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  • 1.
    Amaral, Sarah da Costa
    et al.
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil..
    Barbieri, Shayla Fernanda
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil..
    Ruthes, Andrea C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience. UF, GCREC, Dept Entomol & Nematol, Wimauma, FL USA..
    Bark, Juliana Mueller
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil..
    Brochado Winnischofer, Sheila Maria
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil.;Univ Fed Parana, Dept Biochem & Mol Biol, PB 19046, BR-81531980 Curitiba, PR, Brazil.;Univ Fed Parana, Postgrad Program Cellular & Mol Biol, BR-81531980 Curitiba, PR, Brazil..
    Meira Silveira, Joana Lea
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil.;Univ Fed Parana, Dept Biochem & Mol Biol, PB 19046, BR-81531980 Curitiba, PR, Brazil..
    Cytotoxic effect of crude and purified pectins from Campomanesia xanthocarpa Berg on human glioblastoma cells2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 224, article id UNSP 115140Article in journal (Refereed)
    Abstract [en]

    A new source of pectin with a cytotoxic effect on glioblastoma cells is presented. A homogeneous GWP-FP-S fraction (M-w, of 29,170 g mol(-1)) was obtained by fractionating the crude pectin extract (GW) from Campomanesia xanthocarpa pulp. According to the monosaccharide composition, the GWP-FP-S was composed of galacturonic acid (58.8%), arabinose (28.5%), galactose (11.3%) and rhamnose (1.1%), comprising 57.7% of homogalacturonans (HG) and 42.0% of type I rhamnogalacturonans (RG-I). These structures were characterized by chromatographic and spectroscopic methods; GW and GWP-FP-S fractions were evaluated by MIT and crystal violet assays for their cytotoxic effects. Both fractions induced cytotoxicity (15.55-37.65%) with concomitant increase in the cellular ROS levels in human glioblastoma cells at 25-400 mu g mL(-)(1), after 48 h of treatment, whereas no cytotoxicity was observed for normal NIH 3T3 cells. This is the first report of in vitro bioactivity and the first investigation of the antitumor potential of gabiroba pectins.

  • 2. Andrade Pires, Amanda do Rocio
    et al.
    Ruthes, Andrea Caroline
    KTH, School of Biotechnology (BIO), Glycoscience. Univ Fed Parana, Brazil.
    Suter Correia Cadena, Silvia Maria
    Iacomini, Marcello
    Cytotoxic effect of a mannogalactoglucan extracted from Agaricus bisporus on HepG2 cells2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 170, p. 33-42Article in journal (Refereed)
    Abstract [en]

    A mannogalactoglucan (RK2-Ab; M-w, 1.8 x 10(4) g mol(-1)) composed by Man (27.3%), Gal (24.4%) and Glc (48.3%) was extracted and characterized from Agaricus bisporus, and its biological activity was evaluated on human hepatocarcinoma cells (HepG2). The partially-O-methylated alditol acetates together with the NMR data suggest the main chain to be composed of alpha-D-Galp (32.8%) and beta-D-Glcp (37.0%) units (1 -> 6) -linked, with beta-D-Manp (14.6%), as non-reducing end units, substituting the side chains at O-2 (alpha-D-Galp units; 3.3%) and O-2 and O-4 (beta-D-Glcp units; 3.6%). (1 -> 2) -linked beta-D-Glcp (2.7%) and beta-D-Manp (6.0%) can also be observed. RK2-Ab reduced cellular viability of HepG2 cells, by both, the MTT and lactate dehydrogenase release assays, promoted the increase of cytochrome c release and decrease of ATP content. Suggesting that the mannogalactoglucan from A. bisporus may have antitumor activity by inducing apoptosis by the mitochondria death pathway, and could be used in cancer therapy.

  • 3.
    Azhar, Shoaib
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Theliander, Hans
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Sweden.
    Lindström, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Extraction of hemicelluloses from fiberized spruce wood2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 117, p. 19-24Article in journal (Refereed)
    Abstract [en]

    A novel mechanical pre-treatment method was used to separate the wood chips into fiber bundles in order to extract high molecular weight wood polymers. The mechanical pre-treatment involved chip compression in a conical plug-screw followed by defibration in a fiberizer. The fiberized wood was treated with hot water at various combinations of time and temperature in order to analyze the extraction yield of hemicelluloses at different conditions. Nearly 6 mg/g wood of galactoglucomannan was obtained at 90◦C/120min which was about three times more than what could be extracted from wood chips. The extracted carbohydrates had molecular weight ranging up to 60 kDa. About 10% of each of the extracted material had a molecular weight above 30 kDa. The extraction liquor could also be reused for consecutive extractions with successive increase in the extraction yield of hemicelluloses. 

  • 4.
    Barbieri, Shayla Fernanda
    et al.
    Univ Fed Parana, Biochem & Mol Biol Dept, BR-81531980 Curitiba, Parana, Brazil..
    Amaral, Sarah da Costa
    Univ Fed Parana, Biochem & Mol Biol Dept, BR-81531980 Curitiba, Parana, Brazil..
    Ruthes, Andrea Caroline
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience. Univ Florida, Dept Entomol & Nematol, Gulf Coast Res & Educ Ctr GCREC UF, Wimauma, FL USA..
    de Oliveira Petkowicz, Carmen Lucia
    Univ Fed Parana, Biochem & Mol Biol Dept, BR-81531980 Curitiba, Parana, Brazil..
    Kerkhoven, Nicole Cristine
    Univ Fed Parana, Biochem & Mol Biol Dept, BR-81531980 Curitiba, Parana, Brazil..
    Assuncao da Silva, Elisangela Rodrigues
    Univ Fed Parana, Biochem & Mol Biol Dept, BR-81531980 Curitiba, Parana, Brazil..
    Meira Silveira, Joana Lea
    Univ Fed Parana, Biochem & Mol Biol Dept, BR-81531980 Curitiba, Parana, Brazil..
    Pectins from the pulp of gabiroba (Campomanesia xanthocarpa Berg): Structural characterization and rheological behavior2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 214, p. 250-258Article in journal (Refereed)
    Abstract [en]

    The pulp of gabiroba fruits was submitted to a hot water extraction, giving rise to a crude pectin named GW. GW was shown to be composed mainly of arabinose (54.5%), galacturonic acid (33.5%), galactose (7.6%), and rhamnose (1.6%). GW was characterized by chromatographic and spectroscopic methods indicating the presence of homogalacturonans (HG) with a degree of methyl-esterification (DM) of 60% and rhamnogalacturonans I (RG-I). HG domain represents 31.9% and RG-I domain 65.3%. Furthermore, GW was submitted to sequential fractionation methods, giving rise to GWP-TEP fraction, structurally characterized by the predominance of HG regions, and confirmed by NMR analysis. The rheological behavior of GW was analyzed at 1%, 3%, and 5% (w/v) concentration with 0.1 mol L-1 NaCl. All samples showed shear thinning behavior. In the oscillatory measurements, the 1% GW showed a liquid-like behavior, while the 3% presented a concentrated solution behavior and the 5% GW a gel behavior.

  • 5. Barbieri, Shayla Fernanda
    et al.
    Ruthes, Andrea C.
    KTH, School of Biotechnology (BIO), Glycoscience.
    de Oliveira Petkowicz, Carmen Lucia
    Bueno de Godoy, Rossana Catie
    Sassaki, Guilherme Lanzi
    Santana Filho, Arquimedes Paixao
    Meira Silveira, Joana Lea
    Extraction, purification and structural characterization of a galactoglucomannan from the gabiroba fruit (Campomanesia xanthocarpa Berg), Myrtaceae family2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, p. 887-895Article in journal (Refereed)
    Abstract [en]

    In this study, we isolated and structurally characterized, for the first time, a galactoglucomannan (GGM) from the pulp of gabiroba, a Myrtaceae family species. The HPSEC-MALLS-RI analysis showed a homogeneous polysaccharide with molar mass of 25,340 g mol(-1). The monosaccharide composition showed that the GGM consisted of Man:Glc:Gal in a molar ratio of 1:1:0.6. Methylation and 1D and 2D NMR analyses suggested that the main chain of the GGM consisted of beta-D-Glcp and beta-D-Manp units (1 -> 4)-linked. The alpha-D-Galp substitutions occur mainly at O-6 position of beta-D-Manp units. The glycosidic linkages of the GGM were evident by the presence of the characteristic signals of 4-O-substituted residues at delta 78.6/3.69 for both beta-D-Glcp and beta-D-Manp. Furthermore, the 0-6 substitutions for both beta-D-Glcp and beta-D-Manp units were confirmed by signals at delta 67.1/4.00 and 3.93. The interglycosidic correlations, obtained through the analysis of the HMBC spectrum, further confirm the structure. (C) 2017 Elsevier Ltd. All rights reserved.

  • 6. Berggren, R.
    et al.
    Molin, U.
    Berthold, F.
    Lennholm, H.
    Lindström, Mikael
    Alkaline degradation of birch and spruce: influence of degradation conditions on molecular mass distributions and fibre strength2003In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 51, no 3, p. 255-264Article in journal (Refereed)
    Abstract [en]

    The alkaline degradation of birch and Norway spruce during kraft pulping was studied on a laboratory scale by two degradation strategies, by varying the pulping time using the same initial alkali level and by varying the initial alkali concentration using a constant time. The degradation at the molecular level was monitored by determining the carbohydrate composition, intrinsic viscosity and-molecular mass distribution (MMD). The influence of the degradation on fibre strength was studied as zero-span tensile index. The alkaline degradation was to a large extent homogeneous on a molecular level. However, some significant differences in degradation patterns were found. In the case of birch, the two different degradation strategies (increased alkali level and increased pulping time) caused differences in MMD and fibre strength (comparisons made at a given intrinsic viscosity or M-w). For spruce pulps, the decrease in fibre strength and the shift in MMD were the same in both series, regardless of degradation strategy.

  • 7.
    Bergström, Elina Mabasa
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Salmen, Lennart
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Joby Kochumalayil, Jose
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Plasticized xyloglucan for improved toughness-Thermal and mechanical behaviour2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 87, no 4, p. 2532-2537Article in journal (Refereed)
    Abstract [en]

    Tamarind seed xyloglucan is an interesting polysaccharide of high molar mass with excellent thermomechanical properties. Several plasticizers were studied in order to facilitate thermal processing and improve toughness (work to fracture) of xyloglucan film materials: sorbitol, urea, glycerol and polyethylene oxide. Films of different compositions were cast and studied by thermogravimetric analysis (TGA), calorimetry (DSC), dynamic mechanical thermal analysis (DMA) and tensile tests. Results are analysed and discussed based on mechanisms and practical considerations. Highly favourable characteristics were found with XG/sorbitol combinations, and the thermomechanical properties motivate further work on this material system, for instance as a matrix in biocomposite materials.

  • 8. Biscaia, S. M. P.
    et al.
    Carbonero, E. R.
    Bellan, D. L.
    Borges, B. S.
    Costa, C. R.
    Rossi, G. R.
    Goncalves, J. P.
    Melo, C. M.
    Livero, F. A. R.
    Ruthes, Andrea C.
    KTH, School of Biotechnology (BIO), Glycoscience.
    Zotz, R.
    Silva, E. V.
    Oliveira, C. C.
    Acco, A.
    Nader, H. B.
    Chammas, R.
    Iacomini, M.
    Franco, C. R. C.
    Trindade, E. S.
    Safe therapeutics of murine melanoma model using a novel antineoplasic, the partially methylated mannogalactan from Pleurotus eryngii2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 178, p. 95-104Article in journal (Refereed)
    Abstract [en]

    A heteropolysaccharide was isolated by cold aqueous extraction from edible mushroom Pleurotus eryngii ("King Oyster") basidiocarps and its biological properties were evaluated. Structural assignments were carried out using mono-and bidimensional NMR spectroscopy, monosaccharide composition, and methylation analyses. A man-nogalactan having a main chain of (1 -> 6)-linked alpha-D-galactopyranosyl and 3-O-methyl-alpha-D-galactopyranosyl residues, both partially substituted at OH-2 by beta-D-Manp (MG-Pe) single-unit was found. Biological effects of mannogalactan from P. eryngii (MG-Pe) were tested against murine melanoma cells. MG-Pe was non-cytotoxic, but reduced in vitro melanoma cells invasion. Also, 50 mg/kg MG-Pe administration to melanoma-bearing C57BL/6 mice up to 10 days decreased in 60% the tumor volume compared to control. Additionally, no changes were observed when biochemical profile, complete blood cells count (CBC), organs, and body weight were analyzed. Mg-Pe was shown to be a promising anti-melanoma molecule capable of switching melanoma cells to a non-invasive phenotype with no toxicity to melanoma-bearing mice.

  • 9.
    Boujemaoui, Assya
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Mongkhontreerat, Surinthra
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Preparation and characterization of functionalized cellulose nanocrystals2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 115, p. 457-464Article in journal (Refereed)
    Abstract [en]

    In this work, a series of functional nanocrystals (F-CNCs) was successfully produced by an efficient preparation method, combining acid hydrolysis and Fischer esterification with various organic acids. Functionalities such as ATRP initiators, double bonds, triple bonds, and thiols could be incorporated on CNCs. Surface modification was confirmed by FT-IR, XPS, and elemental analysis. Physical properties of FC-NCs were assessed by AFM, XRD and TGA. Moreover, ATRP initiator functionalized CNCs were utilized to graft poly(methyl methacrylate) via ATRP, thiol functionalized CNCs were reacted with Ellman's reagent to determine the thiol content and dye disperse red 13 was attached to alkyne functionalized CNCs to estimate the propiolate content. The herein presented method is a highly versatile and straightforward procedure for the preparation of F-CNCs which is believed to be a better alternative for the commonly utilized, extensive, multistep, and time consuming post functionalization methods.

  • 10. Cantu-Jungles, Thaisa Moro
    et al.
    Ruthes, Andrea Caroline
    KTH, School of Biotechnology (BIO), Glycoscience. Universidade Federal do Paraná, Brazil.
    El-Hindawy, Marwa
    Moreno, Roberta Barbara
    Zhang, Xiaowei
    Cordeiro, Lucimara M. C.
    Hamaker, Bruce R.
    Iacomini, Marcello
    In vitro fermentation of Cookeina speciosa glucans stimulates the growth of the butyrogenic Clostridium cluster XIVa in a targeted way2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 183, p. 219-229Article in journal (Refereed)
    Abstract [en]

    Dietary fiber chemical and physical structures may be critical to the comprehension of how they may modulate gut bacterial composition. We purified insoluble polymers from Cookeina speciosa, and investigated its fermentation profile in an in vitro human fecal fermentation model. Two glucans, characterized as a (1 -> 3),(1 -> 6)-linked and a (1 -> 3)-linked beta-D-glucans were obtained. Both glucans were highly butyrogenic and propiogenic, with low gas production, during in vitro fecal fermentation and led to distinct bacterial shifts if compared to fructooligosaccharides. Specific increases in Bacteroides uniformis and genera from the Clostridium cluster XIVa, such as butyrogenic Anaerostipes and Roseburia were observed. The (1 -> 3)-linked beta-D-glucan presented a faster fermentation profile compared to the branched (1 -> 3),(1 -> 6)-linked beta-D-glucan. Our findings support the view that depending on its fine chemical structure, and likely its insoluble nature, these dietary fibers can be utilized to direct a targeted promotion of the intestinal microbiota to butyrogenic Clostridium cluster XIVa bacteria.

  • 11. Carosio, F.
    et al.
    Ghanadpour, Maryam
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Alongi, J.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Layer-by-layer-assembled chitosan/phosphorylated cellulose nanofibrils as a bio-based and flame protecting nano-exoskeleton on PU foams2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 202, p. 479-487Article in journal (Refereed)
    Abstract [en]

    The layer-by-layer (LbL) assembly of chitosan (CH) and phosphorylated cellulose nanofibrils (P-CNF) is presented as a novel, sustainable and efficient fire protection system for polyurethane foams. The assembly yields a linearly growing coating where P-CNF is the main component and is embedded in a continuous CH matrix. This CH/P-CNF system homogenously coats the complex 3D structure of the foam producing a nano-exoskeleton that displays excellent mechanical properties increasing the modulus of the foam while maintaining its ability of being cyclically deformed. During combustion the CH/P-CNF exoskeleton efficiently prevents foam collapse and suppresses melt dripping while reducing the heat release rate peak by 31% with only 8% of added weight. The coating behavior during combustion is investigated and correlated to the observed performances. Physical and chemical mechanisms are identified and related to the unique composition and structure of the coating imparted by the LbL assembly.

  • 12.
    Chen, Fei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gällstedt, Mikael
    Olsson, Richard
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gedde, Ulf
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hedenqvist, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Unusual Effects of Monocarboxylic Acids on The Structure and on The Transport and Mechanical Properties of Chitosan Films2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 132, p. 419-429Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to study the transport of monocarboxylic acids in chitosan films, since this is important for understanding and predicting the drying kinetics of chitosan from aqueous solutions. Despite the wealth of data on chitosan films prepared from aqueous monocarboxylic acid solutions, this transport has not been reported. Chitosan films were exposed to formic, acetic, propionic and butyric acid vapours, it was found that the rate of uptake decreased with increasing molecular size. The equilibration time was unexpectedly long, especially for propionic and butyric acid, nine months. A clear two-stage uptake curve was observed for propionic acid. Evidently, the rate of uptake was determined by acid-induced changes in the material. X-ray diffraction and infrared spectroscopy indicated that the structure of the chitosan acetate and buffered chitosan films changed during exposure to acid and during the subsequent drying. The dried films previously exposed to the acid showed less crystalline features than the original material and a novel repeating structure possibly involving acid molecules. The molar mass of the chitosan decreased on exposure to acid but tensile tests revealed that the films were always ductile. The films exposed to acid vapour (propionic and butyric acid) for the longest period of time were insoluble in the size-exclusion chromatography eluent, and they were also the most ductile/extensible of all samples studied.

  • 13. Cozzolino, Carlo A.
    et al.
    Campanella, Gaetano
    Ture, Hasan
    Olsson, Richard
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Farris, Stefano
    Microfibrillated cellulose and borax as mechanical, O-2-barrier, and surface-modulating agents of pullulan biocomposite coatings on BOPP2016In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 143, p. 179-187Article in journal (Refereed)
    Abstract [en]

    Multifunctional composite coatings on bi-oriented polypropylene (BOPP) films were obtained using borax and microfibrillated cellulose (MFC) added to the main pullulan coating polymer. Spectroscopy analyses suggested that a first type of interaction occurred via hydrogen bonding between the C-6-OH group of pullulan and the hydroxyl groups of boric acid, while monodiol and didiol complexation represented a second mechanism. The deposition of the coatings yielded an increase in the elastic modulus of the entire plastic substrate (from similar to 2 GPa of the neat BOPP to similar to 3.1 GPa of the P/B+/MFC-coated BOPP). The addition of MFC yielded a decrease of both static and kinetic coefficients of friction of approximately 22% and 25%, respectively, as compared to the neat BOPP. All composite coatings dramatically increased the oxygen barrier performance of BOPP, especially under dry conditions. The deposition of the high hydrophilic coatings allowed to obtain highly wettable surfaces (water contact angle of similar to 18 degrees).

  • 14. Dax, Daniel
    et al.
    Soledad Chavez, Maria
    Xu, Chunlin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Process Chemistry Centre, C/o Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Finland .
    Willfor, Stefan
    Teixeira Mendonca, Regis
    Sanchez, Julio
    Cationic hemicellulose-based hydrogels for arsenic and chromium removal from aqueous solutions2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 111, p. 797-805Article in journal (Refereed)
    Abstract [en]

    In this work the synthesis of hemicellulose-based hydrogels and their application for the removal of arsenic and chromium ions is described. In a first step O-acetyl galactoglucomannan (GGM) was subjected to a transesterification applying glycidyl methacrylate (GMA) for the synthesis of novel GGM macromonomers. Two distinguished and purified GGM fractions with molar mass of 7.1 and 28 kDa were used as starting materials. The resulting GGM macromonomers (GGM-MA) contained well-defined amounts of methacrylate groups as determined by H-1 NMR spectroscopy. Selected GGM-MA derivatives were consecutively applied as a crosslinker in the synthesis of tailored hydrogels using [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA) as monomer. The swelling rate of the hydrogels was determined and the coherence between the swelling rate and the hydrogel composition was examined. The morphology of the GGM-based hydrogels was analysed by SEM and the hydrogels revealed a high surface area and were assessed in respect to their ability to remove arsenate and chromate ions from aqueous solutions. The presented bio-based hydrogels are of high interest especially for the mining industries as a sustainable material for the treatment of their highly contaminated wastewaters.

  • 15.
    Djahedi, Cyrus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Wohlert, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Molecular deformation mechanisms in cellulose allomorphs and the role of hydrogen bonds2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 130, p. 175-182Article in journal (Refereed)
    Abstract [en]

    Differences in tensile properties between cellulose crystal allomorphs cannot be rationalized by simply counting hydrogen bonds. From molecular dynamics computer simulations the cooperative nature of energy contributions to axial cellulose crystal modulus becomes apparent. Using a decomposition of inter and intrarnolecular forces as a function of tensile strain, the three allomorphs show dramatic differences in terms of how the contributions to elastic energy are distributed between covalent bonds, angles, dihedrals, electrostatic forces, dispersion and steric forces.

  • 16. Eguees, Itziar
    et al.
    Stepan, Agnes M.
    Eceiza, Arantxa
    Toriz, Guillermo
    Gatenholm, Paul
    Wallenberg Wood Sci Ctr, Gothenburg, Sweden.
    Labidi, Jalel
    Corncob arabinoxylan for new materials2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 102, p. 12-20Article in journal (Refereed)
    Abstract [en]

    Corncob agricultural waste was used as a source of arabinoxylan for preparation of films. Three arabinoxylan samples were prepared: crude extract (CCAX), purified by a washing step, and purified by bleaching CCAX. Films prepared with untreated CCAX were water soluble, yellowish in color and had poor mechanical properties. After the purification processes the Young's modulus increased from similar to 293 MPa to similar to 1400-1600 MPa, and strength was improved from similar to 9 MPa to around 53 MPa, while the strain at break was kept at similar to 8% both in untreated and purified CCAX. The contact angle was increased from similar to 21.3 degrees to 67-74 degrees after washing or bleaching CCAX. Acetylation of bleached CCAX showed the highest thermal resistance (325 degrees C), had low T-g (125 degrees C) and a high contact angle (80 degrees), and its films were stronger (strength similar to 67 MPa; Young's modulus similar to 2241 MPa) and more flexible (similar to 13%). These characteristics make purified CCAX a suitable material to be used as a matrix for film applications.

  • 17. Escalante, Alfredo
    et al.
    Goncalves, Ana
    Bodin, Aase
    Stepan, Agnes
    Sandstrom, Corine
    Toriz, Guillermo
    Gatenholm, Paul
    Wallenberg Wood Sci Ctr, Chalmers, Sweden.
    Flexible oxygen barrier films from spruce xylan2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 87, no 4, p. 2381-2387Article in journal (Refereed)
    Abstract [en]

    Arabinoglucuronoxylan was extracted from Norway spruce and films prepared by casting from aqueous solution. The sugar analysis and NMR confirmed that the spruce xylan was composed of arabinose, 4-O-methyl-glucuronic acid and xylose in a ratio of 1:2:11 respectively. Substitutions of 4-O-methyl-alpha-D-GlcpA at O-2 and of alpha-L-Araf at O-3 on the xylose backbone were found by NOE analysis. NOE cross-peaks indicated as well that there is at least one free xylose on the main chain present between two substitutions. Whether the distribution of side chains was random or in blocks was uncertain. The average molecular weight of the sample was determined by size exclusion chromatography to be 12,780 g/mol. Arabinoglucoronoxylan casting yielded transparent flexible films with an average stress at break of 55 MPa, strain at break of 2.7% and a Young's Modulus 2735 MPa. Wide-angle X-ray scattering analysis showed that the arabinoglucuronoxylan films were totally amorphous. Addition of sorbitol as plasticizer resulted in less strong but more flexible films (strain at break of 5%). Peaks of crystallinity could be seen in X-ray which corresponds to sorbitol crystallizing in distinct phases. The dynamic mechanical analysis showed that the arabinoglucuronoxylan film softened at a later relative humidity (80% RH) in comparison with plasticized films (60% RH). The films showed low oxygen permeability and thus have a potential application in food packaging.

  • 18.
    Feng, Zhaoxuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Tunable chitosan hydrogels for adsorption: Property control by biobased modifiers2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 196, p. 135-145Article in journal (Refereed)
    Abstract [en]

    A sustainable strategy to fabricate chitosan-based composite hydrogels with tunable properties and controllable adsorption capacity of trace pharmaceuticals was demonstrated. Two biobased modifiers were utilized to tune the properties, nano-graphene oxide (nGO) derived from chitosan via microwave-assisted carbonization and oxidation, and genipin as the crosslinking agent. An increase in genipin content facilitated an increase in the degree of crosslinking as shown by improved storage modulus and decreased swelling ratio. Increasing nGO content changed the surface microtopography of the hydrogel which correlated with the surface wettability. nGO also catalyzed the genipin-crosslinking reaction. The hydrogel was further shown to be an effective adsorbent for a common anti-inflammatory drug, diclofenac sodium (DCF), with the removal efficiency ranging from 91 to 100% after 48 h. DCF adsorption efficiency could be tuned through simple alteration of nGO and genipin concentration, which provides promising potential for this environmental-friendly adsorbent in removal of DCF from pharmaceutical waste water.

  • 19. Fernandes, Susana C. M.
    et al.
    Freire, Carmen S. R.
    Silvestre, Armando J. D.
    Pascoal Neto, Carlos
    Gandini, Alessandro
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Salmén, Lennart
    Transparent chitosan films reinforced with a high content of nanofibrillated cellulose2010In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 81, no 2, p. 394-401Article in journal (Refereed)
    Abstract [en]

    This paper reports the preparation and characterization of nanocomposite films based on different chitosan matrices and nanofibrillated cellulose (NFC) for the purpose of improving strength properties. The nanocomposite films were prepared by a simple procedure of casting a water-based suspension of chitosan and NFC, and were characterized by several techniques: namely SEM, X-ray diffraction, visible spectrophotometry, TGA, tensile and dynamic-mechanical analysis. The films obtained were shown to be highly transparent (transmittance varying between 90 and 20% depending on the type of chitosan and NFC content), flexible, displayed better mechanical properties, with a maximum increment on the Young's modulus of 78% and 150% for high molecular weight (HCH) and water-soluble high molecular weight (WSHCH) filled chitosans, respectively; and of 200% and 320% for low molecular weight (LCH) and water-soluble filled (WSLCH) chitosans, respectively. The filled films also showed increased thermal stability, with, for example, an increase in the initial degradation temperature (Td(i)) from 227 degrees C in the unfilled LCH film up to 271 degrees C in filled LCHNFC50% nanocomposite films, and a maximum degradation temperature (Tdi) raising from 304 degrees C to 313 degrees C for the same materials.

  • 20. Fortunati, E.
    et al.
    Armentano, I.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Glycoscience.
    Iannoni, A.
    Saino, E.
    Visai, L.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Kenny, J. M.
    Multifunctional bionanocomposite films of poly(lactic acid), cellulose nanocrystals and silver nanoparticles2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 87, no 2, p. 1596-1605Article in journal (Refereed)
    Abstract [en]

    Nanocomposite films were prepared by the addition of cellulose nanocrystals (CNCs) eventually surfactant modified (s-CNC) and silver (Ag) nanoparticles in the polylactic acid (PLA) matrix using melt extrusion followed by a film formation process. Multifunctional composite materials were investigated in terms of morphological, mechanical, thermal and antibacterial response. The nanocomposite films maintained the transparency properties of the PLA matrix. Thermal analysis showed increased values of crystallinity in the nanocomposites, more evident in the s-CNC based formulations that had the highest tensile Young modulus. The presence of surfactant favoured the dispersion of cellulose nanocrystals in the polymer matrix and the nucleation effect was remarkably enhanced. Moreover, an antibacterial activity against Staphylococcus aureus and Escherichia coil cells was detected for ternary systems, suggesting that these novel nanocomposites may offer good perspectives for food packaging applications which require an antibacterial effect constant over time. (C) 2011 Elsevier Ltd. All rights reserved.

  • 21. Gallstedt, M.
    et al.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Packaging-related mechanical and barrier properties of pulp-fiber-chitosan sheets2006In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 63, no 1, p. 46-53Article in journal (Refereed)
    Abstract [en]

    In order to investigate ways of incorporating an oxygen- or air-barrier component, in this case chitosan or chitosan-acetic acid salt (chitosan salt), at an early stage in the paper-making process, sheets of chitosan and pulp fiber were produced in a hand sheet mould or solution cast in petri dishes. Some sheets were buffered in an alkaline solution, in order to reduce the moisture sensitivity. The sheets were characterized with respect to air permeance, oxygen permeability, fracture stress and strain, young's modulus and moisture content. The addition of the chitosan solution to the pulp slurry led to a substantial loss of fiber and chitosan through the wire screen and consequently a low grammage and high sheet porosity and air permeance. Forming a wet pulp fiber sheet before introducing the chitosan solution increased the grammage and the amount of remaining chitosan, the latter revealed by infrared spectroscopy. In addition, pressing the sheets before drying reduced the porosity and the air permeance. Air mixing, included in conventional laboratory sheet making, yielded a more heterogeneous sheet and inferior mechanical and barrier properties. In general, the paper sheets prepared in the hand sheet mould became weaker, softer and less ductile with increasing content of chitosan. Only solution casting in petri dishes resulted in good barrier properties. Scanning electron microscopy showed that holes were absent in this case. In addition, optical microscopy and infrared spectroscopy revealed that the chitosan-salt formed a continuous phase and that it was uniformly distributed in the sheet. Interestingly, the problem of shrinkage when chitosan salt sheets are buffered for improved high-moisture gas-barrier proper-ties, was reduced significantly by the restraining action of the pulp fibers.

  • 22. Guo, Juan
    et al.
    Song, Kunlin
    Salmen, Lennart
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Innventia AB, Sweden .
    Yin, Yafang
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Changes of wood cell walls in response to hygro-mechanical steam treatment2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 115, p. 207-214Article in journal (Refereed)
    Abstract [en]

    The effects of compression combined with steam treatment (CS-treatment), i.e. a hygro-mechanical steam treatment on Spruce wood were studied on a cell-structure level to understand the chemical and physical changes of the secondary cell wall occurring under such conditions. Specially, imaging FT-IR microscopy, nanoindentation and dynamic vapour absorption were used to track changes in the chemical structure, in micromechanical and hygroscopic properties. It was shown that CS-treatment resulted in different changes in morphological, chemical and physical properties of the cell wall, in comparison with those under pure steam treatment. After CS-treatment, the cellular structure displayed significant deformations, and the biopolymer components, e.g. hemicellulo se and lignin, were degraded, resulting in decreased hygroscopicity and increased mechanical properties of the wood compared to both untreated and steam treated wood. Moreover, CS-treatment resulted in a higher degree of degradation especially in earlywood compared to a more uniform behaviour of wood treated only by steam.

  • 23.
    Hassanzadeh, Salman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Aminlashgari, Nina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Chemo-selective high yield microwave assisted reaction turns cellulose to green chemicals2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 112, p. 448-457Article in journal (Refereed)
    Abstract [en]

    Exceptionally high cellulose liquefaction yields, up to 87% as calculated from the amount of solid residue, were obtained under mild conditions by utilizing the synergistic effect of microwave radiation and acid catalysis. The effect of processing conditions on degradation products was fingerprinted by rapid laser desorption ionization-mass spectrometry (LDI-MS) method. The reaction was chemo-tunable, enabling production of glucose (Glc) or levulinic acid (LeA) at significantly high selectivity and yields, the relative molar yields being up to 50 and 69%, respectively. A turning point from pure depolymerization to glucose to further degradation to levulinic acid and formic acid was observed at approximately 50% liquefaction or above 140 degrees C. This was accompanied by the formation of small amounts of solid spherical carbonized residues. The reaction was monitored by multiple analytical techniques. The high yields were connected to the ability of the process to break the strong secondary interactions in cellulose. The developed method has great potential for future production of green platform chemicals.

  • 24.
    Hatton, Fiona L.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kedzior, S. A.
    Cranston, E. D.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Grafting-from cellulose nanocrystals via photoinduced Cu-mediated reversible-deactivation radical polymerization2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 157, p. 1033-1040Article in journal (Refereed)
    Abstract [en]

    In this work we describe the grafting of cellulose nanocrystals (CNCs) by surface-initiated photoinduced Cu-mediated reversible-deactivation radical polymerization (RDRP). Initially, CNCs obtained through sulfuric acid hydrolysis were functionalized with a tertiary bromo-ester moiety as an initiating group for the subsequent RDRP of methyl acrylate, targeting three different degrees of polymerization for the polymer grafts: 50, 300 and 600. The polymerizations proceeded in DMSO in the presence of CuBr2 and Me6TREN as the catalytic system utilizing a UV source (λmax ≈ 360 nm). The technique proved highly versatile for the modification of CNCs with poly(methyl acrylate), where considerably high grafting was achieved in short reaction times (90 min), with simple purification steps. CNC morphology was maintained and polymer grafts were evident through FT-IR spectroscopy, thermal analysis, contact angle measurements, X-ray photoelectron microscopy and x-ray diffraction.

  • 25.
    Henschen, Jonatan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Dongfang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ek, Monica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Preparation of cellulose nanomaterials via cellulose oxalates2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 213, p. 208-216Article in journal (Refereed)
    Abstract [en]

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

  • 26.
    Ibn Yaich, Anas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Adapting wood hydrolysate barriers to high humidity conditions2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 100, p. 135-142Article in journal (Refereed)
    Abstract [en]

    The incorporation of layered silicates in bio-based barrier films resulted in lower water vapor permeability, and significantly lowered oxygen permeability at a relative humidity (RH) as high as 80%, with reduced moisture sensitivity of the wood hydrolysate (WH) based films. The applicability of WH based films was accordingly extended over a wider relative humidity condition range. Crude aqueous process liquor, the WH, was extracted from hardwood and utilized as a feed-stock for films without any upgrading pretreatment, yet producing superior oxygen barrier performance compared to partially upgraded WH and highly purified hemicelluloses. Films composed of crude WH and either one of two types of naturally occurring layered silicates, montmorillonite (MMT) or talc, as mineral additives, were evaluated with respect to oxygen and water vapor permeability, morphological, tensile and dynamic thermo-mechanical properties. Films with an oxygen permeability as low as 1.5 (cm(3) mu m)/(m(2) day kPa) at 80% RH was achieved.

  • 27.
    Ibn Yaich, Anas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Enhanced formability and mechanical performance of wood hydrolysate films through reductive amination chain extension2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 117, p. 346-354Article in journal (Refereed)
    Abstract [en]

    An O-acetyl-4-O methylglucuronoxylan-rich wood hydrolysate (WH), generated by the hydrothermal treatment of hardwood, was chain extended using di- and tri-functionalized amino chain extenders through reductive amination. Chain extension was achieved via facile one- or two-step syntheses. The carbohydrate chain extension efficiency, molecular weights, and branching patterns were determined through a combination of SEC, 1HNMR, FUR and elemental analysis. The mild reaction conditions enabled an increase in the molecular weight while preserving the initial structures of the hemicelluloses. The chain extension strategy developed in this study was demonstrated to significantly improve the formability and mechanical performance of WH films, allowing for the water-casting production of coherent films with higher ratios of WH - 70-85% (w/w) - and reducing the need for co-components. Chain-extended WHs produced stronger and more ductile films than corresponding formulations prepared from unmodified WH. Films made from ethylenediamine chain-extended WH mixed with 30% (w/w) carboxymethyl cellulose showed a tensile strength of 62 MPa and a strain-to-failure of 3.3%. Additionally, chain-extended WHs produced films with an oxygen permeability as low as 0.2 cm(3) mu M m(-2) day(-1) kPa(-1) at 50% RH.

  • 28.
    Imre, Balázs
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience.
    Lidia, García
    AITIIP.
    Puglia, Debora
    University of Perugia.
    Vilaplana, Francisco
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience.
    Reactive Compatibilization of Plant Polysaccharidesand Biobased Polymers: Review on Current Strategies,Expectations and Reality2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344Article in journal (Refereed)
    Abstract [en]

    Our society is amidst a technological revolution towards a sustainable economy, focused on the development of biobased products in virtually all sectors. In this context, plant polysaccharides, as the most abundant macromoleculespresent in biomass represent a fundamental renewable resource for the replacement of fossil-based polymeric materials in commodity and engineering applications. However, native polysaccharides have several disadvantages compared to their synthetic counterparts, including reduced thermal stability, moisture absorption and limited mechanical performance, which hinder their direct application in native form in advanced material systems. Thus, polysaccharides are generally used in a derivatized form and/or in combination with other biobased polymers, requiring the compatibilization of such blends and composites. In this review we critically explore the current status and the future outlook of reactive compatibilization strategies of the most common plant polysaccharides in blends with biobased polymers. The chemical processes for the modification and compatibilization of starch and lignocellulosic based materialsare discussed, together with the practical implementation of these reactive compatibilization strategies with special emphasis on reactive extrusion. The efficiency of these strategies is critically discussed in the context on the definition of blending and compatibilization from a polymer physics standpoint; this relies on the detailed evaluation of the chemical structure of the constituent plant polysaccharides and biobased polymers, the morphology of the heterogeneous polymeric blends, and their macroscopic behavior, in terms of rheological and mechanical properties.

  • 29.
    Joby Kochumalayil, Jose
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Kasai, Wakako
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Regioselective modification of a xyloglucan hemicellulose for high-performance biopolymer barrier films2013In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 93, no 2, p. 466-472Article in journal (Refereed)
    Abstract [en]

    Biobased polymers such as starch and hemicelluloses from wood are of interest for packaging applications, but suffer from limitations in performance under moist conditions. Xyloglucan from industrial tamarind seed waste offers potential, but its Tg is too high for thermal processing applications. Regioselective modification is therefore performed using an approach involving periodate oxidation followed by reduction. The resulting polymer structures are characterized using MALDI-TOF-MS, size-exclusion chromatography, FTIR and carbohydrate analysis. Films are cast from water and characterized by thermo-gravimetry, dynamic mechanical thermal analysis, dynamic water vapor sorption, oxygen transmission and tensile tests. Property changes are interpreted from structural changes. These new polymers show much superior performance to current petroleum-based polymers in industrial use. Furthermore, this regioselective modification can be carefully controlled, and results in a new type of cellulose derivatives with preserved cellulose backbone without the need for harmful solvents.

  • 30.
    Kaldéus, Tahani
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Nordenström, Malin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Insights into the EDC-mediated PEGylation of cellulose nanofibrils and their colloidal stability2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, p. 871-878Article in journal (Refereed)
    Abstract [en]

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

  • 31. Kisonen, Victor
    et al.
    Xu, Chunlin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Eklund, Patrik
    Lindqvist, Hanna
    Sundberg, Anna
    Pranovich, Andrey
    Sinkkonen, Jari
    Vilaplana, Francisco
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Willför, Stefan
    Cationised O-acetyl galactoglucomannans: Synthesis and characterisation2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 99, p. 755-764Article in journal (Refereed)
    Abstract [en]

    Water-soluble O-acetyl-galactoglucomannans (GGMs) can be obtained from Norway spruce by hot-water-extraction of the wood or as a side product by ultrafiltration of mechanical pulping waters. Cationic and amphiphilic polysaccharides and their derivatives are of interest for a number of applications and thus quaternary nitrogen moieties with cationic charge were grafted onto GGMs in the heterogeneous reaction to render a cationic polyelectrolyte. The degree of substitution was measured by elemental analysis of nitrogen, by quantitative C-13 NMR and interestingly also by polyelectrolyte titration and the results were congruent. NMR, matrix-assisted laser desorption/ionisation mass spectroscopy (MALDI-TOF-MS), and FT-IR analysis were used to characterise the product. THF or DMSO with water enhanced the reaction efficiency and decreased M-w reduction in comparison to plain water as a reaction media. Cationised GGM was also successfully acetylated. The cationic derivatives of hemicelluloses can potentially be utilised as polyelectrolyte layers in packaging and pharmaceutical applications.

  • 32. Kuzmenko, Volodymyr
    et al.
    Hagg, Daniel
    Toriz, Guillermo
    Gatenholm, Paul
    In situ forming spruce xylan-based hydrogel for cell immobilization2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 102, p. 862-868Article in journal (Refereed)
    Abstract [en]

    An in situ forming spruce xylan-based hydrogel was synthesized in two steps with the intended use of cell encapsulation and in vivo delivery. First, bioconjugate was obtained through the reaction of glucuronic acid groups from xylan backbone with tyramine (TA). After that, the gelation process was enabled by enzymatic crosslinking of the phenol-containing TA-xylan conjugate. Exhibiting an exponential increase in the storage modulus, a 3D gel network was formed in about 20s. The designed gel showed extensive swelling and retained its mechanical integrity for more than two months. Mesenchymal stem cells were encapsulated in the hydrogel and cultured for one week. The cells retained their adipogenic differentiation capacity inside the gel, as verified by lipid accumulation. From these facts, we conclude that spruce xylan is a promising precursor for in situ forming hydrogels and should be evaluated further for tissue engineering purposes.

  • 33.
    Le Normand, Myriam
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Moriana, Rosana
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Isolation and characterization of cellulose nanocrystals from spruce bark in a biorefinery perspective2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 111, p. 979-987Article in journal (Refereed)
    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.

  • 34.
    Le Normand, Myriam
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Mélida, Hugo
    KTH, School of Biotechnology (BIO), Glycoscience.
    Holmbom, Bjarne
    Åbo Akademi.
    Michaelsen, Terje E.
    Unversity of Oslo.
    Inngjerdingen, Marit
    University of Oslo.
    Bulone, Vincent
    KTH, School of Biotechnology (BIO), Glycoscience.
    Paulsen, B.S.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Hot-water extracts from the inner bark of Norway spruce with immunomodulating activities2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 101, no 1, p. 699-704Article in journal (Refereed)
    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.

  • 35. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Parikka, Kirsti
    Eklund, Patrik
    Sjöholm, Rainer
    Brumer, Harry
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Tenkanen, Maija
    Willför, Stefan
    Targeted allylation and propargylation of galactose-containing polysaccharides in water2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 100, p. 46-54Article in journal (Refereed)
    Abstract [en]

    Galactose units of spruce galactoglucomannan (GGM), guar galactomannan (GM), and tamarind (galacto)xyloglucan (XG) were selectively allylated. Firstly aldehyde functionalities were formed at the C-6 position via enzymatic oxidation by galactose oxidase. The formed aldehydes were further derivatized by an indium mediated Barbier-Grignard type reaction, resulting in the formation of homoallylic alcohols. In addition to allylic halides, the same reaction procedure was also applicable for GGM, when using propargyl bromide as halide. All reaction steps were done in water, thus the polysaccharides were modified in a one-pot reaction. The formation of the allylated, or propargylated, product was identified by MALDI-TOF-MS. All polysaccharide products were isolated and further characterized by GC-MS or NMR spectroscopy. By this chemo-enzymatic process, we have demonstrated a novel method for derivatization of GGM and other galactose-containing polysaccharides. The derivatized polysaccharides are potential platforms for further functionalizations.

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

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

  • 37.
    Liu, Andong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Centres, Biofibre Materials Centre, BiMaC.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Clay nanopaper composites of nacre-like structure based on montmorrilonite and cellulose nanofibers-Improvements due to chitosan addition2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 87, no 1, p. 53-60Article in journal (Refereed)
    Abstract [en]

    Clay nanopaper are nanocomposites with nacre-like structure and multifunctional characteristics including high modulus, significant strength and toughness as well as fire retardancy and low oxygen transmission rate (OTR). Montmorrilonite (MTM) and nanofibrillated cellulose (NFC) hydrocolloids are combined with a chitosan (CS) solution to form high MTM content nanopaper structures by the use of a previously developed papermaking approach. Chitosan functions as flocculation agent and decreases dewatering time to less than 10% compared with MTM-NFC clay nanopaper. The effect of chitosan on the clay nanopaper structure was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Properties were measured by uniaxial tensile testing, thermogravimetric analysis (TGA), OTR and moisture adsorption experiments. A nacre-like multilayered structure was confirmed and the chitosan-clay nanopaper showed favorable mechanical properties at clay contents as high as 44-48 wt%.

  • 38.
    Lopez-Rubio, A.
    et al.
    Institute of Agrochemistry and Food Technology, CSIC.
    Lagaron, J. M.
    Institute of Agrochemistry and Food Technology, CSIC.
    Ankerfors, M.
    STFI-Packforsk.
    Lindström, T.
    STFI-Packforsk.
    Nordqvist, David
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Mattozzi, Alessandro
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Enhanced film forming and film properties of amylopectin using micro-fibrillated cellulose Carbohydr. Polym. 68 (2007) 718-7272008In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 71, no 3, p. 482-482Article in journal (Refereed)
  • 39. Lozhechnikova, A.
    et al.
    Dax, D.
    Vartiainen, J.
    Willför, S.
    Xu, Chunlin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Aalto University, Finland.
    Österberg, M.
    Modification of nanofibrillated cellulose using amphiphilic block-structured galactoglucomannans2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 110, p. 163-172Article in journal (Refereed)
    Abstract [en]

    Nanofibrillated cellulose (NFC) and hemicelluloses have shown to be highly promising renewable components both as barrier materials and in novel biocomposites. However, the hydrophilic nature of these materials restricts their use in some applications. In this work, the usability of modified O-acetyl galactoglucomannan (GGM) for modification of NFC surface properties was studied. Four GGM-block-structured, amphiphilic derivatives were synthesized using either fatty acids or polydimethylsiloxane as hydrophobic tails. The adsorption of these GGM derivatives was consecutively examined in aqueous solution using a quartz crystal microbalance with dissipation monitoring (QCM-D). It was found that the hydrophobic tails did not hinder adsorption of the GGM derivatives to cellulose, which was concluded to be due to the presence of the native GGM-block with high affinity to cellulose. The layer properties of the adsorbed block-co-polymers were discussed and evaluated. Self-standing NFC films were further prepared and coated with the GGM derivatives and the effect of the surface modification on wetting properties and oxygen permeability (OP) of the modified films was assessed.

  • 40. Lu, Ting
    et al.
    Xiang, Tao
    Huang, Xue-Lian
    Li, Cheng
    Zhao, Wei-Feng
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology. Sichuan University, China.
    Zhang, Qian
    Zhao, Chang-Sheng
    Post-crosslinking towards stimuli-responsive sodium alginate beads for the removal of dye and heavy metals2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 133, p. 587-595Article in journal (Refereed)
    Abstract [en]

    Post-crosslinking as a new strategy to prepare sodium alginate (SA) beads with controllable swelling behavior, pH sensitivity and adsorption capacity was developed by using the solution of glutaraldehyde (GA), acetic acid and hydrochloric acid as the coagulating agent, for which could be used to fabricate polysaccharide beads in a large scale. Fourier transform infrared spectroscopy and thermogravimetric analysis convinced the successful cross-linking of SA by GA. The macro-porous structures of the beads were observed by scanning electron microscopy. Both acetic acid and hydrochloric acid had great effects on the swelling behavior and pH sensitivity of the SA beads. The SA beads could adsorb cationic dye (methylene blue) as high as 572 mg/g and other metal ions (Cu2+, Ag+ and Fe3+). The adsorption processes fitted well with the pseudo-second-order kinetic model and the Freundlich isotherm. The large-scale production of SA beads with tunable properties opens a new route to industrially utilize polysaccharide beads in wastewater treatments, intelligent separation and so on.

  • 41.
    López Durán, Verónica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Larsson, Per A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Chemical modification of cellulose-rich fibres to clarify the influence of the chemical structure on the physical and mechanical properties of cellulose fibres and thereof made sheets2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 182, p. 1-7Article in journal (Refereed)
    Abstract [en]

    Despite the different chemical approaches used earlier to increase the ductility of fibre-based materials, it has not been possible to link the chemical modification to their mechanical performance. In this study, cellulose fibres have been modified by periodate oxidation, alone or followed either by borohydride reduction, reductive amination or chlorite oxidation. In addition, TEMPO oxidation, and TEMPO oxidation in combination with periodate oxidation and further reduction with sodium borohydride have also been studied. The objective was to gain understanding of the influence of different functional groups on the mechanical and structural properties of handsheets made from the modified fibres. It was found that the modifications studied improved the tensile strength of the fibres to different extents, but that only periodate oxidation followed by borohydride reduction provided more ductile fibre materials. Changes in density, water-holding capacity and mechanical performance were also quantified and all are dependent on the functional group introduced.

  • 42.
    Lôpez-Rubio, A.
    et al.
    Institute of Agrochemistry and Food Technology, CSIC.
    Lagaron, J. M.
    Institute of Agrochemistry and Food Technology, CSIC.
    Ankerfors, M.
    STFI-Packforsk.
    Lindström, T.
    STFI-Packforsk.
    Nordqvist, David
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Mattozzi, Alessandro
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Enhanced film forming and film properties of amylopectin using micro-fibrillated cellulose2007In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 68, no 4, p. 718-727Article in journal (Refereed)
    Abstract [en]

    This work describes a novel approach to produce amylopectin films with enhanced properties by the addition of micro fibrillated cellulose (MFC). Aqueous dispersions of gelatinized amylopectin, glycerol (0-38 wt%) and MFC (0-10 wt%) were cast at ambient temperature and 50% relative humidity and, after 10 days of storage, the tensile properties were investigated. The structure of the composite films was revealed by optical, atomic force and transmission electron microscopy. The moisture content was determined by thermogravimetry and the temperature-dependent film rigidity was measured by thermal mechanical analysis. Synchrotron simultaneous small- and wide-angle X-ray measurements revealed that the solutions had to be heated to above 85 degrees C in order to achieve complete gelatinization. Optical microscopy and atomic force microscopy revealed uniformly distributed MFC aggregates in the films, with a length of 10-90 mu m and a width spanning from a few hundred nanometers to several microns. Transmission electron microscopy showed that, in addition to aggregates, single MFC microfibrils were also embedded in the amylopectin matrix. It was impossible to cast antylopectin films of sufficient quality with less than 38 wt% glycerol. However, when MFC was added it was possible to produce high quality films even without glycerol. The film without glycerol was stiff and strong but not brittle. It was suggested that this remarkable effect was due to its comparatively high moisture content. Consequently MFC acted both as a "conventional" reinforcement because of its fibrous structure and also indirectly as a plasticiser because its presence led to an increase in film moisture content.

  • 43.
    Maleki, Laleh
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Synthesis of full interpenetrating hemicellulose hydrogel networks2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 170, p. 254-263Article in journal (Refereed)
    Abstract [en]

    Two methods with different cross-linking mechanisms for designing hemicellulose-based full interpenetrating polymer networks (IPNs) were developed through the sequential synthesis of full IPNs from O-acetyl-galactoglucomannan (AcGGM) utilizing free-radical polymerization and a thiol-ene click reaction. A faster swelling rate was observed for all IPN formulations compared with the single-network gels. The highly porous structure of the IPNs with small interconnected pores was verified using scanning electron microscopy. A rheological analysis revealed that the AcGGM IPNs fabricated by the free-radical polymerization of acrylamide and N-N'-methylenebisacrylamide (cross-linker) had shear storage modulus (G') values approximately 5 and 2.5 times higher than that of the corresponding precursor single networks of AcGGM. IPNs achieved through thiol-ene reactions between thiolated AcGGM and polyethylene glycol diacrylate had G' values 35-40 times higher than the single-network reference hydrogels.

  • 44.
    Maleki, Laleh
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Unrefined wood hydrolysates are viable reactants for the reproducible synthesis of highly swellable hydrogels2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 108, no 1, p. 281-290Article in journal (Refereed)
    Abstract [en]

    A value-adding robust and sequential synthetic pathway was elaborated to produce hydrogel structures with ionic character from crude acetylated galactoglucomannan-rich wood hydrolysate (WH). The WH was first-step liquor originating from a sulphite cracking pulp process for dissolving pulp. The synthetically modified WH fractions were verified at each step by NMR and FTIR, and the hydrogels were characterized with respect to their swelling and mechanical properties. Altering the crosslinking chemistry and the content of ionic moieties resulted in hydrogels with various swelling ratios and mechanical properties. Renewable hydrogel formulations with swelling ratios as high as Qeq = 270 were achieved.

  • 45.
    Marais, Andrew
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Kochumalayil, Joby J.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nilsson, Camilla
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Gamstedt, E. Kristofer
    Uppsala Univ, Uppsala, Sweden.
    Toward an alternative compatibilizer for PLA/cellulose composites: Grafting of xyloglucan with PLA2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 89, no 4, p. 1038-1043Article in journal (Refereed)
    Abstract [en]

    Poly(L-lactic acid) (PLLA) chains were grafted on xyloglucan substrates via ring-opening polymerization of the L-Iactide monomer. Different parameters such as the nature of the substrate (native or modified xyloglucan) and the substrate/monomer ratios were varied in the synthesis to achieve different lengths of the grafted chains. A range of experimental techniques including infrared spectroscopy and nuclear magnetic resonance were used to characterize the final product. Thermal analysis showed that the glass transition temperature of xyloglucan was decreased from 252 degrees C to 216 degrees C following the grafting of PLLA. The grafting of less hydrophilic chains from xyloglucan also affected the interaction with water: the PLEA-grafted xyloglucan was insoluble in water and the moisture uptake could be decreased by about 30%. Xyloglucan adsorbs strongly to cellulose; therefore such a graft copolymer may improve the compatibility between cellulose fibers and PLLA. The PLEA-grafted xyloglucan may be useful as a novel compatibilizer in fiber-reinforced PLEA composites.

  • 46.
    Marais, Andrew
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Utsel, Simon
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Gustafsson, Emil
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Towards a super-strainable paper using the Layer-by-Layer technique2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 100, p. 218-224Article in journal (Refereed)
    Abstract [en]

    The Layer-by-Layer technique was used to build a polyelectrolyte multilayer on the surface of pulp fibres. The treated fibres were then used to prepare paper sheets and the mechanical properties of these sheets were evaluated as a function of the number of bi-layers on the fibres. Two different systems were studied: polyethyleneimine (PEI)/nanofibrillated cellulose (NFC), and polyallylamine hydrochloride (PAH)/hyaluronic acid (HA). Model experiments using dual polarization interferometry and SiO2 surfaces showed that the two systems gave different thicknesses for a given number of layers. The outer layer was found to be a key parameter in the PEI/NFC system, whereas it was less important in the PAH/HA system. The mechanical properties of the sheets made from the PAH/HA treated fibres were significantly greater than those made from untreated fibres, reaching 70 Nm/g in tensile index and 6.5% in strain at break. Such a modification could be very useful for 3D forming of paper, opening new perspectives in for example the packaging industry, with a renewable and biodegradable product as a potential substitute for some of the traditional oil-based plastics.

  • 47.
    Menzel, Carolin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience. Univ Politecn Valencia, Inst Ingn Alimentos Desarrolla, Dept Tecnol Alimentos, Valencia, Spain..
    Gonzalez-Martinez, Chelo
    Univ Politecn Valencia, Inst Ingn Alimentos Desarrolla, Dept Tecnol Alimentos, Valencia, Spain..
    Chiralt, Amparo
    Univ Politecn Valencia, Inst Ingn Alimentos Desarrolla, Dept Tecnol Alimentos, Valencia, Spain..
    Vilaplana, Francisco
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience.
    Antioxidant starch films containing sunflower hull extracts2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 214, p. 142-151Article in journal (Refereed)
    Abstract [en]

    This study explores the preparation of antioxidant starch food packaging materials by the incorporation of valuable phenolic compounds extracted from sunflower hulls, which are an abundant by-product from food industry. The phenolic compounds were extracted with aqueous methanol and embedded into starch films. Their effect on starch films was investigated in terms of antioxidant activity, optical, thermal, mechanical, barrier properties and changes in starch molecular structure. The starch molecular structure was affected during thermal processing resulting in a decrease in molar mass, smaller amylopectin molecules and shorter amylose branches. Already 1-2% of extracts were sufficient to produce starch films with high antioxidant capacity. Higher amounts (4-6%) of extract showed the highest antioxidant activity, the lowest oxygen permeability and high stiffness and poor extensibility. The phenolic extracts affected predominantly the mechanical properties, whereas other changes could mainly be correlated to the lower glycerol content which was partially substituted by the extract.

  • 48.
    Mira, Isabel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Persson, Karin
    YKI.
    Villwock, V. Kurtis
    On the effect of surface active agents and their structure on the temperature-induced changes of normal and waxy wheat starch in aqueous suspension.: Part II: A confocal laser scanning microscopy study2007In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 68, no 4, p. 637-646Article in journal (Refereed)
    Abstract [en]

    The location and penetration patterns of two fluorescently labelled, surface active molecules into normal and waxy wheat starch granules prior, during and after the temperature-induced gelatinization were studied by means of confocal laser scanning microscopy (CLSM). Amphiphilic dyes were found to have a tendency to penetrate wheat starch granules in aqueous suspension. The penetration patterns were however found to be dependent on the contact time, type of starch and the chain length (C-12 vs. C-16) of the amphiphilic dye. The penetration of amphiphilic dyes through the starch granule matrix proved to be less restricted in waxy than in normal wheat starch. For a given type of starch, the penetration of the longer chain dye was more constrained than that of the shorter chain one. The extent to which the dye diffuses into the granule matrix as it gelatinizes is also affected by the chain length of the dye, diffusion of the shorter chain dye occurring more profusely and at lower temperatures than for the longer chain one. These differences are suggested to be related to the dissociation temperature of the ANI-amphiphilic dye complexes.

  • 49.
    Mira, Isabel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Persson, Karin
    Willwock, V. Kurtis
    On the effect of surface active agents and their structure on the temperature-induced changes of normal and waxy wheat starch in aqueous suspension.: Part I. Pasting and calorimetric studies2007In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Carbohydrate polymers, Vol. 68, no 4, p. 665-678Article in journal (Refereed)
    Abstract [en]

    Pasting and calorimetric studies of normal and waxy wheat starch were performed in the presence of a series of ionic (sulphates, trimethyl ammonium bromides) and non-ionic (monoglycerides, maltosides) short (12 carbon atoms) and long (16 carbon atoms) n-alkyl chain surfactants. With the exception of the alkyl ammonium bromides, all of the short chain surfactants lower the pasting temperature (PT) in normal wheat starch, while the long chain surfactants have the opposite effect. Contrary, regardless of their chain length, all ionic surfactants lower the PT in waxy wheat starch while the non-ionic surfactants induce small, sometimes almost negligible changes in the PT. Calorimetric studies revealed the absence of a direct connection between the effect of surfactants on the onset of the starch gelatinization transition and the PT. However, in the presence of all surfactants, except the alkyl ammonium bromides, the PT of normal wheat starch was found to lie within or very close the temperature range within which the dissociation of the amylose-surfactant complexes takes place. Waxy wheat starch, in contrast, pasted at temperatures that fell within the temperature range of the starch gelatinization transition. This is taken as evidence of the existence of a correlation between the PT and the dissociation of the amylose-surfactant complexes.

  • 50.
    Morais de Carvalho, Danila
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Abad, Antonio Martinez
    KTH, School of Biotechnology (BIO), Glycoscience.
    Evtuguin, D. V.
    Colodette, J. L.
    Lindström, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Vilaplana, Francisco
    KTH, School of Biotechnology (BIO), Glycoscience.
    Sevastyanova, Olena
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Isolation and characterization of acetylated glucuronoarabinoxylan from sugarcane bagasse and straw2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 156, p. 223-234Article in journal (Refereed)
    Abstract [en]

    Sugarcane bagasse and straw are generated in large volumes as by-products of agro-industrial production. They are an emerging valuable resource for the generation of hemicellulose-based materials and products, since they contain significant quantities of xylans (often twice as much as in hardwoods). Heteroxylans (yields of ca 20% based on xylose content in sugarcane bagasse and straw) were successfully isolated and purified using mild delignification followed by dimethyl sulfoxide (DMSO) extraction. Delignification with peracetic acid (PAA) was more efficient than traditional sodium chlorite (NaClO2) delignification for xylan extraction from both biomasses, resulting in higher extraction yields and purity. We have shown that the heteroxylans isolated from sugarcane bagasse and straw are acetylated glucuronoarabinoxylans (GAX), with distinct molecular structures. Bagasse GAX had a slightly lower glycosyl substitution molar ratio of Araf to Xylp to (0.5:10) and (4-O-Me)GlpA to Xylp (0.1:10) than GAX from straw (0.8:10 and 0.1:10 respectively), but a higher degree of acetylation (0.33 and 0.10, respectively). A higher frequency of acetyl groups substitution at position α-(1 → 3) (Xyl-3Ac) than at position α-(1 → 2) (Xyl-2Ac) was confirmed for both bagasse and straw GAX, with a minor ratio of diacetylation (Xyl-2,3Ac). The size and molecular weight distributions for the acetylated GAX extracted from the sugarcane bagasse and straw were analyzed using multiple-detection size-exclusion chromatography (SEC-DRI-MALLS). Light scattering data provided absolute molar mass values for acetylated GAX with higher average values than did standard calibration. Moreover, the data highlighted differences in the molar mass distributions between the two isolation methods for both types of sugarcane GAX, which can be correlated with the different Araf and acetyl substitution patterns. We have developed an empirical model for the molecular structure of acetylated GAX extracted from sugarcane bagasse and straw with PAA/DMSO through the integration of results obtained from glycosidic linkage analysis, 1H NMR spectroscopy and acetyl quantification. This knowledge of the structure of xylans in sugarcane bagasse and straw will provide a better understanding of the isolation-structure-properties relationship of these biopolymers and, ultimately, create new possibilities for the use of sugarcane xylan in high-value applications, such as biochemicals and bio-based materials. © 2016 Elsevier Ltd

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