindblad, Gunnar
    Iversen, Tommy
    A study on the mechanism of the photoyellowing of partially acetylated groundwood pulps1992Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 7, nr 3, s. 108-112Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of partial acetylation on the photoyellowing of unbleached, peroxide-bleached, and borohydride-reduced groundwood pulps were studied.  Quinone structures and quinone precursors, such as hydroquinones and catechols, are important reactants in the photoyellowing process.

  • 142.
    Moriana, Rosana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Vilaplana, Francisco
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Cellulose Nanocrystals from Forest Residues as Reinforcing Agents for Composites: A Study from Macro- to Nano-Dimensions2016Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 139, s. 139-149Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigates for the first time the feasibility of extracting cellulose nanocrystals (CNCs) from softwood forestry logging residues (woody chips, branches and pine needles), with an obtained gravimetric yield of over 13%. Compared with the other residues, woody chips rendered a higher yield of bleached cellulosic fibers with higher hemicellulose, pectin and lignin content, longer diameter, and lower crystallinity and thermal stability. The isolation of CNCs from these bleached cellulosic fibers was verified by the removal of most of their amorphous components, the increase in the crystallinity index, and the nano-dimensions of the individual crystals. The differences in the physico-chemical properties of the fibers extracted from the three logging residues resulted in CNCs with specific physico-chemical properties. The potential of using the resulting CNCs as reinforcements in nanocomposites was discussed in terms of aspect ratio, crystallinity and thermal stability.

  • 143.
    Moriana, Rosana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Vilaplana, Francisco
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Forest residues as renewable resources for bio-based polymeric materials and bioenergy: chemical composition, structure and thermal properties2015Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, nr 5, s. 3409-3423Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The potential of three different logging residues (woody chips, branches and pine needles) as renewable resources to produce environmentally friendly polymeric materials and/or biofuel has been critically evaluated in terms of their structure, chemical composition and thermal properties. Woody chips constitute the most attractive forest residue to be processed into polymeric materials in terms of their highest cellulose content, crystallinity and thermal stability. In contrast, pine needles and branches offer higher heating values and optimum product distribution for solid fuel applications due to their higher lignin content. In general, forest residual biomass has great potential for conversion into new added value products, such as composites or solid biofuel, thus constituting a sustainable waste management procedure from a biorefinery perspective. The correlation between the chemical and structural properties with the thermal/pyrolytic behavior of residual biomass offers valuable insights to assess their sustainable exploitation.

  • 144.
    Moriana, Rosana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Vilaplana, Francisco
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Zhang, Yujia
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Using waste biomass to obtain a renewable nanocomposite based on cellulosic biofibre and cereal wall polymers2013Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245Artikkel i tidsskrift (Annet vitenskapelig)
  • 145.
    Moriana, Rosana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Zhang, Yujia
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Mischnick, Petra
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Thermal degradation behavior and kinetic analysis of spruce glucomannan and its methylated derivatives2014Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 106, nr 1, s. 60-70Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thermal degradation behavior and kinetics of spruce glucomannan (SGM) and its methylated derivatives were investigated using thermogravimetric analysis to characterize its temperature-dependent changes for use in specific applications. The results were compared with those obtained for commercial konjac glucomannan (KGM). The SGM and the KGM exhibited two overlapping peaks from 200 to 375 C, which correspond to the intensive devolatilization of more than 59% of the total weight. Differences in the pyrolysis-product distributions and thermal stabilities appeared as a result of the different chemical compositions and molecular weights of the two GMs. The Friedman and Flynn-Wall-Ozawa isoconversional methods and the Coats-Redfern were adopted to determine the kinetic triplet of the intensive devolatilization region. Both GMs can be modeled using a complex mechanism that involves both a Dn-type and an Fn-type reaction. The comparative study of partially methylated GM indicated higher homogeneity and thermal resistance for the material with the higher degree of substitution.

  • 146. Nilsson, Helena
    et al.
    Gellerstedt, Göran
    KTH, Tidigare Institutioner, Pappers- och massateknik.
    Sjögren, Tomas
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Improved oxygen delignification of bisulfite pulps.1996Inngår i: Proceedings Int. Pulp Bleaching: Book 2, 1996, s. 14-18Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The role of peracetic acid in improving a second oxygen delignification step of softwood bisulfite pulp was investigated.  The results showed that peracetic acid improved the degree of delignification in a second oxygen stage, probably by increasing the content of free phenolic hydroxyl groups and therefore making the lignin more receptive to a second oxygen stage.  Oxygen pressurized peracetic acid stages were also studied and compared to atm. peracetic acid stages.  Pressurized peracetic acid stages gave only a minor effect in lowering the Kappa no.

  • 147.
    Norberg Samuelsson, Lina
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Moriana, Torró Rosana
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Bäbler, Matthäus U.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Engvall, Klas
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Model-free rate expression for thermal decomposition processes: The case of microcrystalline cellulose pyrolysis2015Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 143, s. 438-447Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We explore the possibility to derive a completely model-free rate expression using isoconversional methods. The Friedman differential method (Friedman, 1964) and the incremental integral method by Vyazovkin (2001) were both extended to allow for an estimation of not only the apparent activation energy but also the effective kinetic prefactor, defined as the product of the pre-exponential factor and the conversion function. Analyzing experimental thermogravimetric data for the pyrolytic decomposition of microcrystalline cellulose, measured at six different heating rates and three different initial sample masses (1.5-10 mg), revealed the presence of secondary char forming reactions and thermal lag, both increasing with increased sample mass. Conditioning of the temperature function enables extraction of more reliable prefactors and we found that the derived kinetic parameters show weak dependence on initial sample mass. Finally, by successful modeling of quasi-isothermal experimental curves, we show that the discrete rate expression estimated from linear heating rate experiments enables modeling of the thermal decomposition rate without any assumptions regarding the chemical process present. These findings can facilitate the design and optimization of industrial isothermal biomass fed reactors.

  • 148.
    Oinonen, Petri
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Krawczyk, H.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Moriana, Rosana
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Bioinspired composites from cross-linked galactoglucomannan and microfibrillated cellulose: Thermal, mechanical and oxygen barrier properties2016Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 136, s. 146-153Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, new wood-inspired films were developed from microfibrillated cellulose and galactoglucomannan-lignin networks isolated from chemothermomechanical pulping side streams and cross-linked using laccase enzymes. To the best of our knowledge, this is the first time that cross-linked galactoglucomannan-lignin networks have been used for the potential development of composite films inspired by woody-cell wall formation. Their capability as polymeric matrices was assessed based on thermal, structural, mechanical and oxygen permeability analyses. The addition of different amounts of microfibrillated cellulose as a reinforcing agent and glycerol as a plasticizer on the film performances was evaluated. In general, an increase in microfibrillated cellulose resulted in a film with better thermal, mechanical and oxygen barrier performance. However, the presence of glycerol decreased the thermal stability, stiffness and oxygen barrier properties of the films but improved their elongation. Therefore, depending on the application, the film properties can be tailored by adjusting the amounts of reinforcing agent and plasticizer in the film formulation.

  • 149.
    Oinonen, Petri
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Rosana, Moriana
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Holger, Krawczyk
    Monica, Ek
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    The composite formation of cross-linked galactoglucomannan-lignin networks and cellulose nanoparticles as defined by thermal and mechanical testingManuskript (preprint) (Annet vitenskapelig)
  • 150.
    Ottenhall, Anna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Illergård, Josefin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Water Purification Using Functionalized Cellulosic Fibers with Nonleaching Bacteria Adsorbing Properties2017Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 13, s. 7616-7623Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

     Portable purifi cation systems are easy ways to obtain clean drinking water when there is no large-scale water treatment available. In this study, the potential to purify water using bacteria adsorbing cellulosic fi bers, functionalized with polyelectrolytes according to the layer-by-layer method, is investigated. The adsorbed polyelectrolytes create a positive charge on the fi ber surface that physically attracts and bonds with bacteria. Three types of cellulosic materials have been modifi ed and tested for the bacterial removal capacity in water. The time, material-water ratio and bacterial concentration dependence, as well as the bacterial removal capacity in water from natural sources, have been evaluated. Freely dispersed bacteria adsorbing cellulosic fi bers can remove greater than 99.9% of Escherichia coli  from nonturbid water, with the most notable reduction occurring within the fi rst hour. A fi ltering approach using modifi ed cellulosic fi bers is desirable for purifi cation of natural water. An initial fi ltration test showed that polyelectrolyte multilayer modifi ed cellulosic fi bers can remove greater than 99% of bacteria from natural water. The bacteria adsorbing cellulosic fi bers do not leach any biocides, and it is an environmentally sustainable and cheap option for disposable water purification devices.

1234 101 - 150 of 179
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