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Sample records for hydrate cellulose film

  1. Solubility Behaviour of Cellulose in a Sodium Hydrate/Urea/Thiourea Aqueous Solvent

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shuai; CHENG Feng-wei; LI Fa-xue; YU Jian-yong; GU Li-xia

    2008-01-01

    Cellulose pulps were directly dissolved in a green solvent of sodium hydrate/urea/thiourea/water with different composition for the purpose to prepare new regenerated cellulose fibers or films. The results showed that the highest solubility of cellulose in the solvent with the composition of 8/8/6.5/77.5. The results revealed that the pulp feeding sequence, stirring rate, pre-treatment of pulp and pulp size affected the cellulose concentration in the green solvent. Accordingly, the more effective dissolution method was proposed in order to get higher concentration of cellulose. Furthermore, the properties of solution prepared by different kinds of pulps in the solvent were investigated by ARES rheometer. Rheological analyses indicated that all cellulose aqueous solutions in their high concentration were pseudoplastic fluids and sensitive to temperature and tended to transform to gel when temperature increased.

  2. Influence of Cellulose Ethers on Hydration Products of Portland Cement

    Institute of Scientific and Technical Information of China (English)

    MA Baoguo; OU Zhihua; JIAN Shouwei; XU Rulin

    2011-01-01

    Cellulose ethers are widely used to mortar formulations, and it is significant to understand the interaction between cellulose ethers and cement pastes. FT-IR spectra, thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article. The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste, but the major hydration products, such as CH (calcium hydroxide), ettringite and C-S-H, appeared later in the modified cement pastes than in the unmodified cement paste. The cellulose ethers decrease the outer products and increase inner products of C-S-H gels. Compared to unmodified cement pastes, no new products are found in the modified cement pastes in the present experiment. The HEMC and HPMC investigation shows almost the same influence on the hydration products of Portland cement.

  3. [Supramolecular reorganizations in cellulose during hydration].

    Science.gov (United States)

    Grunin, Iu B; Grunin, L Iu; Talantsev, V I; Nikol'skaia, E A; Masas, D S

    2015-01-01

    The analysis of modern ideas about the structural organization of the cellulose microfibrils is carried out. The mechanism of the formation of additional capillary-porous system of cellulose under moistening is offered. It is established that when the moisture content of cellulose reaches 8-10%, the filling of its micropores occurs with a simultaneous increase in their cross sizes, a specific surface and reduction in the degree of crystallinity of specimens. Within the proposed model of microfibril construction the parameters of supramolecular structure and capillary-porous system of cotton cellulose are determined.

  4. Flexible Photonic Cellulose Nanocrystal Films

    OpenAIRE

    Guidetti, G.; Atifi, S; Vignolini, S; Hamad, WY

    2016-01-01

    The fabrication of self-assembled cellulose nanocrystal (CNC) films of tunable photonic and mechanical properties using a facile, green approach is demonstrated. The combination of tunable flexibility and iridescence can dramatically expand CNC coating and film barrier capabilities for paints and coating applications, sustainable consumer packaging products, as well as effective templates for photonic and optoelectronic materials and structures. CelluForce Inc., Biotechnology and Biologica...

  5. BIODEGRADATION OF REGENERATED CELLULOSE FILMS BY FUNGI

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; LIU Haiqing; ZHENG Lianshuang; ZHANG Jiayao; DU Yumin; LIU Weili

    1996-01-01

    The biodegradability of Aspergillus niger (A. niger), Mucor (M-305) and Trichoderma (T-311) strains on regenerated cellulose films in media was investigated. The results showed that T-311 strain isolated from soil adhered on the cellulose film fragments has stronger degradation effect on the cellulose film than A. niger strain. The weights, molecular weights and tensile strengths of the cellulose films in both shake culture and solid media decreased with incubation time, accompanied by producing CO2 and saccharides. HPLC, IR and released CO2 analysis indicated that the biodegradation products of the regenerated cellulose films mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO2 and water.After a month, the films were completely decomposed by fungi in the media at 30℃.

  6. Sulfated cellulose thin films with antithrombin affinity

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Cellulose thin films were chemically modified by in situ sulfation to produce surfaces with anticoagulant characteristics. Two celluloses differing in their degree of polymerization (DP: CEL I (DP 215–240 and CEL II (DP 1300–1400 were tethered to maleic anhydride copolymer (MA layers and subsequently exposed to SO3•NMe3 solutions at elevated temperature. The impact of the resulting sulfation on the physicochemical properties of the cellulose films was investigated with respect to film thickness, atomic composition, wettability and roughness. The sulfation was optimized to gain a maximal surface concentration of sulfate groups. The scavenging of antithrombin (AT by the surfaces was determined to conclude on their potential anticoagulant properties.

  7. Thin blend films of cellulose and polyacrylonitrile

    Science.gov (United States)

    Lu, Rui; Zhang, Xin; Mao, Yimin; Briber, Robert; Wang, Howard

    Cellulose is the most abundant renewable, biocompatible and biodegradable natural polymer. Cellulose exhibits excellent chemical and mechanical stability, which makes it useful for applications such as construction, filtration, bio-scaffolding and packaging. To further expand the potential applications of cellulose materials, their alloying with synthetic polymers has been investigated. In this study, thin films of cotton linter cellulose (CLC) and polyacrylonitrile (PAN) blends with various compositions spanning the entire range from neat CLC to neat PAN were spun cast on silicon wafers from common solutions in dimethyl sulfoxide / ionic liquid mixtures. The morphologies of thin films were characterized using optical microscopy, atomic force microscopy, scanning electron microscopy and X-ray reflectivity. Morphologies of as-cast films are highly sensitive to the film preparation conditions; they vary from featureless smooth films to self-organized ordered nano-patterns to hierarchical structures spanning over multiple length scales from nanometers to tens of microns. By selectively removing the PAN-rich phase, the structures of blend films were studied to gain insights in their very high stability in hot water, acid and salt solutions.

  8. Digital Color in Cellulose Nanocrystal Films

    OpenAIRE

    Dumanli, Ahu Gümrah; van der Kooij, Hanne M.; Kamita, Gen; Reisner, Erwin; Baumberg, Jeremy J.; Steiner, Ullrich; Vignolini, Silvia

    2014-01-01

    This is the final published version. It first appeared at http://pubs.acs.org/doi/abs/10.1021/am501995e. Cellulose nanocrystals (CNCs) form chiral nematic phases in aqueous suspensions that can be preserved upon evaporation of water. The resulting films show an intense directional coloration determined by their microstructure. Here, microreflection experiments correlated with analysis of the helicoidal nanostructure of the films reveal that the iridescent colors and the ordering of the ind...

  9. Comparison of physical properties of regenerated cellulose films fabricated with different cellulose feedstocks in ionic liquid.

    Science.gov (United States)

    Pang, JinHui; Wu, Miao; Zhang, QiaoHui; Tan, Xin; Xu, Feng; Zhang, XueMing; Sun, RunCang

    2015-05-05

    With the serious "white pollution" resulted from the non-biodegradable plastic films, considerable attention has been directed toward the development of renewable and biodegradable cellulose-based film materials as substitutes of petroleum-derived materials. In this study, environmentally friendly cellulose films were successfully prepared using different celluloses (pine, cotton, bamboo, MCC) as raw materials and ionic liquid 1-ethyl-3-methylimidazolium acetate as a solvent. The SEM and AFM indicated that all cellulose films displayed a homogeneous and smooth surface. In addition, the FT-IR and XRD analysis showed the transition from cellulose I to II was occurred after the dissolution and regeneration process. Furthermore, the cellulose films prepared by cotton linters and pine possessed the most excellent thermal stability and mechanical properties, which were suggested by the highest onset temperature (285°C) and tensile stress (120 MPa), respectively. Their excellent properties of regenerated cellulose films are promising for applications in food packaging and medical materials.

  10. Model films of cellulose. I. Method development and initial results

    NARCIS (Netherlands)

    Gunnars, S.; Wågberg, L.; Cohen Stuart, M.A.

    2002-01-01

    This report presents a new method for the preparation of thin cellulose films. NMMO (N- methylmorpholine- N-oxide) was used to dissolve cellulose and addition of DMSO (dimethyl sulfoxide) was used to control viscosity of the cellulose solution. A thin layer of the cellulose solution is spin- coated

  11. Molecular Orientation in Dry and Hydrated Cellulose Fibers: A Coherent Anti-Stokes Raman Scattering Microscopy Study

    OpenAIRE

    Zimmerley, Maxwell; Younger, Rebecca; Valenton, Tiffany; Oertel, David C.; Ward, Jimmie L.; Potma, Eric O.

    2010-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is combined with spontaneous Raman scattering microspectroscopy and second harmonic generation (SHG) microscopy to interrogate the molecular alignment in dry and hydrated cellulose fibers. Two types of cellulose were investigated: natural cellulose I in cotton fibers and regenerated cellulose II in rayon fibers. On the basis of the orientation of the methylene symmetric stretching vibration, the molecular alignment of cellulose microfibr...

  12. 21 CFR 177.1400 - Hydroxyethyl cellulose film, water-insoluble.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxyethyl cellulose film, water-insoluble. 177... cellulose film, water-insoluble. Water-insoluble hydroxyethyl cellulose film may be safely used for... cellulose film consists of a base sheet manufactured by the ethoxylation of cellulose under...

  13. Methane hydrate stability in the presence of water-soluble hydroxyalkyl cellulose

    Institute of Scientific and Technical Information of China (English)

    M. Mohammad-Taheri; A. Zarringhalam Moghaddam; K. Nazari; N. Gholipour Zanjani

    2012-01-01

    The effect of low-dosage water-soluble hydroxyethyl cellulose (approximate Mw~90,000 and 250,000) as a member ofhydroxyalkyl cellulosic polymer group on methane hydrate stability was investigated by monitoring hydrate dissociation at pressures greater than atmospheric pressure in a closed vessel.In particular,the influence of molecular weight and mass concentration of hydroxyethyl cellulose (HEC) was studied with respect to hydrate formation and dissociation.Methane hydrate formation was performed at 2 ℃ and at a pressure greater than 100 bar.Afterwards,hydrate dissociation was initiated by step heating from - 10 ℃ at a mild pressure of 13 bar to -3 ℃,0 ℃ and 2 ℃.With respect to the results obtained for methane hydrate formation/dissociation and the amount of gas uptake,we concluded that HEC 90,000 at 5000 ppm is suitable for long-term gas storage and transportation under a mild pressure of 13 bar and at temperatures below the freezing point.

  14. Structure and Property of Silk Fibroin / Cellulose Blend Film

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-qiang; XING Tie-ling

    2004-01-01

    Silk fibroin/cellulose blend films were prepared using N-methylmorpholine -N-oxide (NMMO) as solvent. The effects of different proportions and solid contents on properties of blend films were discussed. The mechanical properties showed that the blend films had preferable moisture permeability and a high strength. The structures of the blend films were investigated by infrared spectrum and X-ray diffraction. The results indicated the occurrence of hydrogen bonds between hydroxyl groups of cellulose and amido groups of fibroin.

  15. Reinforcement of all-cellulose nanocomposite films using native cellulose nanofibrils.

    Science.gov (United States)

    Zhao, Jiangqi; He, Xu; Wang, Yaru; Zhang, Wei; Zhang, Xinxing; Zhang, Xiaodan; Deng, Yulin; Lu, Canhui

    2014-04-15

    All-cellulose nanocomposite films were prepared using native cellulose nanofibrils (CNFs) as fillers and lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) dissolved regenerated cellulose as the matrix. The CNFs, with diameters in the range of 15-40 nm were obtained by combined physical methods of ultrasonic treatment and high shear homogenization. The morphology, structure, and properties of the nanocomposite films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), optical transmittance, thermal gravimetric analysis (TGA), and mechanical testing. The nanocomposite films exhibited good optical transparency, thermal stability, and remarkably enhanced mechanical properties compared to the regenerated cellulose matrix. By varying the CNFs content, the tensile strength of the nanocomposite films increased from 61.56 MPa to 99.92 MPa and the Young's modulus increased from 0.76 GPa to 4.16 GPa. This work provided a promising pathway for manufacturing high performance and environmental-friendly all-cellulose nanocomposites.

  16. Determination of hydration film thickness using atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    PENG Changsheng; SONG Shaoxian; GU Qingbao

    2005-01-01

    Dispersion of a solid particle in water may lead to the formation of hydration film on the particle surface, which can strongly increase the repulsive force between the particles and thus strongly affect the stability of dispersions. The hydration film thickness, which varies with the variation of property of suspension particles, is one of the most important parameters of hydration film, and is also one of the most difficult parameters that can be measured accurately. In this paper, a method, based on force-distance curve of atomic force microscopy, for determining the hydration film thickness of particles is developed. The method utilizes the difference of cantilever deflection before, between and after penetrating the hydration films between tip and sample, which reflect the difference of slope on the force-distance curve. 3 samples, mica, glass and stainless steel, were used for hydration thickness determination, and the results show that the hydration film thickness between silicon tip and mica, glass and stainless steel are 30.0(2.0, 29.0(1.0 and 32.5(2.5 nm, respectively.

  17. Dielectric Characterization of Confined Water in Chiral Cellulose Nanocrystal Films.

    Science.gov (United States)

    Natarajan, Bharath; Emiroglu, Caglar; Obrzut, Jan; Fox, Douglas M; Pazmino, Beatriz; Douglas, Jack F; Gilman, Jeffrey W

    2017-04-26

    A known deterrent to the large-scale development and use of cellulose nanocrystals (CNCs) in composite materials is their affinity for moisture, which has a profound effect on dispersion, wetting, interfacial adhesion, matrix crystallization, water uptake, and hydrothermal stability. To quantify and control the hydration and confinement of absorbed water in CNCs, we studied sulfated-CNCs neutralized with sodium cations and CNCs functionalized with less hydrophilic methyl(triphenyl)phosphonium cations. Films were cast from water suspensions at 20 °C under controlled humidity and drying rate, yielding CNC materials with distinguishably different dielectric properties and cholesteric structures. By controlling the evaporation rate, we obtained self-assembled chiral CNC films with extended uniformity, having helical modulation length (nominal pitch) tunable from 1300 to 600 nm. SEM imaging and UV-vis-NIR total reflectance spectra revealed tighter and more uniform CNC packing in films cast at slow evaporation rates or having lower surface energy when modified with phosphonium. The dielectric constant was measured by a noncontact microwave cavity perturbation method and fitted to a classical mixing model employing randomly oriented ellipsoidal water inclusions. The dielectric constant of absorbed water was found to be significantly smaller than that for free liquid indicating a limited mobility due to binding with the CNC "matrix". In the case of hydrophilic Na-modified CNCs, a decreasing pitch led to greater anisotropy in the shape of moisture inclusions (ellipsoidal to platelet-like) and greater confinement. In contrast, the structure of hydrophobic phosphonium-modified CNC films was found to have reduced pitch, yet the shape of confined water remained predominantly spherical. These results provide a useful perspective on the current state of understanding of CNC-water interactions as well as on CNC self-assembly mechanisms. More broadly, we believe that our results

  18. Ionic liquid-cellulose film for enzyme immobilization

    NARCIS (Netherlands)

    Klein, Manuela Poletto; Scheeren, Carla Weber; Glock Lorenzoni, Andre Soibelmann; Dupont, Jairton; Frazzon, Jeverson; Hertz, Plinho Francisco

    2011-01-01

    beta-Galactosidase was immobilized in an ionic liquid-cellulose film that presents properties as increased flexibility and formability. A polyamine was added during the preparation of the film and their presence was detected by infrared analysis. Glutaraldehyde was used to activate the films in orde

  19. Cellulose aerogels prepared from an aqueous zinc chloride salt hydrate melt.

    Science.gov (United States)

    Schestakow, Maria; Karadagli, Ilknur; Ratke, Lorenz

    2016-02-10

    Monolithic cellulose aerogels are prepared using a salt hydrate melt based on cheap zinc chloride tetrahydrate (ZnCl2·4H2O) that can be washed out of the wet gel-body by using common solvents such as water, ethanol, isopropanol or acetone. Cellulose aerogels with concentrations of 1-5 wt.% cellulose were produced. These aerogels are characterized with respect to shrinkage, density and surface area as well as mechanical properties and micro-structure via SEM. Cellulose aerogels regenerated in acetone show a specific surface area of around 340 m(2)g(-1) being 60% higher than those regenerated in water. The onset of irreversible plastic deformation under compressive load is around 0.8 MPa for acetone-regenerated aerogels and thus a factor of two larger compared to ethanol regenerated ones. The Young's modulus depends almost linearly on the cellulose concentration which is observed for all regenerative fluids with the exception of water. The results achieved are presented in light of the polarity and ability of solvation of ZnCl2·4H2O in the regenerative fluids used.

  20. Effect of hydration on the structure of non aqueous ethyl cellulose/propylene glycol dicaprylate gels.

    Science.gov (United States)

    Bruno, Lilia; Kasapis, Stefan; Heng, Paul W S

    2012-03-01

    Changes in the structural properties of ethyl cellulose/propylene glycol dicaprylate systems (EC/PGD), intended for topical drug delivery, upon addition of water were investigated. Although designed to be a non-aqueous vehicle for moisture sensitive drugs, these systems are expected to experience an aqueous environment during production, storage and application on the skin. Hence, the interaction of water molecules with the non aqueous gel system and their distribution within the gel network is of interest and critical to its application. Experimental techniques of this study were small-deformation dynamic oscillation in shear, modulated differential scanning calorimetry (MDSC), (2)H NMR spectroscopy, ATR-infrared spectroscopy, wide-angle X-ray diffraction patterns and light microscopy. Rheological profiles of the gels containing moisture from 0.1 to 40.0% (w/w) deviated considerably from that of the non aqueous system at levels of water above 10.0% in preparations. Gradual replacement of the EC/PGD dipole interactions with stronger hydrogen bonding between ethyl cellulose chains, as the level of hydration increased, contributed to these observations. Formation of clusters of ethyl cellulose, observed under a light microscope, was thus ensued. X-ray diffraction patterns showed that the rearrangement of the polymer chains led to the loss of liquid crystal structures found in the anhydrous gel. MDSC and (2)H NMR were used to further shed light on the thermodynamic state of added water molecules in the gels. Plots of enthalpy obtained calorimetrically and a good correlation between MDSC and (2)H NMR data indicate that gels with less than two percent hydration contain water in a non-freezable bound state, whereas freezable moieties are obtained at levels of hydration above five percent in composite (EC/PGD/water) gels.

  1. Coassembly of gold nanoparticles and cellulose nanocrystals in composite films.

    Science.gov (United States)

    Lukach, Ariella; Thérien-Aubin, Héloïse; Querejeta-Fernández, Ana; Pitch, Natalie; Chauve, Grégory; Méthot, Myriam; Bouchard, Jean; Kumacheva, Eugenia

    2015-05-12

    Coassembly of nanoparticles with different size-, shape-, and composition-dependent properties is a promising approach to the design and fabrication of functional materials and devices. This paper reports the results of a detailed investigation of the formation and properties of free-stranding composite films formed by the coassembly of cellulose nanocrystals and shape-isotropic plasmonic gold nanoparticles. The effect of gold nanoparticle size, surface charge, and concentration on the structural and optical properties of the composite films has been studied. The composite films retained photonic crystal and chiroptical activity properties. The size and surface charge of gold nanoparticles had a minor effect on the structure and properties of the composite films, while the concentration of gold nanoparticles in the composite material played a more significant role and can be used to fine-tune the optical properties of materials derived from cellulose nanocrystals. These findings significantly broaden the range of nanoparticles that can be used for producing nanocomposite materials based on cellulose nanocrystals. The simplicity of film preparation, the abundance of cellulose nanocrystals, and the robust, free-standing nature of the composite films offer highly advantageous features and pave the way for the generation of functional materials with coupled optical properties.

  2. Investigation of water mobility and diffusivity in hydrating micronized low-substituted hydroxypropyl cellulose, hydroxypropylmethyl cellulose, and hydroxypropyl cellulose matrix tablets by magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, Masazumi; Nakagami, Hiroaki [Daiichi Pharmaceutical Co., Tokyo (Japan). Pharmaceutical Technology Research Lab.

    2002-12-01

    The water mobility and diffusivity in the gel-layer of hydrating low-substituted hydroxypropyl cellulose (LH41) tablets with or without a drug were investigated by magnetic resonance imaging (MRI) and compared with those properties in the gel-layer of hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) tablets. For this purpose, a localized image-analysis method was newly developed, and the spin-spin relaxation time (T{sub 2}) and apparent self-diffusion coefficient (ADC) of water in the gel-layer were visualized in one-dimensional maps. Those maps showed that the extent of gel-layer growth in the tablets was in the order of HPC>HPMC>>LH41, and there was a water mobility gradient across the gel-layers of all three tablet formulations. The T{sub 2} and ADC in the outer parts of the gel-layers were close to those of free water. In contrast, these values in the inner parts of the gel-layer decreased progressively; suggesting that the water mobility and diffusivity around the core interface were highly restricted. Furthermore, the correlation between the T{sub 2} of {sup 1}H proton in the gel-layer of the tablets and the drug release rate from the tablets was observed. (author)

  3. Cellulose antibody films for highly specific evanescent wave immunosensors

    Science.gov (United States)

    Hartmann, Andreas; Bock, Daniel; Jaworek, Thomas; Kaul, Sepp; Schulze, Matthais; Tebbe, H.; Wegner, Gerhard; Seeger, Stefan

    1996-01-01

    For the production of recognition elements for evanescent wave immunosensors optical waveguides have to be coated with ultrathin stable antibody films. In the present work non amphiphilic alkylated cellulose and copolyglutamate films are tested as monolayer matrices for the antibody immobilization using the Langmuir-Blodgett technique. These films are transferred onto optical waveguides and serve as excellent matrices for the immobilization of antibodies in high density and specificity. In addition to the multi-step immobilization of immunoglobulin G(IgG) on photochemically crosslinked and oxidized polymer films, the direct one-step transfer of mixed antibody-polymer films is performed. Both planar waveguides and optical fibers are suitable substrates for the immobilization. The activity and specificity of immobilized antibodies is controlled by the enzyme-linked immunosorbent assay (ELISA) technique. As a result reduced non-specific interactions between antigens and the substrate surface are observed if cinnamoylbutyether-cellulose is used as the film matrix for the antibody immobilization. Using the evanescent wave senor (EWS) technology immunosensor assays are performed in order to determine both the non-specific adsorption of different coated polymethylmethacrylat (PMMA) fibers and the long-term stability of the antibody films. Specificities of one-step transferred IgG-cellulose films are drastically enhanced compared to IgG-copolyglutamate films. Cellulose IgG films are used in enzymatic sandwich assays using mucine as a clinical relevant antigen that is recognized by the antibodies BM2 and BM7. A mucine calibration measurement is recorded. So far the observed detection limit for mucine is about 8 ng/ml.

  4. Preparation of cellulose II and III{sub I} films by allomorphic conversion of bacterial cellulose I pellicles

    Energy Technology Data Exchange (ETDEWEB)

    Faria-Tischer, Paula C.S., E-mail: paula.tischer@pq.cnpq.br [BioPol, Departamento de Química, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); UMR 5628 (LMGP), CNRS and Grenoble Institute of Technology, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Tischer, Cesar A. [BioPol, Departamento de Química, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); CIME Nanotech, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Heux, Laurent [Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); Le Denmat, Simon; Picart, Catherine [UMR 5628 (LMGP), CNRS and Grenoble Institute of Technology, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Sierakowski, Maria-R. [BioPol, Departamento de Química, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); and others

    2015-06-01

    The structural changes resulting from the conversion of native cellulose I (Cel I) into allomorphs II (Cel II) and III{sub I} (Cel III{sub I}) have usually been studied using powder samples from plant or algal cellulose. In this work, the conversion of Cel I into Cel II and Cel III{sub I} was performed on bacterial cellulose films without any mechanical disruption. The surface texture of the films was observed by atomic force microscopy (AFM) and the morphology of the constituting cellulose ribbons, by transmission electron microscopy (TEM). The structural changes were characterized using solid-state NMR spectroscopy as well as X-ray and electron diffraction. The allomorphic change into Cel II and Cel III{sub I} resulted in films with different crystallinity, roughness and hydrophobic/hydrophilicity surface and the films remained intact during all process of allomorphic conversion. - Highlights: • Description of a method to modify the allomorphic structure of bacterial cellulose films • Preparation of films with specific morphologies and hydrophobic/hydrophilic surface characters • First report on cellulose III films from bacterial cellulose under swelling conditions • Detailed characterization of cellulose II and III films with complementary techniques • Development of films with specific properties as potential support for cells, enzymes, and drugs.

  5. All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application.

    Science.gov (United States)

    Ghaderi, Moein; Mousavi, Mohammad; Yousefi, Hossein; Labbafi, Mohsen

    2014-04-15

    All-cellulose nanocomposite (ACNC) film was produced from sugarcane bagasse nanofibers using N,N-dimethylacetamide/lithium chloride solvent. The average diameter of bagasse fibers (14 μm) was downsized to 39 nm after disk grinding process. X-ray diffraction showed that apparent crystallinity and crystallite size decreased relatively to an increased duration of dissolution time. Thermogravimetric analysis confirmed that thermal stability of the ACNC was slightly less than that of the pure cellulose nanofiber sheet. Tensile strength of the fiber sheet, nanofiber sheet and ACNC prepared with 10 min dissolution time were 8, 101 and 140 MPa, respectively. Water vapor permeability (WVP) of the ACNC film increased relatively to an increased duration of dissolution time. ACNC can be considered as a multi-performance material with potential for application in cellulose-based food packaging owing to its promising properties (tough, bio-based, biodegradable and acceptable levels of WVP).

  6. Lactic Acid and Biosurfactants Production from Residual Cellulose Films.

    Science.gov (United States)

    Portilla Rivera, Oscar Manuel; Arzate Martínez, Guillermo; Jarquín Enríquez, Lorenzo; Vázquez Landaverde, Pedro Alberto; Domínguez González, José Manuel

    2015-11-01

    The increasing amounts of residual cellulose films generated as wastes all over the world represent a big scale problem for the meat industry regarding to environmental and economic issues. The use of residual cellulose films as a feedstock of glucose-containing solutions by acid hydrolysis and further fermentation into lactic acid and biosurfactants was evaluated as a method to diminish and revalorize these wastes. Under a treatment consisting in sulfuric acid 6% (v/v); reaction time 2 h; solid liquid ratio 9 g of film/100 mL of acid solution, and temperature 130 °C, 35 g/L of glucose and 49% of solubilized film was obtained. From five lactic acid strains, Lactobacillus plantarum was the most suitable for metabolizing the glucose generated. The process was scaled up under optimized conditions in a 2-L bioreactor, producing 3.4 g/L of biomass, 18 g/L of lactic acid, and 15 units of surface tension reduction of a buffer phosphate solution. Around 50% of the cellulose was degraded by the treatment applied, and the liqueurs generated were useful for an efficient production of lactic acid and biosurfactants using L. plantarum. Lactobacillus bacteria can efficiently utilize glucose from cellulose films hydrolysis without the need of clarification of the liqueurs.

  7. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles

    Science.gov (United States)

    It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of th...

  8. Drug release kinetics from carboxymethylcellulose-bacterial cellulose composite films.

    Science.gov (United States)

    Juncu, Gheorghe; Stoica-Guzun, Anicuta; Stroescu, Marta; Isopencu, Gabriela; Jinga, Sorin Ion

    2016-08-30

    Composite films of sodium carboxymethyl cellulose and bacterial cellulose (NaCMC-BC) cross-linked with citric acid (CA) were prepared by solution casting method. Ibuprofen sodium salt (IbuNa) has been used to study the mechanism of drug release from composite films. Surface morphology was investigated by scanning electron microscopy (SEM) and proved that the BC content influences the aspect of the films. Fourier transformed infrared spectroscopy (FTIR) revealed specific peaks in IR spectra of composite films which sustain that NaCMC was cross-linked with CA. Starting from swelling observations, the release kinetic of IbuNa was described using a model which neglects the volume expansion due to polymer swelling and which considers non-linear diffusion coefficients for drug and solvent. The IbuNa release is also influenced by BC content, the drug release rate was decreasing with the increase of BC content.

  9. Fabrication of cellulose nanofiber transparent films for IT applications

    Science.gov (United States)

    Zhai, Lindong; Song, Sangho; Kim, Jeong Woong; Li, Yaguang; Kim, Jaehwan

    2016-04-01

    One of the abundant renewable biomaterials in the world - cellulose is produced from plants forming micro-fibrils which in turn aggregate of form cellulose fibers. These fibers size can be disintegrated from micro-fibrils to nanofibers by physical and chemical methods. Cellulose nanofibers (CNF) can be a new building block of renewable smart materials. The CNF has excellent mechanical strength, dimensional stability, thermal stability and good optical properties on top of their renewable behavior. This paper reports CNF transparent films made by CNF extracted by the physical method: a high pressure physical, so called aqueous counter collision method. Natural behaviors, extraction and film formation of CNF are explained and their characteristics are illustrated, which is suit for IT applications.

  10. Biodegradable Nanocomposite Films Based on Sodium Alginate and Cellulose Nanofibrils

    Directory of Open Access Journals (Sweden)

    B. Deepa

    2016-01-01

    Full Text Available Biodegradable nanocomposite films were prepared by incorporation of cellulose nanofibrils (CNF into alginate biopolymer using the solution casting method. The effects of CNF content (2.5, 5, 7.5, 10 and 15 wt % on mechanical, biodegradability and swelling behavior of the nanocomposite films were determined. The results showed that the tensile modulus value of the nanocomposite films increased from 308 to 1403 MPa with increasing CNF content from 0% to 10%; however, it decreased with further increase of the filler content. Incorporation of CNF also significantly reduced the swelling percentage and water solubility of alginate-based films, with the lower values found for 10 wt % in CNF. Biodegradation studies of the films in soil confirmed that the biodegradation time of alginate/CNF films greatly depends on the CNF content. The results evidence that the stronger intermolecular interaction and molecular compatibility between alginate and CNF components was at 10 wt % in CNF alginate films.

  11. Complex film of chitosan and carboxymethyl cellulose nanofibers.

    Science.gov (United States)

    Kawasaki, Takuma; Nakaji-Hirabayashi, Tadashi; Masuyama, Kazuhira; Fujita, Satoshi; Kitano, Hiromi

    2016-03-01

    A polymer film composed of a mixture of chitosan (Ch) and carboxymethyl cellulose sodium salt (CMC) nanofibers was deposited on a glass surface. The thin film of the Ch-CMC mixture obtained was stable, and fibroblast adhesion to the film was lowest when the weight ratio of Ch to CMC was 4:6. The ζ-potential and contact angle of the mixture film indicated that a polyion complex of Ch and CMC was formed. The mechanical strength of the film composed of Ch-CMC nanofiber complexes was much higher than that of the film composed of Ch-water-soluble CMC complexes (non-nanofiber), likely because the entanglement of nanofibers was enhanced by electrostatic attractions. These results indicate that the charge-neutralized nanofiber film was highly effective in suppressing cell adhesion and therefore is a promising material for biomedical applications.

  12. Physical and mechanical properties of modified bacterial cellulose composite films

    Science.gov (United States)

    Indrarti, Lucia; Indriyati, Syampurwadi, Anung; Pujiastuti, Sri

    2016-02-01

    To open wide range application opportunities of Bacterial Cellulose (BC) such as for agricultural purposes and edible film, BC slurries were blended with Glycerol (Gly), Sorbitol (Sor) and Carboxymethyl Cellulose (CMC). The physical and mechanical properties of BC composites were investigated to gain a better understanding of the relationship between BC and the additive types. Addition of glycerol, sorbitol and CMC influenced the water solubility of BC composite films. FTIR analysis showed the characteristic bands of cellulose. Addition of CMC, glycerol, and sorbitol slightly changed the FTIR spectrum of the composites. Tensile test showed that CMC not only acted as cross-linking agent where the tensile strength doubled up to 180 MPa, but also acted as plasticizer with the elongation at break increased more than 100% compared to that of BC film. On the other hand, glycerol and sorbitol acted as plasticizers that decreased the tensile strength and increased the elongation. Addition of CMC can improve film transparency, which is quite important in consumer acceptance of edible films in food industry.

  13. Biocompatible Bacterial Cellulose-Poly(2-hydroxyethyl methacrylate Nanocomposite Films

    Directory of Open Access Journals (Sweden)

    Andrea G. P. R. Figueiredo

    2013-01-01

    Full Text Available A series of bacterial cellulose-poly(2-hydroxyethyl methacrylate nanocomposite films was prepared by in situ radical polymerization of 2-hydroxyethyl methacrylate (HEMA, using variable amounts of poly(ethylene glycol diacrylate (PEGDA as cross-linker. Thin films were obtained, and their physical, chemical, thermal, and mechanical properties were evaluated. The films showed improved translucency compared to BC and enhanced thermal stability and mechanical performance when compared to poly(2-hydroxyethyl methacrylate (PHEMA. Finally, BC/PHEMA nanocomposites proved to be nontoxic to human adipose-derived mesenchymal stem cells (ADSCs and thus are pointed as potential dry dressings for biomedical applications.

  14. Biocompatible Bacterial Cellulose-Poly(2-hydroxyethyl methacrylate) Nanocomposite Films

    Science.gov (United States)

    Figueiredo, Andrea G. P. R.; Figueiredo, Ana R. P.; Alonso-Varona, Ana; Fernandes, Susana C. M.; Palomares, Teodoro; Rubio-Azpeitia, Eva; Barros-Timmons, Ana; Silvestre, Armando J. D.; Pascoal Neto, Carlos; Freire, Carmen S. R.

    2013-01-01

    A series of bacterial cellulose-poly(2-hydroxyethyl methacrylate) nanocomposite films was prepared by in situ radical polymerization of 2-hydroxyethyl methacrylate (HEMA), using variable amounts of poly(ethylene glycol) diacrylate (PEGDA) as cross-linker. Thin films were obtained, and their physical, chemical, thermal, and mechanical properties were evaluated. The films showed improved translucency compared to BC and enhanced thermal stability and mechanical performance when compared to poly(2-hydroxyethyl methacrylate) (PHEMA). Finally, BC/PHEMA nanocomposites proved to be nontoxic to human adipose-derived mesenchymal stem cells (ADSCs) and thus are pointed as potential dry dressings for biomedical applications. PMID:24093101

  15. Properties of films composed of cellulose nanowhiskers and a cellulose matrix regenerated from alkali/urea solution.

    Science.gov (United States)

    Qi, Haisong; Cai, Jie; Zhang, Lina; Kuga, Shigenori

    2009-06-01

    All-cellulose composite films were prepared, for the first time, from native cellulose nanowhiskers and cellulose matrix regenerated from aqueous NaOH-urea solvent system on the basis of their temperature-dependent solubility. The cellulose whiskers retained their needlelike morphology with mean length and diameter of 300 and 21 nm as well as native crystallinity when added to the latter solution at ambient temperature. The structure and physical properties of the nanocomposite films were characterized by scanning electron microscope, X-ray diffraction, and tensile tests. The composite films were isotropic and transparent to visible light and showed good mechanical properties as a result of the reinforcement by the whiskers. By varying the ratio of the cellulose whiskers to regenerated cellulose matrix (cellulose II), the tensile strength and elastic modulus of the nanocomposite films could be tuned to reach 124 MPa and 5 GPa, respectively. The tensile strength of the nanocomposite films could reach 157 MPa through a simple drawing process, with the calculated Hermans' orientation parameter of 0.30. This work provided a novel pathway for the preparation of biodegradable all-cellulose nanocomposites, which are expected to be useful as biomaterials and food ingredients.

  16. Birefringence control of solution-cast film of cellulose triacetate

    Science.gov (United States)

    Kiyama, Ayumi; Nobukawa, Shogo; Yamaguchi, Masayuki

    2017-10-01

    We controlled the optical anisotropy of a solution-cast film composed of cellulose triacetate (CTA) by adding ferrocene. Owing to the molecular orientation in the film plane of solution-cast films, which results from the normal stress applied during the solvent evaporation process, the average refractive index is usually higher in the plane of the film than in the thickness direction. We found that the addition of ferrocene, which is miscible with CTA, reduced the optical anisotropy by nematic interaction; i.e., ferrocene molecules are forcibly embedded into the film plane accompanying the CTA chains. Because the direction of anisotropic polarizability of ferrocene is perpendicular to the long axis of the molecule, the refractive index in the thickness direction is reduced. Furthermore, the stress-optical coefficient in the glassy state is reduced by the addition of ferrocene.

  17. Cellulose Nanofibril Film as a Piezoelectric Sensor Material.

    Science.gov (United States)

    Rajala, Satu; Siponkoski, Tuomo; Sarlin, Essi; Mettänen, Marja; Vuoriluoto, Maija; Pammo, Arno; Juuti, Jari; Rojas, Orlando J; Franssila, Sami; Tuukkanen, Sampo

    2016-06-22

    Self-standing films (45 μm thick) of native cellulose nanofibrils (CNFs) were synthesized and characterized for their piezoelectric response. The surface and the microstructure of the films were evaluated with image-based analysis and scanning electron microscopy (SEM). The measured dielectric properties of the films at 1 kHz and 9.97 GHz indicated a relative permittivity of 3.47 and 3.38 and loss tangent tan δ of 0.011 and 0.071, respectively. The films were used as functional sensing layers in piezoelectric sensors with corresponding sensitivities of 4.7-6.4 pC/N in ambient conditions. This piezoelectric response is expected to increase remarkably upon film polarization resulting from the alignment of the cellulose crystalline regions in the film. The CNF sensor characteristics were compared with those of polyvinylidene fluoride (PVDF) as reference piezoelectric polymer. Overall, the results suggest that CNF is a suitable precursor material for disposable piezoelectric sensors, actuators, or energy generators with potential applications in the fields of electronics, sensors, and biomedical diagnostics.

  18. Effect of hydration film on scanning images of atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A standard calibration grating was used for image scanning to investigate the effect of hydration films on imaging resolution by Atomic Force Microscope (AFM). The results showed that the hydration films greatly affect the imaging resolution for the tapping mode, but no evident effect on the contact mode. The possible reasons for the effect of hydration films on scanning images of AFM are also brought forward here.

  19. Investigation of mass transport properties of microfibrillated cellulose (MFC) films

    DEFF Research Database (Denmark)

    Minelli, Matteo; Baschetti, Marco Giacinti; Doghieri, Ferruccio

    2010-01-01

    sorption experiments confirmed the hydrophilic character of these cellulosic materials and showed a dual effect of glycerol which reduced the water uptake at low water activity while enhancing it at high relative humidity. The water diffusion in dry samples was remarkably slow for a porous material...... was observed in permeation experiments. Dry MFC films showed excellent oxygen barrier properties; however, a dramatic decrease in these properties was observed when the water content in the samples was increased....

  20. Effect of ethanol on the water permeability of controlled release films composed of ethyl cellulose and hydroxypropyl cellulose.

    Science.gov (United States)

    Larsson, Mikael; Hjärtstam, Johan; Berndtsson, Jolina; Stading, Mats; Larsson, Anette

    2010-11-01

    The robustness of controlled release formulations when co-ingested with alcohol is a current concern expressed by regulatory authorities, especially with regard to dose dumping. One such controlled release formulation commonly used is film coating composed of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC). The aim of this study was to investigate how the presence of ethanol in the dissolution medium affects the water permeability of such films. Film samples were prepared in various EC-HPC compositions, and the effect of different ethanol concentrations in the dissolution medium on the permeability was studied using a modified Ussing chamber and tritiated water. It was found that the effect of ethanol on the film permeability varied depending on the composition of the films. The results were interpreted in terms of swelling of the EC in the films, where the swelling increased with increasing ethanol concentration. Thus, for films with low HPC content (non-interconnected pores), the water permeability of the films increased with increasing ethanol concentration as the diffusion through the ethyl cellulose increased due to swelling. However, for films with higher HPC content (having interconnected pores through the films), the permeability decreased, likely due to the swelling of the ethyl cellulose blocking the pores. The interpretation of the results was supported by dynamic mechanic analysis and SEM analysis.

  1. Preparation and properties of cellulose nanocrystals reinforced collagen composite films.

    Science.gov (United States)

    Li, Weichang; Guo, Rui; Lan, Yong; Zhang, Yi; Xue, Wei; Zhang, Yuanming

    2014-04-01

    Collagen films have been widely used in the field of biomedical engineering. However, the poor mechanical properties of collagen have limited its application. Here, rod-like cellulose nanocrystals (CNCs) were fabricated and used to reinforce collagen films. A series of collagen/CNCs films were prepared by collagen solution with CNCs suspensions homogeneously dispersed at CNCs: collagen weight ratios of 1, 3, 5, 7, and 10. The morphology of the resulting films was analyzed by scanning electron microscopy (SEM), the enhancement of the thermomechanical properties of the collagen/CNCs composites were demonstrated by thermal gravimetric analysis (TGA) and mechanical testing. Among the CNCs contents used, a loading of 7 wt % led to the maximum mechanical properties for the collagen/CNCs composite films. In addition, in vitro cell culture studies revealed that the CNCs have no negative effect on the cell morphology, viability, and proliferation and possess good biocompatibility. We conclude that the incorporation of CNCs is a simple and promising way to reinforce collagen films without impairing biocompatibility. This study demonstrates that the composite films show good potential for use in the field of skin tissue engineering.

  2. Optical properties of hydroxyethyl cellulose film treated with nitrogen plasma

    Science.gov (United States)

    Mahmoud, K. H.

    2016-03-01

    Hydroxyethyl cellulose (HEC) film has been prepared by casting technique. The prepared sample has been treated with nitrogen plasma at different exposure times. The optical absorption was recorded at room temperature in the wavelength range of 200-800 nm. Absorbance fitting procedure curves revealed a direct allowed transition with optical band gap, Eopt, of 4.9 eV for pristine film, and this value decreases to 4.30 eV for 20 min plasma treatment time. The band tail values (Ee) were found to be increased under plasma time treatment from 1.74 eV in case of the pristine film to 2.20 eV for 20 min. The dispersion of refractive index and complex dielectric constants under plasma treatment was also studied. Variation of color parameters under effect of the plasma treatment is analyzed in the framework of CIE L*U*V* color space.

  3. Nanocrystalline cellulose (NCC) reinforced alginate based biodegradable nanocomposite film.

    Science.gov (United States)

    Huq, Tanzina; Salmieri, Stephane; Khan, Avik; Khan, Ruhul A; Le Tien, Canh; Riedl, Bernard; Fraschini, Carole; Bouchard, Jean; Uribe-Calderon, Jorge; Kamal, Musa R; Lacroix, Monique

    2012-11-06

    Nanocrystalline cellulose (NCC) reinforced alginate-based nanocomposite film was prepared by solution casting. The NCC content in the matrix was varied from 1 to 8% ((w/w) % dry matrix). It was found that the nanocomposite reinforced with 5 wt% NCC content exhibits the highest tensile strength which was increased by 37% compared to the control. Incorporation of NCC also significantly improved water vapor permeability (WVP) of the nanocomposite showing a 31% decrease due to 5 wt% NCC loading. Molecular interactions between alginate and NCC were supported by Fourier Transform Infrared Spectroscopy. The X-ray diffraction studies also confirmed the appearance of crystalline peaks due to the presence of NCC inside the films. Thermal stability of alginate-based nanocomposite films was improved after incorporation of NCC. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Nanoscale cellulose films with different crystallinities and mesostructures--their surface properties and interaction with water.

    Science.gov (United States)

    Aulin, Christian; Ahola, Susanna; Josefsson, Peter; Nishino, Takashi; Hirose, Yasuo; Osterberg, Monika; Wågberg, Lars

    2009-07-07

    A systematic study of the degree of molecular ordering and swelling of different nanocellulose model films has been conducted. Crystalline cellulose II surfaces were prepared by spin-coating of the precursor cellulose solutions onto oxidized silicon wafers before regeneration in water or by using the Langmuir-Schaefer (LS) technique. Amorphous cellulose films were also prepared by spin-coating of a precursor cellulose solution onto oxidized silicon wafers. Crystalline cellulose I surfaces were prepared by spin-coating wafers with aqueous suspensions of sulfate-stabilized cellulose I nanocrystals and low-charged microfibrillated cellulose (LC-MFC). In addition, a dispersion of high-charged MFC was used for the buildup of polyelectrolyte multilayers with polyetheyleneimine on silica with the aid of the layer-by-layer (LbL) technique. These preparation methods produced smooth thin films on the nanometer scale suitable for X-ray diffraction and swelling measurements. The surface morphology and thickness of the cellulose films were characterized in detail by atomic force microscopy (AFM) and ellipsometry measurements, respectively. To determine the surface energy of the cellulose surfaces, that is, their ability to engage in different interactions with different materials, they were characterized through contact angle measurements against water, glycerol, and methylene iodide. Small incidence angle X-ray diffraction revealed that the nanocrystal and MFC films exhibited a cellulose I crystal structure and that the films prepared from N-methylmorpholine-N-oxide (NMMO), LiCl/DMAc solutions, using the LS technique, possessed a cellulose II structure. The degree of crystalline ordering was highest in the nanocrystal films (approximately 87%), whereas the MFC, NMMO, and LS films exhibited a degree of crystallinity of about 60%. The N,N-dimethylacetamide (DMAc)/LiCl film possessed very low crystalline ordering (properties of the films, it was necessary to consider both the

  5. Bio-based Films from Linter Cellulose and Its Acetates: Formation and Properties.

    Science.gov (United States)

    Morgado, Daniella L; Rodrigues, Bruno V M; Almeida, Erika V R; Seoud, Omar A El; Frollini, Elisabete

    2013-06-14

    This paper describes the results obtained on the preparation of films composed of linter cellulose and the corresponding acetates. The acetylation was carried out in the LiCl/DMAc solvent system. Films were prepared from a LiCl/DMAc solution of cellulose acetates (degree of substitution, DS 0.8-2.9) mixed with linter cellulose (5, 10 and 15 wt %). Detailed characterization of the films revealed the following: (i) they exhibited fibrous structures on their surfaces. The strong tendency of the linter cellulose chains to aggregate in LiCl/DMAc suggests that these fibrous elements consist of cellulose chains, as can be deduced from SEM images of the film of cellulose proper; (ii) the cellulose acetate films obtained from samples with DS 2.1 and 2.9 exhibited microspheres on the surface, whose formation seems to be favored for acetates with higher DS; (iii) AFM analysis showed that, in general, the presence of cellulose increased both the asperity thickness and the surface roughness of the analyzed films, indicating that cellulose chains are at least partially organized in domains and not molecularly dispersed between acetate chains; and (iv) the films prepared from cellulose and acetates exhibited lower hygroscopicity than the acetate films, also suggesting that the cellulose chains are organized into domains, probably due to strong intermolecular interactions. The linter and sisal acetates (the latter from a prior study), and their respective films, were prepared using the same processes; however, the two sets of films presented more differences (as in humidity absorption, optical, and tensile properties) than similarities (as in some morphological aspects), most likely due to the different properties of the starting materials. Potential applications of the films prepared in tissue engineering scaffold coatings and/or drug delivery are mentioned.

  6. Selective permeation of hydrogen gas using cellulose nanofibril film.

    Science.gov (United States)

    Fukuzumi, Hayaka; Fujisawa, Shuji; Saito, Tsuguyuki; Isogai, Akira

    2013-05-13

    Biobased membranes that can selectively permeate hydrogen gas have been developed from aqueous dispersions of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCN) prepared from wood cellulose: TOCN-coated plastic films and self-standing TOCN films. Compared with TOCNs with sodium, lithium, potassium, and cesium carboxylate groups, TOCN with free carboxyl groups (TOCN-COOH) had much high and selective H2 gas permeation performance. Because permeabilities of H2, N2, O2, and CO2 gases through the membranes primarily depended on their kinetic diameters, the gas permeation behavior of the various TOCNs can be explained in terms of a diffusion mechanism. Thus, the selective H2 gas permeability for TOCN-COOH was probably due to a larger average size in free volume holes present between nanofibrils in the layer and film than those of other TOCNs with metal carboxylate groups. The obtained results indicate that TOCN-COOH membranes are applicable as biobased H2 gas separation membranes in fuel cell electric power generation systems.

  7. Chemically modified cellulose paper as a thin film microextraction phase.

    Science.gov (United States)

    Saraji, Mohammad; Farajmand, Bahman

    2013-11-01

    In this paper, chemically modified cellulose paper was introduced as a novel extracting phase for thin film microextraction (TFME). Different reagents (Octadecyltrichlorosilane, diphenyldichlorosilane, cyclohexyl isocyanate and phenyl isocyanate) were used to modify the cellulose papers. The modified papers were evaluated as a sorbent for the extraction of some synthetic and natural estrogenic hormones (17α-ethynylestradiol, estriol and estradiol) from aqueous samples. Liquid chromatography-fluorescence detection was used for the quantification of the extracted compounds. The cellulose paper modified with phenyl isocyanate showed the best affinity to the target compounds. TEME parameters such as desorption condition, shaking rate, sample ionic strength and extraction time were investigated and optimized. Limit of detections were between 0.05 and 0.23μgL(-1) and relative standard deviations were less than 11.1% under the optimized condition. The calibration curves were obtained in the range of 0.2-100μgL(-1) with a good linearity (r(2)>0.9935). Wastewater, human urine, pool and river water samples were studied as real samples for the evaluation of the method. Relative recoveries were found to be between 75% and 101%.

  8. Physical and mechanical testing of essential oil-embedded cellulose ester films

    Science.gov (United States)

    Polymer films made from cellulose esters are useful for embedding plant essential oils, either for food packaging or air freshener applications. Studies and testing were done on the physical and mechanical properties of cellulose ester-based films incorporating essential oils (EO) from lemongrass (C...

  9. Properties of cast films made of chayote (Sechium edule Sw.) tuber starch reinforced with cellulose nanocrystals

    Science.gov (United States)

    In this study, cellulose (C) and cellulose nanocrystals (CN) were blended with chayote tuber (Sechium edule Sw.) starch (CS) in formulations cast into films. The films were conditioned at different storage temperatures and relative humidity (RH), and analyzed by mechanical tests, X-ray diffraction, ...

  10. 36 CFR 1237.30 - How do agencies manage records on nitrocellulose-base and cellulose-acetate base film?

    Science.gov (United States)

    2010-07-01

    ... records on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks, Forests... and cellulose-acetate base film? (a) The nitrocellulose base, a substance akin to gun cotton, is... picture film and X-ray film—nitrocellulose base). (b) Agencies must inspect cellulose-acetate...

  11. Tunable Semicrystalline Thin Film Cellulose Substrate for High-Resolution, In-Situ AFM Characterization of Enzymatic Cellulose Degradation.

    Science.gov (United States)

    Ganner, Thomas; Roŝker, Stephanie; Eibinger, Manuel; Kraxner, Johanna; Sattelkow, Jürgen; Rattenberger, Johannes; Fitzek, Harald; Chernev, Boril; Grogger, Werner; Nidetzky, Bernd; Plank, Harald

    2015-12-23

    In the field of enzymatic cellulose degradation, fundamental interactions between different enzymes and polymorphic cellulose materials are of essential importance but still not understood in full detail. One technology with the potential of direct visualization of such bioprocesses is atomic force microscopy (AFM) due to its capability of real-time in situ investigations with spatial resolutions down to the molecular scale. To exploit the full capabilities of this technology and unravel fundamental enzyme-cellulose bioprocesses, appropriate cellulose substrates are decisive. In this study, we introduce a semicrystalline-thin-film-cellulose (SCFTC) substrate which fulfills the strong demands on such ideal cellulose substrates by means of (1) tunable polymorphism via variable contents of homogeneously sized cellulose nanocrystals embedded in an amorphous cellulose matrix; (2) nanoflat surface topology for high-resolution and high-speed AFM; and (3) fast, simple, and reproducible fabrication. The study starts with a detailed description of SCTFC preparation protocols including an in-depth material characterization. In the second part, we demonstrate the suitability of SCTFC substrates for enzymatic degradation studies by combined, individual, and sequential exposure to TrCel6A/TrCel7A cellulases (Trichoderma reesei) to visualize synergistic effects down to the nanoscale.

  12. Hydrate film growth on the surface of a gas bubble suspended in water.

    Science.gov (United States)

    Peng, B Z; Dandekar, A; Sun, C Y; Luo, H; Ma, Q L; Pang, W X; Chen, G J

    2007-11-01

    The lateral film growth rate of CH4, C2H4, CO2, CH4 + C2H4, and CH4 + C3H8 hydrates in pure water were measured at four fixed temperatures of 273.4, 275.4, 277.4, and 279.4 K by means of suspending a single gas bubble in water. The results showed that the lateral growth rates of mixed-gas CH4 + C2H4 hydrate films were slower than that of pure gas (CH4 or C2H4) for the same driving force and that of mixed-gas CH4 + C3H8 hydrate film growth was the slowest. The dependence of the thickness of hydrate film on the driving force was investigated, and it was demonstrated that the thickness of hydrate film was inversely proportional to the driving force. It was found that the convective heat transfer control model reported in the literature could be used to formulate the lateral film growth rate v(f) with the driving force DeltaT perfectly for all systems after introduction of the assumption that the thickness of hydrate films is inversely proportional to the driving force DeltaT; i.e., v(f) = psiDeltaT(5/2) is correct and independent of the composition of gas and the type of hydrate. The thicknesses of different gas hydrate films were estimated, and it is demonstrated that the thicknesses of mixed-gas hydrate films were thicker than those of pure gases, which was qualitatively consistent with the experimental result.

  13. Smooth deuterated cellulose films for the visualisation of adsorbed bio-macromolecules.

    Science.gov (United States)

    Su, Jielong; Raghuwanshi, Vikram S; Raverty, Warwick; Garvey, Christopher J; Holden, Peter J; Gillon, Marie; Holt, Stephen A; Tabor, Rico; Batchelor, Warren; Garnier, Gil

    2016-10-31

    Novel thin and smooth deuterated cellulose films were synthesised to visualize adsorbed bio-macromolecules using contrast variation neutron reflectivity (NR) measurements. Incorporation of varying degrees of deuteration into cellulose was achieved by growing Gluconacetobacter xylinus in deuterated glycerol as carbon source dissolved in growth media containing D2O. The derivative of deuterated cellulose was prepared by trimethylsilylation(TMS) in ionic liquid(1-butyl-3-methylimidazolium chloride). The TMS derivative was dissolved in toluene for thin film preparation by spin-coating. The resulting film was regenerated into deuterated cellulose by exposure to acidic vapour. A common enzyme, horseradish peroxidase (HRP), was adsorbed from solution onto the deuterated cellulose films and visualized by NR. The scattering length density contrast of the deuterated cellulose enabled accurate visualization and quantification of the adsorbed HRP, which would have been impossible to achieve with non-deuterated cellulose. The procedure described enables preparing deuterated cellulose films that allows differentiation of cellulose and non-deuterated bio-macromolecules using NR.

  14. Smooth deuterated cellulose films for the visualisation of adsorbed bio-macromolecules

    Science.gov (United States)

    Su, Jielong; Raghuwanshi, Vikram S.; Raverty, Warwick; Garvey, Christopher J.; Holden, Peter J.; Gillon, Marie; Holt, Stephen A.; Tabor, Rico; Batchelor, Warren; Garnier, Gil

    2016-10-01

    Novel thin and smooth deuterated cellulose films were synthesised to visualize adsorbed bio-macromolecules using contrast variation neutron reflectivity (NR) measurements. Incorporation of varying degrees of deuteration into cellulose was achieved by growing Gluconacetobacter xylinus in deuterated glycerol as carbon source dissolved in growth media containing D2O. The derivative of deuterated cellulose was prepared by trimethylsilylation(TMS) in ionic liquid(1-butyl-3-methylimidazolium chloride). The TMS derivative was dissolved in toluene for thin film preparation by spin-coating. The resulting film was regenerated into deuterated cellulose by exposure to acidic vapour. A common enzyme, horseradish peroxidase (HRP), was adsorbed from solution onto the deuterated cellulose films and visualized by NR. The scattering length density contrast of the deuterated cellulose enabled accurate visualization and quantification of the adsorbed HRP, which would have been impossible to achieve with non-deuterated cellulose. The procedure described enables preparing deuterated cellulose films that allows differentiation of cellulose and non-deuterated bio-macromolecules using NR.

  15. Cellulose nanocrystals as organic nanofillers for transparent polycarbonate films

    Energy Technology Data Exchange (ETDEWEB)

    Xu Weinan; Qin Zongyi, E-mail: phqin@dhu.edu.cn; Yu Houyong; Liu Yannan; Liu Na; Zhou Zhe; Chen Long, E-mail: happyjack@dhu.edu.cn [College of Materials Science and Engineering, Donghua University, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials (China)

    2013-04-15

    Cellulose nanocrystals (CNCs) produced by sulfuric acid hydrolysis as organic nanofillers were dispersed into polycarbonate (PC) in organic solution through a solvent exchange procedure, and their influence on the optical, mechanical, and thermal properties of the resulting composite films were studied. It is demonstrated that due to the good dispersion of the nanofillers in the polymeric matrix, the formation of strong hydrogen bonds between carbonyl groups of PC and hydroxyl groups of the CNCs can be achieved, leading to a simultaneous reinforcement effect on mechanical and thermal properties of the composite films. Moreover, it was further found that the existence of nanofillers in the composite efficiently hindered the main thermal degradation pathways of PC involving the chain scission at carbonate linkage and rearrangement of carbonate groups. Compared with neat PC, the composite film with 3 wt% CNCs has an increase of about 30.6 % in tensile strength, 27.3 % in Young's modulus, and 3.3 % in maximum decomposition temperature, but still remain quite transparent.

  16. Reduction of the water wettability of cellulose film through controlled heterogeneous modification.

    Science.gov (United States)

    Li, Wei; Wu, Yuehan; Liang, Weiwei; Li, Bin; Liu, Shilin

    2014-04-23

    A facile method had been applied to introduce hydrophobic properties to cellulose materials by incorporation of polyurethane acrylate (PUA) prepolymers into the porous structured cellulose matrix through dip-coating; then, PUA prepolymers were cured around interconnected cellulose fibers under UV light, encapsulating a cellulose matrix with a hydrophobic polymer shell. The characterization of the composite films confirmed the success of the heterogeneous modification, and the chemical structure of the cellulose matrix was preserved. The composite films integrated the merits of cellulose and PUA resin, but the highly hydrophilic behavior of cellulose has been reduced. Contact angle measurements with water demonstrated that the composite films had obvious hydrophobic properties and an obvious reduction in the water uptake and the permeability toward water vapor gas at different relative humidity was also observed. The transmittance of the composite films at 550 nm was about 85%. The thermal and mechanical properties of the composite films were improved when compared with that of PUA resin. The obtained composite based on cellulose and UV curing technology was a good choice for the development of biomass materials with modified surface properties.

  17. Physical properties and morphology of films prepared from microfibrillated cellulose and microfibrillated cellulose in combination with amylopectin

    DEFF Research Database (Denmark)

    Plackett, David; Anturi, Harvey; Hedenqvist, Mikael

    2010-01-01

    Two types of microfibrillated cellulose (MFC) were prepared using either a sulfite pulp containing a high amount of hemicellulose (MFC 1) or a carboxymethylated dissolving pulp (MFC 2). MFC gels were then combined with amylopectin solutions to produce solvent-cast MFC-reinforced amylopectin films...... to illustrate the morphology of MFC nanofibers in pure films and in an amylopectin matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010...

  18. Biodegradable polymer films from seaweed polysaccharides: A review on cellulose as a reinforcement material

    Directory of Open Access Journals (Sweden)

    H. P. S. Abdul Khalil

    2017-04-01

    Full Text Available Seaweed and cellulose are promising natural polymers. This article reviews the basic information and recent developments of both seaweed and cellulose biopolymer materials as well as analyses the feasible formation of seaweed/cellulose composite films. Seaweed and cellulose both exhibit interesting film-forming properties. Nevertheless, seaweed has poor water vapour barrier and mechanical properties, whereas cellulose is neither meltable nor soluble in water or common organic solvents due to its highly crystalline structure. Therefore, modification of these hydrocolloids has been done to exploit their useful properties. Blending of biopolymers is a must recommended approach to improve the desired characteristics. From the review, seaweed is well compatible with cellulose, which possesses excellent mechanical strength and water resistance properties. Moreover, seaweed/cellulose composite films can prolong a product’s shelf life while maintaining its biodegradability. Additionally, the films show potential in contributing to the bioeconomy. In order to widen seaweed and cellulose in biocomposite application across various industries, some of the viewpoints are highlighted to be focused for future developments and applications.

  19. Thermal Expansion of Self-Organized and Shear-Oriented Cellulose Nanocrystal Films

    Science.gov (United States)

    Jairo A. Diaz; Xiawa Wu; Ashlie Martini; Jeffrey P. Youngblood; Robert J. Moon

    2013-01-01

    The coefficient of thermal expansion (CTE) of cellulose nanocrystal (CNC) films was characterized using novel experimental techniques complemented by molecular simulations. The characteristic birefringence exhibited by CNC films was utilized to calculate the in-plane CTE of selforganized and shear-oriented self-standing CNC films from room temperature to 100 °...

  20. Effect of doping on TSD relaxation in cellulose acetate films

    Indian Academy of Sciences (India)

    P K Khare; P L Jain; R K Pandey

    2000-12-01

    Thermally stimulated depolarization current (TSDC) studies have been performed on solution grown cellulose acetate films doped with different concentrations of acrylic acid (AA) prepared at the poling temperatures (40–75°C) with poling fields (10–50 kV/cm). The TSDC spectra of pure and AA doped CA films reveal two relaxation peaks at 80°C and 180 ± 2°C, having activation energies centred around 0.25 and 0.55 eV. The phenomena of the existence of these current maxima have been analyzed and discussed in terms of the molecular motion of the polar side groups and release of the remaining part of the frozen dipoles by their cooperative motion with adjoining segments of the main polymer chain. The peak currents, released charge and activation energies associated with the peaks are affected by AA doping. The effect of doping with acrylic acid on the discharge current indicates the formation of molecular aggregates.

  1. Preparation and properties of biodegradable films from Sterculia urens short fiber/cellulose green composites.

    Science.gov (United States)

    Jayaramudu, J; Reddy, G Siva Mohan; Varaprasad, K; Sadiku, E R; Sinha Ray, S; Varada Rajulu, A

    2013-04-02

    The development of commercially viable "green products", based on natural resources for the matrices and reinforcements, in a wide range of applications, is on the rise. The present paper focuses on Sterculia urens short fiber reinforced pure cellulose matrix composite films. The morphologies of the untreated and 5% NaOH (alkali) treated S. urens fibers were observed by SEM. The effect of 5% NaOH treated S. urens fiber (5, 10, 15 and 20% loading) on the mechanical properties and thermal stability of the composites films is discussed. This paper presents the developments made in the area of biodegradable S. urens short fiber/cellulose (SUSF/cellulose) composite films, buried in the soil and later investigated by the (POM), before and after biodegradation has taken place. SUSF/cellulose composite films have great potential in food packaging and for medical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. STUDIES ON TUNG OIL COATED REGENERATED CELLULOSE FILMS WITH WATER-RESISTANCE

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; YAN Shanhong

    1995-01-01

    Regenerated cellulose films with water-resistance were obtained by an improved method of preparing cellulose cuoxam solution from pulps of agricultural wastes (linters,wheat straw,reed and Bamao). Experimental results showed that the mechanical properties of both the dry and wet films were excellent. Data from IR, SEM and tensile strength measurements implied that the significant improvement of water-resistance of the films was due to the cohesion between the thin Tung oil covers with hydrophobicity and the regenerated cellulose films. The films were completely biodegraded after being buried in soil for 100 days. The transmittance of the films derived from linter and reed in visible band range were 80-90%.

  3. High performance films of cellulose butyral derivative having a necklace-like annular structure in the side chains

    OpenAIRE

    2014-01-01

    We fabricated high performance films using cellulose butyral (CB) synthesized from native cellulose. Two-step reactions were adopted to produce the derivative CB, including etherification of cellulose with glycidol in NaOH/urea aqueous solution to yield O-(2, 3-dihydroxypropyl) cellulose (DHPC), and butyralization of DHPC. Both DHPC and CB products were easily processed into a thin film by hot-press molding. The butyral modifier significantly improved the tenacity of highly ductile DHPC, by v...

  4. Characterization of bamboo cellulose-based green composite film by NMMO technology

    Institute of Scientific and Technical Information of China (English)

    Hongxia FANG; Jinyu SUN; Lei ZHANG

    2008-01-01

    Bamboo cellulose, lignin and starch have been molecularly blended to form homogeneous composite films by NMMO-technology. The structural properties of the films were investigated with FTIR, WAXD and AFM technologies, respectively. The results show that bamboo cellulose, lignin and starch have been molecularly blended through NMMO-technology. There was a two-phase system consisting of ternary composite components as one phase and pores as the other on the surface of the composite film. Because of the existence of homogeneous phase structure formed by the rearrangement of the nat-ural polymer molecules, the film shows good properties originating from the mutual supplement of different nat-ural components.

  5. Synthesis and characterization of cellulose nanocrystal/graphene oxide blended films

    Science.gov (United States)

    Kafy, Abdullahil; Akther, Asma; Shishir, Md. I. R.; Jo, Eun Byul; Kim, Jaehwan

    2016-04-01

    Hybrid composites with organic and inorganic materials are drawing interest to researchers by adopting advantages of organic materials and inorganic materials. Cellulose is biocompatible, cheap, environmentally friendly, renewable and lightweight material. Nano crystalline form of cellulose (CNC) is a needle like rigid structure with a very high mechanical strength. Graphene, crystalline forms of carbon, provides basic platform for many electronic and optoelectronic devices. This paper introduces the fabrication process of cellulose nanocrystal/graphene oxide blended nanocomposite film. Cellulose nanocrystal/graphene oxide nanocomposite films are prepared by mixing graphene oxide (GO) into cellulose nanocrystal suspension using ultrasonic homogenizer. Scanning electron microscopy is used to study morphology. Optical properties of the composite was characterized to evaluate the change in transparency after addition of GO in CNC.

  6. Effect of cellulose nanocrystals and gelatin in corn starch plasticized films.

    Science.gov (United States)

    Alves, J S; dos Reis, K C; Menezes, E G T; Pereira, F V; Pereira, J

    2015-01-22

    Cellulose at the nanoparticle scale has been studied as a reinforcement for biodegradable matrices to improve film properties. The goal has been to investigate the properties of starch/gelatin/cellulose nanocrystals (CNC) films. Eleven treatments were considered using RCCD (rotatable central composite design), in addition to four control treatments. For each assay, the following dependent variables were measured: water vapor permeability (WVP), thickness, opacity and mechanical properties. The microstructure and thermal properties of the films were also assessed. Increases in gelatin and CNC concentrations lead to increases in film thickness, strength and elongation at break. The films containing only gelatin in their matrix displayed better results than the starch films, and the addition of CNC had a positive effect on the assessed response variables. The films exhibited homogeneous and cohesive structures, indicating strong interactions between the filler and matrix. Films with low levels of gelatin and CNC presented the maximum degradation temperature.

  7. Tensile and characterization properties of regenerated cellulose empty fruit bunch biocomposite films using ionic liquid

    Science.gov (United States)

    Husseinsyah, Salmah; Zailuddin, Nur Liyana Izyan; Li, Chew Li; Mostapha @ Zakaria, Marliza

    2016-07-01

    The regenerated cellulose (RC) empty fruit bunch (EFB) biocomposite films were prepared using ionic liquid. The tensile strength and modulus of elasticity of regenerated cellulose biocomposite films achieved maximum value at 2 wt% of EFB contents while at 3 and 4 wt% of EFB the tensile strength and modulus of elasticity tend to decreased. The elongation at break tends to decreased at 2 wt% of EFB content but increased at 3 and 4 wt% of EFB contents. The crystallinity index reaches maximum at 2 wt% EFB content, followed by declination with further addition of EFB content. The morphology study illustrated that regenerated cellulose biocomposite films at 2 wt% of EFB contents exhibit a smooth surface that suggested the reinforcement was surrounded by the regenerated cellulose matrix, while at 4 wt% EFB content shows a rough morphology.

  8. "Green" films from renewable resources: properties of epoxidized soybean oil plasticized ethyl cellulose films.

    Science.gov (United States)

    Yang, Dong; Peng, Xinwen; Zhong, Linxin; Cao, Xuefei; Chen, Wei; Zhang, Xueming; Liu, Shijie; Sun, Runcang

    2014-03-15

    Epoxidized soybean oil (ESO), which is a biomass-derived resource, was first used as a novel plasticizer for ethyl cellulose (EC) film preparation. Surface morphologies, mechanical performances, thermal properties, oxygen and water vapor permeabilities of plasticized EC films were detected in detail to evaluate the plasticizing effect of ESO and explore the plastication mechanisms. Results showed that ESO was an effective plasticizer that outstripped conventional plasticizers, i.e. dibutyl phthalate (DBP) and triethyl citrate (TEC) in producing high-quality films. Especially, at plasticizer concentrations of 15-25%, ESO-EC films had preferable mechanical properties and better thermal stability, as well as non-flammability. In addition, the water vapor permeability of ESO-EC films was lower than that of traditional plasticized films. Their oxygen permeability was also remained in a low level. These outstanding performances were related to the relatively high molecular weight, hydrophobicity, chemical structure of ESO, and the intermolecular interactions between ESO and EC chains. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Effects of heat treatment on chitosan nanocomposite film reinforced with nanocrystalline cellulose and tannic acid.

    Science.gov (United States)

    Rubentheren, V; Ward, Thomas A; Chee, Ching Yern; Nair, Praveena; Salami, Erfan; Fearday, Christopher

    2016-04-20

    This article presents an analysis of the influence of heat treatment on chitosan nanocomposite film. A series of samples comprising: pure chitosan film, chitosan film embedded with nanocrystalline cellulose (NCC), chitosan film crosslinked with tannic acid and chitosan film with a blend of NCC and tannic acid were heat treated using a convection oven. Fourier-transform-infrared spectroscopy (FTIR) and X-ray diffraction test (XRD) shows the changes in chemical interaction of the heat treated films. The heat treated films show significant improvements in moisture absorption. Tensile strength and Young's Modulus were increased up to 7MPa and 259MPa, respectively when the samples were subjected to heat treatment. For the NCC particles, a transmission electron microscope (TEM) was used to inspect the structural properties of cellulose particle in suspension form.

  10. Production and physicochemical properties of carboxymethyl cellulose films enriched with spent coffee grounds polysaccharides

    DEFF Research Database (Denmark)

    Ballesteros, Lina F.; Cerqueira, Miguel A.; Teixeira, Jose A.

    2017-01-01

    Extracts rich in polysaccharides were obtained by alkali pretreatment (PA) or autohydrolysis (PB) of spent coffee grounds, and incorporated into a carboxymethyl cellulose (CMC)-based film aiming at the development of bio-based films with new functionalities. Different concentrations of PA or PB (up...

  11. Preparation and characterization of cellulose acetate organic/inorganic hybrid films

    Science.gov (United States)

    Saeed S. Shojaie; Timothy G. Rials; Stephen S. Kelley

    1995-01-01

    A series of organic/inorganic hybrid (OIH) films were prepared using cellulose acetate (CA) as the organic component and tetraethyl orthosilicate (TEOS) as the inorganic component. The chemical, morphological, and mechanical properties of these films were evaluated with a variety of analytical techniques. The results of these evaluations showed that crosslinked CA OIH...

  12. Influence of high loading of cellulose nanocrystals in polyacrylonitrile composite films

    Science.gov (United States)

    Jeffrey Luo; Huibin Chang; Amir A. Bakhtiary Davijani; H. Clive Liu; Po-Hsiang Wang; Robert J. Moon; Satish Kumar

    2017-01-01

    Polyacrylonitrile-co-methacrylic acid (PAN-co-MAA) and cellulose nanocrystal (CNC) composite films were produced with up to 40 wt% CNC loading through the solution casting method. The rheological properties of the solution/suspensions and the structural, optical, thermal, and mechanical properties of the resulting films were investigated. The viscosity of the composite...

  13. Fabrication and Characterization of Regenerated Cellulose Films Using Different Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Jin-Hui Pang

    2014-01-01

    Full Text Available The demand for substitution of fossil-based materials by renewable bio-based materials is increasing with the fossil resources reduction and its negative impacts on the environment. In this study, environmentally friendly regenerated cellulose films were successfully prepared using 1-allyl-3-methylimidazolium chloride (AmimCl, 1-butyl-3-methylimidazolium chloride (BmimCl, 1-ethyl-3-methylimidazolium chloride (EmimCl, and 1-ethyl-3-methylimidazolium acetate (EmimAc as solvents, respectively. The results of morphology from scanning electron microscopy (SEM and atomic force microscopy (AFM showed that all the cellulose films possessed smooth, highly uniform, and dense surface. The solid-state cross-polarization/magic angle spinning (CP/MAS 13C NMR spectra and X-ray diffraction (XRD corroborated that the transition from cellulose I to II had occurred after preparation. Moreover, it was shown that the ionic liquid EmimAc possessed much stronger dissolubility for cellulose as compared with other ionic liquids and the cellulose film regenerated from EmimCl exhibited the most excellent tensile strength (119 Mpa. The notable properties of regenerated cellulose films are promising for applications in transparent biodegradable packaging and agricultural purpose as a substitute for PP and PE.

  14. Hydrate film growth at the interface between gaseous CO2 and sodium chloride solution

    Institute of Scientific and Technical Information of China (English)

    PENG BaoZi; SUN ChangYu; CHEN GuangJin; YANG LanYing; ZHOU Wei; PANG WeiXin

    2009-01-01

    Greenhouse gas CO2 has become a serious problem for human beings. The hydrate technology has been considered as a possible approach to sequester CO2. In this work, the lateral growth rates of a CO2 hydrate film in aqueous NaCl solutions of different concentrations were measured by means of suspending a single gas bubble in liquid. The results show that the film growth rates depended on not only the driving force, but also the NaCl concentration, and the film growth rates decreased with the increasing NaCl concentration. The simple relationship vf∝△T6/2 could be used to correlate the hydrate film growth rate of a CO2 + NaCl + water system by introducing a NaCl concentration-dependent coef-ficient. The film thickness was investigated experimentally and evaluated theoretically; the results show that it became thicker at a higher NaCl concentration when the temperature and pressure were specified. In addition, a series of interesting phenomena, such as the occurrence of double hydrate films, were displayed and discussed.

  15. Hydrate film growth at the interface between gaseous CO2 and sodium chloride solution

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Greenhouse gas CO2 has become a serious problem for human beings. The hydrate technology has been considered as a possible approach to sequester CO2. In this work, the lateral growth rates of a CO2 hydrate film in aqueous NaCl solutions of different concentrations were measured by means of suspending a single gas bubble in liquid. The results show that the film growth rates depended on not only the driving force, but also the NaCl concentration, and the film growth rates decreased with the increasing NaCl concentration. The simple relationship vf ∝ΔT5/2 could be used to correlate the hydrate film growth rate of a CO2 + NaCl + water system by introducing a NaCl concentration-dependent coefficient. The film thickness was investigated experimentally and evaluated theoretically; the results show that it became thicker at a higher NaCl concentration when the temperature and pressure were specified. In addition, a series of interesting phenomena, such as the occurrence of double hydrate films, were displayed and discussed.

  16. Equilibrium Water Contents of Cellulose Films Determined via Solvent Exchange and Quartz Crystal Microbalance with Dissipation Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kittle, Joshua D; Du, Xiaosong; Jiang, Feng; Qian, Chen; Heinze, Thomas; Roman, Maren; Esker, Alan R

    2011-08-08

    Model cellulose surfaces have attracted increasing attention for studying interactions with cell wall matrix polymers and as substrates for enzymatic degradation studies. Quartz crystal microbalance with dissipation monitoring (QCM-D) solvent exchange studies showed that the water content of regenerated cellulose (RC) films was proportional to the film thickness (d) and was consistent with about five water molecules per anhydroglucose unit. Sulfated nanocrystalline cellulose (SNC) and desulfated nanocrystalline cellulose (DNC) films had comparable water contents and contained about five times more water than RC films. A cellulase mixture served as a probe for studies of substrate accessibility and degradation. Cellulase adsorption onto RC films was independent of d, whereas degradation times increased with d. However, adsorption onto SNC and DNC films increased with d, whereas cellulase degradation times for DNC films were independent of studied d. Enhanced access to guest molecules for SNC and DNC films revealed they are more porous than RC films.

  17. Equilibrium water contents of cellulose films determined via solvent exchange and quartz crystal microbalance with dissipation monitoring.

    Science.gov (United States)

    Kittle, Joshua D; Du, Xiaosong; Jiang, Feng; Qian, Chen; Heinze, Thomas; Roman, Maren; Esker, Alan R

    2011-08-08

    Model cellulose surfaces have attracted increasing attention for studying interactions with cell wall matrix polymers and as substrates for enzymatic degradation studies. Quartz crystal microbalance with dissipation monitoring (QCM-D) solvent exchange studies showed that the water content of regenerated cellulose (RC) films was proportional to the film thickness (d) and was consistent with about five water molecules per anhydroglucose unit. Sulfated nanocrystalline cellulose (SNC) and desulfated nanocrystalline cellulose (DNC) films had comparable water contents and contained about five times more water than RC films. A cellulase mixture served as a probe for studies of substrate accessibility and degradation. Cellulase adsorption onto RC films was independent of d, whereas degradation times increased with d. However, adsorption onto SNC and DNC films increased with d, whereas cellulase degradation times for DNC films were independent of studied d. Enhanced access to guest molecules for SNC and DNC films revealed they are more porous than RC films.

  18. Formulation of cellulose film containing permeation enhancers for prolonged delivery of propranolol hydrocloride.

    Science.gov (United States)

    Bigucci, Federica; Abruzzo, Angela; Cerchiara, Teresa; Gallucci, Maria Caterina; Luppi, Barbara

    2015-06-01

    The aim of this study was to evaluate the capacity of cellulose films enriched with oleic acid and polysorbate 80 to enhance the transdermal permeation of propranolol hydrochloride. Polymeric films were prepared by casting and drying aqueous solutions of hydroxypropylmethylcellulose or carboxymethylcellulose and characterized in chemical-physical properties, such as drug content, thickness, morphology and water uptake capacity. In vitro transport experiments were performed in order to evaluate the permeation enhancing ability of oleic acid and polysorbate 80. All carboxymethylcellulose films showed lower cumulative amounts of drug permeated than hydroxypropylmethylcellulose. Moreover, films containing both oleic acid and polysorbate 80 provided a greater permeation in comparison to film without permeation enhancers or only with one of these. The results obtained confirm that propranolol hydrochloride permeation can be easily modulated by varying the cellulose and enhancer type used for film preparation.

  19. Water-soluble nanocrystalline cellulose films with highly transparent and oxygen barrier properties

    Science.gov (United States)

    Cheng, Shaoling; Zhang, Yapei; Cha, Ruitao; Yang, Jinliang; Jiang, Xingyu

    2015-12-01

    By mixing a guar gum (GG) solution with a nanocrystalline cellulose (NCC) dispersion using a novel circular casting technology, we manufactured biodegradable films as packaging materials with improved optical and mechanical properties. These films could act as barriers for oxygen and could completely dissolve in water within 5 h. We also compared the effect of nanocomposite films and commercial food packaging materials on the preservation of food.By mixing a guar gum (GG) solution with a nanocrystalline cellulose (NCC) dispersion using a novel circular casting technology, we manufactured biodegradable films as packaging materials with improved optical and mechanical properties. These films could act as barriers for oxygen and could completely dissolve in water within 5 h. We also compared the effect of nanocomposite films and commercial food packaging materials on the preservation of food. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07647a

  20. Regenerated cellulose/halloysite nanotube nanocomposite films prepared with an ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Soheilmoghaddam, Mohammad [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia (UTM), Johor (Malaysia); Wahit, Mat Uzir, E-mail: mat.uzir@cheme.utm.my [Center for Composites, Universiti Teknologi Malaysia (UTM), 81310 Skudai, Johor (Malaysia); Mahmoudian, Shaya [Department of Textile Engineering, Kashan Branch, Islamic Azad University, Kashan (Iran, Islamic Republic of); Hanid, Nurbaiti Abdul [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia (UTM), Johor (Malaysia)

    2013-09-16

    Regenerated cellulose/halloysite nanotube (RC/HNT) nanocomposite films were successfully prepared in ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl) using solution casting method. The structural, morphological, thermal and mechanical properties of RC/HNT nanocomposites were investigated. X-ray diffraction analysis revealed a cellulose II crystalline structure and well dispersed HNT in RC/HNT nanocomposite films. At 6 wt.% HNT film, tensile strength and Young's modulus of RC films improved by 55.3% and 100%, respectively. Moisture absorption by the nanocomposites in an environment with 75% constant relative humidity was reduced by the addition of HNT to the RC. The presence of HNT enhanced the thermal stability and char yield of RC. The significant reinforcing effects of HNTs demonstrated that there is a possible interface interaction between cellulose and HNT which yielded better thermal and mechanical properties of the nanocomposite films as compared to pure RC. - Highlights: • The RC/HNT nanocomposite films were prepared via ionic liquid, BMIMCl. • XRD diffraction patterns and FESEM revealed well dispersed HNT in cellulose matrix. • The nanocomposite films exhibited excellent mechanical properties. • Moisture absorption and diffusion coefficient of RC reduced by HNT incorporation. • Addition of HNT enhanced thermal stability and activation energy of the RC.

  1. Concentration selective hydration and phase states of hydroxyethyl cellulose (HEC) in aqueous solutions.

    Science.gov (United States)

    Arfin, Najmul; Bohidar, H B

    2012-04-01

    Solution behaviour of hydroxyethyl cellulose (HEC) is reported in the polymer concentration range spanning over two decades (c=0.002-5% (w/v)). The results conclude the following: (i) dilute solution regime prevailed for cCole-Cole plots revealed phase homogeneity and miscibility was limited to concentrations less than ~2% (w/v). For higher polymer concentrations, strong fibre-fibre interactions prevailed and samples became heterogeneous.

  2. Modeling the methane hydrate formation in an aqueous film submitted to steady cooling

    Energy Technology Data Exchange (ETDEWEB)

    Avendano-Gomez, J.R. [ESIQIE, Laboratorio de Ingenieria Quimica Ambiental, Mexico (Mexico). Inst. Politecnico Nacional; Garcia-Sanchez, F. [Laboratorio de Termodinamica, Mexico (Mexico). Inst. Mexicano del Petroleo; Gurrola, D.V. [UPIBI, Laboratorio de Diseno de Plantas, Mexico (Mexico). Inst. Politecnico Nacional

    2008-07-01

    Gas hydrates, or clathrate hydrates, are ice-like compounds that results from the kinetic process of crystallization of an aqueous solution supersaturated with a dissolved gas. This paper presented a model that took into account two factors involved in the hydrate crystallization, notably the stochastic nature of crystallization that causes sub-cooling and the heat resulting from the exothermic enthalpy of hydrate formation. The purpose of this study was to model the thermal evolution inside a hydrate forming system which was submitted to an imposed steady cooling. The study system was a cylindrical thin film of aqueous solution at 19 Mpa. The study involved using methane as the hydrate forming molecule. It was assumed that methane was homogeneously dissolved in the aqueous phase. Ethane hydrate was formed through a kinetic process of nucleation and crystallization. In order to predict the onset time of nucleation, the induction time needed to be considered. This paper discussed the probability of nucleation as well as the estimation of the rate of nucleation. It also presented the mathematical model and boundary conditions. These included assumptions and derivation of the model; boundary conditions; initial conditions; and numerical solution of the model equation. It was concluded that the heat source must be considered when investigating crystallization effects. 34 refs., 2 tabs., 2 figs.

  3. Formation of hydrated layers in PMMA thin films in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Akers, Peter W. [School of Chemical Sciences, University of Auckland, Auckland (New Zealand); Nelson, Andrew R.J. [The Bragg Institute, Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia); Williams, David E. [School of Chemical Sciences, University of Auckland, Auckland (New Zealand); MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington (New Zealand); McGillivray, Duncan J., E-mail: d.mcgillivray@auckland.ac.nz [School of Chemical Sciences, University of Auckland, Auckland (New Zealand); MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington (New Zealand)

    2015-10-30

    Graphical abstract: - Highlights: • Homogeneous thin PMMA films prepared on Si/SiOx substrates and measured in air and water. • Reproducible formation of highly hydrated layer containing 50% water at the PMMA/SiOx interface. • When heated the films swell at 50 °C without loss of material. • Upon re-cooling to 25 °C the surface roughens and material is lost. - Abstract: Neutron reflectometry (NR) measurements have been made on thin (70–150 Å) poly(methylmethacrylate) (PMMA) films on Si/SiOx substrates in aqueous conditions, and compared with parameters measured using ellipsometry and X-Ray reflectometry (XRR) on dry films. All techniques show that the thin films prepared using spin-coating techniques were uniform and had low roughness at both the silicon and subphase interfaces, and similar surface energetics to thicker PMMA films. In aqueous solution, NR measurements at 25 °C showed that PMMA forms a partially hydrated layer at the SiOx interface 10 Å under the film, while the bulk film remains intact and contains around 4% water. Both the PMMA film layer and the sublayer showed minimal swelling over a period of 24 h. At 50 °C, PMMA films in aqueous solution roughen and swell, without loss of PMMA material at the surface. After cooling back to 25 °C, swelling and roughening increases further, with loss of material from the PMMA layer.

  4. Processing and Characterization of Cellulose Nanocrystals/Polylactic Acid Nanocomposite Films

    Directory of Open Access Journals (Sweden)

    Erin M. Sullivan

    2015-12-01

    Full Text Available The focus of this study is to examine the effect of cellulose nanocrystals (CNC on the properties of polylactic acid (PLA films. The films are fabricated via melt compounding and melt fiber spinning followed by compression molding. Film fracture morphology, thermal properties, crystallization behavior, thermo-mechanical behavior, and mechanical behavior were determined as a function of CNC content using scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, dynamic mechanical analysis, and tensile testing. Film crystallinity increases with increasing CNC content indicating CNC act as nucleating agents, promoting crystallization. Furthermore, the addition of CNC increased the film storage modulus and slightly broadened the glass transition region.

  5. Physical properties of edible emulsified films based on carboxymethyl cellulose and oleic acid.

    Science.gov (United States)

    Ghanbarzadeh, Babak; Almasi, Hadi

    2011-01-01

    Glycerol and oleic acid (OA) were incorporated into carboxymethyl cellulose (CMC) films by an emulsification method. Films containing different amounts of glycerol and OA were examined for mechanical properties, water vapor permeability (WVP), and moisture uptake, optical and thermal properties. Addition of OA to the CMC films significantly improved the barrier property. However, the effect of OA on the mechanical properties was lower than glycerol. By increasing of OA content, the cloudiness of the CMC films was intensified and Hunter value (b) of the films increased (by ca. 35.8%).

  6. Cross-linkage effect of cellulose/laponite hybrids in aqueous dispersions and solid films.

    Science.gov (United States)

    Yuan, Zaiwu; Fan, Qingrui; Dai, Xiaonan; Zhao, Chao; Lv, Aijie; Zhang, Jingjing; Xu, Guiying; Qin, Menghua

    2014-02-15

    Homogenous cellulose/laponite aqueous dispersions and composite films were respectively prepared from the pre-cooling NaOH/urea aqueous systems. Rheological measurements of aqueous dispersions demonstrated a sol-to-gel transition triggered by loading of laponite, reflecting a cross-linkage effect of cellulose/laponite hybrids. Similarly, based on scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) characterizations, as well as mechanical and thermal measurements, the cross-linkage effect of cellulose/laponite hybrids was also found in solid films, which played an important role in improving the tensile strength (σb) of composite films. For instance, the σb exhibited a largest enhancement up to 75.7% at a critical laponite content of 0.100 wt%, indicating that the property of composite film was closely related with the dispersion and interaction state of laponite, i.e. its content in cellulose matrix. These results were expected to provide significant information for fabrication and utility of cellulose-based materials.

  7. The Preparation of Cellulose/Collagen Composite Films using 1-Ethyl-3-Methylimidazolium Acetate as a Solvent

    Directory of Open Access Journals (Sweden)

    Min Zhang

    2013-12-01

    Full Text Available Cellulose/collagen composite films with weight ratios of 30/1 (Blend-1 and 10/1 (Blend-2 were prepared using 1-ethyl-3-methylimidazolium acetate as a common solvent. The morphology of the films observed with a field-emission scanning electron microscope displayed a dependence on the ratio of cellulose/collagen. Collagen was successfully composited with cellulose without degradation and showed a denaturation temperature (Td higher than that of native collagen. Fourier transform infrared spectroscopy suggested that there were hydrogen-bond interactions between collagen and cellulose in the regenerated composite films. Thermogravimetric analysis revealed that the maximum decomposition temperature (Tmax of cellulose decreased after regeneration, while the Tmax of Blend-1 increased; however, it was reduced again for Blend-2. Elastic moduli from dynamic mechanical analysis exhibited a trend similar to that of Tmax. As indicated by X-ray diffraction, the distance between cellulose molecular chains was shortened for Blend-1 and elongated for Blend-2. Furthermore, the crystallization indices were calculated to be 75.3%, 68.3%, 66.2%, and 55.4% for native cellulose, regenerated films of cellulose, Blend-1, and Blend-2, respectively. These results confirm the dependence of the structural properties of composite films on cellulose/collagen ratios through the interactions between cellulose and collagen.

  8. Formulation of mefenamic acid loaded transfersomal gel by thin film hydration technique and hand shaking method

    Directory of Open Access Journals (Sweden)

    Krishna Sailaja

    2017-04-01

    Full Text Available Objective(s: The aim of present study is to formulate mefenamic acid transdermal gel based on vesicular drug delivery approaches.Materials and Methods: For the preparation of mefenamic acid transdermal gel, transfersomes were selected as colloidal carriers. Transfersomes were prepared by hand shaking and thin film hydration techniques. The obtained transfersomes were characterized for vesicular diameter, zeta potential, drug content, entrapment efficiency and in vitro diffusion studies.Results: Among Different formulations of transfersomes, T10(prepared by thin film hydration and containing soya lecithin: span60 ratio 1:2 was considered as the best formulation because of its mean vesicular diameter of 369 nm, zeta potential of -14 mV, drug content of 99.6%, entrapment efficiency of 84.4%, and sustained drug release of 93.3% after 12 h.T10 formulation was incorporated into gel. Comparative study was made among plain gel, and transfersomal gel. Among these two gels, transfersomal gel considered as best because of its highest drug content (91%, spreadability (43.5 g.cm/sec, pH (6.9 and sustained drug release profile for 12 h.Conclusion: By comparing  hand shaking and thin film hydration techniques, it was found thin film hydration technique produced better results and transfersomal gel was indicated better results than plain gel.

  9. Effects of the water level hydrated in NMMO on the physical properties of cellulose fiber in dry jet-wet spinning

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.B.; Lee, W.S.; Kim, B.C.; Jo, S.M.; Park, J.S. [Korea Institute of Science and Technology, Seoul (Korea, Republic of); Lee, Y.M. [Hanyang University, Seoul (Korea, Republic of)

    1998-03-01

    The effects of the amount of water hydrated in N-methylmorpholine N-oxide (NMMO) in dry jet-wet spinning of cellulose was investigated in terms of rheological properties of the spinning dope and the physical properties of the fiber. At the identical polymer concentration of 12 wt%, the solution of cellulose in 90.4 wt% NMMO gave higher viscosity and higher storage modulus (G`) than that in 86.7 wt% NMMO, which was more noticeable at 110 {sup o} C than at 12 {sup o} C. Decrease in the hydrated water level or increase in the air-gap or spin draw ratio increased such physical properties of the fiber as birefringence, initial modulus and tensile strength. The tensile fractured morphology revealed that the fiber from NMMO containing less water gave more fibrils resulting from higher orientation. Further, it produced thicker and longer fibrils when treated with an ultrasonic generator.

  10. Polyelectrolyte films based on chitosan/olive oil and reinforced with cellulose nanocrystals.

    Science.gov (United States)

    Pereda, Mariana; Dufresne, Alain; Aranguren, Mirta I; Marcovich, Norma E

    2014-01-30

    Composite films designed as potentially edible food packaging were prepared by casting film-forming emulsions based on chitosan/glycerol/olive oil containing dispersed cellulose nanocrystals (CNs). The combined use of cellulose nanoparticles and olive oil proved to be an efficient method to reduce the inherently high water vapor permeability of plasticized chitosan films, improving at the same time their tensile behavior. At the same time, it was found that the water solubility slightly decreased as the cellulose content increased, and further decreased with oil addition. Unexpectedly, opacity decreased as cellulose content increased, which balanced the reduced transparency due to lipid addition. Contact angle decreased with CN addition, but increased when olive oil was incorporated. Results from dynamic mechanical tests revealed that all films present two main relaxations that could be ascribed to the glycerol- and chitosan-rich phases, respectively. The response of plasticized chitosan-nanocellulose films (without lipid addition) was also investigated, in order to facilitate the understanding of the effect of both additives.

  11. Regenerated cellulose/multiwalled carbon nanotube composite films with efficient electric heating performance.

    Science.gov (United States)

    Lee, Tae-Won; Jeong, Young Gyu

    2015-11-20

    We have manufactured regenerated cellulose-based composite films reinforced with pristine multiwalled carbon nanotube (MWCNT) by a facile casting of cellulose/DMAc/LiCl solutions containing 0.2-10.0wt% MWCNT and have investigated their application as electric heating materials by examining microstructure, thermal stability, and electrical properties. TEM images showed that the pristine MWCNT was dispersed well in the regenerated cellulose matrix. The composite films were found to be stable thermally up to ∼275°C. The electrical resistivity of the regenerated cellulose/MWCNT composite films decreased significantly from ∼10(9)Ωcm to ∼10(1)Ωcm with increasing the MWCNT loading, particularly at a certain MWCNT content between 2.0 and 3.0wt%. Accordingly, the composite films with 5.0-10.0wt% MWCNT contents, which possessed low electrical resistivity of ∼10(2)-10(1)Ωcm, exhibited excellent electric heating performance in aspects of temperature responsiveness, steady-state maximum temperature, and electrical energy efficiency at constant applied voltages. For instance, the composite film with 10.0wt% MWCNT had well-controlled steady-state maximum temperatures of 40-189°C at 20-80V, characteristic temperature growth constant of ∼1s, and electric power efficiency of ∼5.4mW/°C, which performance remained unchanged under repeated experiments for several hours. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Crosslinked cellulose thin film composite nanofiltration membranes with zero salt rejection

    KAUST Repository

    Puspasari, Tiara

    2015-05-14

    We report a new synthetic route of fabricating regenerated cellulose nanofiltration membranes. The membranes are composite membranes with a thin selective layer of cellulose, which was prepared by regeneration of trimethylsilyl cellulose (a hydrophobic cellulose derivative) film followed by crosslinking. Filtration experiments using mixtures of sugar and sodium chloride showed that solutes above 300 Da were highly rejected whereas practically no rejection was observed for NaCl. This is a big advantage for a complete desalination as the existing commercial nanofiltration membranes typically exhibit NaCl rejection in the range of 30–60%. Membranes with zero NaCl rejection are required for recovery and purification applications in food, chemical and pharmaceutical industry.

  13. Characterization of films made with chayote tuber and potato starches blending with cellulose nanoparticles.

    Science.gov (United States)

    Aila-Suárez, Selene; Palma-Rodríguez, Heidi M; Rodríguez-Hernández, Adriana I; Hernández-Uribe, Juan P; Bello-Pérez, Luis A; Vargas-Torres, Apolonio

    2013-10-15

    The aim of this study was to characterize chayotextle starch films reinforced with cellulose (C) and cellulose nanoparticle (CN) (at concentrations of 0.3%, 0.5%, 0.8% and 1.2%), using thermal, mechanical, physicochemical, permeability, and water solubility tests. C was acid-treated to obtain CN. The films were prepared by casting; potato starch and C were used as the control. The solubility of the starch films decreased with the addition of C and CN compared with its respective film without C and CN. No statistical difference (α=0.05) was found in the films added with different concentrations of C and CN. In general, the mechanical properties were improved with the addition of C and CN, and higher values of tensile strength and elastic modulus were determined in the films reinforced with CN. The melting temperature and enthalpy increased with the addition of C and CN, and the values of both thermal parameters were higher in the films with CN than with C; the enthalpy value of the film decreased when the concentration of C or CN increased in the composite. Low concentration of C and CN is better distributed in the matrix film. The addition of C and CN in the starch films improved some mechanical, barrier, and functional properties.

  14. Preparation and characterization agar-based nanocomposite film reinforced by nanocrystalline cellulose.

    Science.gov (United States)

    Atef, Maryam; Rezaei, Masoud; Behrooz, Rabi

    2014-09-01

    Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) with particle size of 24.7 μm using sulfuric acid hydrolysis technique. The obtained NCC revealed size of 0-100 nm, which the major part of them was about 30 nm. Then different contents (2.5, 5 and 10 wt%) of these NCC incorporated in agar film solution and the morphology, structure, and properties of the nanocomposite films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), mechanical, physical and optical testing. Results showed that the water vapor permeability (WVP) and water solubility (WS) of the agar-based nanocomposite films significantly (P0.05). In addition, swelling percentage, transparency and light transmission of the films were decreased by incorporating NCC into polymer matrix.

  15. Effect of degree of substitution on the mechanical and thermomechanical properties of lauroyl cellulose ester films

    OpenAIRE

    2006-01-01

    International audience; Cellulose-based plastic films were prepared in homogeneous media with a range of lauroyl fatty acid attachments by ester formation, expressed as the degree of substitution (DS). The esters were cast to form films and their mechanical properties studied. This study showed a surprising relationship between DS and elastic modulus as well as DS and tensile strength, where a peak was observed at DS 2.4. The unexpected variation of static elastic modulus (E) was confirmed by...

  16. Macroscopic control of helix orientation in films dried from cholesteric liquid crystalline cellulose nanocrystal suspensions


    OpenAIRE

    2014-01-01

    The intrinsic ability of cellulose nanocrystals (CNCs) to self-organize into films and bulk materials with helical order in a cholesteric liquid crystal is scientifically intriguing and potentially important for the production of renewable multifunctional materials with attractive optical properties. A major obstacle, however, has been the lack of control of helix direction, which results in a defect-rich, mosaic-like domain structure. Herein, a method for guiding the helix during film format...

  17. Flexible cellulose nanofibril composite films with reduced hygroscopic capacity

    Science.gov (United States)

    Yan Qing; Ronald Sabo; Zhiyong Cai; Yiqiang Wu

    2013-01-01

    Cellulose nanofibrils (CNFs), which are generated from abundant, environmentally friendly natural plant resources, display numerous interesting properties such as outstanding mechanical strength, negligible light scattering, and low thermal expansion (Zimmermann et al., 2010). These nanofibers are usually created by mechanical fibrillation or chemical oxidation of pulp...

  18. Tuning the iridescence of chiral nematic cellulose nanocrystals and mesoporous silica films by substrate variation.

    Science.gov (United States)

    Nguyen, Thanh-Dinh; Hamad, Wadood Y; MacLachlan, Mark J

    2013-12-14

    We have discovered that the self-assembly of cellulose nanocrystals (CNCs) into chiral nematic phases varies significantly with the substrate and evaporation rate. These variables allow the reflectance peak of iridescent chiral nematic films of CNCs and mesoporous silica templated from CNCs to be tuned over a wide range of wavelengths.

  19. Utilization of Cellulose from Pineapple Leaf Fibers as Nanofiller in Polyvinyl Alcohol-Based Film

    Directory of Open Access Journals (Sweden)

    Kendri Wahyuningsih

    2016-08-01

    Full Text Available Cellulose from pineapple leaf fibers as one of the natural polymer which has biodegradable property in a nanometer’s scale, can be formed as a filler in composite of Poly(vinyl Alcohol/PVA is expected to increase the physical, thermal, and barrier properties of composite films similar to conventional plastic. The aim of this study was to examine the effect of fibrillation of cellulose fibers from pineapple leaf fibers using a combined technique of chemical-mechanical treatments, to investigate the reinforcing effect of concentration of nanocellulose fibrils in the polyvinyl alcohol (PVA matrix on physical properties, thermal properties, water vapor transmission rate, light transmittance and morphological with and without addition of glycerol. Nanocellulose was made from cellulose of pineapple leaf fiber using wet milling (Ultra Fine Grinder. The composite film production was carried out by using casting solution method by mixing PVA solution with nanocellulose (10-50% and glycerol (0-1%. The characterization of film covered physical properties (thickness, moisture content and density, thermal properties, permeability (WVTR, light transmittance, morphology, and crystallinity. Nanocellulose from pineapple leaf fibers was produced by Ultra Fine Grinder shows that the size reduction process was accurate. Nanocellulose addition on PVA composite film was affected to increasing the physical, thermal, and barrier properties. Meanwhile, decreasing the percentage of composite film transmittance, thus the transparency decrease (opaque. Water vapor transmission rate (WVTR the film was increased with increasing glycerol concentration, but the physical and thermal properties was decreased.

  20. Active biopolymer film based on carboxymethyl cellulose and ascorbic acid for food preservation

    Science.gov (United States)

    Halim, Al Luqman Abdul; Kamari, Azlan

    2017-05-01

    In the present study, an active biopolymer film based on carboxymethyl cellulose (CMC) and ascorbic acid (AA) was synthesised at an incorporation rate of 15% (w/w). Several analytical instruments such as Fourier Transform Infrared Spectrometer (FTIR), Thermogravimetry Analyser (TGA), UV-Visible Spectrophotometer (UV-Vis), Scanning Electron Microscope (SEM) and Universal Testing Machine were used to characterise the physical and chemical properties of CMC-AA film. The addition of AA significantly reduced elongation at break (322%) and tensile strength (10 MPa) of CMC-AA film. However, CMC-AA film shows a better antimicrobial property against two bacteria, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as compared to CMC film. The CMC-AA film was able to preserve cherry tomato with low weight loss and browning index. Overall, results from this study highlight the feasibility of CSAA film for food preservation.

  1. Analysis of vaginal microbicide film hydration kinetics by quantitative imaging refractometry.

    Science.gov (United States)

    Rinehart, Matthew; Grab, Sheila; Rohan, Lisa; Katz, David; Wax, Adam

    2014-01-01

    We have developed a quantitative imaging refractometry technique, based on holographic phase microscopy, as a tool for investigating microscopic structural changes in water-soluble polymeric materials. Here we apply the approach to analyze the structural degradation of vaginal topical microbicide films due to water uptake. We implemented transmission imaging of 1-mm diameter film samples loaded into a flow chamber with a 1.5×2 mm field of view. After water was flooded into the chamber, interference images were captured and analyzed to obtain high resolution maps of the local refractive index and subsequently the volume fraction and mass density of film material at each spatial location. Here, we compare the hydration dynamics of a panel of films with varying thicknesses and polymer compositions, demonstrating that quantitative imaging refractometry can be an effective tool for evaluating and characterizing the performance of candidate microbicide film designs for anti-HIV drug delivery.

  2. Analysis of vaginal microbicide film hydration kinetics by quantitative imaging refractometry.

    Directory of Open Access Journals (Sweden)

    Matthew Rinehart

    Full Text Available We have developed a quantitative imaging refractometry technique, based on holographic phase microscopy, as a tool for investigating microscopic structural changes in water-soluble polymeric materials. Here we apply the approach to analyze the structural degradation of vaginal topical microbicide films due to water uptake. We implemented transmission imaging of 1-mm diameter film samples loaded into a flow chamber with a 1.5×2 mm field of view. After water was flooded into the chamber, interference images were captured and analyzed to obtain high resolution maps of the local refractive index and subsequently the volume fraction and mass density of film material at each spatial location. Here, we compare the hydration dynamics of a panel of films with varying thicknesses and polymer compositions, demonstrating that quantitative imaging refractometry can be an effective tool for evaluating and characterizing the performance of candidate microbicide film designs for anti-HIV drug delivery.

  3. Gas permeability and selectivity of cellulose nanocrystals films (layers) deposited by spin coating.

    Science.gov (United States)

    Herrera, Martha A; Mathew, Aji P; Oksman, Kristiina

    2014-11-04

    Cellulose nanocrystals (CNC) were extracted from a cellulose residue using two different acid hydrolysis procedures. CNC extracted with sulfuric acid (CNC(S)) showed higher surface charge (339 μmol/g) compared with crystals extracted with hydrochloric acid (CNC(HCl)). Spin-coated films with two different configurations were prepared; the first with alternate layers of poly(allylamine hydrochloride) (PAHCl) and CNC, and the second with a single layer of PAHCl coated with multilayers of CNC. Film characteristics such as roughness, thickness, contact angle, orientation, gas permeability and gas selectivity were studied. Optical microscopy showed more homogeneous films of CNC(S) compared to CNC(HCl). The surface charge of the crystals impacted the films' hydrophobicity, being highest for 25 alternate layers of PAHCl and CNC(HCl). The gas permeability coefficient was different for each film, depending primarily on the surface charge of the crystals and secondly on the film configuration. The films made with CNC(HCl) displayed gas barriers with nitrogen and oxygen, and gas selectivity with some gas combinations. CNC(S) films did not show gas selectivity. These results indicate that CNC with low surface charge can be further developed for gas separation and barrier applications.

  4. Effect of carboxymethyl cellulose (CMC) as biopolymers to the edible film sorghum starch hydrophobicity characteristics

    Science.gov (United States)

    Putri, Rr. Dewi Artanti; Setiawan, Aji; Anggraini, Puji D.

    2017-03-01

    The use of synthetic plastic should be limited because it causes the plastic waste that can not be decomposed quickly, triggering environmental problems. The solution of the plastic usage is the use of biodegradable plastic as packaging which is environmentally friendly. Synthesis of edible film can be done with a variety of components. The component mixture of starch and cellulose derivative products are one of the methods for making edible film. Sorghum is a species of cereal crops containing starch amounted to 80.42%, where the use of sorghum in Indonesia merely fodder. Therefore, sorghum is a potential material to be used as a source of starch synthesis edible film. This research aims to study the characteristics of edible starch films Sorghum and assess the effect of CMC (Carboxymethyl Cellulose) as additional materials on the characteristics of biopolymers edible film produced sorghum starch. This study is started with the production of sorghum starch, then the film synthesizing with addition of CMC (5, 10, 15, 20, and 25% w/w starch), and finally the hydrophobicity characteristics test (water uptake test and water solubility test). The addition of CMC will decrease the percentage of water absorption to the film with lowest level of 65.8% in the degree of CMC in 25% (w/w starch). The addition of CMC also influences the water solubility of film, where in the degree of 25% CMC (w/w starch) the solubility of water was the lowest, which was 28.2% TSM.

  5. Study on the Preparation and Characteristics of Cellulose/Silver Iodide Nanocomposite Film.

    Science.gov (United States)

    Lee, Yang Hun; Han, Sung Soo; Kang, Young Ah; Shin, Eun Joo

    2016-06-01

    In this study, the structure and properties of an organic-inorganic composite material prepared from cellulose doped with fine particles of silver iodide (AgI) were examined. The preparation of the composite involved the complexation of cellulose with polyiodide ions, such as I- and 13-, by immersion in iodine/potassium iodide (I2/KI: 0.2, 0.4, 0.6, 0.8, 1.0 M) or potassium iodide (KI: 0.6, 1.2, 1.8, 2.4, 3.0 M) aqueous solutions followed by reaction in a silver nitrate (AgNO3:1.0 M) aqueous solution. These procedures resulted in the in situ formation of fine β-AgI particles within the cellulose matrix. The characteristics and conductivities of prepared cellulose/silver iodide (AgI) nanocomposite films with different I2/KI and KI concentrations were investigated. AgI particle formation and aggregation increased on increasing I2/KI and KI concentrations as determined by SEM. X-ray results showed that KI could penetrate the cellulose crystal region and form AgI particles. The electrical conductivities of nanocomposite films treated with KI were higher than that of I2/KI at < 1.0 M of I2/KI and 3 M of KI, although the weight gain by AgI formation was lower than that of I2/KI. This was also attributed to the formation of smaller AgI particles and crystal defects. Highest electrical conductivity (3.8 x 10(-7) Ω(-1) cm(-1)) was obtained from the cellulose films (1.25 x 10(-11) Ω(-1) cm(-1)) treated with the aqueous solutions of 1.0 M I2/KI and 1.0 M AgNO3.

  6. Chiral Nematic Structure of Cellulose Nanocrystal Suspensions and Films; Polarized Light and Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Derek G. Gray

    2015-11-01

    Full Text Available Cellulosic liquid crystalline solutions and suspensions form chiral nematic phases that show a rich variety of optical textures in the liquid crystalline state. These ordered structures may be preserved in solid films prepared by evaporation of solvent or suspending medium. Film formation from aqueous suspensions of cellulose nanocrystals (CNC was investigated by polarized light microscopy, optical profilometry and atomic force microscopy (AFM. An attempt is made to interpret qualitatively the observed textures in terms of the orientation of the cellulose nanocrystals in the suspensions and films, and the changes in orientation caused by the evaporative process. Mass transfer within the evaporating droplet resulted in the formation of raised rings whose magnitude depended on the degree of pinning of the receding contact line. AFM of dry films at short length scales showed a radial orientation of the CNC at the free surface of the film, along with a radial height variation with a period of approximately P/2, ascribed to the anisotropic shrinkage of the chiral nematic structure.

  7. Nanofibrillated Cellulose and Copper Nanoparticles Embedded in Polyvinyl Alcohol Films for Antimicrobial Applications

    Science.gov (United States)

    Zhong, Tuhua; Oporto, Gloria S.; Jaczynski, Jacek; Jiang, Changle

    2015-01-01

    Our long-term goal is to develop a hybrid cellulose-copper nanoparticle material as a functional nanofiller to be incorporated in thermoplastic resins for efficiently improving their antimicrobial properties. In this study, copper nanoparticles were first synthesized through chemical reduction of cupric ions on TEMPO nanofibrillated cellulose (TNFC) template using borohydride as a copper reducing agent. The resulting hybrid material was embedded into a polyvinyl alcohol (PVA) matrix using a solvent casting method. The morphology of TNFC-copper nanoparticles was analyzed by transmission electron microscopy (TEM); spherical copper nanoparticles with average size of 9.2 ± 2.0 nm were determined. Thermogravimetric analysis and antimicrobial performance of the films were evaluated. Slight variations in thermal properties between the nanocomposite films and PVA resin were observed. Antimicrobial analysis demonstrated that one-week exposure of nonpathogenic Escherichia coli DH5α to the nanocomposite films results in up to 5-log microbial reduction. PMID:26137482

  8. Characterization of konjac glucomannan-ethyl cellulose film formation via microscopy.

    Science.gov (United States)

    Xiao, Man; Wan, Li; Corke, Harold; Yan, Wenli; Ni, Xuewen; Fang, Yapeng; Jiang, Fatang

    2016-04-01

    Konjac glucomannan-ethyl cellulose (KGM-EC, 7:3, w/w) blended film shows good mechanical and moisture resistance properties. To better understand the basis for the KGM-EC film formation, optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) were used to observe the formation of the film from emulsion. Optical microscopy images showed that EC oil droplets were homogeneously dispersed in KGM water phase without obviously coalescence throughout the entire drying process. SEM images showed the surface and cross-sectional structures of samples maintained continuous and homogeneous appearance from the emulsion to dried film. AFM images indicated that KGM molecules entangled EC molecules in the emulsion. Interactions between KGM and EC improved the stability of KGM-EC emulsion, and contributed to uniformed structures of film formation. Based on these output information, a schematic model was built to elucidate KGM-EC film-forming process.

  9. Anti-fogging and anti-frosting behaviors of layer-by-layer assembled cellulose derivative thin film

    Science.gov (United States)

    Shibraen, Mahmoud H. M. A.; Yagoub, Hajo; Zhang, Xuejian; Xu, Jian; Yang, Shuguang

    2016-05-01

    Two cellulose derivatives, quaternized cellulose (QC) and carboxymethyl cellulose (CMC), were layer-by-layer (LbL) assembled to prepare a thin film. QC was also LbL assembled with two synthetic polyelectrolytes, poly(acrylic acid) (PAA) and poly(styrene sulfonate) (PSS), separately. The anti-fogging and anti-frosting properties of the assembled films were studied. QC/CMC thin film exhibits anti-fogging and anti-frosting behaviors, whereas QC/PAA and QC/PSS films do not have capacity for anti-fogging and anti-frosting. The anti-fogging and anti-frosting properties of QC/CMC film are attributed to that water molecules can be quickly adsorbed into the matrix of the film. The water adsorption of QC/CMC film was illustrated by the optical thickness increment.

  10. The preparation, characterization and evaluation of regenerated cellulose/collagen composite hydrogel films.

    Science.gov (United States)

    Cheng, Yongmei; Lu, Jinting; Liu, Shilin; Zhao, Peng; Lu, Guozhong; Chen, Jinghua

    2014-07-17

    Porous structured regenerated cellulose films were oxidized by periodate oxidation to obtain 2,3-dialdehyde cellulose (DARC) films, which were then reacted with collagen to obtain DARC/Col composite films. The subsequent FT-IR spectra indicated that collagen was immobilized on the DARC matrix via the Schiff base reaction between NH2 in collagen and CHO in DARC backbone. Scanning electron microscopy revealed that DARC/Col exhibited a refined 3D network structure and its porosity and pore size decreased with increasing of collagen concentration. The composite films demonstrated a good equilibrium-swelling ratio, air permeability and water retention properties. The composite films also showed excellent mechanical properties, which was vital for practical application. Finally, the cytotoxicity of the composite film was evaluated using NIH3T3 mice fibroblast cells, the results revealed that DARC/Col composite films have good biocompatibility for use as scaffold material in tissue engineering. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Cellulose Acetate/N-TiO2 Biocomposite Flexible Films with Enhanced Solar Photochromic Properties

    Science.gov (United States)

    Radhika, T.; Anju, K. R.; Silpa, M. S.; Ramalingam, R. Jothi; Al-Lohedan, Hamad A.

    2017-07-01

    Flexible cellulose acetate/N-TiO2 nanocomposite films containing various concentrations of nanosized N-TiO2 and an intelligent methylene blue ink have been prepared by solution casting. The hydrothermally prepared nitrogen-doped titania (N-TiO2) and the films were characterized in detail. The photochromic properties of the prepared films were investigated under ultraviolet (UV), visible light, and simulated solar irradiation by UV-Vis spectrophotometry. Upon irradiation, the films exhibited rapid photochromic response that was reversible at room temperature. Films with higher content of nano N-TiO2 showed enhanced decoloration/recoloration under all irradiation conditions, with fast decoloration/recoloration under simulated solar irradiation. These results suggest that the amount of nano N-TiO2 in the composite, the concentration of methylene blue, and the solvent greatly influence the photochromic properties of the films. Such flexible and transparent cellulose acetate/N-TiO2 films with enhanced decoloration/recoloration properties under solar irradiation are promising smart materials for use in photoreversible printed electronics applications.

  12. Synthesis, characterization and antibacterial activity of biodegradable starch/PVA composite films reinforced with cellulosic fibre.

    Science.gov (United States)

    Priya, Bhanu; Gupta, Vinod Kumar; Pathania, Deepak; Singha, Amar Singh

    2014-08-30

    Cellulosic fibres reinforced composite blend films of starch/poly(vinyl alcohol) (PVA) were prepared by using citric acid as plasticizer and glutaraldehyde as the cross-linker. The mechanical properties of cellulosic fibres reinforced composite blend were compared with starch/PVA crossed linked blend films. The increase in the tensile strength, elongation percentage, degree of swelling and biodegradability of blend films was evaluated as compared to starch/PVA crosslinked blend films. The value of different evaluated parameters such as citric acid, glutaraldehyde and reinforced fibre to starch/PVA (5:5) was found to be 25 wt.%, 0.100 wt.% and 20 wt.%, respectively. The blend films were characterized using Fourier transform-infrared spectrophotometry (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG). Scanning electron microscopy illustrated a good adhesion between starch/PVA blend and fibres. The blend films were also explored for antimicrobial activities against pathogenic bacteria like Staphylococcus aureus and Escherichia coli. The results confirmed that the blended films may be used as exceptional material for food packaging. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Piezoresistive Effect of Doped carbon Nanotube/Cellulose Films

    Institute of Scientific and Technical Information of China (English)

    王万录; 廖克俊; 李勇; 王永田

    2003-01-01

    The strain-induced resistance changes in iodine-doped and undoped carbon nanotube films were investigated by a three-point bending test. Carbon nanotubes were fabricated by hot filament chemical vapour deposition. The experimental results showed that there has a striking piezoresistive effect in carbon nanotube films. The gauge factor for I-doped and undoped carbon nanotube films under 500 microstrain was about 125 and 65 respectively at room temperature, exceeding that of polycrystalline silicon (30) at 35℃. The origin of the piezoresistivity in the films may be ascribed to a strain-induced change in the band gap for the doped tubes and to the intertube contact resistance for the undoped tubes.

  14. Biodegradable Nanocomposite Films Based on Sodium Alginate and Cellulose Nanofibrils

    National Research Council Canada - National Science Library

    Deepa, B; Abraham, Eldho; Pothan, Laly; Cordeiro, Nereida; Faria, Marisa; Thomas, Sabu

    2016-01-01

    ...) into alginate biopolymer using the solution casting method. The effects of CNF content (2.5, 5, 7.5, 10 and 15 wt %) on mechanical, biodegradability and swelling behavior of the nanocomposite films were determined...

  15. Wheat straw hemicelluloses added with cellulose nanocrystals and citric acid. Effect on film physical properties.

    Science.gov (United States)

    Pereira, Paulo H F; Waldron, Keith W; Wilson, David R; Cunha, Arcelina P; Brito, Edy S de; Rodrigues, Tigressa H S; Rosa, Morsyleide F; Azeredo, Henriette M C

    2017-05-15

    Wheat straw has been used as a source of hemicelluloses (WSH) and cellulose nanocrystals (CNC) for the elaboration of biodegradable films. Different films have been formed by using WSH as a matrix and different contents of CNC and citric acid. The predominant hemicelluloses were arabinoxylans. CNC reinforced the films, improving tensile strength and modulus, water resistance and water vapor barrier. Citric acid, on the other hand, presented concomitant plasticizing and crosslinking effects (the latter also evidenced by FTIR), probably due to a crosslinking extension by glycerol. The use of 5.9wt% CNC and 30wt% citric acid was defined as optimal conditions, resulting in minimum water sensitivity and permeability, while maintaining a good combination of tensile properties. Under those conditions, the films presented enhanced modulus, elongation, water resistance, and barrier to water vapor when compared to the control WSH film, and might be used for wrapping or coating a variety of foods.

  16. Composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose for drug controlled release.

    Science.gov (United States)

    Pavaloiu, Ramona-Daniela; Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin Ion; Dobre, Tanase

    2014-07-01

    Mono and multilayer composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose (PVA/chitosan/BC) have been prepared to achieve controlled release of ibuprofen sodium salt (IbuNa) as model drug. The composite films have been characterized by Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Surface morphology was investigated by scanning electron microscopy (SEM). Equilibrium swelling was measured in water at two different pH values and in vitro release of IbuNa in pH 1.2 and pH 7.4 media was studied. The release experiments revealed that drug release is pH sensitive. The release kinetics of IbuNa could be described by the Fickian model of diffusion with a good agreement. The IbuNa release rate was decreasing for all the films as the BC concentration was increased in the films composition, the decrease being higher for the multilayer films.

  17. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  18. The Effect of Mechanochemical Treatment of the Cellulose on Characteristics of Nanocellulose Films

    Science.gov (United States)

    Barbash, V. A.; Yaschenko, O. V.; Alushkin, S. V.; Kondratyuk, A. S.; Posudievsky, O. Y.; Koshechko, V. G.

    2016-09-01

    The development of the nanomaterials with the advanced functional characteristics is a challenging task because of the growing demand in the market of the optoelectronic devices, biodegradable plastics, and materials for energy saving and energy storage. Nanocellulose is comprised of the nanosized cellulose particles, properties of which depend on characteristics of plant raw materials as well as methods of nanocellulose preparation. In this study, the effect of the mechanochemical treatment of bleached softwood sulfate pulp on the optical and mechanical properties of nanocellulose films was assessed. It was established that the method of the subsequent grinding, acid hydrolysis and ultrasound treatment of cellulose generated films with the significant transparency in the visible spectral range (up to 78 % at 600 nm), high Young's modulus (up to 8.8 GPa), and tensile strength (up to 88 MPa) with increased ordering of the packing of the cellulose macromolecules. Morphological characterization was done using the dynamic light scattering (DLS) analyzer and transmission electron microscopy (TEM). The nanocellulose particles had an average diameter of 15-30 nm and a high aspect ratio in the range 120-150. The crystallinity was increased with successive treatments as shown by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The thermal degradation behavior of cellulose samples was explored by thermal gravimetric analysis (TGA).

  19. Conducting Graphite/Cellulose Composite Film as a Candidate for Chemical Vapor-Sensing Material

    Directory of Open Access Journals (Sweden)

    Kaihua Liu

    2014-07-01

    Full Text Available A type of conductive graphite/cellulose composite film used for chemical vapor-sensing material was prepared at room temperature in the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIm]Cl. Graphite was pretreated with both oxidation and reduction processes. Due to the use of N,N-carbonyldiimidazole (CDI, as a covalent cross-linking agent in [BMIm]Cl, there were limited chemical bonds between the graphite and cellulose. The composite film was analyzed using Fourier transform infrared spectroscopy (FT-IR, Raman spectroscopy, and X-ray photoelectron spectroscopy (XRD. When these conducting films were exposed to certain organic vapors, their electrical resistances quickly changed, showing gas sensitivity. The percolation threshold of the conducting film was about 5 wt%. The gas-sensing behavior of these films in solvent were the opposite of those gas-sensing materials based on a non-polar polymer matrix. A typical negative vapor coefficient (NVC was observed when the film was placed in polar organic solvents such as methanol, ethanol, and acetone.

  20. Structural Variations in Hybrid All-Nanoparticle Gibbsite Nanoplatelet/Cellulose Nanocrystal Multilayered Films.

    Science.gov (United States)

    Martin, Clélia; Barker, Robert; Watkins, Erik B; Dubreuil, Frédéric; Cranston, Emily D; Heux, Laurent; Jean, Bruno

    2017-08-15

    Cellulose nanocrystals (CNCs) are promising biosourced building blocks for the production of high performance materials. In the last ten years, CNCs have been used in conjunction with polymers for the design of multilayered thin films via the layer-by-layer assembly technique. Herein, polymer chains have been replaced with positively charged inorganic gibbsite nanoplatelets (GN) to form hybrid "nanoparticle-only" composite films. A combination of atomic force microscopy and neutron reflectivity experiments was exploited to investigate the growth and structure of the films. Data show that the growth and density of GN/CNC films can be tuned over a wide range during preparation by varying the ionic strength in the CNC suspension and the film drying protocol. Specifically, thin and dense multilayered films or very thick, more porous mixed slabs, as well as intermediate internal structures, could be obtained in a predictable manner. The influence of key physicochemical parameters on the multilayer film buildup was elucidated and the film architecture was linked to the dominating interaction forces between the components. The degree of structural control over these hybrid nanoparticle-only films is much higher than that reported for CNC/polymer films, which offers new properties and potential applications as separation membranes or flame retardant coatings.

  1. Molecular mobility of hydroxyethyl cellulose (HEC) films characterised by thermally stimulated currents (TSC) spectroscopy.

    Science.gov (United States)

    Owusu-Ware, Samuel K; Boateng, Joshua; Jordan, Daniel; Portefaix, Sara; Tasseto, Renata; Ramano, Camila D; Antonijević, Milan D

    2016-01-30

    Molecular mobility has long been established to relate to textural properties and stability of polymer films and is therefore an important property to characterise to better understand pharmaceutical film formulations. The molecular mobility of solvent cast hydroxyethyl cellulose (HEC) films has been investigated by means of thermally stimulated current (TSC) below the temperature at which the film was formed. Preliminary physical characterisation of the films was performed using XRPD, TGA, DSC and texture analysis (tensile properties). XRPD results showed the films to be completely amorphous with Tg determined by DSC to be 127 ± 1°C. TGA analysis showed the films to contain 8 ± 1% water and film was dried to only 0.06 ± 0.01% water content when heated to 160°C. Application of TSC detected molecular mobility in HEC films at sub-zero temperatures. Two motional transitions with average relaxation time of 50 ± 3s were identified; a β-relaxation at -57 ± 2°C, attributed to localised non-cooperative orientation of HEC polymer chain ends and the hydroxyethyl side groups and an α-relaxation, originating from cooperative segmental mobility, at -20 ± 2°C. The tensile properties i.e., elongation, tensile strength and elastic modulus of the HEC film have been related to the molecular relaxation processes detected by TSC.

  2. Green and biodegradable composite films with novel antimicrobial performance based on cellulose.

    Science.gov (United States)

    Wu, Yuehan; Luo, Xiaogang; Li, Wei; Song, Rong; Li, Jing; Li, Yan; Li, Bin; Liu, Shilin

    2016-04-15

    In order to obtain a safe and biodegradable material with antimicrobial properties from cellulose for food packaging, we presented a facile way to graft chitosan onto the oxidized cellulose films. The obtained films had a high transparent property of above 80% transmittance, excellent barrier properties against oxygen and antimicrobial properties against Escherichia coli and Staphylococcus aureus. The antimicrobial properties, mechanical properties, and water vapor permeability of composites are essential characteristics in determining their applicability as food-packaging materials. Moreover, using a sausage model, it was shown that the composites exhibited better performance than traditional polyethylene packaging material and demonstrated good potential as food packaging materials. The results presented a new insight into the development of green materials for food packaging.

  3. Highly improved hydration level sensing properties of copper oxide films with sodium and potassium doping

    Science.gov (United States)

    Sahin, Bünyamin; Kaya, Tolga

    2016-01-01

    In this study, un-doped, Na-doped, and K-doped nanostructured CuO films were successfully synthesized by the successive ionic layer adsorption and reaction (SILAR) technique and then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and current-voltage (I-V) measurements. Structural properties of the CuO films were affected from doping. The XRD pattern indicates the formation of polycrystalline CuO films with no secondary phases. Furthermore, doping affected the crystal structure of the samples. The optimum conductivity values for both Na and K were obtained at 4 M% doping concentrations. The comparative hydration level sensing properties of the un-doped, Na-doped, and K-doped CuO nanoparticles were also investigated. A significant enhancement in hydration level sensing properties was observed for both 4 M% Na and K-doped CuO films for all concentration levels. Detailed discussions were reported in the study regarding atomic radii, crystalline structure, and conductivity.

  4. Preparation and properties of self-reinforced cellulose composite films from Agave microfibrils using an ionic liquid.

    Science.gov (United States)

    Reddy, K Obi; Zhang, Jinming; Zhang, Jun; Rajulu, A Varada

    2014-12-19

    The applications of natural fibers and their microfibrils are increasing rapidly due to their environment benefits, specific strength properties and renewability. In the present work, we successfully extracted cellulose microfibrils from Agave natural fibers by chemical method. The extracted microfibrils were characterized by chemical analysis. The cellulose microfibrils were found to dissolve in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) to larger extent along with little quantity of undissolved microfibrils. Using this solution, the self-reinforced regenerated cellulose composite films were prepared. The raw fiber, extracted cellulose microfibrils and regenerated cellulose composite films were characterized by FTIR, (13)C CP-MAS NMR, XRD, TGA and SEM techniques. The average tensile strength, modulus and elongation at break of the self-reinforced cellulose composite films were found to be 135 MPa, 8150 MPa and 3.2%, respectively. The high values of tensile strength and modulus were attributed to the self-reinforcement of Agave fibers in their generated matrix. These self-reinforced cellulose biodegradable composite films prepared from renewable source can find applications in packaging field.

  5. Cellulose acetobutyrate films and beryllium oxide discs for low-level radiation monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Ventura, S.A.; Kleinschmidt, D.E.; Mbu, J.B.

    1976-10-01

    The effect of mylar films on the attenuation of alpha particle energy and the production of etchable tracks in cellulose acetobutyrate was studied. A model developed predicts a 15-..mu.. optimum mylar film thickness, while experimental results indicated a 22.8-..mu.. optimum. The effect of alpha particle and potassium hydroxide solution interaction with CAB was reviewed and process improvements suggested. The TSEE response of BeO discs to tritium at 5.0 mCi/m/sup 3/ for up to 15-hr exposure was also investigated. An average TSEE/..beta.. ratio of 0.02 was obtained.

  6. Sodium alginate/carboxymethyl cellulose films containing pyrogallic acid: physical and antibacterial properties.

    Science.gov (United States)

    Han, Yingying; Wang, Lijuan

    2017-03-01

    Antibacterial films were prepared using sodium alginate (SA) and carboxymethyl cellulose (CMC) as a matrix, glycerin as a plasticizer and CaCl2 as a cross-linking agent, and by incorporating the natural antibacterial agent pyrogallic acid (PA). The present study describes the microstructure and the physical, barrier, mechanical, optical and antibacterial properties of blended films prepared by incorporating different concentrations of PA into the SA/CMC matrix. The microstructure of the films was investigated by Fourier transform infrared spectroscopy and scanning electron microscopy, which revealed that PA interacts with the SA/CMC matrix through hydrogen bonding. Moreover, the incorporation of PA increased the moisture content, water vapor permeability and oxygen permeability of SA/CMC films. Films containing 40 g kg(-1) of PA had the highest elongation at break result (39.60%). Compared with pure SA/CMC films, the incorporation of PA improved the barrier properties against ultraviolet light; however, it decreased the color parameter L* value and increased the a* and b* values of the films. Furthermore, films with PA, especially at higher concentrations, were more effective against Escherichia coli and Staphylococcus aureus. Antibacterial SA/CMC films incorporating PA appear to have good potential to enhance the safety of foods and food products. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. Preparation and physical properties of tara gum film reinforced with cellulose nanocrystals.

    Science.gov (United States)

    Ma, Qianyun; Hu, Dongying; Wang, Lijuan

    2016-05-01

    Cellulose nanocrystals (CNC) prepared from microcrystalline cellulose were blended in tara gum solution to prepare nanocomposite films. The morphology, crystallinity, and thermal properties of the CNC and films were evaluated by using transmission electron microscopy, X-ray diffractometry, and thermogravimetric analysis, respectively. The resultant CNC was rod-shaped with diameters of around 8.6 nm. The effect of CNC content on physical and thermal properties of films was studied. The composite film tensile strength increased from 27.86 to 65.73 MPa, elastic modulus increased from 160.98 MPa to 882.49 MPa and the contact angle increased from 55.8° to 98.7° with increasing CNC content from 0 to 6 wt%. However, CNC addition increased the thermal stability slightly and CNC content above 6 wt% decreased the tensile strength by CNC aggregation in the matrix. The nanocomposite film containing 6 wt% CNC possessed the highest light transmittance, mechanical properties, and lowest oxygen permeability. CNC addition is a suitable method to modify tara gum matrix polymer properties.

  8. Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films

    Directory of Open Access Journals (Sweden)

    Sriburi Pensiri

    2011-02-01

    Full Text Available Abstract Background Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers. Results Cassava starch (5%w/v based films plasticized with glycerol (30 g/100 g starch were characterized with respect to the effect of carboxymethyl cellulose (CMC concentrations (0, 10, 20, 30 and 40%w/w total solid and relative humidity (34 and 54%RH on the mechanical properties of the films. Additionally, intermolecular interactions were determined by Fourier transform infrared spectroscopy (FT-IR, melting temperature by differential scanning calorimetry (DSC, and morphology by scanning electron microscopy (SEM. Water solubility of the films was also determined. Increasing concentration of CMC increased tensile strength, reduced elongation at break, and decreased water solubility of the blended films. FT-IR spectra indicated intermolecular interactions between cassava starch and CMC in blended films by shifting of carboxyl (C = O and OH groups. DSC thermograms and SEM micrographs confirmed homogeneity of cassava starch-CMC films. Conclusion The addition of CMC to the cassava starch films increased tensile strength and reduced elongation at break of the blended films. This was ascribed to the good interaction between cassava starch and CMC. Cassava starch-CMC composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low moisture food and pharmaceutical products.

  9. Preparation and Characterization of Blended Films from Quaternized Hemicelluloses and Carboxymethyl Cellulose

    Directory of Open Access Journals (Sweden)

    Xian-Ming Qi

    2015-12-01

    Full Text Available Utilization of hemicelluloses from biomass energy is an important approach to explore renewable resources. A convenient, quick, and inexpensive method for the preparation of blended films from quaternized hemicelluloses (QH and carboxymethyl cellulose (CMC was introduced into this study. QH and CMC solution were first mixed to form homogeneous suspension, and then were dried under vacuum to fabricate the blended films. The FT-IR and XRD results indicated that the linkage between QH and CMC was due to the hydrogen bonding and electrostatic interaction. From the results of mechanical properties and water vapor permeability (WVP, the tensile strength of the blended films increased with the QH/CMC content ratio increasing in appropriate range, and the WVP of the blended films decreased. The maximum value of tensile strength of blend film achieved was 27.4 MPa. In addition, the transmittances of the blended films increased with the decreasing of QH/CMC content ratio. When the weight ratio (QH: CMC was 1:1.5, the blend film showed the best light transmittance (45%. All the results suggested that the blended films could be used in areas of application in the coating and packaging fields from the good tensile strength, transmittance, and low WVP.

  10. Incorporation of ovalbumin into ISCOMs and related colloidal particles prepared by the lipid film hydration method.

    Science.gov (United States)

    Demana, Patrick H; Davies, Nigel M; Berger, Bianca; Rades, Thomas

    2004-07-08

    The aim of this study was to investigate the incorporation of a model antigen, fluorescently labelled ovalbumin (FITC-OVA), into various colloidal particles including immune stimulating complexes (ISCOMs), liposomes, ring and worm-like micelles, lamellae and lipidic/layered structures that are formed from various combinations of the triterpene saponin Quil A, cholesterol and phosphatidylethanolamine (PE) following hydration of PE/cholesterol lipid films with aqueous solutions of Quil A. Colloidal dispersions of these three components were also prepared by the dialysis method for comparison. FITC-OVA was conjugated with palmitic acid (P) and PE to produce P-FITC-OVA and PE-FITC-OVA, respectively. Both P-FITC-OVA and PE-FITC-OVA could be incorporated in all colloidal structures whereas FITC-OVA was incorporated only into liposomes. The incorporation of PE-FITC-OVA into all colloidal structures was significantly higher than P-FITC-OVA (P < 0.05). The degree of incorporation of protein was in the order: ring and worm-like micelles < liposomes and lipidic/layered structures < ISCOMs and lamellae. The incorporation of protein into the various particles prepared by the lipid film hydration method was similar to those for colloidal particles prepared by the dialysis method (provided both methods lead to the formation of the same colloidal structures). In the case of different colloidal structures arising due to the preparation method, differences in encapsulation efficiency were found (P < 0.05) for formulations with the same polar lipid composition. This study demonstrates that the various colloidal particles formed as a result of hydrating PE/cholesterol lipid films with different amounts of Quil A are capable of incorporating antigen, provided it is amphipathic. Some of these colloidal particles may be used as effective vaccine delivery systems.

  11. The effect of chemical composition on microfibrillar cellulose films from wood pulps: mechanical processing and physical properties.

    Science.gov (United States)

    Spence, Kelley L; Venditti, Richard A; Habibi, Youssef; Rojas, Orlando J; Pawlak, Joel J

    2010-08-01

    Films of microfibrillated celluloses (MFCs) from pulps of different yields, containing varying amounts of extractives, lignin, and hemicelluloses, were produced by combining refining and high-pressure homogenization techniques. MFC films were produced using a casting-evaporation technique and the physical and mechanical properties (including density, roughness, fold endurance and tensile properties) were determined. Homogenization of bleached and unbleached Kraft pulps gave rise to highly individualized MFCs, but not for thermo-mechanical pulp (TMP). The resulting MFC films had a roughness equivalent to the surface upon which the films were cast. Interestingly, after homogenization, the presence of lignin significantly increased film toughness, tensile index, and elastic modulus. The hornification of fibers through a drying and rewetting cycle prior to refining and homogenization did not produce any significant effect compared to films from never-dried fibers, indicating that MFC films can potentially be made from low-cost recycled cellulosic materials.

  12. High-flux Thin-film Nanofibrous Composite Ultrafiltration Membranes Containing Cellulose Barrier Layer

    Energy Technology Data Exchange (ETDEWEB)

    Ma, H.; Yoon, K; Rong, L; Mao, Y; Mo, Z; Fang, D; Hollander, Z; Gaiteri, J; Hsiao , B; Chu, B

    2010-01-01

    A novel class of thin-film nanofibrous composite (TFNC) membrane consisting of a cellulose barrier layer, a nanofibrous mid-layer scaffold, and a melt-blown non-woven substrate was successfully fabricated and tested as an ultrafiltration (UF) filter to separate an emulsified oil and water mixture, a model bilge water for on-board ship bilge water purification. Two ionic liquids: 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate, were chosen as the solvent to dissolve cellulose under mild conditions. The regenerated cellulose barrier layer exhibited less crystallinity (determined by wide-angle X-ray diffraction, WAXD) than the original cotton linter pulps, but good thermal stability (determined by thermal gravimetric analysis, TGA). The morphology, water permeation, and mechanical stability of the chosen TFNCmembranes were thoroughly investigated. The results indicated that the polyacrylonitrile (PAN) nanofibrous scaffold was partially imbedded in the cellulose barrier layer, which enhanced the mechanical strength of the top barrier layer. The permeation flux of the cellulose-based TFNCmembrane was significantly higher (e.g. 10x) than comparable commercial UFmembranes (PAN10 and PAN400, Sepro) with similar rejection ratios for separation of oil/water emulsions. The molecular weight cut-off (MWCO) of TFNC membranes with cellulose barrier layer was evaluated using dextran feed solutions. The rejection was found to be higher than 90% with a dextran molecular weight of 2000 KDa, implying that the nominal pore size of the membrane was less than 50 nm. High permeation flux was also observed in the filtration of an emulsified oil/water mixture as well as of a sodium alginate aqueous solution, while high rejection ratio (above 99.5%) was maintained after prolonged operation. A variation of the barrier layer thickness could dramatically affect the permeation flux and the rejection ratio of the TFNCmembranes, while different sources of cellulose

  13. Photoactive layer-by-layer films of cellulose phosphate and titanium dioxide containing phosphotungstic acid

    Science.gov (United States)

    Ullah, Sajjad; Acuña, José Javier Sáez; Pasa, André Avelino; Bilmes, Sara A.; Vela, Maria Elena; Benitez, Guillermo; Rodrigues-Filho, Ubirajara Pereira

    2013-07-01

    A versatile layer-by-layer (LbL) procedure for the preparation of highly dispersed, adherent and porous multilayer films of TiO2 nanoparticles (NPs) and phosphotungstic acid (HPW) on a variety of substrates at room temperature was developed based on the use of cellulose phosphate (CP) as an efficient and non-conventional polyelectrolyte. UV/vis absorption spectroscopy confirmed the linear and regular growth of the films with the number of immersion cycles and a strong adsorption ability of CP towards TiO2 NPs. FTIR spectroscopy showed that HPW binds to the surface of TiO2 through the oxygen atom at the corner of the Keggin structure. XPS results showed that the interaction between TiO2 and CP is through Ti-O-P linkage. A model is proposed for the TiO2-HPW interaction based on XPS and FTIR results. FEG/SEM study of the surface morphology revealed a porous film structure with a homogenous distribution of the TiO2 NPs induced by CP. HRTEM studies showed that the resulting composite films consist of crystalline anatase and rutile phases and poly-nano-crystalline HPW with a semi-crystalline TiO2-HPW interface. These CP/TiO2 and CP/TiO2/HPW LbL films showed good photoactivity against both saturated and unsaturated species, for instance, stearic acid (SA), crystal violet (CV) and methylene blue (MB) under UV irradiation. The CP/HPW films formed on bacterial cellulose (BC) showed good photochromic response which is enhanced in presence of TiO2 due to an interfacial electron transfer from TiO2 to HPW. This simple and environmentally safe method can be used to form coatings on a variety of surfaces with photoactive TiO2 and TiO2/HPW films.

  14. Extraction of microcrystalline cellulose from rice straw and its effect on polyvinyl alcohol biocomposites film

    Science.gov (United States)

    Chin, Kwok-Mern; Ting, Sam Sung; Lin, Ong Hui; Owi, Wei Tieng

    2017-07-01

    The poor management and underutilization of agricultural wastes had proliferated interest of researchers around the world to find alternatives to utilize them as potential value-added products. One of the green alternatives is by extracting cellulose from these waste materials and incorporating them in polymer as reinforcement fillers. The surging amount of plastic waste also posed major issues to the environment due to its recalcitrance to degrade. Microcrystalline cellulose (MCC-RS) was extracted from rice straw through cyclic alkaline and bleaching treatment to remove hemicellulose and lignin respectively. Polyvinyl alcohol (PVOH) was chosen as the matrix and different ratios of PVOH / MCC-RS films were prepared (2.5, 5.0, 7.5 and 10.0wt% of MCC) through solution casting method and its tensile, thermal and morphological properties were studied. X-ray powder diffraction (XRD) results showed increased crystallinity of MCC-RS after chemical treatment (from 44.5% to 60.8%) due to the successful removal of lignin and hemicellulose, which was then confirmed with Fourier transform infrared spectroscopy (FTIR) results. For the biocomposites, both tensile strength and Young's modulus of the films increased with increasing MCC-RS content up until 7.5wt%, supported with scanning electron microscopy (SEM) results which depicted improvement in the interfacial adhesion between MCC-RS and PVOH. From the overall results, the improvement in properties of biocomposite from cellulose-based microfiller had shown promising future in application of the water soluble plastic packaging industry.

  15. Synthesis of nano cellulose fibers and effect on thermoplastics starch based films.

    Science.gov (United States)

    Savadekar, N R; Mhaske, S T

    2012-06-01

    Starch based films limit their application due to highly hydrophilic nature and poor mechanical properties. This problem was sought to be overcome by forming a nanocomposite of Thermoplastic starch (TPS) and Nano-Cellulose fibers (NCF). NCF was successfully synthesised from short stable cotton fibres by a chemo-mechanical process. TPS/NCF composite films were prepared by solution casting method, and their characterizations were done in terms of differential scanning calorimeter (DSC), morphology (SEM), water vapor permeability (WVTR), oxygen transmission rate (OTR), X-ray diffractograms, light transmittance and tensile properties. At very low concentration of NCF filled TPS composite film showed improvement in properties. The 0.4 t% NCF loaded TPS films showed 46.10% improved tensile strength than by base polymer film, beyond that 0.5 t% concentration tensile strength starts to deteriorate. WVTR and OTR results showed improved water vapor barrier property of TPS matrix. The DSC thermograms of TPS and composite films did not show any significant effect on the melting point of composite film to the base polymer TPS.

  16. Hygroscopic Swelling Determination of Cellulose Nanocrystal (CNC) Films by Polarized Light Microscopy Digital Image Correlation.

    Science.gov (United States)

    Shrestha, Shikha; Diaz, Jairo A; Ghanbari, Siavash; Youngblood, Jeffrey P

    2017-05-08

    The coefficient of hygroscopic swelling (CHS) of self-organized and shear-oriented cellulose nanocrystal (CNC) films was determined by capturing hygroscopic strains produced as result of isothermal water vapor intake in equilibrium. Contrast enhanced microscopy digital image correlation enabled the characterization of dimensional changes induced by the hygroscopic swelling of the films. The distinct microstructure and birefringence of CNC films served in exploring the in-plane hygroscopic swelling at relative humidity values ranging from 0% to 97%. Water vapor intake in CNC films was measured using dynamic vapor sorption (DVS) at constant temperature. The obtained experimental moisture sorption and kinetic profiles were analyzed by fitting with Guggenheim, Anderson, and deBoer (GAB) and Parallel Exponential Kinetics (PEK) models, respectively. Self-organized CNC films showed isotropic swelling, CHS ∼0.040 %strain/%C. By contrast, shear-oriented CNC films exhibited an anisotropic swelling, resulting in CHS ∼0.02 and ∼0.30 %strain/%C, parallel and perpendicular to CNC alignment, respectively. Finite element analysis (FEA) further predicted moisture diffusion as the predominant mechanism for swelling of CNC films.

  17. Radiation-sensitive indicator based on radiation-chemical formation of acids in polyvinyl butyral films containing chloral hydrate

    Science.gov (United States)

    Abdel-Fattah, Atef A.; El-Kelany, M.

    1998-03-01

    Radiation-sensitive indicators based on dyed polyvinyl butyral (PVB) containing acid-sensitive dye (bromophenol blue, BPB) and chloral hydrate (CCl 3CH(OH) 2, 2,2,2-trichloroethane-1, 1-diol) have been developed. These plastic film dosimeters undergo colour change from blue (the alkaline form of BPB) to yellow (the acidic form of BPB), indicating acid formation. The concentration of radiation-formed acids in the films containing different concentrations of chloral hydrate was calculated at different doses. The kinetics of the acid-formation reaction is discussed, indicating a half-order reaction with respect to chloral hydrate concentration. These films can be used as dosimeters for food irradiation applications where the maxima of the useful dose ranges are between 1 and 4 kGy depending on chloral hydrate concentration in the film. The response of these films depends on temperature during irradiation; therefore a correction should be applied. These films have the advantage of negligible humidity effects on response in the intermediate range of relative humidity from 10 to 70% as well as good post-irradiation stability when stored in the dark at room temperature.

  18. Biopolymer-based nanocomposites: effect of lignin acetylation in cellulose triacetate films

    Science.gov (United States)

    Nevárez, Laura Alicia Manjarrez; Casarrubias, Lourdes Ballinas; Celzard, Alain; Fierro, Vanessa; Muñoz, Vinicio Torres; Davila, Alejandro Camacho; Lubian, José Román Torres; Sánchez, Guillermo González

    2011-01-01

    We have prepared all-biopolymer nanocomposite films using lignin as a filler and cellulose triacetate (CTA) as a polymer matrix, and characterized them by several analytical methods. Three types of lignin were tested: organosolv, hydrolytic and kraft, with or without acetylation. They were used in the form of nanoparticles incorporated at 1 wt% in CTA. Self-supported films were prepared by vapor-induced phase separation at controlled temperature (35–55 °C) and relative humidity (10–70%). The efficiency of acetylation of each type of lignin was studied and discussed, as well as its effects on film structure, homogeneity and mechanical properties. The obtained results are explained in terms of intermolecular filler-matrix interaction at the nanometer scale, for which the highest mechanical resistance was reached using hydrolytic lignin in the nanocomposite. PMID:27877425

  19. Tissue soldering with biodegradable polymer films: in-vitro investigation of hydration effects on weld strength

    Science.gov (United States)

    Sorg, Brian S.; Welch, Ashley J.

    2001-05-01

    Previous work demonstrated increased breaking strengths of tissue repaired with liquid albumin solder reinforced with a biodegradable polymer film compared to unreinforced control specimens. It was hypothesized that the breaking strength increase was due to reinforcement of the liquid solder cohesive strength. Immersion in a moist environment can decrease the adhesion of solder to tissue and negate any strength benefits gained from reinforcement. The purpose of this study was to determine if hydrated specimens repaired with reinforced solder would still be stronger than unreinforced controls. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with 806-nm diode laser light. A poly(DL-lactic- co-glycolic acid) film was used to reinforce the solder (the controls had no reinforcement). The repaired tissues were immersed in phosphate buffered saline for time periods of 1 and 2 days. The breaking strengths of all of the hydrated specimens decreased compared to the acute breaking strengths. However, the reinforced specimens still had larger breaking strengths than the unreinforced controls. These results indicate that reinforcement of a liquid albumin solder may have the potential to improve the breaking strength in a clinical setting.

  20. Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models

    National Research Council Canada - National Science Library

    Warzinski, Robert P; Lynn, Ronald; Haljasmaa, Igor; Leifer, Ira; Shaffer, Frank; Anderson, Brian J; Levine, Jonathan S

    2014-01-01

    Predicting the fate of subsea hydrocarbon gases escaping into seawater is complicated by potential formation of hydrate on rising bubbles that can enhance their survival in the water column, allowing...

  1. Morphological, physical, antimicrobial and release properties of ZnO nanoparticles-loaded bacterial cellulose films.

    Science.gov (United States)

    Shahmohammadi Jebel, Fereshteh; Almasi, Hadi

    2016-09-20

    Bacterial cellulose (BC) monolayer and multilayer films, incorporating 5wt.% ZnO nanoparticles (NPs) have been obtained. Ultrasound (US) irradiation (40kHz) was applied during ZnO-BC nanocomposites preparation. X-ray diffraction (XRD) patterns showed that ZnO NPs were crystallized in their pure phase. SEM scanning electron microscopy (SEM) results indicated that US treatment causes to decrease ZnO particle size, forming a stable hybrid nanostructure and evenly distributed ZnO NPs coated BC nanofibers. ZnO NPs enhanced the mechanical properties and diminished water vapor permeability and moisture absorption of BC films. Antibacterial activity of ZnO-BC films against Staphylococcus aureus was more than Escherichia coli. The antibacterial activity was enhanced with the utilization of US irradiation. The ZnO release was influenced by films composition; the multilayer and US treated films being promising in order to achieve controlled release of ZnO. Results suggest that ZnO-BC films may be used as controlled release antimicrobial food active packaging.

  2. Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility

    Science.gov (United States)

    Reid, Michael S.; Villalobos, Marco; Cranston, Emily D.

    2016-06-01

    The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of the interactions between components. Measuring the cohesive particle-particle interactions and the adhesive particle-polymer interactions is challenging due to nanoscale dimensions and poor colloidal stability of nanoparticles in many solvents. We demonstrate a new cohesive interaction measurement method using cellulose nanocrystals (CNCs) as a model system; CNCs have recently gained attention in the composites community due to their mechanical strength and renewable nature. Multi-wavelength surface plasmon resonance spectroscopy (SPR) was used to monitor the swelling of CNC thin films to elucidate the primary forces between CNCs. This was achieved by measuring swelling in situ in water, acetone, methanol, acetonitrile, isopropanol, and ethanol and relating the degree of swelling to solvent properties. Films swelled the most in water where we estimate 1.2-1.6 nm spacings between CNCs (or 4-6 molecular layers of water). Furthermore, a correlation was found between film swelling and the solvent's Hildebrand solubility parameter (R2 = 0.9068). The hydrogen bonding component of the solubility parameters was more closely linked to swelling than the polar or dispersive components. The films remained intact in all solvents, and using DLVO theory we have identified van der Waals forces as the main cohesive interaction between CNCs. The trends observed suggest that solvents (and polymers) alone are not sufficient to overcome CNC-CNC cohesion and that external energy is required to break CNC agglomerates. This work not only demonstrates that SPR can be used as a tool to measure cohesive particle-particle interactions but additionally advances our fundamental understanding of CNC interactions which is necessary for the design of cellulose nanocomposites.The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of

  3. Minocycline-loaded cellulose nano whiskers/poly(sodium acrylate) composite hydrogel films as wound dressing.

    Science.gov (United States)

    Bajpai, S K; Pathak, V; Soni, Bhawna

    2015-08-01

    In this work, antibiotic drug Minocycline (Mic) loaded cellulose nano-whiskers (CNWs)/poly(sodium acrylate) hydrogel films were prepared and investigated for their drug releasing capacity in physiological buffer solution (PBS) at 37 °C. The (CNWs)/poly(sodium acrylate) film, containing 9.7% (w/w) of CNWs, demonstrated Mic release of 2500 μg/g while the plain poly(acrylate) film showed 3100 μg/g of drug release. In addition, with the increase in the concentration of cross-linker N,N'-methylene bisacrylamide (MB) from to, the drug release from the resulting films decreased from 507 to 191 μg/g. The release exponent 'n' for films with different compositions was found in the range of 0.45 to 0.89, thus indicating non-Fickian release mechanism. The Schott model was employed to interpret the kinetic drug release data successfully. The film samples poly(SA) and CNWs/poly(SA) (both not containing drug) showed thrombus formation of 0.010±0.001 g and 0.007±0.001 g, respectively, thus showing the non-thrombogenic behavior. In percent Hemolysis, both of the film samples of 1.136±0.012 and 0.5±0.020, respectively, thus indicating non-hemolytic behavior. In addition, both of the film samples demonstrated protein adsorption of 49.02±0.59μ g/μL and 51.20±0.51 μg/μL per cm(2), thus revealing a fair degree of protein adsorption. Finally, the Mic-loaded films showed fair anti-fungal and antibacterial properties.

  4. Surface hydrophobic modification of cellulose membranes by plasma-assisted deposition of hydrocarbon films

    Directory of Open Access Journals (Sweden)

    Mudtorlep Nisoa

    2010-03-01

    Full Text Available Surface modification by plasma polymerization is an efficient method to change the surface properties of a membrane. Desirable functionality such as hydrophobicity or hydrophilicity can be obtained, depending on plasma chemistry of gas precursors and discharge conditions. In this work, RF magnetron plasma is produced using acetylene and nitrogen as precursor gases. Variations of RF power, particle flux, deposited time and pressure of the precursor gases have been made to observe coating effects on the cellulose membranes. When appropriated conditions are used, a thin brownish film of hydrocarbon was formed on the membrane, and the water contact angle increased from 35 to 130 degrees.

  5. In Situ Carbonized Cellulose-Based Hybrid Film as Flexible Paper Anode for Lithium-Ion Batteries.

    Science.gov (United States)

    Cao, Shaomei; Feng, Xin; Song, Yuanyuan; Liu, Hongjiang; Miao, Miao; Fang, Jianhui; Shi, Liyi

    2016-01-20

    Flexible free-standing carbonized cellulose-based hybrid film is integrately designed and served both as paper anode and as lightweight current collector for lithium-ion batteries. The well-supported heterogeneous nanoarchitecture is constructed from Li4Ti5O12 (LTO), carbonized cellulose nanofiber (C-CNF) and carbon nanotubes (CNTs) using by a pressured extrusion papermaking method followed by in situ carbonization under argon atmospheres. The in situ carbonization of CNF/CNT hybrid film immobilized with uniform-dispersed LTO results in a dramatic improvement in the electrical conductivity and specific surface area, so that the carbonized paper anode exhibits extraordinary rate and cycling performance compared to the paper anode without carbonization. The flexible, lightweight, single-layer cellulose-based hybrid films after carbonization can be utilized as promising electrode materials for high-performance, low-cost, and environmentally friendly lithium-ion batteries.

  6. The effect of different anti-solvent and coconut shell content on properties of coconut shell regenerated cellulose biocomposite films

    Science.gov (United States)

    Hahary, Farah Norain; Husseinsyah, Salmah; Mostapha@Zakaria, Marliza

    2016-07-01

    In this study, coconut shell (CS) regenerated cellulose (RC) biocomposite films was prepared using dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system. The effect of anti-solvents such as water and methanol for regeneration of cellulose and coconut shell content on properties of CS-RC biocomposite films was investigated. The used of water as anti-solvent for cellulose regeneration was found to have higher tensile properties compared to regenerated cellulose using methanol. Besides, the X-Ray diffraction (XRD) analysis also revealed that RC using water as anti-solvent have higher crystallinity index (CrI) than CS-RC biocomposite film using methanol. The tensile strength and modulus elasticity of CS-RC biocomposite films increased up to 3 wt% CS and decreased with further addition of CS. The elongation at break of CS-RC biocomposite films decreased with the increment of CS. The CrI of CS-RC bioocmposite films up to 3 wt% and decreased with at higher content of CS.

  7. The dual effects of lignin content on enzymatic hydrolysis using film composed of cellulose and lignin as a structure model.

    Science.gov (United States)

    Zhang, Lu; Zhang, Liming; Zhou, Tian; Wu, Yuying; Xu, Feng

    2016-01-01

    The degree of delignification during pretreatment is a critical question for economic conversion of biomass to sugar platform. Many models have been used to study the optimum lignin content in biomass, but few of them are able to study without disturbances, such as the complex component and structure of biomass. A novel film model composed of only cellulose and lignin was used to investigate the effect of lignin on enzymatic hydrolysis. High lignin-cellulose proportion (10.00-31.25%) hindered enzymatic hydrolysis, whereas low lignin-cellulose proportion (2.00-8.00%) showed a notable potential to promote enzymatic hydrolysis. The enzymatic hydrolysis rate of lignin-cellulose (6.00%) film was 11.5% higher than that of pure cellulose films. Further study indicated that the promotion was due to the enhancement of film porosity and roughness by residual lignin. Thus, based on the biomimetic model, excessive delignification is not recommended in view of efficient conversion and economy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Bio-nanocomposite films reinforced with cellulose nanocrystals: Rheology of film-forming solutions, transparency, water vapor barrier and tensile properties of films.

    Science.gov (United States)

    El Miri, Nassima; Abdelouahdi, Karima; Barakat, Abdellatif; Zahouily, Mohamed; Fihri, Aziz; Solhy, Abderrahim; El Achaby, Mounir

    2015-09-20

    This study was aimed to develop bio-nanocomposite films of carboxymethyl cellulose (CMC)/starch (ST) polysaccharide matrix reinforced with cellulose nanocrystals (CNC) using the solution casting method. The CNC were extracted at the nanometric scale from sugarcane bagasse via sulfuric acid hydrolysis and used as reinforcing phase to produce CMC/ST-CNC bio-nanocomposite films at different CNC loading levels (0.5-5.0 wt%). Steady shear viscosity and dynamic viscoelastic measurements of film-forming solution (FFS) of neat CMC, CMC/ST blend and CMC/ST-CNC bio-nanocomposites were evaluated. Viscosity measurements revealed that a transition from Newtonian behavior to shear thinning occurred when CNC were added. The dynamic tests confirmed that all FFS have a viscoelastic behavior with an entanglement network structure, induced by the hydrogen bonding. In regard to the cast film quality, the rheological data showed that all FFS were suitable for casting of films at ambient temperature. The effect of CNC addition on the optical transparency, water vapor permeability (WVP) and tensile properties of bio-nanocomposite films was studied. It was found that bio-nanocomposite films remain transparent due to CNC dispersion at the nanoscale. The WVP was significantly reduced and the elastic modulus and tensile strength were increased gradually with the addition of CNC. Herein, the steps to form new eco-friendly bio-nanocomposite films were described by taking advantage of the combination of CMC, ST and CNC. The as-produced films exhibited good optical transparency, reduced WVP and enhanced tensile properties, which are the main properties required for packaging applications.

  9. Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models

    Science.gov (United States)

    Warzinski, Robert P.; Lynn, Ronald; Haljasmaa, Igor; Leifer, Ira; Shaffer, Frank; Anderson, Brian J.; Levine, Jonathan S.

    2014-10-01

    Predicting the fate of subsea hydrocarbon gases escaping into seawater is complicated by potential formation of hydrate on rising bubbles that can enhance their survival in the water column, allowing gas to reach shallower depths and the atmosphere. The precise nature and influence of hydrate coatings on bubble hydrodynamics and dissolution is largely unknown. Here we present high-definition, experimental observations of complex surficial mechanisms governing methane bubble hydrate formation and dissociation during transit of a simulated oceanic water column that reveal a temporal progression of deep-sea controlling mechanisms. Synergistic feedbacks between bubble hydrodynamics, hydrate morphology, and coverage characteristics were discovered. Morphological changes on the bubble surface appear analogous to macroscale, sea ice processes, presenting new mechanistic insights. An inverse linear relationship between hydrate coverage and bubble dissolution rate is indicated. Understanding and incorporating these phenomena into bubble and bubble plume models will be necessary to accurately predict global greenhouse gas budgets for warming ocean scenarios and hydrocarbon transport from anthropogenic or natural deep-sea eruptions.

  10. Adhesive layer-by-layer films of carboxymethylated cellulose nanofibril-dopamine covalent bioconjugates inspired by marine mussel threads.

    Science.gov (United States)

    Karabulut, Erdem; Pettersson, Torbjörn; Ankerfors, Mikael; Wågberg, Lars

    2012-06-26

    The preparation of multifunctional films and coatings from sustainable, low-cost raw materials has attracted considerable interest during the past decade. In this respect, cellulose-based products possess great promise due not only to the availability of large amounts of cellulose in nature but also to the new classes of nanosized and well-characterized building blocks of cellulose being prepared from trees or annual plants. However, to fully utilize the inherent properties of these nanomaterials, facile and also sustainable preparation routes are needed. In this work, bioinspired hybrid conjugates of carboxymethylated cellulose nanofibrils (CNFC) and dopamine (DOPA) have been prepared and layer-by-layer (LbL) films of these modified nanofibrils have been built up in combination with a branched polyelectrolyte, polyethyleneimine (PEI), to obtain robust, adhesive, and wet-stable nanocoatings on solid surfaces. It is shown that the chemical functionalization of CNFCs with DOPA molecules alters their conventional properties both in liquid dispersion and at the interface and also influences the LbL film formation by reducing the electrostatic interaction. Although the CNFC-DOPA conjugates show a lower colloidal stability in aqueous dispersions due to charge suppression, it was possible to prepare the LbL films through the consecutive deposition of the building blocks. Adhesive forces between multilayer films prepared using chemically functionalized CNFCs and a silica probe are much stronger in the presence of Fe(3+) than those between a multilayer film prepared from unmodified nanofibrils and a silica probe. The present work demonstrates a facile way to prepare chemically functionalized cellulose nanofibrils whereby more extended applications can produce novel cellulose-based materials with different functionalities.

  11. THERMOPLASTIC STARCH FILMS. INFLUENCE OF INCORPORATION OF HYDROXYPROPYL-METHYL-CELLULOSE AND CITRIC ACID

    Directory of Open Access Journals (Sweden)

    Rodrigo Ortega Toro

    2014-12-01

    Full Text Available The aim of this work was to analyze the influence of citric acid (CA and hydroxypropyl-methyl-cellulose (HPMC addition in thermoplastic starch films obtained by compression-molding. Two ratios of HPMC- starch (10% and 20% were considered while starch: CA ratio was of 1: 0,01. The films were characterized as to micro- and nano-structure using Scanning Electron Microscopy (SEM and X-ray diffraction. Further, the water solubility, CA linked, mechanical and thermal properties were characterized. The starch-HPMC films showed phase separation although the glass transition analysis showed partial miscibility of the starch and HPMC which is accentuated with the addition of CA. The incorporation of HPMC and CA promoted the decrease of water vapor permeability and a slight increase in the oxygen permeability. The CA addition resulted in an increase of the elasticity modulus and decrease in the extensibility of films, which agrees with the cross-linking effect. The optical properties show a decrease in the material compactness with the CA presence causing higher film transparency

  12. Properties of plasticized composite films prepared from nanofibrillated cellulose and birch wood xylan

    DEFF Research Database (Denmark)

    Hansen, Natanya Majbritt Louie; Blomfeldt, Thomas O. J.; Hedenqvist, Mikael S.

    2012-01-01

    Xylans, an important sub-class of hemicelluloses, represent a largely untapped resource for new renewable materials derived from biomass. As with other carbohydrates, nanocellulose reinforcement of xylans is interesting as a route to new bio-materials. With this in mind, birch wood xylan was comb......Xylans, an important sub-class of hemicelluloses, represent a largely untapped resource for new renewable materials derived from biomass. As with other carbohydrates, nanocellulose reinforcement of xylans is interesting as a route to new bio-materials. With this in mind, birch wood xylan...... was combined with nanofibrillated cellulose (NFC) and films were cast with and without glycerol, sorbitol or methoxypolyethylene glycol (MPEG) as plasticizers. Microscopy revealed some NFC agglomeration in the composite films as well as a layered nanocellulose structure. Equilibrium moisture content...

  13. Multiple internal reflectance infrared spectra of variably hydrated hemoglobin and myoglobin films: effects of globin hydration on ligand conformer dynamics and reactivity at the heme.

    Science.gov (United States)

    Brown, W E; Sutcliffe, J W; Pulsinelli, P D

    1983-06-07

    Multiple internal reflectance infrared (IR) spectra are reported for variably hydrated films (1.2-0.1 g of H2O/g of protein) of the carbon monoxy and oxy forms of human Hb and sperm whale Mb. The spectra show that even the limited removal of liquid and icelike hydration constraints at the globin surface is sufficient to cause a dramatic, but completely reversible, shift toward a normally minute population of sterically unhindered, linear-perpendicular, Fe-CO conformer modes (nu CO = 1968-1967 cm-1), and the destabilization of distally hindered, tilted (or bent), Fe-CO modes (nu CO = 1951, 1944-1933 cm-1). Corroborative evidence from IR band broadening trends [delta delta nu 1/2 (1968, 1967 cm-1) approximately 2-4 cm-1], corresponding changes in the visible, and H-D exchange kinetics confirm that the shift toward 1968-1967 cm-1 results in a more open distal heme pocket configuration and that it is also accompanied by a buildup of deoxy-like steric hindrance proximal to the heme. Denaturation effects are eliminated as a potential cause of the shifts, as are specific protein-protein, ion-protein, intersubunit, and MIR crystal-film surface interactions. The hydration effect exhibits globin-dependent and ligand-dependent differences, which highlight the intrinsic importance of distal steric effects within the heme pocket and their dynamic coupling with exterior solvent constraints. CO-photodissociation and O2-exchange experiments conducted on rapidly interconverting (coupled and fully hydrated) and noninterconverting (uncoupled and partially hydrated) Fe-CO conformers also suggest that the open linear-perpendicular mode corresponds to a more tightly bound form of CO than the axially distorted Fe-CO species; similar differences are not evident in Fe-O2, which already prefers a bent end-on geometry within the heme pocket. Control IR spectra aimed at monitoring the progressive effects of various denaturants on HbCO further indicate that this same open mode serves as a

  14. Photoactive layer-by-layer films of cellulose phosphate and titanium dioxide containing phosphotungstic acid

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Sajjad [Instituto de Química de São Carlos, Universidade de São Paulo, PO Box 780, São Carlos, São Paulo 13564-970 (Brazil); Acuña, José Javier Sáez [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo Andre, Sao Paulo, 09210-170 (Brazil); Pasa, André Avelino [Surface and Thin Film Laboratory, Physics Department, Federal University of Santa Catarina, PO Box 476, Florianópolis, SC 88040-900 (Brazil); Bilmes, Sara A. [Universidad de Buenos Aires, Facultad Ciencias Exactas y Naturales, Instituto de Química Física de los Materiales, Medio Ambiente y Energía – INQUIMAE, Ciudad Universitaria, Pab. 2, Buenos Aires C1428EHA (Argentina); Vela, Maria Elena; Benitez, Guillermo [Laboratorio de Nanoscopías y Fisicoquímica de Superficies, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata – CONICET, diagonal 113 esquina 64. C.C.16.Suc.4, 1900 La Plata (Argentina); Rodrigues-Filho, Ubirajara Pereira, E-mail: uprf@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, PO Box 780, São Carlos, São Paulo 13564-970 (Brazil)

    2013-07-15

    A versatile layer-by-layer (LbL) procedure for the preparation of highly dispersed, adherent and porous multilayer films of TiO{sub 2} nanoparticles (NPs) and phosphotungstic acid (HPW) on a variety of substrates at room temperature was developed based on the use of cellulose phosphate (CP) as an efficient and non-conventional polyelectrolyte. UV/vis absorption spectroscopy confirmed the linear and regular growth of the films with the number of immersion cycles and a strong adsorption ability of CP towards TiO{sub 2} NPs. FTIR spectroscopy showed that HPW binds to the surface of TiO{sub 2} through the oxygen atom at the corner of the Keggin structure. XPS results showed that the interaction between TiO{sub 2} and CP is through Ti–O–P linkage. A model is proposed for the TiO{sub 2}–HPW interaction based on XPS and FTIR results. FEG/SEM study of the surface morphology revealed a porous film structure with a homogenous distribution of the TiO{sub 2} NPs induced by CP. HRTEM studies showed that the resulting composite films consist of crystalline anatase and rutile phases and poly-nano-crystalline HPW with a semi-crystalline TiO{sub 2}–HPW interface. These CP/TiO{sub 2} and CP/TiO{sub 2}/HPW LbL films showed good photoactivity against both saturated and unsaturated species, for instance, stearic acid (SA), crystal violet (CV) and methylene blue (MB) under UV irradiation. The CP/HPW films formed on bacterial cellulose (BC) showed good photochromic response which is enhanced in presence of TiO{sub 2} due to an interfacial electron transfer from TiO{sub 2} to HPW. This simple and environmentally safe method can be used to form coatings on a variety of surfaces with photoactive TiO{sub 2} and TiO{sub 2}/HPW films.

  15. THE FORMATION AND CHARACTERIZATION OF SUSTAINABLE LAYERED FILMS INCORPORATING MICROFIBRILLATED CELLULOSE (MFC

    Directory of Open Access Journals (Sweden)

    Galina Rodionova,

    2012-06-01

    Full Text Available Microfibrillated cellulose (MFC, TEMPO-pretreated MFC, and hybrid polymer/MFC mix were used for the production of layered films with interesting properties for application in food packaging. The series of samples were prepared from MFC (base layers using a dispersion-casting method. The same procedure as well as a bar coating technique was applied to form top layers of different basis weights. The barrier properties and formation of the layered films were investigated in relationship to the preparation procedures, combination of layers, and areal weight (basis weight. Characterization was done with respect to oxygen transmission rates (OTR, water vapor transmission rates (WVTR, tensile properties, and contact angles (CA with water. The produced layered films yielded OTR values of 4 mL m-2 day-1 and fulfilled oxygen barrier requirements for a modified atmosphere packaging (MAP. Hornification of the MFC films, however, occurred during drying, which may result in a loss of the film’s beneficial properties.

  16. Effect of gamma irradiation on biopolymer composite films of poly(vinyl alcohol) and bacterial cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Jipa, Iuliana Mihaela; Stroescu, Marta [University Politehnica of Bucharest, Department of Chemical Engineering, 313 Splaiul Independentei, Polizu 1-3, 060042 Bucharest (Romania); Stoica-Guzun, Anicuta, E-mail: stoica.anicuta@gmail.com [University Politehnica of Bucharest, Department of Chemical Engineering, 313 Splaiul Independentei, Polizu 1-3, 060042 Bucharest (Romania); Dobre, Tanase; Jinga, Sorin [University Politehnica of Bucharest, Department of Chemical Engineering, 313 Splaiul Independentei, Polizu 1-3, 060042 Bucharest (Romania); Zaharescu, Traian [Advanced Research Institute for Electrical Engineering, 313 Splaiul Unirii, 030138 Bucharest (Romania)

    2012-05-01

    Highlights: Black-Right-Pointing-Pointer The paper reports the obtaining of composite materials between PVA and BC. Black-Right-Pointing-Pointer The composite films were {gamma}-irradiated at doses up to 50 kGy. Black-Right-Pointing-Pointer The films have a good resistance, being suitable as food packaging materials. - Abstract: Composite materials containing in different ratios poly(vinyl alcohol) (PVA), bacterial cellulose (BC) and glycerol (G) as plasticizer were obtained and exposed to different {gamma} radiation doses using an irradiator GAMMATOR provided with {sup 137}Cs source. These films successively received up to 50 kGy absorbed doses at a dose rate of 0.4 kGy/h at room temperature. In order to study the chemical and structural changes during {gamma} irradiation, Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and UV-Vis spectroscopy were used. Water vapour permeability (WVP), Hunter colour parameters and hardness were also measured for the irradiated samples. Investigation revealed that WVP was not significantly affected by the irradiation. Colour measurements indicated a slight decrease of pure PVA films transparency and it made clear that all samples became more reddish and yellowish after irradiation. The samples hardness was not affected by the irradiation doses used. However, the results showed no drastic structural or chemical changes of the irradiated samples, which prove, in consequence, a good durability. These composite materials could be used as packaging materials for {gamma} irradiated products.

  17. CW laser-induced photothermal conversion and shape transformation of gold nanodogbones in hydrated chitosan films

    Energy Technology Data Exchange (ETDEWEB)

    Ratto, Fulvio, E-mail: f.ratto@ifac.cnr.it; Matteini, Paolo [National Research Council of Italy, Institute of Applied Physics (Italy); Cini, Alberto [University of Florence, Department of Physics and Astronomy (Italy); Centi, Sonia [University of Florence, Department of Clinical Physiopathology (Italy); Rossi, Francesca [National Research Council of Italy, Institute of Applied Physics (Italy); Fusi, Franco [University of Florence, Department of Clinical Physiopathology (Italy); Pini, Roberto [National Research Council of Italy, Institute of Applied Physics (Italy)

    2011-09-15

    We investigate the photothermal conversion and transformation of gold nanoparticles with an initial dogbone shape after dispersion in hydrated chitosan films, which is a representative model of biological tissue, and excitation by a CW diode laser for 1 min. Gold nanodogbones are observed to undergo a distinct modification above a sharp threshold of {approx}11 W cm{sup -2} and 110 Degree-Sign C. Surprisingly, the very same modification is achieved up to at least 36 W cm{sup -2} and 250 Degree-Sign C. We use an analytical model derived from Gans theory to associate the change in color of the films with the change in shape statistics of these gold nanoparticles. This model proves both convenient and dependable. We interpret the photothermal transformation as a rearrangement of particles with a dogbone shape and an aspect ratio of 4.1 into rods with an aspect ratio of 2.5, where material from the end lobes of the dogbones may relocate to the waists of the rods. In turn, additional transitions to stable gold nanospheres may exhibit fairly slower kinetics.

  18. Hydrolysis of model cellulose films by cellulosomes: Extension of quartz crystal microbalance technique to multienzymatic complexes.

    Science.gov (United States)

    Zhou, Shanshan; Li, Hsin-Fen; Garlapalli, Ravinder; Nokes, Sue E; Flythe, Michael; Rankin, Stephen E; Knutson, Barbara L

    2017-01-10

    Bacterial cellulosomes contain highly efficient complexed cellulases and have been studied extensively for the production of lignocellulosic biofuels and bioproducts. A surface measurement technique, quartz crystal microbalance with dissipation (QCM-D), was extended for the investigation of real-time binding and hydrolysis of model cellulose surfaces from free fungal cellulases to the cellulosomes of Clostridium thermocellum (Ruminiclostridium thermocellum). In differentiating the activities of cell-free and cell-bound cellulosomes, greater than 68% of the cellulosomes in the crude cell broth were found to exist unattached to the cell across multiple growth stages. The initial hydrolysis rate of crude cell broth measured by QCM was greater than that of cell-free cellulosomes, but the corresponding frequency drop (a direct measure of the mass of enzyme adsorbed to the film) of crude cell broth was less than that of the cell-free cellulosomes, consistent with the underestimation of the cell mass adsorbed using QCM. Inhibition of hydrolysis by cellobiose (0-10g/L), which is similar for crude cell broth and cell-free cellulosomes, demonstrates the sensitivity of the QCM to environmental perturbations of multienzymatic complexes. QCM measurements using multienzymatic complexes may be used to screen and optimize hydrolysis conditions and to develop mechanistic, surface-based models of enzymatic cellulose deconstruction. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Hierarchically Self-Assembled Nanofiber Films from Amylose-Grafted Carboxymethyl Cellulose

    Directory of Open Access Journals (Sweden)

    Daisuke Hatanaka

    2014-01-01

    Full Text Available In this paper, we report the formation of hierarchically self-assembled nanofiber films from amylose-grafted sodium carboxymethyl celluloses (NaCMCs that were synthesized by a chemoenzymatic approach. First, maltooligosaccharide primer-grafted NaCMCs were prepared by a chemical reaction using two kinds of NaCMCs with different degrees of polymerization (DPs from Avicel and cotton sources. Then, phosphorylase-catalyzed enzymatic polymerization of α-d-glucose 1-phosphate from the nonreducing ends of the primer chains on the products was conducted to produce the prescribed amylose-grafted NaCMCs. The films were obtained by drying aqueous alkaline solutions of the amylose-grafted NaCMCs. The scanning electron microscopy (SEM image of the film fabricated from the material with the higher DP from the cotton source showed a clear, self-assembled, highly condensed tangle of nanofibers. The SEM image of the material with the lower DP from the Avicel source, on the other hand, showed an unclear nanofiber morphology. These results indicate that the DPs of the main chains in the materials strongly affected the hierarchically self-assembled nanofiber formation. The SEM images of the films after washing out the alkali, furthermore, showed that the fibers partially merged with each other at the interfacial area owing to the double helix formation between the amylose-grafted chains. The mechanical properties of the films under tensile mode also depended on the self-assembled morphologies of the amylose-grafted NaCMCs from the different sources.

  20. Direct surface force measurements of polyelectrolyte multilayer films containing nanocrystalline cellulose.

    Science.gov (United States)

    Cranston, Emily D; Gray, Derek G; Rutland, Mark W

    2010-11-16

    Polyelectrolyte multilayer films containing nanocrystalline cellulose (NCC) and poly(allylamine hydrochloride) (PAH) make up a new class of nanostructured composite with applications ranging from coatings to biomedical devices. Moreover, these materials are amenable to surface force studies using colloid-probe atomic force microscopy (CP-AFM). For electrostatically assembled films with either NCC or PAH as the outermost layer, surface morphology was investigated by AFM and wettability was examined by contact angle measurements. By varying the surrounding ionic strength and pH, the relative contributions from electrostatic, van der Waals, steric, and polymer bridging interactions were evaluated. The ionic cross-linking in these films rendered them stable under all solution conditions studied although swelling at low pH and high ionic strength was inferred. The underlying polymer layer in the multilayered film was found to dictate the dominant surface forces when polymer migration and chain extension were facilitated. The precontact normal forces between a silica probe and an NCC-capped multilayer film were monotonically repulsive at pH values where the material surfaces were similarly and fully charged. In contrast, at pH 3.5, the anionic surfaces were weakly charged but the underlying layer of cationic PAH was fully charged and attractive forces dominated due to polymer bridging from extended PAH chains. The interaction with an anionic carboxylic acid probe showed similar behavior to the silica probe; however, for a cationic amine probe with an anionic NCC-capped film, electrostatic double-layer attraction at low pH, and electrostatic double-layer repulsion at high pH, were observed. Finally, the effect of the capping layer was studied with an anionic probe, which indicated that NCC-capped films exhibited purely repulsive forces which were larger in magnitude than the combination of electrostatic double-layer attraction and steric repulsion, measured for PAH

  1. Influence of the simultaneous addition of bentonite and cellulose fibers on the mechanical and barrier properties of starch composite-films.

    Science.gov (United States)

    de Moraes, J Oliveira; Müller, C M O; Laurindo, J B

    2012-02-01

    The addition of nanoclay or cellulose fibers has been presented in the literature as a suitable alternative for reinforcing starch films. The aim of the present work was to evaluate the effect of the simultaneous incorporation of nanoclay (bentonite) and cellulose fibers on the mechanical and water barrier properties of the resultant composite-films. Films were prepared by casting with 3% in weight of cassava starch, using glycerol as plasticizer (0.30 g per g of starch), cellulose fibers at a concentration of 0.30 g of fibers per g of starch and nanoclay (0.05 g clay per g starch and 0.10 g clay per g starch). The addition of cellulose fibers and nanoclay increased the tensile strength of the films 8.5 times and the Young modulus 24 times but reduced the elongation capacity 14 times. The water barrier properties of the composite-films to which bentonite and cellulose fibers were added were approximately 60% inferior to those of starch films. Diffractograms showed that the nanoclay was intercalated in the polymeric matrix. These results indicate that the simultaneous addition of bentonite and cellulose fibers is a suitable alternative to increase the tensile strength of the films and decrease their water vapor permeabilities.

  2. Application of Response Surface Methodology in Development of Sirolimus Liposomes Prepared by Thin Film Hydration Technique

    Directory of Open Access Journals (Sweden)

    Saeed Ghanbarzadeh

    2013-04-01

    Full Text Available Introduction: The present investigation was aimed to optimize the formulating process of sirolimus liposomes by thin film hydration method. Methods: In this study, a 32 factorial design method was used to investigate the influence of two independent variables in the preparation of sirolimus liposomes. The dipalmitoylphosphatidylcholine (DPPC /Cholesterol (Chol and dioleoyl phosphoethanolamine(DOPE /DPPC molar ratios were selected as the independent variables. Particle size (PS and Encapsulation Efficiency (EE % were selected as the dependent variables. To separate the un-encapsulated drug, dialysis method was used. Drug analysis was performed with a validated RP-HPLC method. Results: Using response surface methodology and based on the coefficient values obtained for independent variables in the regression equations, it was clear that the DPPC/Chol molar ratio was the major contributing variable in particle size and EE %. The use of a statistical approach allowed us to see individual and/or interaction effects of influencing parameters in order to obtain liposomes with desired properties and to determine the optimum experimental conditions that lead to the enhancement of characteristics. In the prediction of PS and EE % values, the average percent errors are found to be as 3.59 and 4.09%. This value is sufficiently low to confirm the high predictive power of model. Conclusion: Experimental results show that the observed responses were in close agreement with the predicted values and this demonstrates the reliability of the optimization procedure in prediction of PS and EE % in sirolimus liposomes preparation.

  3. Effect of various penetration enhancers concentrations on diclafenac sodium release from cellulose acetate phthalate polymeric film

    Directory of Open Access Journals (Sweden)

    El-Nahas Hanan

    2011-01-01

    Full Text Available An investigation was conducted to evaluate the influence of different penetration enhancers in various concentrations on the release of diclofenac sodium (DFS as a water-soluble drug from Cellulose acetate phthalate polymeric films containing 50% w/w PEG 600 as plasticizer, to choose the most appropriate enhancer and its optimum concentration to be used to achieve the maximum release and permeation of the drug. The addition of various enhancers, as isopropylmyristate (IPM; 0.2_5% w/w, oleic acid (OA; 0.2_5% w/w and linoleic acid (LOA; 0.2_5% w/w, Tween 80 (T80;1_10% w/w and transcutol, (TC; 1_10% w/w enhanced the DFS release from the polymeric films. The enhancement ratio of the penetration enhancers used in the formulation of DFS were found to increase in the order of IPM>LOA>OA>T80>TC. (56.2, 54.1, 50, 48.7 and 48%, respectively. In vitro permeation studies were performed using rabbit abdominal skin as the permeating membrane. The results indicated that maximum permeation was obtained at 24hrs (0.5% IPM, 0.2% LOA, 1% OA, 0.5% T80 and 10% TC, increased skin permeation of DFS by 4.46, 4.06, 3.37, 1.65 and 1.49 time, respectively. IPM was found to be the most efficient enhancer. The results obtained from ANOVA test indicate that the difference in drug permeation rates is highly significant compared to the control formulation (P<0.05. The mechanism of drug release from the polymeric films obey Higuchi′s model.

  4. Effect Of Ether Derivative Cellulose Polymers On Hydration, Erosion And Release Kinetics Of Diclofenac Sodium Matrix Tablets

    Directory of Open Access Journals (Sweden)

    Muhammad Akhlaq*1,2, Gul Majid Khan1 , Abdul Wahab1, Waqas Rabbani1, Abid Hussain1, Asif Nawaz1, & Alam Zeb1

    2011-09-01

    Full Text Available Objectives: The work aims to investigate the effect ofhydrophilic and hydrophobic polymers swelling and erosionon the release behaviour of DCL-Na from controlled matrixtablets prepared by direct compression and wet-granulationtechniques.Materials and Methods: Powder preformulation studies wereconducted. Tablets were prepared by direct compressiontechnique and their physicochemical properties wereevaluated. Drug-polymer interaction was analyzed by FTIRspectroscopy. The in-vitro drug release study was conductedusing phosphte buffer pH 7.4 as dissolution medium anddifferent kinetic parameters were applied.Results and Discussion: F-1 and F-5 containing ethycelluloseprepared by direct compression and wet granulationtechniques released 94 % and 84 % drug after 24hrs, while F-2and F-6 containing hydroxypropylmethylcellulose polymerprepared by direct compression and wet granulation released98.46 % and 91.25 % drug after within 24 hrs respectively.Ethylcellulose and hydroxypropylmethylcellulose based matrixtablets showed the best anomalous drug release behaviour,with the release exponents “ n ” ranging from 0.685 to 0.809.Conclusion: It has been concluded that ethylcellulose etherderivative polymer is used to prepare oral controlled releasematrix tablet of diclofenac sodium. Fickian drug diffusion,polymer hydration and erosion mechanisms occurredsimultaneously and were considered as the main drug releasecontrolling factors.

  5. The effect of low frequency ultrasound on the production and properties of nanocrystalline cellulose suspensions and films.

    Science.gov (United States)

    Csiszar, Emilia; Kalic, Petra; Kobol, Akos; Ferreira, Eduardo de Paulo

    2016-07-01

    Suspension of nanocrystalline cellulose (NCC) produced from bleached cotton by controlled sulphuric acid hydrolysis was treated with low frequency ultrasound at 20 kHz and 60% amplitude for 0, 1, 2, 5 and 10 min and the effects of sonication on the properties of both the cellulose nanocrystals and their aqueous suspensions were investigated. Furthermore, a series of nanocellulose films were manufactured from the suspensions that were sonicated for different periods of time and tested. Laser diffraction analysis and transmission electron microscopy proved that sonication not only disintegrated the large NCC aggregates (Dv50 14.7 μm) to individual nanowhiskers with an average length and width of 171 ± 57 and 17 ± 4 nm, respectively, but also degraded the nanocrystals and yielded shorter and thinner particles (118 ± 45 and 13 ± 3 nm, respectively) at 10-min sonication. The ultrasound-assisted disintegration to nano-sized cellulose whiskers decreased the optical haze of suspensions from 98.4% to 52.8% with increasing time from 0 to 10 min, respectively. Sonication of the suspensions significantly contributed to the preparation of films with low haze (high transparency) and excellent tensile properties. With the increasing duration of sonication, the haze decreased and the tensile strength rose gradually. Irrespectively of sonication, however, all films had an outstanding oxygen transmission rate in a range of 5.5-6.9 cm(3)/m(2)day, and a poor thermal stability.

  6. Photodegradation of Azo-dye by Y2O3/TiO2 Loaded on Carboxymethyl Cellulose Films

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-yun; CHEN Ri-yao; ZHENG Xi; CHEN Zhen

    2005-01-01

    Nanosize TiO2, Y2 O3/TiO2 particles were prepared by the sol-gel process. The structure was characterized by means of XRD,TEM. The photoelectric properties of the nanoparticles were studied by PL.The thickness and the surface of the carboxymethyl cellulose film was measured by SEM. Based on a model reaction, the photocatalytic degradation of methylene blue with positive charge was investigated in TiO2,Y2O3/TiO2 nanopowder composite films irradiated by UV lamp. The results revealed that the degradation process belonged to the first-order kinetic reaction.

  7. 177 fs erbium-doped fiber laser mode locked with a cellulose polymer film containing single-wall carbon nanotubes

    Science.gov (United States)

    Tausenev, A. V.; Obraztsova, E. D.; Lobach, A. S.; Chernov, A. I.; Konov, V. I.; Kryukov, P. G.; Konyashchenko, A. V.; Dianov, E. M.

    2008-04-01

    A mode-locked soliton erbium-doped fiber laser generating 177fs pulses is demonstrated. The laser pumped by a 85mW, 980nm laser diode emits 7mW at 1.56μm at a pulse repetition rate of 50MHz. Passive mode locking is achieved with a saturable absorber made of a high-optical quality film based on cellulose derivative with dispersed carbon single-wall nanotubes. The film is prepared with the original technique by using carbon nanotubes synthesized by the arc-discharge method.

  8. Incorporation of citrus essential oils into bacterial cellulose-based edible films and assessment of their physical properties

    Science.gov (United States)

    Indrarti, L.; Indriyati

    2017-03-01

    The use of edible films in food protection and preservation has recently gained more interest since they offer several advantages over synthetic packaging materials. Biocellulose (BC) offers great opportunity as edible film due to their unique physical and mechanical properties. In this study, biocellulose films were prepared by solution casting with addition of 30% carboxymethyl cellulose (CMC) and 30% glycerol as the homogenizer and plasticizer, respectively. Furthermore, various citrus essential oils (EOs) including lemon, lime, and sweet orange were added at 50% w/w of BC dried weight. The solutions were then cast on the tray and allowed to dry in the air convection oven at 40°C overnight. The films were characterized for water solubility, tensile strength (TS), elongation at break (EB), water vapour transmission rate (WVTR), and color. Those characteristics may influence consumer acceptability of the packaged products. Results revealed that addition of lemon and sweet orange EOs into BC-based edible film decreased water solubility and TS, but improved EB, as these oils acted as plasticizers in the film. However, different trend was observed for BC-based film incorporated with lime oil, which had higher solubility and TS, but lower EB and WVTR compared with that of control film. Addition of citrus EOs into BC-based films did not have much effect on color properties as stated in L*, a*, and b* values.

  9. Investigation of Regenerated Cellulose/Poly(acrylic acid Composite Films for Potential Wound Healing Applications: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Manjula Bajpai

    2014-01-01

    Full Text Available Regenerated cellulose/poly(acrylic acid composite films have been synthesized for wound dressing applications. The water absorbency of these films was studied as a function of amount of cross-linker N,N′-methylenebisacrylamide and cellulose contents in the feed mixture. The samples, having different compositions, showed tensile strength and percent elongation in the range of 9.98×105 to 13.40×105 N/m2 and 110 to 265, respectively. The water vapor transmission rate (WVTR for various films was found to be in the range of 2.03 to 7.18 mg/cm2/h. These films were loaded with antibacterial drug miconazole nitrate and their release was studied in the physiological pH at 37°C. The release data was found to fit well the diffusion controlled Higuchi model. Finally the films demonstrated fair antibacterial and antifungal action, thus establishing their strong candidature as wound dressing materials.

  10. Effect of Mixed Solvents Consisting of Water and Organic Solvent on Preparation of Medium-Responsive Grafted Cellulose Film by Means of Photografting

    Directory of Open Access Journals (Sweden)

    Irwan Ginting-Suka

    2006-11-01

    Full Text Available Cellulose having a medium-responsive function were synthesized by photografting of methacrylic acid (MAA on regenerated cellulose film (thickness = 20 µm at 60°C using mixed solvent consisting of water and organic solvents such as acetone and methanol. Xanthone was used as photoinitiator by coating on the film surfaces. A maximum percentage of grafting was observed at a certain concentration of organic solvent. MAA-grafted cellulose films produced showing homogeneous distribution of grafted chains, which was examined by scanning electron microscopy. The modified films also exhibit medium responsive character, it shrinks in acidic and swells in basic solution. Moreover, the grafted film exhibited the ability to absorb copper ion, which was not influenced by the solvent used in grafting processes.

  11. Silane Modification of Cellulose Acetate Dense Films as Materials for Acid Gas Removal

    KAUST Repository

    Achoundong, Carine S. K.

    2013-07-23

    The modification of cellulose acetate (CA) films via grafting of vinyltrimethoxysilane (VTMS) to -OH groups, with subsequent condensation of hydrolyzed methoxy groups on the silane to form a polymer network is presented. The technique is referred to as GCV-modification. The modified material maintains similar H2S/CH4 and CO2/CH 4 selectivities compared to the unmodified material; however the pure CO2 and H2S permeabilities are 139 and 165 barrers, respectively, which are more than an order of magnitude higher than the neat polymer. The membranes were tested at feed pressures of up to 700 psia in a ternary 20 vol. %H2S/20 vol. % CO2/60 vol. % CH 4 mixture. Even under aggressive feed conditions, GCV-modified CA showed comparable selectivities and significantly higher permeabilities. Furthermore, GCV-modified membrane had a lower Tg, lower crystallinity, and higher flexibility than neat CA. The higher flexibility is due to the vinyl substituent provided by VTMS, thereby reducing brittleness, which could be helpful in an asymmetric membrane structure. © 2013 American Chemical Society.

  12. Graft Copolymerization of N-ISO Propylacrylamide on Cellulose Film Induced by UV-Irradiation and its Characterization

    Directory of Open Access Journals (Sweden)

    Irwan Ginting Suka

    2010-04-01

    Full Text Available The effect of monomer and initiator concentrations, graft polymerization temperature, polymerization system and organic solvents on photografting of N-isopropylacrylamide on regenerated cellulose films (thickness = 20 µm in UV irradiation were investigated. The higher percentage of grafting was afforded for the system with the higher monomer and initiator concentration. The photografting initiated even in the system at 30°C by using a longer irradiation time. It was found that the maximum percentage of grafting was attained at 2.5 (%Vol of methanol/acetone in the mixed solvent. The resulting NIPAAm-grafted cellulose films were characterized by attenuated total-reflection IR spectroscopy, showed a peak at 1640 and 1550 cm-1 due to the amide groups of the NIPAAm-grafted chains. According to scanning electron microscopy characterization, the grafted chains was found to distribute inside the film sample even in the grafted films with lower percentage of grafting. The grafted samples showing a temperature-responsive character swelling and shrinking in water at 5°C and 50°C, respectively.

  13. Effect of interfibrillar PVA bridging on water stability and mechanical properties of TEMPO/NaClO2 oxidized cellulosic nanofibril films.

    Science.gov (United States)

    Hakalahti, Minna; Salminen, Arto; Seppälä, Jukka; Tammelin, Tekla; Hänninen, Tuomas

    2015-08-01

    TEMPO/NaClO2 oxidized cellulosic nanofibrils (TCNF) were covalently bonded with poly(vinyl alcohol) (PVA) to render water stable films. Pure TCNF films and TCNF-PVA films in dry state showed similar humidity dependent behavior in the elastic region. However, in wet films PVA had a significant effect on stability and mechanical characteristics of the films. When soaked in water, pure TCNF films exhibited strong swelling behavior and poor wet strength, whereas covalently bridged TCNF-PVA composite films remained intact and could easily be handled even after 24h of soaking. Wet tensile strength of the films was considerably enhanced with only 10 wt% PVA addition. At 25% PVA concentration wet tensile strengths were decreased and films were more yielding. This behavior is attributed to the ability of PVA to reinforce and plasticize TCNF-based films. The developed approach is a simple and straightforward method to produce TCNF films that are stable in wet conditions.

  14. Hydrolysis of model cellulose films by cellulosomes: Extension of quartz crystal microbalance techniques to multienzymatic complexes

    Science.gov (United States)

    Clostridium thermocellum, a well-studied cellulolytic bacterium, produces highly active cellulases in the form of cellulosomes. The ability of the cellulose binding module within the cellulosome to adhere C. thermocellum cells to the cellulosic substrate is considered to contribute to its high cellu...

  15. Performance of hydrate cellulose membrane for zinc-silver battery after remodeling%锌银电池用水化纤维素膜改性后的性能

    Institute of Scientific and Technical Information of China (English)

    张红平; 郑艳丽; 赵力群

    2011-01-01

    讨论了在不同组成的反应液中,反应温度和时间对锌银电池用水化纤维素膜进行改性的影响.对面积电阻、耐电解液的腐蚀能力、吸碱率及保液能力等测试以及实验电池电性能分析,总结了水化纤维素膜的性能.当甲醛浓度为30%,温度为20℃、反应时间为10 min时,改性后水化纤维素膜的各项物理性能比改性前提高近5%,制备的8 Ah XYZ8型锌银电池的循环寿命增加9次,放电容量、放电电压分别提高约20%和8%.%The remolding of hydrate cellulose membrane for zino-silver battery in the solution with different composition, temperature and reaction time was discussed. The performance of hydrate cellulose membrane was summarized by the tests of area resistance, electrolyte corrosion resistance ability, alkali uptake and liquid preserving ability, the electrical performance analysis of experimental battery. When the formaldehyde content was 30% , the temperature was 20 ℃, the reaction time was 10 min, the physical properties of hydrate cellulose membrane after remolding increased nearly 5% than before remolding, the life of prepared 8 Ah XYZ8 zinc-silver battery increased 9 cycles, the discharge capacity and discharge voltage increased about 20% and 8%, respectively.

  16. Effects of Methyl Cellulose on the Hydration Process of Carbon Fiber Reinforced Concrete%CFRC中分散剂甲基纤维素对水泥水化的影响

    Institute of Scientific and Technical Information of China (English)

    王明明; 徐协文; 刘其城

    2011-01-01

    用直接测温、XRD、SEM及DTA等技术,系统研究了CFRC中分散剂甲基纤维素(MC)对水泥水化的水化热、初期产物与后期产物的影响.实验结果表明:添加质量为水泥干重0.5%的MC,水泥净浆出现了缓凝现象,其水化放热曲线的第二个放热峰被分割成两个放热峰,Ca(OH)2比C-S-H首先成核.在水泥净浆的后期水化中,MC并没有参与反应,其对水泥水化的最终产物没有影响,只作为一种高分子聚合物存在,增强了水泥石的强度.%Effect of methyl cellulose on the hydration process of carbon fiber reinforced concrete,including hydration heat, initial and final concrete composition, were investigated by direct temperature measurement( DTM ), X-ray diffraction ( XRD ), scanning electron microscope ( SEM ) and differential thermal analysis techniques. The results showed that the setting time of the CFRC with MC is delayed and the second exothermic peaks of CFRC' s hydration exothermic curves is divided into two peaks. What' s more, Ca( OH)2 have a better nucleation rate than C-S-H. While in later period of hydration, MC as akind of high polymer improved the strength of CFRC, Which don't involved in the hydration reaction and have little influence on the final hydration composition.

  17. Achieving a Collapsible, Strong, and Highly Thermally Conductive Film Based on Oriented Functionalized Boron Nitride Nanosheets and Cellulose Nanofiber.

    Science.gov (United States)

    Wu, Kai; Fang, Jinchao; Ma, Jinrui; Huang, Rui; Chai, Songgang; Chen, Feng; Fu, Qiang

    2017-09-06

    Boron nitride nanosheet (BNNS) films receive wide attention in both academia and industry because of their high thermal conductivity (TC) and good electrical insulation capability. However, the brittleness and low strength of the BNNS film largely limit its application. Herein, functionalized BNNSs (f-BNNSs) with a well-maintained in-plane crystalline structure were first prepared utilizing urea in the aqueous solution via ball-milling for the purpose of improving their stability in water and enhancing the interaction with the polymer matrix. Then, a biodegradable and highly thermally conductive film with an orderly oriented structure based on cellulose nanofibers (CNFs) and f-BNNSs was prepared just by simple vacuum-assisted filtration. The modification of the BNNS and the introduction of the CNF result in a better orientation of the f-BNNS, sufficient connection between f-BNNS themselves, and strong interaction between f-BNNS and CNF, which not only make the prepared composite film strong and tough but also possess higher in-plane TC. An increase of 70% in-plane TC, 63.2% tensile strength, and 77.8% elongation could be achieved for CNF/f-BNNS films, compared with that for CNF/BNNS films at the filler content of 70%. Although at such a high f-BNNS content, this composite film can be bended and folded. It is even more interesting to find that the in-plane TC could be greatly enhanced with the decrease of the thickness of the film, and a value of 30.25 W/m K can be achieved at the thickness of ∼30 μm for the film containing 70 wt % f-BNNS. We believe that this highly thermally conductive film with good strength and toughness could have potential applications in next-generation highly powerful and collapsible electronic devices.

  18. A3-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

    Directory of Open Access Journals (Sweden)

    Jian-Lin Huang

    2013-07-01

    Full Text Available We decorated HS-functionalized cellulose nanocrystallite (CNC films with monodisperse Au nanoparticles (AuNPs to form a novel nanocomposite catalyst AuNPs@HS-CNC. The uniform, fine AuNPs were made by the reduction of HAuCl4 solution with thiol (HS- group-functionalized CNC films. The AuNPs@HS-CNC nanocomposites were examined by X-ray photoelectron spectroscopy (XPS, TEM, ATR-IR and solid-state NMR. Characterizations suggested that the size of the AuNPs was about 2–3 nm and they were evenly distributed onto the surface of CNC films. Furthermore, the unique nanocomposite Au@HS-CNC catalyst displayed high catalytic efficiency in promoting three-component coupling of an aldehyde, an alkyne, and an amine (A3-coupling either in water or without solvent. Most importantly, the catalyst could be used repetitively more than 11 times without significant deactivation. Our strategy also promotes the use of naturally renewable cellulose to prepare reusable nanocomposite catalysts for organic synthesis.

  19. Effect of cellulose reinforcement on the properties of organic acid modified starch microparticles/plasticized starch bio-composite films.

    Science.gov (United States)

    Teacă, Carmen-Alice; Bodîrlău, Ruxanda; Spiridon, Iuliana

    2013-03-01

    The present paper describes the preparation and characterization of polysaccharides-based bio-composite films obtained by the incorporation of 10, 20 and 30 wt% birch cellulose (BC) within a glycerol plasticized matrix constituted by the corn starch (S) and chemical modified starch microparticles (MS). The obtained materials (coded as MS/S, respectively MS/S/BC) were further characterized. FTIR spectroscopy and X-ray diffraction were used to evidence structural and crystallinity changes in starch based films. Morphological, thermal, mechanical, and water resistance properties were also investigated. Addition of cellulose alongside modified starch microparticles determined a slightly improvement of the starch-based films water resistance. Some reduction of water uptake for any given time was observed mainly for samples containing 30% BC. Some compatibility occurred between MS and BC fillers, as evidenced by mechanical properties. Tensile strength increased from 5.9 to 15.1 MPa when BC content varied from 0 to 30%, while elongation at break decreased significantly.

  20. A3-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

    Science.gov (United States)

    Huang, Jian-Lin

    2013-01-01

    Summary We decorated HS-functionalized cellulose nanocrystallite (CNC) films with monodisperse Au nanoparticles (AuNPs) to form a novel nanocomposite catalyst AuNPs@HS-CNC. The uniform, fine AuNPs were made by the reduction of HAuCl4 solution with thiol (HS-) group-functionalized CNC films. The AuNPs@HS-CNC nanocomposites were examined by X-ray photoelectron spectroscopy (XPS), TEM, ATR-IR and solid-state NMR. Characterizations suggested that the size of the AuNPs was about 2–3 nm and they were evenly distributed onto the surface of CNC films. Furthermore, the unique nanocomposite Au@HS-CNC catalyst displayed high catalytic efficiency in promoting three-component coupling of an aldehyde, an alkyne, and an amine (A3-coupling) either in water or without solvent. Most importantly, the catalyst could be used repetitively more than 11 times without significant deactivation. Our strategy also promotes the use of naturally renewable cellulose to prepare reusable nanocomposite catalysts for organic synthesis. PMID:23946833

  1. Processing and properties of eco-friendly bio-nanocomposite films filled with cellulose nanocrystals from sugarcane bagasse.

    Science.gov (United States)

    El Achaby, Mounir; El Miri, Nassima; Aboulkas, Adil; Zahouily, Mohamed; Bilal, Essaid; Barakat, Abdellatif; Solhy, Abderrahim

    2017-03-01

    Novel synthesis strategy of eco-friendly bio-nanocomposite films have been exploited using cellulose nanocrystals (CNC) and polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) blend matrix as a potential in food packaging application. The CNC were extracted from sugarcane bagasse using sulfuric acid hydrolysis, and they were successfully characterized regarding their morphology, size, crystallinity and thermal stability. Thereafter, PVA/CMC-CNC bio-nanocomposite films, at various CNC contents (0.5-10wt%), were fabricated by the solvent casting method, and their properties were investigated. It was found that the addition of 5wt% CNC within a PVA/CMC increased the tensile modulus and strength by 141% and 83% respectively, and the water vapor permeability was reduced by 87%. Additionally, the bio-nanocomposites maintained the same transparency level of the PVA/CMC blend film (transmittance of ∼90% in the visible region), suggesting that the CNC were dispersed at the nanoscale. In these bio-nanocomposites, the adhesion properties and the large number of functional groups that are present in the CNC's surface and the macromolecular chains of the PVA/CMC blend are exploited to improve the interfacial interactions between the CNC and the blend. Consequently, these eco-friendly structured bio-nanocomposites with superior properties are expected to be useful in food packaging applications.

  2. Reactive coating of soybean oil-based polymer on nanofibrillated cellulose film for water vapor barrier packaging.

    Science.gov (United States)

    Lu, Peng; Xiao, Huining; Zhang, Weiwei; Gong, Glen

    2014-10-13

    Nanofibrillated cellulose (NFC) easily forms a high strength film but is unable to withstand the influence of water vapor when used in high moisture situations. The water vapor transmission rate (WVTR) of a NFC film was as high as 5088 g/m(2)24h (38 °C, 90% RH). The addition of beeswax latex in a NFC casting film (NFX) lowered the WVTR to 3918 g/m(2)24h. To further reduce the WVTR, a coating agent comprised of acrylated epoxidized soybean oil (AESO) and 3-aminopropyltriethoxysilane (APTS) was applied onto the NFX film using a rod coater. A combination of the suitable AESO/APTS ratio, initiator dosing, curing time and temperature could reduce the WVTR to 188 g/m(2) 24h when the coat weight was 5 g/m(2). Moreover, the coated NFX film was highly hydrophobic along with the improved transparency and thermal stability. This biodegradable polymer-coated NFC film can be used as potential packaging barrier in certain areas.

  3. Novel cellulose ester substrates for high performance flat-sheet thin-film composite (TFC) forward osmosis (FO) membranes

    KAUST Repository

    Ong, Rui Chin

    2015-01-01

    A novel hydrophilic cellulose ester with a high intrinsic water permeability and a water partition coefficient was discovered to construct membrane supports for flat-sheet thin film composite (TFC) forward osmosis (FO) membranes for water reuse and seawater desalination with high performance. The performance of TFC-FO membranes prepared from the hydrophilic cellulose ester containing a high degree of OH and a moderate degree of Pr substitutions clearly surpasses those prepared from cellulose esters and other polymers with moderate hydrophilicity. Post-treatments of TFC-FO membranes using sodium dodecyl sulfate (SDS) and glycerol followed by heat treatment further enhance the water flux without compromising the selectivity. Positron annihilation lifetime analyses have confirmed that the SDS/glycerol post-treatment increases the free volume size and fractional free volume of the polyamide selective layer. The newly developed post-treated TFC-FO membranes exhibit a remarkably high water flux up to 90 LMH when the selective layer is oriented towards the draw solution (i.e., PRO mode) using 1. M NaCl as the draw solution and DI water as the feed. For seawater desalination, the membranes display a high water flux up to 35 LMH using a 2. M NaCl draw solution. These water fluxes exceeded the water fluxes achieved by other types of FO membranes reported in literatures. © 2014 Elsevier B.V.

  4. Changes induced by UV radiation in the presence of sodium benzoate in films formulated with polyvinyl alcohol and carboxymethyl cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Villarruel, S. [Faculty of Exact Sciences, UNLP (Argentina); Giannuzzi, L.; Rivero, S. [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Pinotti, A., E-mail: acaimpronta@hotmail.com [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Faculty of Engineering, UNLP, La Plata 1900 (Argentina)

    2015-11-01

    This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), and iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of polymer–polymer interaction at a molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of microorganisms. From a physicochemical perspective, the UV treatment of films also changed their morphology rendering them more insoluble in water, turning the functionalized blend films into a potential material to be applied as food packaging. - Highlights: • CMC:PVOH blend films were developed with the addition of sodium benzoate (SB). • Exposition to UV radiation was carried out with sodium benzoate as photoinitiator. • Blend films were exposed to UV radiation to modify their surface morphology. • Low O{sub 2} permeability of UV treated blends allow them to be used as selective packaging. • Efficacy of SB as an antimicrobial agent was examined with and without UV radiation.

  5. Highly Anisotropic Thermal Conductivity of Layer-by-Layer Assembled Nanofibrillated Cellulose/Graphene Nanosheets Hybrid Films for Thermal Management.

    Science.gov (United States)

    Song, Na; Jiao, Dejin; Cui, Siqi; Hou, Xingshuang; Ding, Peng; Shi, Liyi

    2017-01-25

    An anisotropic thermally conductive film with tailorable microstructures and macroproperties is fabricated using a layer-by-layer (LbL) assembly of graphene oxide (GO) and nanofibrillated cellulose (NFC) on a flexible NFC substrate driven by hydrogen bonding interactions, followed by chemical reduction process. The resulting NFC/reduced graphene oxide (RGO) hybrid film reveals an orderly hierarchical structure in which the RGO nanosheets exhibit a high degree of orientation along the in-plane direction. The assembly cycles dramatically increase the in-plane thermal conductivity (λX) of the hybrid film to 12.6 W·m(-1)·K(-1), while the cross-plane thermal conductivity (λZ) shows a lower value of 0.042 W·m(-1)·K(-1) in the hybrid film with 40 assembly cycles. The thermal conductivity anisotropy reaches up to λX/λZ = 279, which is substantially larger than that of similar polymeric nanocomposites, indicating that the LbL assembly on a flexible NFC substrate is an efficient technique for the preparation of polymeric nanocomposites with improved heat conducting property. Moreover, the layered hybrid film composed of 1D NFC and 2D RGO exhibits synergetic mechnical properties with outstanding flexibility and a high tensile strength (107 MPa). The combination of anisotropic thermal conductivity and superior mechanical performance may facilitate the applications in thermal management.

  6. Preparation of microfibrillated cellulose/chitosan-benzalkonium chloride biocomposite for enhancing antibacterium and strength of sodium alginate films.

    Science.gov (United States)

    Liu, Kai; Lin, Xinxing; Chen, Lihui; Huang, Liulian; Cao, Shilin; Wang, Huangwei

    2013-07-03

    The nonantibacterial and low strength properties of sodium alginate films negatively impact their application for food packaging. In order to improve these properties, a novel chitosan-benzalkonium chloride (C-BC) complex was prepared by ionic gelation using tripolyphosphate (TPP) as a coagulant, and a biocomposite obtained through the adsorption of C-BC complex on microfibrillated cellulose, MFC/C-BC, was then incorporated into a sodium alginate film. The TEM image showed that the C-BC nanoparticles were spherical in shape with a diameter of about 30 nm, and the adsorption equilibrium time of these nanoparticles on the surface of MFC was estimated to be 6 min under the driving forces of hydrogen bonds and electrostatic interactions. According to the disc diffusion method, the MFC/C-BC biocomposite-incorporated sodium alginate film exhibited remarkable antibacterial activity against Staphylococcus aureus and certain antibacterial activity against Escherichia coli . The strength tests indicated that the tensile strength of the composite sodium alginate film increased about 225% when the loading of MFC/C-BC biocomposite was 10 wt %. These results suggested that the MFC/C-BC biocomposite-incorporated sodium alginate film with excellent antibacterial and strength properties would be a promising material for food packaging, and the MFC/C-BC may also be a potential multifunctional biocomposite for other biodegradable materials.

  7. Development of Chitosan/Bacterial Cellulose Composite Films Containing Nanodiamonds as a Potential Flexible Platform for Wound Dressing

    Directory of Open Access Journals (Sweden)

    Fatemeh Ostadhossein

    2015-09-01

    Full Text Available Chitosan/bacterial cellulose composite films containing diamond nanoparticles (NDs with potential application as wound dressing are introduced. Microstructural studies show that NDs are uniformly dispersed in the matrix, although slight agglomeration at concentrations above 2 wt % is seen. Fourier transform infrared spectroscopy reveals formation of hydrogen bonds between NDs and the polymer matrix. X-ray diffraction analysis indicates reduced crystallinity of the polymer matrix in the presence of NDs. Approximately 3.5-fold increase in the elastic modulus of the composite film is obtained by the addition of 2 wt % NDs. The results of colorimetric analysis show that the composite films are transparent but turn to gray-like and semitransparent at high ND concentrations. Additionally, a decrease in highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO gap is also seen, which results in a red shift and higher absorption intensity towards the visible region. Mitochondrial activity assay using L929 fibroblast cells shows that the nanocomposite films are biocompatible (>90% after 24 h incubation. Multiple lamellapodia and cell-cell interaction are shown. The results suggest that the developed films can potentially be used as a flexible platform for wound dressing.

  8. Reducing Water Vapor Permeability of Poly(lactic acid Film and Bottle through Layer-by-Layer Deposition of Green-Processed Cellulose Nanocrystals and Chitosan

    Directory of Open Access Journals (Sweden)

    Katalin Halász

    2015-01-01

    Full Text Available Layer-by-layer electrostatic self-assembly technique was applied to improve the barrier properties of poly(lactic acid (PLA films and bottles. The LbL process was carried out by the alternate adsorption of chitosan (CH (polycation and cellulose nanocrystals (CNC produced via ultrasonic treatment. Four bilayers (on each side of chitosan and cellulose nanocrystals caused 29 and 26% improvement in barrier properties in case of films and bottles, respectively. According to the results the LbL process with CH and CNC offered a transparent “green” barrier coating on PLA substrates.

  9. Design and in vitro evaluation of haloperidol lactate transdermal patches containing ethyl cellulose-povidone as film formers

    Directory of Open Access Journals (Sweden)

    Sadashivaiah R

    2008-01-01

    Full Text Available Matrix-type transdermal drug delivery systems of haloperidol lactate were prepared using different ratios of ethyl cellulose (EC:polyvinyl pyrrolidone (PVP (3:2, 2:3, 4:1, 1:2, 2:1, and 1:4 by solvent-evaporation technique. Physicochemical parameters were characterized, and dissolution studies of the formulated films were performed. In addition, solubility studies at various values of pH were carried out, and partition coefficient in octanol/water system, flux, and enhancement ratio were also evaluated. In vitro permeation studies were done using modified Franz diffusion cells through human cadaver skin utilizing 20% PEG 400 in normal saline. Permeation studies illustrated that 4% hyaluronidase enzyme was a good enhancer. The prepared films were subjected to scanning electron microscopy (SEM and fourier transform infrared spectroscopy (FT-IR spectral analysis. Higuchi and Peppas models were used for optimizing the formulation.

  10. Influence of hydration water on CHsub>3sub>NHsub>3sub>PbIsub>3sub> perovskite films prepared through one-step procedure.

    Science.gov (United States)

    Wang, Ziyi; Yuan, Sijian; Li, Dahai; Jin, Feng; Zhang, Rongjun; Zhan, Yiqiang; Lu, Ming; Wang, Songyou; Zheng, Yuxiang; Guo, Junpeng; Fan, Zhiyong; Chen, Liangyao

    2016-10-31

    Organic-inorganic perovskites were fabricated through a one-step procedure with different levels of hydration water in precursor solutions. The optical properties of CHsub>3sub>NHsub>3sub>PbIsub>3sub> films were investigated through spectroscopic ellipsometry and photoluminescence measurements. With the measured optical constants, the efficiency limit of perovskite solar cells is predicted with a detailed balance model. By comparing the optical measurement to that of planar heterojunction solar cells, we conclude that the radiative efficiency and porosity of the perovskite film significantly influence the performance of perovskite solar cells. An optimized hydration-water concentration is obtained for the 3CHsub>3sub>NHsub>3sub>I:1PbAcsub>2sub>•xHsub>2sub>O precursor solution. The results can provide guidance for further optimization of the device performance of perovskite solar cells by utilizing hydration water.

  11. A comparison of pseudo-ternary diagrams of aqueous mixtures of Quil A, cholesterol and phospholipid prepared by lipid-film hydration and dialysis.

    Science.gov (United States)

    Demana, P H; Davies, N M; Berger, B; Vosgerau, U; Rades, T

    2004-05-01

    Pseudo-ternary diagrams for Quil A, phospholipid (phosphatidylcholine (PC) or phosphatidylethanolamine (PE)) and cholesterol were established in order to identify combinations that result in the formation of immune-stimulating complex (ISCOM) matrices and other colloidal structures produced by these three components in aqueous systems following lipid-film hydration or dialysis (methods that can be used to produce ISCOMs). In addition, the effect of equilibration time (1 month at 4 degrees C) on the structures formed by the various combinations of the three components was investigated. Depending on the ratio of Quil A, cholesterol and phospholipid, different colloidal particles, including ISCOM matrices, liposomes and ring-like micelles, were found irrespective of the preparation method used. In contrast, worm-like micelles were only observed in systems prepared by lipid-film hydration. For samples prepared by dialysis, ISCOM matrices were predominantly found near the Quil A apex of the pseudo-ternary diagram (> 50% Quil A). On the other hand, for samples prepared by lipid-film hydration, ISCOM matrices were predominantly found near the phospholipid apex of the pseudo-ternary diagram (> 50% phospholipid). The regions in the pseudo-ternary diagrams in which ISCOM matrices were observed increased following an extended equilibration time, particularly for samples prepared by lipid-film hydration. Differences were also observed between pseudoternary diagrams prepared using either PE or PC as phospholipids.

  12. Pseudo-ternary phase diagrams of aqueous mixtures of Quil A, cholesterol and phospholipid prepared by the lipid-film hydration method.

    Science.gov (United States)

    Demana, Patrick H; Davies, Nigel M; Vosgerau, Uwe; Rades, Thomas

    2004-02-11

    Pseudo-ternary phase diagrams of the polar lipids Quil A, cholesterol (Chol) and phosphatidylcholine (PC) in aqueous mixtures prepared by the lipid film hydration method (where dried lipid film of phospholipids and cholesterol are hydrated by an aqueous solution of Quil A) were investigated in terms of the types of particulate structures formed therein. Negative staining transmission electron microscopy and polarized light microscopy were used to characterize the colloidal and coarse dispersed particles present in the systems. Pseudo-ternary phase diagrams were established for lipid mixtures hydrated in water and in Tris buffer (pH 7.4). The effect of equilibration time was also studied with respect to systems hydrated in water where the samples were stored for 2 months at 4 degrees C. Depending on the mass ratio of Quil A, Chol and PC in the systems, various colloidal particles including ISCOM matrices, liposomes, ring-like micelles and worm-like micelles were observed. Other colloidal particles were also observed as minor structures in the presence of these predominant colloids including helices, layered structures and lamellae (hexagonal pattern of ring-like micelles). In terms of the conditions which appeared to promote the formation of ISCOM matrices, the area of the phase diagrams associated with systems containing these structures increased in the order: hydrated in water/short equilibration period<hydrated in buffer/short equilibration period<hydrated in water/prolonged equilibration period. ISCOM matrices appeared to form over time from samples, which initially contained a high concentration of ring-like micelles suggesting that these colloidal structures may be precursors to ISCOM matrix formation. Helices were also frequently found in samples containing ISCOM matrices as a minor colloidal structure. Equilibration time and presence of buffer salts also promoted the formation of liposomes in systems not containing Quil A. These parameters however, did not

  13. In situ self-assembly of polarizing chromogen nanofibers catalyzed with hybrid films of gold nanoparticles and cellulose

    Science.gov (United States)

    Liu, Zhiming; Wu, Wenjian

    2017-09-01

    Hybrid materials of metal nanoparticles and biopolymers with catalytic properties are very promising to be used as detectors in biochemical reactions. In this work, the catalytic properties and relevant in situ self-assembly abilities of hybrid films of gold nanoparticles (GNPs) and cellulose for the oxidation of benign chromogen 3,3‧,5,5‧-tetramethylbenzidine (TMB) with hydrogen peroxide (H2O2) are revealed for the first time. The peroxidase-like properties of hybrid films are inherited from those of colloidal GNPs and increase with their contents of GNPs. It is discovered that the oxidized products of TMB grow in situ and assemble into rod-like and tumbleweed-like nanofiber assemblies on hybrid films. The rod-like nanofibers show a magnificent polarizing phenomenon under polarized light because of polycrystalline globular nanoparticles inside. The in situ self-assembly of polarizing nanofibers of chromogen catalyzed with hybrid films creates an opportunity for the synthesis of novel organic nanomaterials and the enhanced detection of biochemical products under polarized light.

  14. Iridescent cellulose nanocrystal/polyethylene oxide composite films with low coefficient of thermal expansion

    Science.gov (United States)

    Jairo A. Diaz; Julia L. Braun; Robert J. Moon; Jeffrey P. Youngblood

    2015-01-01

    Simultaneous control over optical and thermal properties is particularly challenging and highly desired in fields like organic electronics. Here we incorporated cellulose nanocrystals (CNCs) into polyethylene oxide (PEO) in an attempt to preserve the iridescent CNC optical reflection given by their chiral nematic organisation, while reducing the composite thermal...

  15. Analysis of Vaginal Microbicide Film Hydration Kinetics by Quantitative Imaging Refractometry

    OpenAIRE

    Matthew Rinehart; Sheila Grab; Lisa Rohan; David Katz; Adam Wax

    2014-01-01

    We have developed a quantitative imaging refractometry technique, based on holographic phase microscopy, as a tool for investigating microscopic structural changes in water-soluble polymeric materials. Here we apply the approach to analyze the structural degradation of vaginal topical microbicide films due to water uptake. We implemented transmission imaging of 1-mm diameter film samples loaded into a flow chamber with a 1.5×2 mm field of view. After water was flooded into the chamber, interf...

  16. PLLA-grafted cellulose nanocrystals: Role of the CNC content and grafting on the PLA bionanocomposite film properties.

    Science.gov (United States)

    Lizundia, Erlantz; Fortunati, Elena; Dominici, Franco; Vilas, José Luis; León, Luis Manuel; Armentano, Ilaria; Torre, Luigi; Kenny, Josè M

    2016-05-20

    Cellulose nanocrystals (CNC), extracted from microcrystalline cellulose by acid hydrolysis, were grafted by ring opening polymerization of L-Lactide initiated from the hydroxyl groups available at their surface and two different CNC:L-lactide ratios (20:80 and 5:95) were obtained. The resulting CNC-g-PLLA nanohybrids were incorporated in poly(lactic acid) (PLA) matrix by an optimized extrusion process at two different content (1 wt.% and 3 wt.%) and obtained bionanocomposite films were characterized by thermal, mechanical, optical and morphological properties. Thermal analysis showed CNC grafted with the higher ratio of lactide play a significant role as a nucleating agent. Moreover, they contribute to a significant increase in the crystallization rate of PLA, and the best efficiency was revealed with 3 wt.% of CNC-g-PLLA. This effect was confirmed by the increased in Young's modulus, suggesting the CNC graft ratio and content contribute significantly to the good dispersion in the matrix, positively affecting the final bionanocomposite properties.

  17. Characterization of Type-II Acetylated Cellulose Nanocrystals with Various Degree of Substitution and Its Compatibility in PLA Films

    Directory of Open Access Journals (Sweden)

    Feng Dong

    2017-08-01

    Full Text Available In order to decrease the self-agglomeration and improve the hydrophobic properties of type-II acetylated cellulose nanocrystals (ACNC II, various degree of substitution (DS values of ACNCs were successfully prepared by a single-step method from microcrystalline cellulose with anhydrous phosphoric acid as the solvent, and acetic anhydride as the acetylation reagent, under different reaction temperatures (20–40 °C. To thoroughly investigate the DS values of ACNC II, analyses were performed using Fourier transform infrared spectroscopy (FT-IR, 13C cross polarization-magic angle spinning (CP-MAS nuclear magnetic resonance (NMR, and X-ray photoelectron spectroscopy (XPS. At a reaction temperature of 40°C, the highest DS value was successfully obtained. XRD proved that the crystal structure of ACNC II with various DS values was maintained after acetylation. TEM showed the threadlike shape for ACNC II with various DS values. The ACNC II with various DS values was introduced into a polylactic acid (PLA matrix to produce PLA/ACNC composite films, which showed improved rheological and thermal properties. This improvement was primarily attributed to good dispersion of the ACNC II, and the interfacial compatibility between ACNC II and the PLA matrix. This study aims to analyze the compatibility of ACNC II with various DS values in the PLA matrix by microstructure, crystallization, and rheological and thermal tests.

  18. Free radical grafting of gallic acid (GA) on cellulose nanocrystals (CNCS) and evaluation of antioxidant reinforced gellan gum films

    Science.gov (United States)

    Criado, P.; Fraschini, C.; Salmieri, S.; Becher, D.; Safrany, A.; Lacroix, M.

    2016-01-01

    Antiradical properties were introduced on cellulose nanocrystals (CNCs) by redox pair (RP) initiator and γ-radiation treatments. Different procedures were tested on CNC, first a 2 h reaction of hydrogen peroxide (H2O2)/ascorbic acid (AA) was performed on CNC solution. γ-Radiation treatment at 20 kGy dose was then applied and immediately after GA was reacted during 24 h with the pretreated CNCs, giving CNC-H2O2-AA-γ-GA. The formation of new carboxylic acids and carbonyl groups were characterized by FT-IR at 1650 and 1730 cm-1 respectively. Carboxylic acid functionalities were also analyzed by conductometric titration where an increase from 49 to 134 mmol COOH kg-1 was found from native to irradiated CNCs. A similar increase in the carboxylic acid content (132 mmol kg-1) was observed for CNC-H2O2-AA-γ-GA, showing the highest radical scavenging properties (8 mM Trolox eq/mg CNC). Thermogravimetric analysis confirmed the structural changes onto CNC. Film packaging containing 20% of CNC-H2O2-AA-γ-GA was then added to a gellan-based film packaging. A significant improvement (p<0.05) of the tensile strength (TS), the tensile modulus (TM) and the elongation at break (EB) and water vapor permeability reduction was observed when CNC-H2O2-AA-γ-GA was added to the film packaging formulation.

  19. Application of thin film cellulose composite membrane for dye wastewater reuse

    KAUST Repository

    Puspasari, Tiara

    2016-09-22

    The use of low cost membranes with high salt/dye selectivity and high flux is ideal for an economic and eco-friendly treatment of dye wastewater. Here, regenerated cellulose membranes prepared from trimethylsilyl cellulose are studied for treating artificial dye effluents. In the experiments using a feed containing Congo Red and high NaCl concentration, the membrane featured impressive dye removal with zero salt rejection combined with high flux. More interestingly, the membrane reached as much as 600 LMH flux at 80 °C and 4 bar while maintaining high dye rejection close to 98%. In prolonged experiments up to 75 h the membrane exhibited good antifouling behavior with nearly 100% flux recovery. This study may provide a promising alternative of dye effluent treatment where high amounts of monovalent salts are present. © 2016

  20. Highly transparent films from carboxymethylated microfibrillated cellulose: The effect of multiple homogenization steps on key properties

    DEFF Research Database (Denmark)

    Siró, Istvan; Plackett, David; Hedenqvist, M.

    2011-01-01

    We produced microfibrillated cellulose by passing carboxymethylated sulfite-softwood-dissolving pulp with a relatively low hemicellulose content (4.5%) through a high-shear homogenizer. The resulting gel was subjected to as many as three additional homogenization steps and then used to prepare so...... of homogenization, whereas the mean tensile strength, modulus of elasticity, and strain at break were increased by two or three extra homogenization steps. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011...

  1. Reflection of circularly polarized light and the effect of particle distribution on circular dichroism in evaporation induced self-assembled cellulose nanocrystal thin films

    Science.gov (United States)

    Hewson, D.; Vukusic, P.; Eichhorn, S. J.

    2017-06-01

    Evaporation induced self-assembled (EISA) thin films of cellulose nanocrystals (CNCs) have shown great potential for displaying structural colour across the visible spectrum. They are believed primarily to reflect left handed circularly polarised (LCP) light due to their natural tendency to form structures comprising left handed chirality. Accordingly the fabrication of homogenously coloured CNC thin films is challenging. Deposition of solid material towards the edge of a dried droplet, via the coffee-stain effect, is one such difficulty in achieving homogenous colour across CNC films. These effects are most easily observed in films prepared from droplets where observable reflection of visible light is localised around the edge of the dry film. We report here, the observation of both left and right hand circularly polarised (LCP/RCP) light in reflection from distinct separate regions of CNC EISA thin films and we elucidate how these reflections are dependent on the distribution of CNC material within the EISA thin film. Optical models of reflection are presented which are based on structures revealed using high resolution transmission electron microscopy (TEM) images of film cross sections. We have also employed spectroscopic characterisation techniques to evaluate the distribution of solid CNC material within a selection of CNC EISA thin films and we have correlated this distribution with polarised light spectra collected from each film. We conclude that film regions from which RCP light was reflected were associated with lower CNC concentrations and thicker film regions.

  2. Reflection of circularly polarized light and the effect of particle distribution on circular dichroism in evaporation induced self-assembled cellulose nanocrystal thin films

    Directory of Open Access Journals (Sweden)

    D. Hewson

    2017-06-01

    Full Text Available Evaporation induced self-assembled (EISA thin films of cellulose nanocrystals (CNCs have shown great potential for displaying structural colour across the visible spectrum. They are believed primarily to reflect left handed circularly polarised (LCP light due to their natural tendency to form structures comprising left handed chirality. Accordingly the fabrication of homogenously coloured CNC thin films is challenging. Deposition of solid material towards the edge of a dried droplet, via the coffee-stain effect, is one such difficulty in achieving homogenous colour across CNC films. These effects are most easily observed in films prepared from droplets where observable reflection of visible light is localised around the edge of the dry film. We report here, the observation of both left and right hand circularly polarised (LCP/RCP light in reflection from distinct separate regions of CNC EISA thin films and we elucidate how these reflections are dependent on the distribution of CNC material within the EISA thin film. Optical models of reflection are presented which are based on structures revealed using high resolution transmission electron microscopy (TEM images of film cross sections. We have also employed spectroscopic characterisation techniques to evaluate the distribution of solid CNC material within a selection of CNC EISA thin films and we have correlated this distribution with polarised light spectra collected from each film. We conclude that film regions from which RCP light was reflected were associated with lower CNC concentrations and thicker film regions.

  3. Cellulose Buccoadhesive Film Bearing Glimepiride: Physicomechanical Characterization and Biophysics of Buccoadhesion.

    Science.gov (United States)

    Meher, Jaya Gopal; Tarai, Magdaline; Patnaik, Ansuman; Mishra, Paresh; Yadav, Narayan Prasad

    2016-08-01

    The present study aimed to develop buccoadhesive film of glimepiride with unique combination of polymers and to investigate its effect(s) on physicomechanical parameters, drug-release, and permeation of films. Drug-polymer interaction was examined by FTIR and DSC analysis. Films were prepared by solvent casting technique and characterized for film strength (320 ± 8.5 g, 28.98 ± 2.00 mJ), buccoadhesive strength (28.8 ± 1.37 g, 3.04 ± 0.32 mJ), and tensile strength (260 ± 6.88 g, 18.00 ± 0.44 mJ) by new instrumental techniques. Increase in polymer concentration augmented zeta potential of polymeric matrix-mucin mixture and exhibited strong buccoadhesion (electrical theory). Buccoadhesion was also influenced by particle size (adsorption theory) and swelling (wetting theory). Erosion behavior of films was observed in swelling and SEM studies. Film GM4 exhibited 98 ± 2% in vitro drug release and 85 ± 8% ex vivo drug permeation in 12 h with controlled diffusion mechanism. Films were compatible with oral probiotic microorganisms. Stability studies revealed no significant (P < 0.05) variation in physicomechanical characteristics.

  4. Nano-gold assisted highly conducting and biocompatible bacterial cellulose-PEDOT:PSS films for biology-device interface applications.

    Science.gov (United States)

    Khan, Shaukat; Ul-Islam, Mazhar; Ullah, Muhammad Wajid; Israr, Muhammad; Jang, Jae Hyun; Park, Joong Kon

    2017-09-18

    This study reports the fabrication of highly conducting and biocompatible bacterial cellulose (BC)-gold nanoparticles (AuNPs)-poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) (BC-AuNPs-PEDOT:PSS) composites for biology-device interface applications. The composites were fabricated using ex situ incorporation of AuNPs and PEDOT:PSS into the BC matrix. Structural characterization, using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) analysis, confirmed the uniform nature of the synthesized BC-AuNPs and BC-AuNPs-PEDOT:PSS composites. Four-point probe analysis indicated that the BC-AuNPs and BC-AuNPs-PEDOT:PSS films had high electrical conductivity. The composites were also tested for biocompatibility with animal osteoblasts (MC3T3-E1). The composite films supported adhesion, growth, and proliferation of MC3T3-E1 cells, indicating that they are biocompatible and non-cytotoxic. AuNPs and PEDOT:PSS, imparted a voltage response, while BC imparted biocompatibility and bio-adhesion to the nanocomposites. Therefore, our BC-AuNPs-PEDOT:PSS composites are candidate materials for biology-device interfaces to produce implantable devices in regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Nanoplate-like tungsten trioxide (hydrate) films prepared by crystal-seed-assisted hydrothermal reaction

    Science.gov (United States)

    Wang, P.; Yang, L.; Dai, B.; Yang, Z.; Guo, S.; Zhu, J.

    2017-07-01

    Vertically-aligned WO3 nanoplates on transparent conducting fluorine-doped tin oxide (FTO) glass were prepared by a facile template-free crystal-seed-assisted hydrothermal method. The effects of the hydrothermal temperature and reaction time on the crystal structure and morphology of the products were investigated by XRD and SEM. The XRD results showed that the as-prepared thin films obtained below 150∘C comprised orthorhombic WO3 ṡ H2O and completely converted to monoclinic WO3 at 180∘C. It was also noted that there was a phase transformation from orthorhombic to monoclinic by increasing the reaction time from 1 to 12 h. SEM analysis revealed that WO3 thin films are composed of plate-like nanostructures.

  6. Films of chitin, chitosan and cellulose obtained from aqueous suspension treated by irradiation of high intensity ultrasound; Filmes de quitina, quitosana e celullose de sisal obtidos a partir de suspensoes aquosas tratadas com irradiacao de ultrassom de alta intensidade

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Erika V.R.; Mariano, Mario S.; Campana-Filho, Sergio P., E-mail: erikavi@iqsc.usp.br [Universidade de Sao Paulo (IQSC/USP), Instituto de Quimica de Sao Carlos, Sao Carlos, SP (Brazil)

    2011-07-01

    Films of chitin, chitin/chitosan and chitin/sisal cellulose were obtained by casting their aqueous suspensions previously treated with irradiation of high intensity ultrasound. The films were characterized for surface morphology by scanning electron microscopy and it is possible notice that the films containing chitosan are much more homogeneous. The thermal behavior of the films was evaluated by dynamic mechanical thermal analysis, differential scanning calorimetry, and thermogravimetric analysis and revealing similarity in comparison with the thermal behavior of polysaccharide isolated. The tensile strength was determined and the film containing chitosan showed the best result when compared to other films. The crystallinity index of the films analyzed by X-ray diffraction showed that the films are amorphous material. The analysis by infrared spectroscopy showed that treatment of aqueous suspensions of polysaccharides with irradiation of high intensity ultrasound did not change the chemical structure of polymers. The crystallinity index was determined by X-ray diffraction, revealing that the films are amorphous materials. The results of this study indicate the possibility of processing of chitin, chitosan and cellulose, polysaccharides whose solubilities are limited to a few solvent systems, by treating their aqueous suspensions with high intensity ultrasound. (author)

  7. Redox-active cellulose Langmuir-Blodgett films containing beta-carotene as a molecular wire.

    Science.gov (United States)

    Sakakibara, Keita; Kamitakahara, Hiroshi; Takano, Toshiyuki; Nakatsubo, Fumiaki

    2007-05-01

    Redox-active Langmuir-Blodgett (LB) films containing dihydrophytyl ferrocenoate (DFc) and beta-carotene (betaC) were fabricated by use of 6-O-dihydrophytylcellulose (DHPC) as a matrix. A mixture of DFc-DHPC formed a stable monolayer. Atomic force microscopy images revealed that the DFc molecules were dispersed uniformly throughout the surface in the ratio DFc:DHPC = 2:8 at 30 mN m-1. The DFc-DHPC monolayer was transferred successfully onto a substrate, yielding Y-type LB films. Cyclic voltammograms for the DFc-DHPC LB films on an indium tin oxide (ITO) electrode exhibited a well-defined surface wave. The voltammograms of the DFc-DHPC LB films exhibited 60-40% redox-active ferrocene moieties, whereas those of the DFc-DHPC-betaC LB films exhibited 90-70%. X-ray diffraction patterns indicated that the distance between layers was independent of betaC molecules incorporated into the LB films. Consequently, these results suggested that betaC can function as a molecular wire.

  8. Effect of post-treatments and concentration of cotton linter cellulose nanocrystals on the properties of agar-based nanocomposite films.

    Science.gov (United States)

    Oun, Ahmed A; Rhim, Jong-Whan

    2015-12-10

    Cellulose nanocrystals (CNCs) were prepared by acid hydrolysis of cotton linter pulp fibers and three different purification methods, i.e., without post purification (CNC1), dialyzed against distilled water (CNC2), and neutralized with NaOH (CNC3), and their effect on film properties was evaluated by preparation of agar/CNCs composite films. All the CNCs were rod in shape with diameter of 15-50 nm and length of 210-480 nm. FTIR result indicated that there was no distinctive differences in the chemical structure between CNCs and cotton linter cellulose fiber. No significant relationship was observed between the sulfate content and crystallinity index of CNCs. The CNC3 showed higher thermal stability than the other type of CNCs due to the less adverse effect on the thermal stability of sulfate groups induced by the neutralization with NaOH. The tensile strength (TS) of agar film increased by 15% with incorporation of 5 wt% of CNC3, on the contrary, it decreased by 10% and 15% with incorporation of CNC1 and CNC2, respectively. Other performance properties of agar/CNCs composite films such as optical and water vapor barrier properties showed that the CNC3 was more effective filler than the other CNCs. In the range of concentration of CNC3 tested (1-10 wt%), inclusion of 5 wt% of CNC3 was the maximum concentration for improving or maintaining film properties of the composite films. The neutralization of acid hydrolyzed cellulose using NaOH was simple and convenient for the preparation of CNC and bionanocomposite films.

  9. Magnetic Cellulose Nanocrystal Based Anisotropic Polylactic Acid Nanocomposite Films: Influence on Electrical, Magnetic, Thermal, and Mechanical Properties.

    Science.gov (United States)

    Dhar, Prodyut; Kumar, Amit; Katiyar, Vimal

    2016-07-20

    This paper reports a single-step co-precipitation method for the fabrication of magnetic cellulose nanocrystals (MGCNCs) with high iron oxide nanoparticle content (∼51 wt % loading) adsorbed onto cellulose nanocrystals (CNCs). X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopic studies confirmed that the hydroxyl groups on the surface of CNCs (derived from the bamboo pulp) acted as anchor points for the adsorption of Fe3O4 nanoparticles. The fabricated MGCNCs have a high magnetic moment, which is utilized to orient the magnetoresponsive nanofillers in parallel or perpendicular orientations inside the polylactic acid (PLA) matrix. Magnetic-field-assisted directional alignment of MGCNCs led to the incorporation of anisotropic mechanical, thermal, and electrical properties in the fabricated PLA-MGCNC nanocomposites. Thermomechanical studies showed significant improvement in the elastic modulus and glass-transition temperature for the magnetically oriented samples. Differential scanning calorimetry (DSC) and XRD studies confirmed that the alignment of MGCNCs led to the improvement in the percentage crystallinity and, with the absence of the cold-crystallization phenomenon, finds a potential application in polymer processing in the presence of magnetic field. The tensile strength and percentage elongation for the parallel-oriented samples improved by ∼70 and 240%, respectively, and for perpendicular-oriented samples, by ∼58 and 172%, respectively, in comparison to the unoriented samples. Furthermore, its anisotropically induced electrical and magnetic properties are desirable for fabricating self-biased electronics products. We also demonstrate that the fabricated anisotropic PLA-MGCNC nanocomposites could be laminated into films with the incorporation of directionally tunable mechanical properties. Therefore, the current study provides a novel noninvasive approach of orienting nontoxic bioderived CNCs in the presence of low

  10. Role of Cellulose Nanocrystals on the Microstructure of Maleic Anhydride Plasma Polymer Thin Films.

    Science.gov (United States)

    Brioude, Michel M; Roucoules, Vincent; Haidara, Hamidou; Vonna, Laurent; Laborie, Marie-Pierre

    2015-07-01

    Recently, it was shown that the microstructure of a maleic anhydride plasma polymer (MAPP) could be tailored ab initio by adjusting the plasma process parameters. In this work, we aim to investigate the ability of cellulose nanocrystals (CNCs) to induce topographical structuration. Thus, a new approach was designed based on the deposition of MAPP on CNCs model surfaces. The nanocellulosic surfaces were produced by spin-coating the CNC suspension on a silicon wafer substrate and on a hydrophobic silicon wafer substrate patterned with circular hydrophilic microsized domains (diameter of 86.9 ± 4.9 μm), resulting in different degrees of CNC aggregation. By depositing the MAPP over these surfaces, it was possible to observe that the surface fraction of nanostructures increased from 20% to 35%. This observation suggests that CNCs can act as nucleation points resulting in more structures, although a critical density of the CNCs is required.

  11. Formation of porous gas hydrates

    CERN Document Server

    Salamatin, Andrey N

    2015-01-01

    Gas hydrates grown at gas-ice interfaces are examined by electron microscopy and found to have a submicron porous texture. Permeability of the intervening hydrate layers provides the connection between the two counterparts (gas and water molecules) of the clathration reaction and makes further hydrate formation possible. The study is focused on phenomenological description of principal stages and rate-limiting processes that control the kinetics of the porous gas hydrate crystal growth from ice powders. Although the detailed physical mechanisms involved in the porous hydrate formation still are not fully understood, the initial stage of hydrate film spreading over the ice surface should be distinguished from the subsequent stage which is presumably limited by the clathration reaction at the ice-hydrate interface and develops after the ice grain coating is finished. The model reveals a time dependence of the reaction degree essentially different from that when the rate-limiting step of the hydrate formation at...

  12. Preparation and application of nanocrystalline cellulose derived from sugarcane waste as filler modified alkanolamide on crosslink of natural rubber latex film

    Science.gov (United States)

    Harahap, Hamidah; Hayat, Nuim; Lubis, Marfuah

    2017-07-01

    Sugarcane waste is abundant sources of cellulose and it has potential to reutilize. Cellulose from sugarcane waste can be derived into nanocystalline cellulose (NCC) from crystalline region. The NCC as a filler has capability to reinforce natural rubber latex product. The crosslink in vulcanized natural rubber latex film influences several properties of product. In this work, we extracted NCC from sugarcane waste then added into natural rubber latex as filler modified alkanolamide (ALK) and also studied the crosslink of natural rubber latex films. NCC were produced from sugarcane waste by hydrolysis process with sulfuric acid 45%. The obtained NCC was characterized by using x-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infra red (FTIR). NCC was modified by alkanolamide and dispersed in water with filler concentration of 10%. Then the dispersion were added into latex system followed by pre-vulcanization at 70 °C. The films were prepared by coagulant dipping method and dried at 100 °C and 120 °C for 20 minutes. Characterization of NCC from sugarcane waste by using FTIR was done, it clearly showed the functional groups of cellulose. TEM showed the obtained NCC were rod-shaped with about 40-160 nm in diameter and several hundred nm in length, and XRD showed that the degree of crystalinity of NCC from sugarcane waste is 92.33%. The crosslink of natural rubber films were studied by measure the crosslink density for different filler loading by using swelling measurement with toluene solution. The result show that the crosslink density increased in line with amount of filler which added into the system, and also the crosslink density that obtained from vulcanization at 120 °C were higher than 100 °C.

  13. Cellulase and alcohol dehydrogenase immobilized in Langmuir and Langmuir-Blodgett films and their molecular-level effects upon contact with cellulose and ethanol.

    Science.gov (United States)

    Rodrigues, Dilmer; Camilo, Fernanda Ferraz; Caseli, Luciano

    2014-02-25

    The key challenges for producing devices based on nanostructured films with control over the molecular architecture are to preserve the catalytic activity of the immobilized biomolecules and to provide a reliable method for determining the intermolecular interactions and the accommodation of molecules at very small scales. In this work, the enzymes cellulase and alcohol dehydrogenase (ADH) were coimmobilized with dipalmitoylphosphatidylcholine (DPPC) as Langmuir-Blodgett (LB) films, and their biological activities were assayed by accommodating the structure formed in contact with cellulose. For this purpose, the polysaccharide was dissolved in an ionic liquid, 1-buthyl-3-methylimidazolium chloride (BMImCl), and dropped on the top of the hybrid cellulase-ADH-DPPC LB film. The interactions between cellulose and ethanol, which are the catalytic substrates of the enzymes as well as important elements in the production of second-generation fuels, were then investigated using polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Investigation of the secondary structures of the enzymes was performed using PM-IRRAS, through which the presence of ethanol and cellulose was observed to highly affect the structures of ADH and cellulase, respectively. The detection of products formed from the catalyzed reactions as well as the changes of secondary structure of the enzymes immobilization could be carried out, which opens the possibility to produce a means for producing second-generation ethanol using nanoscale arrangements.

  14. Chitin nanofibers as reinforcing and antimicrobial agents in carboxymethyl cellulose films: Influence of partial deacetylation

    Science.gov (United States)

    The development of edible, environmentally friendly, mechanically strong and antimicrobial biopolymer films for active food packaging has gained considerable interest in recent years. The present work deals with the extraction and deacetylation of chitin nanofibers (ChNFs) from crab shells and their...

  15. Surface modification of nanofibrillated cellulose films by atmospheric pressure dielectric barrier discharge

    DEFF Research Database (Denmark)

    Siró, Istvan; Kusano, Yukihiro; Norrman, Kion

    2013-01-01

    -of-flight secondary ion mass spectrometry, while surface morphology was illustrated by atomic force microscopy. Wettability was characterized through the static sessile drop method. The adhesion between NFC and polylactide (PLA) laminated films was tested by the double cantilever beam technique. As a result...

  16. Incorporation of N-doped TiO2 nanorods in regenerated cellulose thin films fabricated from recycled newspaper as a green portable photocatalyst.

    Science.gov (United States)

    Mohamed, Mohamad Azuwa; Salleh, W N W; Jaafar, Juhana; Ismail, A F; Abd Mutalib, Muhazri; Jamil, Siti Munira

    2015-11-20

    In this work, an environmental friendly RC/N-TiO2 nanocomposite thin film was designed as a green portable photocatalyst by utilizing recycled newspaper as sustainable cellulose resource. Investigations on the influence of N-doped TiO2 nanorods incorporation on the structural and morphological properties of RC/N-TiO2 nanocomposite thin film are presented. The resulting nanocomposite thin film was characterized by FESEM, AFM, FTIR, UV-vis-NIR spectroscopy, and XPS analysis. The results suggested that there was a remarkable compatibility between cellulose and N-doped TiO2 nanorods anchored onto the surface of the RC/N-TiO2 nanocomposite thin film. Under UV and visible irradiation, the RC/N-TiO2 nanocomposite thin film showed remarkable photocatalytic activity for the degradation of methylene blue solution with degradation percentage of 96% and 78.8%, respectively. It is crucial to note that the resulting portable photocatalyst produced via an environmental and green technique in its fabrication process has good potential in the field of water and wastewater treatment application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Optical sensor platform based on cellulose nanocrystals (CNC) - 4'-(hexyloxy)-4-biphenylcarbonitrile (HOBC) bi-phase nematic liquid crystal composite films.

    Science.gov (United States)

    Santos, Moliria V; Tercjak, Agnieszka; Gutierrez, Junkal; Barud, Hernane S; Napoli, Mariana; Nalin, Marcelo; Ribeiro, Sidney J L

    2017-07-15

    The preparation of composite materials has gained tremendous attention due to the potential synergy of the combined materials. Here we fabricate novel thermal/electrical responsive photonic composite films combining cellulose nanocrystals (CNC) with a low molecular weight nematic liquid crystal (NLC), 4'-(hexyloxy)-4-biphenylcarbonitrile (HOBC). The obtained composite material combines both intense structural coloration of photonic cellulose and thermal and conductive properties of NLC. Scanning electron microscopy (SEM) results confirmed that liquid crystals coated CNC films maintain chiral nematic structure characteristic of CNC film and simultaneously, transversal cross-section scanning electron microscopy images indicated penetration of liquid crystals through the CNC layers. Investigated composite film maintain NLC optical properties being switchable as a function of temperature during heating/cooling cycles. The relationship between the morphology and thermoresponsive in the micro/nanostructured materials was investigated by using transmission optical microscopy (TOM). Conductive response of the composite films was proved by Electrostatic force microscopy (EFM) measurement. Designed thermo- and electro-responsive materials open novel simple pathway of fabrication of CNC-based materials with tunable properties. Copyright © 2017. Published by Elsevier Ltd.

  18. PREPARATION AND PROPERTIES OF ETHYL-CYANOETHYL CELLULOSE/POLYACRYLIC ACID COMPOSITE FILMS WITH REFLECTION COLORS

    Institute of Scientific and Technical Information of China (English)

    Yong Huang

    2001-01-01

    Ethyl-cyanoethyl cellulose [(E-CE)C]/acrylic acid (AA) becomes a cholesteric liquid crystalline solution with vivid colors when the (E-CE)C concentration is 42 wt% ~52 wt%. (E-CE)C/polyacrylic acid (PAA) composites with cholesteric structure were prepared by polymerizing AA in (E-CE)C/AA liquid crystalline solutions. The layers of ordered polymer chains in the cholesteric phase were inclined during polymerization and the degree of the inclination depended on the polymerization temperature and the concentration of the solution before polymerization. The cholesteric structure in the composites could not be changed when temperature was lower than 100C. Cross-linking of the PAA in composites improved their water-resistance. The cholesteric order of the composites without cross-linking was destroyed when they where immersed in water. The color derived from the selective reflection of the cholesteric phase of the cross-linked composites turned from blue to red after the composites absorbed water. The color of the composites could be returned to the original one when the absorbed water was removed from the swollen composites.

  19. Layer-by-Layer assembled hybrid multilayer thin film electrodes based on transparent cellulose nanofibers paper for flexible supercapacitors applications

    Science.gov (United States)

    Wang, Xi; Gao, Kezheng; Shao, Ziqiang; Peng, Xiaoqing; Wu, Xue; Wang, Feijun

    2014-03-01

    Cellulose nanofibers (CNFs) paper with low thermal expansion and electrolyte absorption properties is considered to be a good potential substrate for supercapacitors. Unlike traditional substrates, such as glass or plastic, CNFs paper saves surfaces pretreatment when Layer-by-Layer (LbL) assembly method is used. In this study, negatively charged graphene oxide (GO) nanosheets and poly(3,4-ethylenedioxythiophene: poly(styrene sulfonate)) (PEDOT:PSS) nanoparticles are deposited onto CNFs paper with positively charged polyaniline (PANI) nanowires as agents to prepare multilayer thin film electrodes, respectively. Due to the different nanostructures of reduced graphene oxide (RGO) and PEDOT:PSS, the microstructures of the electrodes are distinguishing. Our work demonstrate that CNFs paper/PANI/RGO electrode provides a more effective pathway for ion transport facilitation compared with CNFs paper/PANI/PEDOT:PSS electrode. The supercapacitor fabricated by CNFs/[PANI-RGO]8 (S-PG-8) exhibits an excellent areal capacitance of 5.86 mF cm-2 at a current density of 0.0043 mA cm-2, and at the same current density the areal capacitance of the supercapacitor fabricated by CNFs/[PANI-PEDOT:PSS]8 (S-PP-8) is 4.22 mF cm-2. S-PG-8 also exhibits good cyclic stability. This study provides a novel method using CNFs as substrate to prepare hybrid electrodes with diverse microstructures that are promising for future flexible supercapacitors.

  20. Organic fouling of thin-film composite polyamide and cellulose triacetate forward osmosis membranes by oppositely charged macromolecules.

    Science.gov (United States)

    Gu, Yangshuo; Wang, Yi-Ning; Wei, Jing; Tang, Chuyang Y

    2013-04-01

    Fouling of cellulose triacetate (CTA) and thin-film composite (TFC) forward osmosis (FO) membranes by organic macromolecules were studied using oppositely charged lysozyme (LYS) and alginate (ALG) as model foulants. Flux performance and foulant deposition on membranes were systematically investigated for a submerged membrane system. When an initial flux of 25 L/m(2)h was applied, both flux reduction and foulant mass deposition were severe for feed water containing the mixture of LYS and ALG (e.g., 50% LYS and 50% ALG at a total foulant concentration of 100 mg/L). In comparison, fouling was much milder for feed water containing either LYS or ALG alone. Compared to the CTA FO membrane, the TFC FO membrane showed greater fouling propensity under mild FO fouling conditions due to its much rougher surface. Nevertheless, under severe FO fouling conditions, fouling was dominated by foulant-deposited-foulant interaction and membrane surface properties played a less important role. Furthermore, when the feed water contained both LYS and ALG in sufficient amount, the deposited cake layer foulant composition (i.e., the LYS/ALG mass ratio) was not strongly affected by membrane types (CTA versus TFC) nor testing modes (pressure-driven NF mode versus osmosis-driven FO mode). In contrast, solution chemistry such as pH and calcium concentration had remarkable effect on the cake layer composition due to their effects on foulant-foulant interaction.

  1. Early stage hydration law of cement pastes under the coupling effect" of cellulose ether and expanded perlite%纤维素醚-膨胀珍珠岩耦合作用下水泥浆体早期水化规律

    Institute of Scientific and Technical Information of China (English)

    苏雷; 马保国; 蹇守卫; 赵志广; 刘敏

    2012-01-01

    Early hydration law of cement pastes modified with hydroxypropyl methyl cellulose ether and expanded perlite and their mechanism in cement pastes were studied by hydration exothermic rate, XRD, FT-IR, DTG and Ca(OH)2 content. The results show that hydroxypropyl methyl cellulose ether can significantly reduce the peak of hydration exothermic rate of cement paste in early stage. Hydration induction period and acceleration period of cement pastes were delayed. It had little retarding influence on middle and late period hydration of cement paste. The peak hydration exothermic rate of cement pastes modified with expanded perlite was decreased. The effect was worse than the hydroxypropyl methyl cellulose. Expanded perlite had no retarding effects on cement hydration. It had obvious coupling effect under combined action of hydroxypropyl methyl cellulose ether and expanded perlite. Hydroxypropyl methyl cellulose ether and expanded perlite can significantly reduce the content of Ca(OH)2 after 12h hydration. The content of Ca(OH)2 in cement pastes respectively decreased by 43.6% and 9.1% than blank samples. After 24 and 72h hydration, the trendy of decreasing of Ca (OH)2 content in cement paste became very slow with both hydroxypropyl methyl cellulose ether and expanded perlite mixing.%利用水化放热速率、XRD、FT-IR、DTG和Ca(OH)2含量测试手段,研究了羟丙基甲基纤维素醚和膨胀珍珠岩两种保水因子单掺和耦合作用条件下水泥浆体的早期水化规律及二者的作用机理。结果表明羟丙基甲基纤维素醚能够显著降低水泥浆体早期水化放热速率峰值,且能延缓诱导期和加速期出现的时间,对水泥浆体中后期水化没有明显的延缓效应。膨胀珍珠岩可以降低早期水化放热速率峰值,效果较羟丙基甲基纤维素醚差,但对水泥水化无延缓效应。当二者耦合作用时,具有显著的叠加效应。水化12h时,羟丙基甲基纤维素醚和膨

  2. 采用氧化甲基吗啉制备纤维素膜的研究进展%Research Progress of New Functional Cellulose Film Made by NMMO Process

    Institute of Scientific and Technical Information of China (English)

    袁恒森; 王晓敏; 肖静; 年鹤

    2011-01-01

    从氧化甲基吗啉(NMMO)纤维素膜的成膜工艺、改性与应用等方面介绍了利用NMMO制备纤维素膜的研究进展,分析了NMMO纤维素膜末得到工业化应用的原因,并对NMMO纤维素膜今后的发展趋势进行了展望.%Research progress of cellulose film made by NMMO process in recent years is introduced in this paper. Film forming process, modification and application of cellulose film are expounded. The reasons of no widely industrial application of cellulose film are analyzed and its development trend is predicted.

  3. Integrated fast assembly of free-standing lithium titanate/carbon nanotube/cellulose nanofiber hybrid network film as flexible paper-electrode for lithium-ion batteries.

    Science.gov (United States)

    Cao, Shaomei; Feng, Xin; Song, Yuanyuan; Xue, Xin; Liu, Hongjiang; Miao, Miao; Fang, Jianhui; Shi, Liyi

    2015-05-27

    A free-standing lithium titanate (Li4Ti5O12)/carbon nanotube/cellulose nanofiber hybrid network film is successfully assembled by using a pressure-controlled aqueous extrusion process, which is highly efficient and easily to scale up from the perspective of disposable and recyclable device production. This hybrid network film used as a lithium-ion battery (LIB) electrode has a dual-layer structure consisting of Li4Ti5O12/carbon nanotube/cellulose nanofiber composites (hereinafter referred to as LTO/CNT/CNF), and carbon nanotube/cellulose nanofiber composites (hereinafter referred to as CNT/CNF). In the heterogeneous fibrous network of the hybrid film, CNF serves simultaneously as building skeleton and a biosourced binder, which substitutes traditional toxic solvents and synthetic polymer binders. Of importance here is that the CNT/CNF layer is used as a lightweight current collector to replace traditional heavy metal foils, which therefore reduces the total mass of the electrode while keeping the same areal loading of active materials. The free-standing network film with high flexibility is easy to handle, and has extremely good conductivity, up to 15.0 S cm(-1). The flexible paper-electrode for LIBs shows very good high rate cycling performance, and the specific charge/discharge capacity values are up to 142 mAh g(-1) even at a current rate of 10 C. On the basis of the mild condition and fast assembly process, a CNF template fulfills multiple functions in the fabrication of paper-electrode for LIBs, which would offer an ever increasing potential for high energy density, low cost, and environmentally friendly flexible electronics.

  4. Microbiological quality and other characteristics of refrigerated chicken meat in contact with cellulose acetate-based film incorporated with rosemary essential oil

    Directory of Open Access Journals (Sweden)

    Adriane Alexandre Machado de Melo

    2012-12-01

    Full Text Available Antimicrobial active packaging delays or inhibits microorganism growth in packed products, and it can be used in a variety of food systems. The objective of the present research was to develop packaging incorporated with natural antimicrobial agents (active film. The effects of the active film on the spoilage, pathogenic microorganism counts, pH and color of the refrigerated chicken breast cuts were analyzed. Cellulose acetate-based active films incorporating two concentrations (20% and 50%, v/w of rosemary (Rosmarinus officinalis L. essential oil were manufactured and placed in contact with the chicken breast cuts for six days. An analysis of variance and mean comparison tests (Tukey's test, p<0.05 were performed on the results. The films that contained 20% essential oil and were intercalated with chicken breast samples did not demonstrate significant effects on the control of psychrotrophic or total coliform microorganisms during the storage period; however, the films incorporated with 50% essential oil demonstrated efficacy toward the control of coliforms during the storage of the samples (6 days, 2 ± 2ºC. The pH was related to the psychrotrophic microorganism count and was not influenced by the treatment. The color was not influenced by the time of storage or the treatment. The results demonstrate that active films incorporating 50% rosemary essential oil are effective at controlling certain microorganisms in chicken breast cuts.

  5. A comparative study on cellulose nanocrystals extracted from bleached cotton and flax and used for casting films with glycerol and sorbitol plasticisers.

    Science.gov (United States)

    Csiszár, Emilia; Nagy, Sebestyén

    2017-10-15

    Cellulose nanocrystals (CNCs) were released from bleached cotton and flax by a sulphuric acid hydrolysis with about 40 and 34% yield, respectively. The rod-like cotton-CNC particles were slightly longer and wider and had a less pronounced aggregation ability in aqueous suspension than the flax-CNC ones. Films were cast from the CNC suspensions with sorbitol and glycerol plasticisers. The concept behind this research was to explore how the plasticisers - with similar structure but different molecular weight - and their concentrations affect the perceptible and measured properties of CNC films. Results revealed that the type of plasticiser determined the morphology and the optical and tensile properties of films. The best quality CNC film with an averaged thickness of 50μm was obtained with 20% sorbitol from cotton-CNC. It was proved that behaviour of sorbitol and glycerol plasticisers in CNC films was very similar to that reported previously for starch films. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference.

  7. Alexa Fluor-labeled Fluorescent Cellulose Nanocrystals for Bioimaging Solid Cellulose in Spatially Structured Microenvironments

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Mo, Kai-For; Shin, Yongsoon; Vasdekis, Andreas; Warner, Marvin G.; Kelly, Ryan T.; Orr, Galya; Hu, Dehong; Dehoff, Karl J.; Brockman, Fred J.; Wilkins, Michael J.

    2015-03-18

    Cellulose nanocrystal materials have been labeled with modern Alexa Fluor dyes in a process that first links the dye to a cyanuric chloride molecule. Subsequent reaction with cellulose nanocrystals provides dyed solid microcrystalline cellulose material that can be used for bioimaging and suitable for deposition in films and spatially structured microenvironments. It is demonstrated with single molecular fluorescence microscopy that these films are subject to hydrolysis by cellulose enzymes.

  8. Cellulose nanocrystal-based materials : from liquid crystal self-assembly and glass formation to multifunctional thin films

    OpenAIRE

    Jan P. F. Lagerwall; Schütz, Christina; Salajkova, Michaela; Noh, Junghyun; PARK, JI HYUN; Scalia, Giusy; Bergström, Lennart

    2014-01-01

    Cellulose nanocrystals (CNCs), produced by the acid hydrolysis of wood, cotton or other cellulose-rich sources, constitute a renewable nanosized raw material with a broad range of envisaged uses: for example, in composites, cosmetics and medical devices. The intriguing ability of CNCs to self-organize into a chiral nematic (cholesteric) liquid crystal phase with a helical arrangement has attracted significant interest, resulting in much research effort, as this arrangement gives dried CNC fil...

  9. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes.

    Science.gov (United States)

    Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M

    2016-02-23

    Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-film-immobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases.

  10. Preparation and Characterization of All-Biomass Soy Protein Isolate-Based Films Enhanced by Epoxy Castor Oil Acid Sodium and Hydroxypropyl Cellulose

    Directory of Open Access Journals (Sweden)

    La Wang

    2016-03-01

    Full Text Available All-biomass soy protein-based films were prepared using soy protein isolate (SPI, glycerol, hydroxypropyl cellulose (HPC and epoxy castor oil acid sodium (ECOS. The effect of the incorporated HPC and ECOS on the properties of the SPI film was investigated. The experimental results showed that the tensile strength of the resultant films increased from 2.84 MPa (control to 4.04 MPa and the elongation at break increased by 22.7% when the SPI was modified with 2% HPC and 10% ECOS. The increased tensile strength resulted from the reaction between the ECOS and SPI, which was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR, scanning electron microscopy (SEM and X-ray diffraction analysis (XRD. It was found that ECOS and HPC effectively improved the performance of SPI-based films, which can provide a new method for preparing environmentally-friendly polymer films for a number of commercial applications.

  11. Cellulose Nanocrystals/ZnO as a Bifunctional Reinforcing Nanocomposite for Poly(vinyl alcohol/Chitosan Blend Films: Fabrication, Characterization and Properties

    Directory of Open Access Journals (Sweden)

    Susan Azizi

    2014-06-01

    Full Text Available In this study, cellulose nanocrystals/zinc oxide (CNCs/ZnO nanocomposites were dispersed as bifunctional nano-sized fillers into poly(vinyl alcohol (PVA and chitosan (Cs blend by a solvent casting method to prepare PVA/Cs/CNCs/ZnO bio-nanocomposites films. The morphology, thermal, mechanical and UV-vis absorption properties, as well antimicrobial effects of the bio-nanocomposite films were investigated. It demonstrated that CNCs/ZnO were compatible with PVA/Cs and dispersed homogeneously in the polymer blend matrix. CNCs/ZnO improved tensile strength and modulus of PVA/Cs significantly. Tensile strength and modulus of bio-nanocomposite films increased from 55.0 to 153.2 MPa and from 395 to 932 MPa, respectively with increasing nano-sized filler amount from 0 to 5.0 wt %. The thermal stability of PVA/Cs was also enhanced at 1.0 wt % CNCs/ZnO loading. UV light can be efficiently absorbed by incorporating ZnO nanoparticles into a PVA/Cs matrix, signifying that these bio-nanocomposite films show good UV-shielding effects. Moreover, the biocomposites films showed antibacterial activity toward the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The improved physical properties obtained by incorporating CNCs/ZnO can be useful in variety uses.

  12. Preparation and characterization of chitosan/cellulose blend films using ZnCl2·3H2O as a solvent

    Directory of Open Access Journals (Sweden)

    Shan Lin

    2012-11-01

    Full Text Available Chitosan (CS/cellulose (BC blend films were successfully prepared using ZnCl2•3H2O as a solvent. Homogeneous structures without obvious phase separation between CS and BC for all blend films were observed by scanning electron microscope (SEM analysis. The tensile strengths of CS/BC blend films decreased with the increase of chitosan content. The results of X-ray diffraction (XRD analysis indicated that the crystal structures of BC and CS were disrupted during the processes of dissolving and regeneration. Also, the reformation of hydrogen bonds between CS and BC during dissolution and regeneration processes resulted in the shift of diffraction peaks. Fourier transforms infrared spectroscopy (FT-IR and thermogravimetric analysis (TGA analysis results confirmed this observation. Moreover, obvious antimicrobial capability of CS/BC blend films against E. coli has been observed, indicating that antibacterial activity of chitosan has not been significantly inactivated while using ZnCl2•3H2O as a solvent. Therefore, ZnCl2•3H2O can be regarded as a promising solvent to prepare degradable films with antibacterial properties.

  13. Preparation of nanocellulose from micro-crystalline cellulose: The effect on the performance and properties of agar-based composite films.

    Science.gov (United States)

    Shankar, Shiv; Rhim, Jong-Whan

    2016-01-01

    A facile approach has been performed to prepare nanocellulose (NC) from micro-crystalline cellulose (MCC) and test their effect on the performance properties of agar-based composite films. The NC was characterized by STEM, XRD, FTIR, and TGA. The NC was well dispersed in distilled water after sonication and their size was in the range of 100-500nm. The XRD results revealed the crystallinity of NC. The crystallinity index of NC (0.71) was decreased compared to the MCC (0.81). The effect of NC or MCC content (1, 3, 5 and 10wt% based on agar) on the mechanical, water vapor permeability (WVP), and thermal properties of the composites were studied. The NC obtained from MCC can be used as a reinforcing agent for the preparation of biodegradable composites films for their potential use in the development of biodegradable food packaging materials.

  14. Effects of Modified Iron Oxide Nanoparticles on the Thermal and Dynamic Mechanical Properties of Cellulose Poly(vinyl alcohol Blend Films

    Directory of Open Access Journals (Sweden)

    Mehdi Roohani

    2015-11-01

    Full Text Available This study was designed to investigate the effect of modified iron oxide nanoparticles (MINP and cellulose nanocrystals (NCC on magnetic, thermal and dynamic-mechanical properties of poly(vinyl alcohol based nanocomposites. Fe3O4 nanoparticles have been synthesized using a chemical co-precipitation route. Nanocomposite films were developed by solvent casting method and their properties were characterized by vibrating sample magnetometer (VSM, differential scanning calorimetry (DSC and dynamic mechanical analysis (DMA. DSC results found that with incorporation of nanoparticles, the glass transition temperature increase slightly to higher temperatures; however, the degree of crystallinity and the values of the melting temperature are found to decrease. Dynamic mechanical analysis revealed that, at the elevated temperatures, improvement of mechanical properties due to the presence of nanoparticles was even more noticeable. Addition of nanoparticles resulted in increased thermal stability of PVA due to the reduction in mobility of matrix molecules by strong hydrogen bonds between nanocomposite components. Results indicated that, MINP and NCC have synergistic effect on improving of poly(vinyl alcohol properties. The VSM findings showed that the saturation magnetization of iron oxide nanoparticles reduced after modification. This can be attributed to formation of hydroxyapatite on nanoparticles surface. The saturation magnetization (Ms of PVA- MINP films was higher than PVA-MINP- NCC film. This result probably is related to more amount of magnetic nanoparticles in PVA-MINP films.

  15. Effect of compounding approaches on fiber dispersion and performance of poly(lactic acid)/cellulose nanocrystal composite blown films

    Science.gov (United States)

    Sonal S. Karkhanis; Laurent M. Matuana; Nicole M. Stark; Ronald C. Sabo

    2017-01-01

    This study was aimed to identify the best approach for incorporating cellulose nanocrystals (CNCs) into a poly(lactic acid) (PLA) matrix by examining two different CNC addition approaches. The first approach consisted of melt blending PLA and CNCs in a three-piece internal mixer whereas the second method involved the direct dry mixing of PLA and CNCs. The prepared...

  16. Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose

    Science.gov (United States)

    Sani, Negar; Wang, Xin; Granberg, Hjalmar; Andersson Ersman, Peter; Crispin, Xavier; Dyreklev, Peter; Engquist, Isak; Gustafsson, Göran; Berggren, Magnus

    2016-06-01

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future “internet of things” viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-μPs) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-μPs and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-μPs. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm2, a current rectification ratio up to 4 × 103 between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

  17. Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose.

    Science.gov (United States)

    Sani, Negar; Wang, Xin; Granberg, Hjalmar; Andersson Ersman, Peter; Crispin, Xavier; Dyreklev, Peter; Engquist, Isak; Gustafsson, Göran; Berggren, Magnus

    2016-01-01

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future "internet of things" viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-μPs) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-μPs and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-μPs. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm(2), a current rectification ratio up to 4 × 10(3) between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

  18. Cellulose nanocrystal submonolayers by spin coating.

    Science.gov (United States)

    Kontturi, Eero; Johansson, Leena-Sisko; Kontturi, Katri S; Ahonen, Päivi; Thüne, Peter C; Laine, Janne

    2007-09-11

    Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images, anionic cellulose nanocrystals formed small aggregates on the anionic silica substrate, whereas a uniform two-dimensional distribution of nanocrystals was achieved on the cationic titania substrate. The uniform distribution of cellulose nanocrystal submonolayers on titania is an important factor when dimensional analysis of the nanocrystals is desired. Furthermore, the amount of nanocrystals deposited on titania was multifold in comparison to the amounts on silica, as revealed by AFM image analysis and X-ray photoelectron spectroscopy. Amorphous cellulose, the third substrate, resulted in a somewhat homogeneous distribution of the nanocrystal submonolayers, but the amounts were as low as those on the silica substrate. These differences in the cellulose nanocrystal deposition were attributed to electrostatic effects: anionic cellulose nanocrystals are adsorbed on cationic titania in addition to the normal spin coating deposition. The anionic silica surface, on the other hand, causes aggregation of the weakly anionic cellulose nanocrystals which are forced on the repulsive substrate by spin coating. The electrostatically driven adsorption also influences the film thickness of continuous ultrathin films of cellulose nanocrystals. The thicker films of charged nanocrystals on a substrate of opposite charge means that the film thickness is not independent of the substrate when spin coating cellulose nanocrystals in the ultrathin regime (<100 nm).

  19. Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

    Science.gov (United States)

    Wang, Xinhua; Zhao, Yanxiao; Yuan, Bo; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

    2016-02-01

    There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-D-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-D-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties.

  20. Crystal growth of calcium carbonate on the cellulose acetate/pyrrolidon blend films in the presence of L-aspartic acid

    Science.gov (United States)

    Zhang, Xiuzhen; Xie, Anjian; Huang, Fangzhi; Shen, Yuhua

    2014-03-01

    The morphogenesis and growth process of calcium carbonate on the cellulose acetate/polyvinyl pyrrolidone (CA/PVP) blend films in the presence of L-aspartic acid was carefully investigated. The results showed that the concentration of L-aspartic acid, the initial pH value of reaction solution and temperature turned out to be important factors for the control of morphologies and polymorphs of calcium carbonate. Complex morphologies of CaCO3 particles, such as cubes, rose-like spheres, twinborn-spheres, cone-like, bouquet-like, etc. could be obtained under the different experimental conditions. The dynamic process of formation of rose-like sphere crystals was analyzed by monitoring the continuous morphological and structural evolution and components of crystals in different crystal stages. This research may provide a promising method to prepare other inorganic materials with complex morphologies.

  1. Cellulose nanocrystals as templates for cetyltrimethylammonium bromide mediated synthesis of Ag nanoparticles and their novel use in PLA films.

    Science.gov (United States)

    Yalcinkaya, E E; Puglia, D; Fortunati, E; Bertoglio, F; Bruni, G; Visai, L; Kenny, J M

    2017-02-10

    In the present paper, we reported how cellulose nanocrystals (CNC) from microcrystalline cellulose have the capacity to assist in the synthesis of metallic nanoparticles chains. A cationic surfactant, cetyltrimethylammonium bromide (CTAB), was used as modifier for CNC surface. Silver nanoparticles were synthesized on CNC, and nanoparticle density and size were optimized by varying concentrations of nitrate and reducing agents, and the reduction time. The experimental conditions were optimized for the synthesis and the resulting Ag grafted CNC (Ag-g-CNC) were characterized by means of TGA, SEM, FTIR and XRD, and then introduced in PLA matrix. PLA nanocomposite containing silver grafted cellulose nanocrystals (PLA/0.5Ag-g-1CNC) was characterized by optical and thermal analyses and the obtained data were compared with results from PLA nanocomposites containing 1% wt. of CNC (PLA/1CNC), 0.5% wt. of silver nanoparticles (PLA/0.5Ag) and hybrid system containing CNC and silver in the same amount (PLA/1CNC/0.5Ag). The results demonstrated that grafting of silver nanoparticles on CNC positively affected the thermal degradation process and cold crystallization processes of PLA matrix. Finally, the antibacterial activity of the different systems was studied at various incubation times and temperatures, showing the best performance for PLA/1CNC/0.5Ag based nanocomposite. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Loratidine buccal films for allergic rhinitis: development and evaluation.

    Science.gov (United States)

    Kumria, Rachna; Nair, Anroop B; Al-Dhubiab, Bandar E

    2014-05-01

    The objective of this study was to develop a novel patient compliant buccoadhesive film capable of providing a prolonged protection against allergic symptoms. Polymeric buccoadhesive films of loratidine were prepared using hydroxypropylmethyl cellulose (HPMC)-E5 and K100 blend and Eudragit® NE 30D as retardant. Films were prepared using solvent-casting method. The developed films were evaluated for physical properties, hydration, mucoadhesion time, drug release, etc. All the prepared films exhibited excellent mechanical strength and uniform drug content. Increase in drug content did not influence the physicomechanical properties of the film. The mucoadhesive strength of films was significantly enhanced with increase in HPMC content. Increase in Eudragit® NE 30 D content in the film decreases the hydration, erosion and drug release, but enhances the mucoadhesion time. Furthermore, the release of loratidine from the prepared films followed Hixson-Crowell kinetics. Studies in healthy human volunteers using placebo films indicate that the prepared films possess prolonged mucoadhesion in-vivo, and this could potentially lead to clinically relevant drug delivery system.

  3. High strength, flexible and transparent nanofibrillated cellulose-nanoclay biohybrid films with tunable oxygen and water vapor permeability.

    Science.gov (United States)

    Aulin, Christian; Salazar-Alvarez, German; Lindström, Tom

    2012-10-21

    A novel, technically and economically benign procedure to combine vermiculite nanoplatelets with nanocellulose fibre dispersions into functional biohybrid films is presented. Nanocellulose fibres of 20 nm diameters and several micrometers in length are mixed with high aspect ratio exfoliated vermiculite nanoplatelets through high-pressure homogenization. The resulting hybrid films obtained after solvent evaporation are stiff (tensile modulus of 17.3 GPa), strong (strength up to 257 MPa), and transparent. Scanning electron microscopy (SEM) shows that the hybrid films consist of stratified nacre-like layers with a homogenous distribution of nanoplatelets within the nanocellulose matrix. The oxygen barrier properties of the biohybrid films outperform commercial packaging materials and pure nanocellulose films showing an oxygen permeability of 0.07 cm(3) μm m(-2) d(-1) kPa(-1) at 50% relative humidity. The oxygen permeability of the hybrid films can be tuned by adjusting the composition of the films. Furthermore, the water vapor barrier properties of the biohybrid films were also significantly improved by the addition of nanoclay. The unique combination of excellent oxygen barrier behavior and optical transparency suggests the potential of these biohybrid materials as an alternative in flexible packaging of oxygen sensitive devices such as thin-film transistors or organic light-emitting diode displays, gas storage applications and as barrier coatings/laminations in large volume packaging applications.

  4. Transparent bionanocomposite films based on chitosan and tempo-oxidized cellulose nanofibers with enhanced mechanical and barrier properties

    Science.gov (United States)

    The development of biobased active films for use in food packaging is increasing due to low cost, environmental appeal, renewability and availability. The objective of this research was to develop an effective and complete green approach for the production of bionanocomposite films with enhanced mec...

  5. Metallization of bacterial cellulose for electrical and electronic device manufacture

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Jansen, Valerie Malyvanh; Woodward, Jonathan

    2011-06-07

    A method for the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a metal comprises placing a bacterial cellulose matrix in a solution of a metal salt such that the metal salt is reduced to metallic form and the metal precipitates in or on the matrix. The method for the construction of a fuel cell comprises placing a hydrated bacterial cellulose support structure in a solution of a metal salt such that the metal precipitates in or on the support structure, inserting contact wires into two pieces of the metal impregnated support structure, placing the two pieces of metal impregnated support structure on opposite sides of a layer of hydrated bacterial cellulose, and dehydrating the three layer structure to create a fuel cell.

  6. Contribution of TEMPO-Oxidized Cellulose Gel in the Formation of Flower-Like Zinc Oxide Superstructures: Characterization of the TOCgel/ZnO Composite Films

    Directory of Open Access Journals (Sweden)

    Khalil Jradi

    2015-11-01

    Full Text Available In the present paper, we report on a simple and new approach for the synthesis of hierarchical flower-like zinc oxide superstructures ZnO (FL in the presence of the TEMPO-oxidized cellulose gel (TOCgel through a room temperature sol-gel process in aqueous medium. Resulting composite films based on TOCgel and ZnO were investigated by several techniques including scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS, thermogravimetric analysis (TGA and mechanical tests. SEM images demonstrated the formation of well-shaped flower-like ZnO superstructures within the fibrous structure of the TOCgel with a uniform diameter (~5 μm. FTIR and XPS results clearly confirmed the formation of such ZnO structures. We suggested that the carboxylate groups of TOCgel fibers act as capping agents and promote the construction of such flower-like ZnO via a nucleation-growth process. A proposed mechanism based on the oriented attachment-driven growth was discussed in order to explain the formation of ZnO (FL. The photocatalytic activity of the TOCgel/ZnO composite in the degradation of methylene blue (MB under UV irradiation was clearly confirmed. Finally, mechanical tests demonstrated that the former TOCgel/ZnO film maintained a good flexibility (bent up to ~120° without losing its photocatalytic activity.

  7. 水化膜对原子力显微镜扫描图像的影响%Effect of Hydration Film on Scanning Images of Atomoc Force Microscope

    Institute of Scientific and Technical Information of China (English)

    彭昌盛; 宋少先

    2004-01-01

    原子力显微镜(AFM)有接触和轻敲两种工作方式,可以在气相和液相下工作.在液相工作状态下,浸没于水中的探针和样品表面会形成一层水化膜.在探针和样品表面形成的水化膜是否会对扫描图像产生影响以及产生何种影响是一个值得研究的问题.本文用原子力显微镜对1μm标准校正光栅在空气和水两种媒质中进行了图像扫描,扫描分别采用接触和轻敲两种工作方式.扫描图像显示,在液相工作环境中,水化膜在探针和样品表面的形成将严重影响轻敲工作方式所形成的图像,而接触方式的扫描图像基本不受影响.%Atomic force microscope (AFM) can operate with contact and tapping modes, under air and water conditions. It is well known that hydration films will be formed on the surface of tip and sample after they immersed in water. So it is necessary to know the effect of hydration films on scanning images. A 1 μm standard calibration grating was used for image scanning to investigate the effect of hydration films on imaging resolution in this paper. The results show that the hydration films can greatly affect the imaging resolution for tapping mode, but no evident effect on contact mode.

  8. Hydrothermal deposition and the photochromic properties of molybdenum oxide hydrate (MoO{sub 3}⋅(H{sub 2}O){sub 0.69}) films induced by D, L-malic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yi, E-mail: sysy7373@163.com; Xiao, Yilin; Yan, Peng; Yang, Yali; Hu, Fengping; Li, Zhen

    2014-03-05

    Graphical abstract: The molybdenum oxide hydrate (MoO{sub 3}⋅(H{sub 2}O){sub 0.69}) films were synthetized through a hydrothermal route with or without the D, L-malic acid as capping agent. The SEM images indicate that the films obtained without D, L-malic acid show the hexagonal prismatic structures while the films prepared with the capping agent reveal the dandelion-like hierarchical structures, and all the films have double-layer structures. Compared with the films synthetized without the D, L-malic acid, the films prepared with the capping agent show a superior photochromic properties. And the more complete the dandelion-like structures, the better performance the films possess. The best performance appeared when the film was prepared with molar ratio of D, L-malic acid and sodium molybdate at 1:5. The enhanced photochromic performances of the films may be ascribed to the dandelion-like hierarchical structures which can provide large exposed surface and ultimately, increase the amount of the photogenerated electron–hole pairs and the proton diffusion rates. -- Highlights: • Two kinds of films with novel morphologies were obtained with simple hydrothermal process. • Adding D, L-malic acid to the hydrothermal system obviously change the structure of the films. • The film with dandelion-like hierarchical structures showed better photochromic properties. -- Abstract: Two kinds of molybdenum oxide hydrate films were successfully synthesized by a simple hydrothermal deposition method. The X-ray diffraction shows that all the samples can be indexed to hexagonal structure of MoO{sub 3}·(H{sub 2}O){sub 0.69}. Scanning electron microscopy images of the products revealed that hexagonal prismatic structures were revealed on the surface of the sample prepared without capping. While the surface of ones obtained with D, L-malic acid were covered by dandelion-like hierarchical structures, which may result from the effect of hydrogen bonds, and the dandelion

  9. Gas hydrates

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.

    and the role it plays in the global climate and the future of fuels. Russia, Japan, Nigeria, Peru, Chile, Pakistan, Indonesia, Korea, etc are various countries who are perusing the gas hydrates studies as a future resource for fuel. Indian Initiative..., 1993, Free gas at the base of the gas hydrate zone in the vicinity of the Chile Triple junction: Geology, v. 21, pp. 905-908. Borowski, W.S., C.K. Paull, and U. William, III, 1999, Global and local variations of interstitial sulfate gradients...

  10. Performance Study about Film of Mercerizing Reguar and Microcrystalline Cellulose in the Ionic Liquids%丝瓜络和微晶纤维素在离子液体中成膜性能研究

    Institute of Scientific and Technical Information of China (English)

    陈梅; 魏莉; 王迎; 赵吉祥

    2011-01-01

    [ Objective] The aim was to study performance about film of mercerizing reguar and mierocrystalline cellulose in the ionic liquids. [Method] Regenerated cellulose film was prepared from mercerizing reguar in 1-butyl, 3-methylimidazolium chloride ionic liquid. Properties and structures of the mercerizing reguar and obtained regenerated cellulose films were investigated by FTIR and polarized light microscopy, then contrasted by microcrystalline cellulose. At last, the performance of film was evaluatied. [Result] The results showed that, 1-butyl, 3-methylimidazolium chloride ionic liquid was good non-derivatizing solvents for mercerizing reguar. Mercerizing reguar and mierocrystalline cellulose were compared, it found that dissolve time and solubility in ionic liquids were serious influenced by the degree of polymerization. [ Conclusion] Cellulose film had a certain hole rate and aperture, could be used in permeation and separation field.%[目的]研究丝瓜络和微晶纤维素在离子液体中成膜性能.[方法]以离子液体[BMIM]Cl为溶剂溶解预处理过的丝瓜络,制得纤维素膜,用红外光谱和偏光显微镜对溶解前后的丝瓜络纤维进行表征,并对纤维素膜作了基本的性能评价.[结果]与微晶纤维素为原料的对比试验表明,[BMIM]Cl是丝瓜络纤维的直接溶剂,溶解过程中没有衍生物生成.原料聚合度的大小严重影响纤维素在离子液体中的溶解时间和溶解度.[结论]制备的纤维素平板膜具备一定的空隙率和孔径,可广泛应用于渗透、分离等领域.

  11. Antioxidant films based on cross-linked methyl cellulose and native Chilean berry for food packaging applications.

    Science.gov (United States)

    López de Dicastillo, Carol; Rodríguez, Francisco; Guarda, Abel; Galotto, Maria José

    2016-01-20

    Development of antioxidant and antimicrobial active food packaging materials based on biodegradable polymer and natural plant extracts has numerous advantages as reduction of synthetic additives into the food, reduction of plastic waste, and food protection against microorganisms and oxidation reactions. In this way, active films based on methylcellulose (MC) and maqui (Aristotelia chilensis) berry fruit extract, as a source of antioxidants agents, were studied. On the other hand, due to the high water affinity of MC, this polymer was firstly cross-linked with glutaraldehyde (GA) at different concentrations. The results showed that the addition of GA decreased water solubility, swelling, water vapor permeability of MC films, and the release of antioxidant substances from the active materials increased with the concentration of GA. Natural extract and active cross-linked films were characterized in order to obtain the optimal formulation with the highest antioxidant activity and the best physical properties for latter active food packaging application.

  12. Co-processing as a tool to improve aqueous dispersibility of cellulose ethers.

    Science.gov (United States)

    Sharma, Payal; Modi, Sameer R; Bansal, Arvind K

    2015-01-01

    Cellulose ethers are important materials with numerous applications in pharmaceutical industry. They are widely employed as stabilizers and viscosity enhancers for dispersed systems, binders in granulation process and as film formers for tablets. These polymers, however, exhibit challenge during preparation of their aqueous dispersions. Rapid hydration of their surfaces causes formation of a gel that prevents water from reaching the inner core of the particle. Moreover, the surfaces of these particles become sticky, thus leading to agglomeration, eventually reducing their dispersion kinetics. Numerous procedures have been tested to improve dispersibility of cellulose ethers. These include the use of cross-linking agents, alteration in the synthesis process, adjustment of water content of cellulose ether, modification by attaching hydrophobic substituents and co-processing using various excipients. Among these, co-processing has provided the most encouraging results. This review focuses on the molecular mechanisms responsible for the poor dispersibility of cellulose ethers and the role of co-processing technologies in overcoming the challenge. An attempt has been made to highlight various co-processing techniques and specific role of excipients used for co-processing.

  13. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja Salomon

    2012-01-01

    or enzymatic hydrolysis of plant cell walls is carried out simultaneously with the application of shear stress, plant cells such as fibers or tracheids break at their dislocations. At present it is not known whether specific carbohydrate binding modules (CBMs) and/or cellulases preferentially access cellulose......Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we...... are not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid...

  14. Regenerated cellulose-silk fibroin blends fibers.

    Science.gov (United States)

    Marsano, Enrico; Corsini, Paola; Canetti, Maurizio; Freddi, Giuliano

    2008-08-15

    Fibers made of cellulose and silk fibroin at different composition were wet spun from solutions by using N-methylmorpholine N-oxide hydrates (NMMO/H(2)O) as solvent and ethanol as coagulant. Different spinning conditions were used. The fibers were characterized by different techniques: FTIR-Raman, scanning electron microscopy, wide-angle x-ray diffraction, DSC analysis. The results evidence a phase separation in the whole blends compositions. The tensile characterization, however, illustrates that the properties of the blends fibers are higher respect to a linear behaviour between the pure polymers, confirming a good compatibility between cellulose and silk fibroin. The fibers containing 75% of cellulose show better mechanical properties than pure cellulose fibers: modulus of about 23 GPa and strength to break of 307 MPa.

  15. Structure and transformation of tactoids in cellulose nanocrystal suspensions

    Science.gov (United States)

    Wang, Pei-Xi; Hamad, Wadood Y.; MacLachlan, Mark J.

    2016-05-01

    Cellulose nanocrystals obtained from natural sources are of great interest for many applications. In water, cellulose nanocrystals form a liquid crystalline phase whose hierarchical structure is retained in solid films after drying. Although tactoids, one of the most primitive components of liquid crystals, are thought to have a significant role in the evolution of this phase, they have evaded structural study of their internal organization. Here we report the capture of cellulose nanocrystal tactoids in a polymer matrix. This method allows us to visualize, for the first time, the arrangement of cellulose nanocrystals within individual tactoids by electron microscopy. Furthermore, we can follow the structural evolution of the liquid crystalline phase from tactoids to iridescent-layered films. Our insights into the early nucleation events of cellulose nanocrystals give important information about the growth of cholesteric liquid crystalline phases, especially for cellulose nanocrystals, and are crucial for preparing photonics-quality films.

  16. Clathrate hydrates in nature.

    Science.gov (United States)

    Hester, Keith C; Brewer, Peter G

    2009-01-01

    Scientific knowledge of natural clathrate hydrates has grown enormously over the past decade, with spectacular new findings of large exposures of complex hydrates on the sea floor, the development of new tools for examining the solid phase in situ, significant progress in modeling natural hydrate systems, and the discovery of exotic hydrates associated with sea floor venting of liquid CO2. Major unresolved questions remain about the role of hydrates in response to climate change today, and correlations between the hydrate reservoir of Earth and the stable isotopic evidence of massive hydrate dissociation in the geologic past. The examination of hydrates as a possible energy resource is proceeding apace for the subpermafrost accumulations in the Arctic, but serious questions remain about the viability of marine hydrates as an economic resource. New and energetic explorations by nations such as India and China are quickly uncovering large hydrate findings on their continental shelves.

  17. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  18. Efficient recyclable organic solar cells on cellulose nanocrystal substrates with a conducting polymer top electrode deposited by film-transfer lamination

    Science.gov (United States)

    Yinhua Zhou; Talha M. Khan; Jen-Chieh Liu; Canek Fuentes-Hernandez; Jae Won Shim; Ehsan Najafabadi; Jeffrey P. Youngblood; Robert J. Moon; Bernard Kippelen

    2014-01-01

    We report on efficient solar cells on recyclable cellulose nanocrystal (CNC) substrates with a new device structure wherein polyethylenimine-modified Ag is used as the bottom electron-collecting electrode and high-conductivity poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS, PH1000) is used as the semitransparent top holecollecting electrode. The...

  19. Characterization of cellulose extracted from oil palm empty fruit bunch

    Science.gov (United States)

    Sisak, Muhammad Asri Abdul; Daik, Rusli; Ramli, Suria

    2015-09-01

    Recently, cellulose has been studied by many researchers due to its promising properties such as biodegradability, biocompatibility, hydrophilicity and robustness. Due to that it is applied in many fields such as paper, film, drug delivery, membranes, etc. Cellulose can be extracted from various plants while oil palm empty fruit bunch (OPEFB) is the one of its sources. In this study, cellulose was extracted by chemical treatments which involved the use of formic acid and hydrogen peroxide to remove hemicellulose and lignin components. Maximum yield was 43.22%. Based on the FT-IR spectra, the peak of wax (1735 cm-1), hemicellulose (1375 cm-1) and lignin (1248 cm-1 and 1037 cm-1) were not observed in extracted cellulose. TGA analysis showed that the extracted cellulose starts to thermally degrade at 340 °C. The SEM analysis suggested that the cellulose extracted from OPEFB was not much different from commercial cellulose.

  20. A comparative study of green composites based on tapioca starch and celluloses

    Science.gov (United States)

    Owi, Wei Tieng; Lin, Ong Hui; Sam, Sung Ting; Mern, Chin Kwok; Villagracia, Al Rey; Santos, Gil Nonato C.; Akil, Hazizan Md

    2017-07-01

    The objective of this study was to compare the properties of green composites based on tapioca starch (TS) and celluloses isolated from empty fruit bunches (EFB) and commercial celluloses from cotton linter (supplied by Sigma). Empty fruit bunches (EFB) acted as the main source to obtain the cellulose by using a chemical approach whereas the commercial cellulose from Sigma was used as reference. The TS/cellulose composite films were prepared using cellulose in varying proportions as filler into TS matrix by a casting method. The amount of celluloses added into the tapioca starch were 5, 10, 15, 20 and 25 phr (as per dry mass of TS). The celluloses were characterized using Fourier transform infrared (FTTR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). While the green composite films were analyzed in terms of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), SEM and tensile properties. FTTR analysis confirmed the removal of non-cellulosic materials such as hemicelluloses and lignin from raw EFB after the chemical treatment. XRD diffractograms revealed that the crystallinity of celluloses EFB increased from 43.1 % of raw EFB to 52.1 %. SEM images showed the fibrillar structure of cellulose isolated from EFB. The TGA and derivative thermogravimetric (DTG) curves of green composite films showed no significant effect on the thermal stability. Melting temperature of TS/cellulose EFB higher than neat TS while TS/cellulose Sigma lower than neat TS. The green composite films with 15 phr cellulose from EFB filler loading provided the best tensile properties in term of its strength and modulus. However, in term of elongation at break, the percentage elongation decreased with the increased of the amount of filler loading. SEM images of the films demonstrated a good interaction between cellulose filler and TS matrix especially with the addition of 15 phr of cellulose from EFB.

  1. Cellulose metabolism in plants.

    Science.gov (United States)

    Hayashi, Takahisa; Yoshida, Kouki; Park, Yong Woo; Konishi, Teruko; Baba, Kei'ichi

    2005-01-01

    Many bacterial genomes contain a cellulose synthase operon together with a cellulase gene, indicating that cellulase is required for cellulose biosynthesis. In higher plants, there is evidence that cell growth is enhanced by the overexpression of cellulase and prevented by its suppression. Cellulase overexpression could modify cell walls not only by trimming off the paracrystalline sites of cellulose microfibrils, but also by releasing xyloglucan tethers between the microfibrils. Mutants for membrane-anchored cellulase (Korrigan) also show a typical phenotype of prevention of cellulose biosynthesis in tissues. All plant cellulases belong to family 9, which endohydrolyzes cellulose, but are not strong enough to cause the bulk degradation of cellulose microfibrils in a plant body. It is hypothesized that cellulase participates primarily in repairing or arranging cellulose microfibrils during cellulose biosynthesis in plants. A scheme for the roles of plant cellulose and cellulases is proposed.

  2. 纳米微晶纤维/聚乙烯醇复合薄膜的制备及性能%Preparation and Property of Composite Films of Nano-Crystalline Cellulose/Polymer-Poly Vinyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    田景阳; 朱琦; 张璠; 黄崇杏; 杨崎峰

    2012-01-01

    Films of Nano-Crystalline Cellulose/Polymer-Polyv inyl Alcohol(NCC/PVA) with different NCC content were obtained through the sol/gel process ,and NCC with 20 - 50nm particle size was obtained from bagasse. The influnce of NCC content on composite films was fucosed 'on. The results show that these composite films have improved thermal stability with the adding of NCC. The composite films' tensile strength increased 115% and water absorption reduced 12.0% and elongation ruduced 68% when the content of NCC was 0.5%.%采用蔗渣为原料制备出粒径大小为20~50nm的纳米微晶纤维素(NCC),并用溶胶/凝胶方法制备出不同NCC含量的纳米微晶纤维素/聚乙烯醇(NCC/PVA)复合薄膜,重点研究了NCC加入量对复合薄膜综合性能的影响。结果表明,NCC的加入能使薄膜的热稳定性有所提高,当NCC的添加量在0.5%时,聚乙烯醇薄膜的拉伸强度提高了115%,吸水性降低了12.0%,断裂伸长率减少了68%。

  3. Cooperative action of cellulase enzyme and carboxymethyl cellulose on cotton fabric cleanability from a topographical standpoint

    NARCIS (Netherlands)

    Calvimontes, A.; Lant, N.J.; Dutschk, Victoria

    2011-01-01

    In this study, the effect of cotton treatment with cellulose and carboxymethyl cellulose on soil release of three different types of fabric: woven plain, woven twill and knitted were systematically studied. A recent study of the effect of a cleaning cellulase enzyme on cellulose films has proven

  4. Cooperative action of cellulase enzyme and carboxymethyl cellulose on cotton fabric cleanability from a topographical standpoint

    NARCIS (Netherlands)

    Calvimontes, A.; Lant, N.J.; Dutschk, V.

    2011-01-01

    In this study, the effect of cotton treatment with cellulose and carboxymethyl cellulose on soil release of three different types of fabric: woven plain, woven twill and knitted were systematically studied. A recent study of the effect of a cleaning cellulase enzyme on cellulose films has proven tha

  5. Aspects physico-chimiques de l'interaction des éthers de cellulose avec la matrice cimentaire

    OpenAIRE

    Pourchez, Jérémie

    2006-01-01

    Cellulose ethers are of universal use in factory-made mortars, though their influences on mortar properties at a molecular scale are poorly understood. Especially, a main issue deals with the control of secondary effects generated by these admixtures such as cement hydration retardation. In this frame, a study of the impact of cellulose ethers molecule parameters on cement hydration was carried out. Low influence of molecular weight was observed. On the contrary, our results emphasize that th...

  6. Photooxidation of cellulose nitrate: new insights into degradation mechanisms.

    Science.gov (United States)

    Berthumeyrie, Sebastien; Collin, Steeve; Bussiere, Pierre-Olivier; Therias, Sandrine

    2014-05-15

    Cellulose nitrate (or nitrocellulose) has received considerable interest due to its uses in various applications, such as paints, photographic films and propellants. However, it is considered as one of the primary pollutants in the energetic material industries because it can be degraded to form polluting chemical species. In this work, the UV light degradation of cellulose nitrate films was studied under conditions of artificially accelerated photooxidation. To eliminate the reactivity of nitro groups, the degradation of ethylcellulose was also investigated. Infrared spectroscopy analyses of the chemical modifications caused by the photooxidation of cellulose nitrate films and the resulting formation of volatile products revealed the occurrence of de-nitration and the formation of oxidation photoproducts exhibiting lactone and anhydride functions. The impact of these chemical modifications on the mechanical and thermal properties of cellulose nitrate films includes embrittlement and lower temperatures of ignition when used as a propellant.

  7. Cellulose-Based Nanomaterials for Energy Applications.

    Science.gov (United States)

    Wang, Xudong; Yao, Chunhua; Wang, Fei; Li, Zhaodong

    2017-09-13

    Cellulose is the most abundant natural polymer on earth, providing a sustainable green resource that is renewable, degradable, biocompatible, and cost effective. Recently, nanocellulose-based mesoporous structures, flexible thin films, fibers, and networks are increasingly developed and used in photovoltaic devices, energy storage systems, mechanical energy harvesters, and catalysts components, showing tremendous materials science value and application potential in many energy-related fields. In this Review, the most recent advancements of processing, integration, and application of cellulose nanomaterials in the areas of solar energy harvesting, energy storage, and mechanical energy harvesting are reviewed. For solar energy harvesting, promising applications of cellulose-based nanostructures for both solar cells and photoelectrochemical electrodes development are reviewed, and their morphology-related merits are discussed. For energy storage, the discussion is primarily focused on the applications of cellulose-based nanomaterials in lithium-ion batteries, including electrodes (e.g., active materials, binders, and structural support), electrolytes, and separators. Applications of cellulose nanomaterials in supercapacitors are also reviewed briefly. For mechanical energy harvesting, the most recent technology evolution in cellulose-based triboelectric nanogenerators is reviewed, from fundamental property tuning to practical implementations. At last, the future research potential and opportunities of cellulose nanomaterials as a new energy material are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Fabrication of Cellulose ZnO Hybrid Nanocomposite and Its Strain Sensing Behavior

    Directory of Open Access Journals (Sweden)

    Hyun-U Ko

    2014-10-01

    Full Text Available This paper reports a hybrid nanocomposite of well-aligned zinc oxide (ZnO nanorods on cellulose and its strain sensing behavior. ZnO nanorods are chemically grown on a cellulose film by using a hydrothermal process, termed as cellulose ZnO hybrid nanocomposite (CEZOHN. CEZOHN is made by seeding and growing of ZnO on the cellulose and its structural properties are investigated. The well-aligned ZnO nanorods in conjunction with the cellulose film shows enhancement of its electromechanical property. Strain sensing behaviors of the nanocomposite are tested in bending and longitudinal stretching modes and the CEZOHN strain sensors exhibit linear responses.

  9. Posidonia oceanica as a Renewable Lignocellulosic Biomass for the Synthesis of Cellulose Acetate and Glycidyl Methacrylate Grafted Cellulose

    Directory of Open Access Journals (Sweden)

    Elena Vismara

    2013-05-01

    Full Text Available High-grade cellulose (97% α-cellulose content of 48% crystallinity index was extracted from the renewable marine biomass waste Posidonia oceanica using H2O2 and organic peracids following an environmentally friendly and chlorine-free process. This cellulose appeared as a new high-grade cellulose of waste origin quite similar to the high-grade cellulose extracted from more noble starting materials like wood and cotton linters. The benefits of α-cellulose recovery from P. oceanica were enhanced by its transformation into cellulose acetate CA and cellulose derivative GMA-C. Fully acetylated CA was prepared by conventional acetylation method and easily transformed into a transparent film. GMA-C with a molar substitution (MS of 0.72 was produced by quenching Fenton’s reagent (H2O2/FeSO4 generated cellulose radicals with GMA. GMA grafting endowed high-grade cellulose from Posidonia with adsorption capability. GMA-C removes β-naphthol from water with an efficiency of 47%, as measured by UV-Vis spectroscopy. After hydrolysis of the glycidyl group to glycerol group, the modified GMA-C was able to remove p-nitrophenol from water with an efficiency of 92%, as measured by UV-Vis spectroscopy. α-cellulose and GMA-Cs from Posidonia waste can be considered as new materials of potential industrial and environmental interest.

  10. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    OpenAIRE

    Sigal Meirovitch; Zvi Shtein; Tal Ben-Shalom; Shaul Lapidot; Carmen Tamburu; Xiao Hu; Kluge, Jonathan A.; Uri Raviv; Kaplan, David L.; Oded Shoseyov

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhib...

  11. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    OpenAIRE

    Sigal Meirovitch; Zvi Shtein; Tal Ben-Shalom; Shaul Lapidot; Carmen Tamburu; Xiao Hu; Kluge, Jonathan A; Uri Raviv; Kaplan, David L.; Oded Shoseyov

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhib...

  12. Investigation of the physico-mechanical properties of electrospun PVDF/cellulose nanofibers.

    OpenAIRE

    Issa, A. A. [احمد عبد السلام عيسى; Al-Maadeed, M.; Luyt,A.S.; Mrlik, M.; Hassan, M. K.

    2016-01-01

    The electro-activity and mechanical properties of PVDF depends mainly on the b-phase content and degree of crystallinity. In this study, cellulose fibers were used to improve these characteristics. This could be achieved because the hydroxyl groups on cellulose would force the fluorine atoms in PVDF to be in the trans-conformation, and the cellulose particles could act as nucleation centers. Electrospinning was used to prepare the PVDF/cellulose (nano)fibrous films, and this improved the tota...

  13. Synthesis of TiO₂-loaded Co0.85Se thin films with heterostructure and their enhanced catalytic activity for p-nitrophenol reduction and hydrazine hydrate decomposition.

    Science.gov (United States)

    Zuo, Yong; Song, Ji-Ming; Niu, He-Lin; Mao, Chang-Jie; Zhang, Sheng-Yi; Shen, Yu-Hua

    2016-04-08

    P-nitrophenol (4-NP) and hydrazine hydrate are considered to be highly toxic pollutants in wastewater, and it is of great importance to remove them. Herein, TiO2-loaded Co0.85Se thin films with heterostructure were successfully synthesized by a hydrothermal route. The as-synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy and selective-area electron diffraction. The results demonstrate that TiO2 nanoparticles with a size of about 10 nm are easily loaded on the surface of graphene-like Co0.85Se nanofilms, and the NH3 · H2O plays an important role in the generation and crystallization of TiO2 nanoparticles. Brunauer-Emmett-Teller measurement shows that the obtained nanocomposites have a larger specific surface area (199.3 m(2) g(-1)) than that of Co0.85Se nanofilms (55.17 m(2) g(-1)) and TiO2 nanoparticles (19.49 m(2) g(-1)). The catalytic tests indicate Co0.85Se-TiO2 nanofilms have the highest activity for 4-NP reduction and hydrazine hydrate decomposition within 10 min and 8 min, respectively, compared with the corresponding precursor Co0.85Se nanofilms and TiO2 nanoparticles. The enhanced catalytic performance can be attributed to the larger specific surface area and higher rate of interfacial charge transfer in the heterojunction than that of the single components. In addition, recycling tests show that the as-synthesized sample presents stable conversion efficiency for 4-NP reduction.

  14. Synthesis of TiO2-loaded Co0.85Se thin films with heterostructure and their enhanced catalytic activity for p-nitrophenol reduction and hydrazine hydrate decomposition

    Science.gov (United States)

    Zuo, Yong; Song, Ji-Ming; Niu, He-Lin; Mao, Chang-Jie; Zhang, Sheng-Yi; Shen, Yu-Hua

    2016-04-01

    P-nitrophenol (4-NP) and hydrazine hydrate are considered to be highly toxic pollutants in wastewater, and it is of great importance to remove them. Herein, TiO2-loaded Co0.85Se thin films with heterostructure were successfully synthesized by a hydrothermal route. The as-synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy and selective-area electron diffraction. The results demonstrate that TiO2 nanoparticles with a size of about 10 nm are easily loaded on the surface of graphene-like Co0.85Se nanofilms, and the NH3 · H2O plays an important role in the generation and crystallization of TiO2 nanoparticles. Brunauer-Emmett-Teller measurement shows that the obtained nanocomposites have a larger specific surface area (199.3 m2 g-1) than that of Co0.85Se nanofilms (55.17 m2 g-1) and TiO2 nanoparticles (19.49 m2 g-1). The catalytic tests indicate Co0.85Se-TiO2 nanofilms have the highest activity for 4-NP reduction and hydrazine hydrate decomposition within 10 min and 8 min, respectively, compared with the corresponding precursor Co0.85Se nanofilms and TiO2 nanoparticles. The enhanced catalytic performance can be attributed to the larger specific surface area and higher rate of interfacial charge transfer in the heterojunction than that of the single components. In addition, recycling tests show that the as-synthesized sample presents stable conversion efficiency for 4-NP reduction.

  15. An Investigation into the Properties and Microstructure of Cement Mixtures Modified with Cellulose Nanocrystal

    Science.gov (United States)

    Flores, Jessica; Kamali, Mahsa; Ghahremaninezhad, Ali

    2017-01-01

    This paper aims to examine the effect of cellulose nanocrystals (CNC) on the hydration, transport behavior, and microstructure of cement mixtures. The addition of CNC delayed hydration at an early age but improved hydration at later ages. A small increase in the electrical resistivity of the cement mixtures with CNC was observed. Statistical nanoindentation showed a small tendency to a larger volume fraction of high density calcium-silicate-hydrate (C-S-H) and a smaller volume fraction of low-density C-S-H in the mixture with CNC. PMID:28772857

  16. Origins of hydration lubrication.

    Science.gov (United States)

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob

    2015-01-14

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication.

  17. Electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  18. 玉米秸秆微晶纤维素/聚乳酸复合膜的制备与性能%Preparation and properties of corn stalks cellulose microcrystal reinforced poly(lactic acid) composite film

    Institute of Scientific and Technical Information of China (English)

    李春光; 徐鹏飞; 李云霞; 王彦秋; 林鹏; 张锐

    2011-01-01

    The biodegradable composite films were prepared from corn stalks cellulose microcrystal(CSCMC) as the filler and poly(lactic acid)(PLA) as the polymeric matrix.The crystallinity,the tensile properties and the thermal properties of the composite flim were tested.The results show that the tensile properties and the thermal properties of the CSCMC/PLA composite were improved by the addition of corn stalks cellulose microcrystal.When the mass fraction of CSCMC is 10%,the initial decomposition temperature increases by 34.38℃,the tensile strength increases by 58.3% and the elongation at break increases by 31.1% compared to that of the pure PLA.%采用玉米秸秆微晶纤维素(CSCMC)作为增强材料,生物可降解材料聚乳酸(PLA)作为基体,制备了CSCMC/PLA复合膜材料,并对复合膜的结晶度、热稳定性能、力学性能进行了测试。结果表明,复合膜材料的热稳定性能和力学性能优于纯聚乳酸膜。当CSCMC的质量分数为10%时,复合膜的热稳定性能和力学性能达到最佳,与纯PLA膜相比,起始分解温度提高了34.38℃,拉伸强度提高了58.3%,断裂伸长率提高了31.1%。

  19. Hydration Assessment of Athletes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ KEY POINTS · Although there is no scientific consensus for 1 ) howbest to assess the hydration status of athletes, 2)what criteria to use as acceptable outcome measurements, or 3) the best time to apply practical assessment methods, there are methods that can be used toprovide athletes with useful feedback about their hydration status

  20. Cellulose nanofibrils improve the properties of all-cellulose composites by the nano-reinforcement mechanism and nanofibril-induced crystallization

    Science.gov (United States)

    Yang, Quanling; Saito, Tsuguyuki; Berglund, Lars A.; Isogai, Akira

    2015-10-01

    All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials.All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials. Electronic supplementary information (ESI) available: Fig. S1-S3 show an AFM image of TOCN, SEM

  1. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications.

    Science.gov (United States)

    H P S, Abdul Khalil; Saurabh, Chaturbhuj K; A S, Adnan; Nurul Fazita, M R; Syakir, M I; Davoudpour, Y; Rafatullah, M; Abdullah, C K; M Haafiz, M K; Dungani, R

    2016-10-01

    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications.

  2. Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Josefsson, Gabriella; Gamstedt, E. Kristofer [The Ångström Laboratory, Department of Engineering Sciences, Division of Applied Mechanics, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Ahvenainen, Patrik [Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 University of Helsinki (Finland); Mushi, Ngesa Ezekiel [Department of Fiber and Polymer Technology, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden)

    2015-06-07

    The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils.

  3. Preparation and Characterization of Cellulose Nanofibers from Two Commercial Hardwood and Softwood Pulps

    DEFF Research Database (Denmark)

    Stelte, Wolfgang; Sanadi, Anand R.

    2009-01-01

    The aim of this work was to study the mechanical fibrillation process for the preparation of cellulose nanofibers from two commercial hard- and softwood cellulose pulps. The process consisted of initial refining and subsequent high-pressure homogenization. The progress in fibrillation was studied...... using different microscopy techniques, mechanical testing, and fiber density measurements of cellulose films prepared after different processing stages. The mechanical properties of cellulose films showed an increase in strength and stiffness with decreasing fiber size, and this stabilized after...... a certain number of passes in the homogenizer. Atomic force microscopy studies showed that the obtained cellulose nanofibers had diameters in the 10−25-nm range. The significant difference between the two samples was that the ultimate failure strain for cellulose films made of softwood fibers increased...

  4. Light Transmittance Study on Cellulose Nanofibers/Epoxy Resin Composite Film%纤维素纳米纤丝/环氧树脂复合薄膜的透光性研究

    Institute of Scientific and Technical Information of China (English)

    潘佳; 李大纲; 邓巧云; 林东亮; 王玉梅

    2012-01-01

    对杨木木粉进行酸碱处理后得到纯纤维素溶液,之后通过超声和研磨均质两种方法对纤维素进行机械开纤处理,得到两种不同尺寸的纤维素纤丝溶液.通过场发射扫描电镜观察,超声后的纤维素纤丝的直径分布在200~ 250nm,研磨均质后的纤维素纤丝直径主要分布在20~100 nm.由于纤维素纤维直径的细化,研磨均质后的纯纤维素薄膜的透光率高于超声后的,并且比普通打印纸提高近四倍.浸渍环氧树脂的复合薄膜也随着纤维素纳米纤丝直径减小,透光率提高,研磨均质后的复合薄膜透光率相比纯环氧树脂,仅损失3%.这表明研磨均质的纤维素纳米纤丝增强环氧树脂薄膜可以作为高透明性材料使用.%The poplar wood powder was treated to be the cellulose solution by the acid and alkali agents, then the ultrasound and grind and homogenization methods were used to separate the wood fiber to cellulose nanofibers( CNFs)in different sizes. The FE-SEM images revealed that the diameter distribution of CNFs by the ultrasound was in 200- 250 nm, and that by the grind and homogenization was in 20- 100 nm. Because of the decrease of the CNFs' diameter, the light transmittance of the CNFs film by the grind and homogenization was higher than that by the ultrasound, and it was nearly 4 times compared with that of the normal paper. The light transmittance of the CNFs-reinforced epoxy composite was increased when the CNFs' diameter decreased, and the light transmittance was just lost 3% after the CNFs film by the grind and homogenization dipped into the epoxy resin. These data showed that the CNFs-reinforced epoxy composite can used to be the high transparency materials.

  5. Behavior of freezable bound water in the bacterial cellulose produced by Acetobacter xylinum: an approach using thermoporosimetry.

    Science.gov (United States)

    Kaewnopparat, Sanae; Sansernluk, Kamonlawat; Faroongsarng, Damrongsak

    2008-01-01

    The aim of the study is to examine thermal behavior of water within reticulated structure of bacterial cellulose (BC) films by sub-ambient differential scanning calorimetry (DSC). BC films with different carbon source, either manitol (BC (a)) or glycerol (BC (b)), were produced by Acetobacter xylinum using Hestrin and Shramm culture medium under static condition at 30 +/- 0.2 degrees C for 3 days. BC samples were characterized by electron scanning microscopy and X-ray diffraction spectroscopy. The pore analysis was done by B.H.J. nitrogen adsorption. The pre-treated with 100% relative humidity, at 30.0 +/- 0.2 degrees C for 7 days samples were subjected to a between 25 and -150 degrees C-cooling-heating cycle of DSC at 5.00 degrees C/min rate. The pre-treated samples were also hydrated by adding 1 mul of water and thermally run with identical conditions. It is observed that cellulose fibrils of BC (a) were thinner and reticulated to form slightly smaller porosity than those of BC (b). They exhibited slightly but non-significantly different crystalline features. The freezable bound water behaved as a water confinement within pores rather than a solvent of polymer which is possible to use thermoporosimetry based on Gibb-Thomson equation to approach pore structure of BC. In comparison with nitrogen adsorption, it was found that thermoporosimetry underestimated the BC porosity, i.e., the mean diameters of 23.0 nm vs. 27.8 nm and 27.9 nm vs. 33.9 nm for BC (a) and BC (b), respectively, by thermoporosimetry vs. B.H.J. nitrogen adsorption. It may be due to large non-freezable water fraction interacting with cellulose, and the validity of pore range based on thermodynamic assumptions of Gibb-Thomson theory.

  6. Hydration rate of obsidian.

    Science.gov (United States)

    Friedman, I; Long, W

    1976-01-30

    The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years.

  7. Magnetic alignment and patterning of cellulose fibers

    Directory of Open Access Journals (Sweden)

    Fumiko Kimura and Tsunehisa Kimura

    2008-01-01

    Full Text Available The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved

  8. Magnetic alignment and patterning of cellulose fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Fumiko; Kimura, Tsunehisa [Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: tkimura@kais.kyoto-u.ac.jp

    2008-04-01

    The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved.

  9. Application of ultra cellulose fiber for the enhancement of the durability

    OpenAIRE

    Saaid I. Zaki

    2015-01-01

    Ultra Cellulose Fibers are hydrophilic fibers which can hold most of their weight water when it is mixed into concrete, after concrete is hardened, these fibers will slowly release this water to unhydrated cement during the critical early phases of curing which assist in more complete hydration, this internal self curing action results in more completely hydrated cement which contributes to more strength development and more control of internal microcracking, particularly when normal curin...

  10. Solar photocatalytic gas-phase degradation of n-decane--a comparative study using cellulose acetate monoliths coated with P25 or sol-gel TiO₂ films.

    Science.gov (United States)

    Miranda, Sandra M; Lopes, Filipe V S; Rodrigues-Silva, Caio; Martins, Susana D S; Silva, Adrián M T; Faria, Joaquim L; Boaventura, Rui A R; Vilar, Vítor J P

    2015-01-01

    Cellulose acetate monoliths (CAM) were used as the substrate for the deposition of TiO2 films to produce honeycombed photoactive structures to fill a tubular photoreactor equipped with a compound parabolic collector. By using such a setup, an efficient single-pass gas-phase conversion was achieved in the degradation of n-decane, a model volatile organic compound. The CAM three-dimensional, gas-permeable transparent structure with a rugged surface enables a good adhesion of the catalytic coating. It also provides a rigid structure for packing the tubular photoreactor, and maximizing the illuminated catalyst surface. The efficiency of the photocatalytic oxidation (PCO) process on n-decane degradation was evaluated under different operating conditions, such as feeding concentration (73 and 146 ppm), gas stream flow rate (73, 150, and 300 mL min(-1)), relative humidity (3 and 25 %), and UV irradiance (18.9, 29.1, and 38.4 WUV m(-2)). The results show that n-decane degradation by neat photolysis is negligible, but mineralization efficiencies of 86 and 82 % were achieved with P25-CAM and SG-CAM, respectively, for parent pollutant conversions above 95 %, under steady-state conditions. A mass transfer model, considering the mass balance to the plug-flow packed photoreactor, and PCO reaction given by a Langmuir-Hinshelwood bimolecular non-competitive two types of sites equation, was able to predict well the PCO kinetics under steady-state conditions, considering all the operational parameters tested. Overall, the performance of P25-CAM was superior taking into account mineralization efficiency, cost of preparation, surface roughness, and robustness of the deposited film.

  11. Feasibility of e-paper made with cellulose

    Science.gov (United States)

    Yoo, K. H.; Han, K. J.; Chen, Yi; Kang, K. S.; Kim, Jaehwan

    2008-03-01

    Cellulose is a beneficial material that has low cost, light weight, high compatibility, and biodegradability. Recently electro-active paper (EAPap) composed with cellulose was discovered as a smart material for application to variety industrial fields such as smart wall-paper, actuator, and magic carpet. It also exhibited actuator property through ion migration and piezoelectric effect. Since cellulose acetate (CA) film has optically transparent property, we focused on optical field application, such as electronic paper, prismsheet, and polarized film. Since CA can be easily dissolved in variety of organic solvent, various weight % (from 1 to 25 wt. %) of CA solution in acetone was prepared. Polydimethylsilane (PDMS) master pattern was fabricated on the silicone wafer. CA solution was poured to the master mold and dried using spin-coating or tape casting method. Various shape and height patterns, such as circle, honeycomb, and rectangular patterns were fabricated using 12 wt. % CA solution. The resulting pattern showed uniform size in the large area without defect. These patterns can be utilized as a substrate and cell pattern for the electronic paper. To investigate saponification (SA) effect to convert CA to regenerated cellulose, CA film was immersed into the sodium methoxide solution in methanol for various times. The fabricated CA films were stretched and immersed into the sodium methoxide solution in methanol to desubstitute the acetate group. These regenerated cellulose films have larger mechanical strength than CA films. Although the UV-visible transmittance was decreased as increasing SA time, the transmittance of the further SA process and stretched film backed up near untreated CA film. Although the cross-sectional image of the saponified and unstretched CA film did not have specific directional structure, the cross-sectional FESEM image of the saponified and stretched CA film had one directional fiber structure. The fiber was aligned to the stretched

  12. Hydrate morphology: Physical properties of sands with patchy hydrate saturation

    Science.gov (United States)

    Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

    2012-01-01

    The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

  13. Wet hydrate dissolution plant

    OpenAIRE

    Stanković Mirjana S.; Kovačević Branimir T.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with capacity of 50,000 t/y was manufactured, at "Zeolite Mira", Mira (VE), Italy, in 1997, for increasing detergent zeolite production from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate ...

  14. Cellulose Degradation by Cellulose-Clearing and Non-Cellulose-Clearing Brown-Rot Fungi

    OpenAIRE

    Highley, Terry L.

    1980-01-01

    Cellulose degradation by four cellulose-clearing brown-rot fungi in the Coniophoraceae—Coniophora prasinoides, C. puteana, Leucogyrophana arizonica, and L. olivascens—is compared with that of a non-cellulose-clearing brown-rot fungus, Poria placenta. The cellulose- and the non-cellulose-clearing brown-rot fungi apparently employ similar mechanisms to depolymerize cellulose; most likely a nonenzymatic mechanism is involved.

  15. Cellulose binding domain proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  16. Bacterial cellulose-lactoferrin as an antimicrobial edible packaging

    OpenAIRE

    Padrão, Jorge; S. Gonçalves; Silva, João P.; Sencadas, Vítor João Gomes Silva; Lanceros-Méndez, S.; A. C. Pinheiro; Vicente, A.A.; RODRIGUES, L. R.; Dourado, Fernando

    2016-01-01

    Bacterial cellulose (BC) films from two distinct sources (obtained by static culture with Gluconacetobacter xylinus ATCC 53582 (BC1) and from a commercial source (BC2)) were modified by bovine lactoferrin (bLF) adsorption. The functionalized films (BC+bLF) were assessed as edible antimicrobial packaging, for use in direct contact with highly perishable foods, specifically fresh sausage as a model of meat products. BC+bLF films and sausage casings were characterized regarding their water vapou...

  17. High Performance Regenerated Cellulose Membranes from Trimethylsilyl Cellulose

    KAUST Repository

    Ali, Ola

    2013-05-01

    Regenerated cellulose (RC) membranes are extensively used in medical and pharmaceutical separation processes due to their biocompatibility, low fouling tendency and solvent resistant properties. They typically possess ultrafiltration and microfiltration separation characteristics, but recently, there have been attempts to widen their pool of applications in nanofiltration processes. In this work, a novel method for preparing high performance composite RC membranes was developed. These membranes reveal molecular weight cut-offs (MWCO) of less than 250 daltons, which possibly put them ahead of all commercial RC membranes and in competition with high performance nanofiltration membranes. The membranes were prepared by acidic hydrolysis of dip-coated trimethylsilyl cellulose (TMSC) films. TMSC, with a degree of silylation (DS) of 2.8, was prepared from microcrystalline cellulose by reaction with hexamethyldisilazane under the homogeneous conditions of LiCl/DMAC solvent system. Effects of parameters, such as coating solution concentration and drying rates, were investigated. It was concluded that higher TMSC concentrations as well as higher solvent evaporation rates favor better MWCOs, mainly due to increase in the selective layer thickness. Successful cross-linking of prepared membranes with glyoxal solutions, in the presence of boric acid as a catalyst, resulted in MWCOs less than 250 daltons. The suitability of this crosslinking reaction for large scale productions was already proven in the manufacturing of durable-press fabrics. For us, the inexpensive raw materials as well as the low reaction times and temperatures were of interest. Moreover, the non-toxic nature of glyoxal is a key advantage in medical and pharmaceutical applications. The membranes prepared in this work are strong candidates for separation of small organic solutes from organic solvents streams in pharmaceutical industries. Their hydrophilicity, compared to typical nanofiltration membranes, offer

  18. Characterisation of solution cast cellulose nanofibre – reinforced poly(lactic acid

    Directory of Open Access Journals (Sweden)

    2010-01-01

    Full Text Available Cellulose nanofibres, 20 nm in diameter and 300 nm long, were prepared by acid hydrolysis of flax yarns. Composite films containing 2.5 and 5.0 wt% flax cellulose (FC fibres were prepared by solution casting of mixtures of poly(lactic acid (PLA solution and cellulose nanofibre suspension in chloroform. The resulting composite films and solution cast pure PLA film, with thickness of around 160 m, showed good transparency. For composites with 2.5 and 5.0 wt% FC, the tensile strength increased by 25 and 59% and tensile modulus by 42 and 47%, respectively, compared to pure PLA film. The composite film with 2.5 wt% FC combined high strength and ductility with tensile strength of 24.3 MPa and 70% elongation at break. Flax cellulose appeared to facilitate nucleation and subsequent crystallisation of PLA more effectively in the amorphous composites than in the crystalline composites.

  19. Impact of hydration on the micromechanical properties of the polymer composite structure of wood investigated with atomistic simulations

    Science.gov (United States)

    Kulasinski, Karol; Derome, Dominique; Carmeliet, Jan

    2017-06-01

    A model of the secondary layer of wood cell wall consisting of crystalline cellulose, hemicellulose, and lignin is constructed and investigated with molecular dynamics simulations in the full range of hydration: from dry to saturated state. The model is considered a composite with the cellulose fibrils embedded in hemicellulose and lignin, forming a soft amorphous matrix. Its complex structure leads to nonlinear and anisotropic swelling and mechanical weakening. The water diffusivity through the pores is affected by an interplay between stiff cellulose fibers and weakening amorphous polymers. The formation and breaking of hydrogen bonds within the polymers and at the interfaces is found to be the underlying mechanism of adsorption-induced mechanical softening. The model is tested for adsorption isotherm, mechanical moduli, hydrogen bonds, and water diffusivity that all undergo a substantial change as the hydration increases. The determined physical and mechanical properties, changing with hydration, agree qualitatively with experimental measurements.

  20. Hazy Transparent Cellulose Nanopaper

    Science.gov (United States)

    Hsieh, Ming-Chun; Koga, Hirotaka; Suganuma, Katsuaki; Nogi, Masaya

    2017-01-01

    The aim of this study is to clarify light scattering mechanism of hazy transparent cellulose nanopaper. Clear optical transparent nanopaper consists of 3–15 nm wide cellulose nanofibers, which are obtained by the full nanofibrillation of pulp fibers. At the clear transparent nanopaper with 40 μm thickness, their total transmittance are 89.3–91.5% and haze values are 4.9–11.7%. When the pulp fibers are subjected to weak nanofibrillation, hazy transparent nanopapers are obtained. The hazy transparent nanopaper consists of cellulose nanofibers and some microsized cellulose fibers. At the hazy transparent nanopaper with 40 μm thickness, their total transmittance were constant at 88.6–92.1% but their haze value were 27.3–86.7%. Cellulose nanofibers are solid cylinders, whereas the pulp fibers are hollow cylinders. The hollow shape is retained in the microsized cellulose fibers, but they are compressed flat inside the nanopaper. This compressed cavity causes light scattering by the refractive index difference between air and cellulose. As a result, the nanopaper shows a hazy transparent appearance and exhibits a high thermal durability (295–305 °C), and low thermal expansion (8.5–10.6 ppm/K) because of their high density (1.29–1.55 g/cm3) and crystallinity (73–80%).

  1. Polyethylenimine surface layer for enhanced virus immobilization on cellulose

    Science.gov (United States)

    Tiliket, Ghania; Ladam, Guy; Nguyen, Quang Trong; Lebrun, Laurent

    2016-05-01

    Thin regenerated cellulose films are prepared by hydrolysis of cellulose acetate (CA). A polycation, namely polyethylenimine (PEI), is then adsorbed onto the films. From QCM-D analysis, PEI readily adsorbs from a 0.1% w/v solution in NaCl 0.2 M (ca. 100 ng cm-2). Further PEI adsorption steps at higher PEI concentrations induce a linear growth of the PEI films, suggesting that free adsorption sites still exist after the initial adsorption. The adsorbed PEI chains are resistant to variations of the ionic strength up to NaCl 1 M. Promisingly, the adsorption of T4D bacteriophages are 15-fold more efficient onto the PEI-treated, compared to the native regenerated cellulose films, as measured by QCM-D. This confirms the strong affinity between the negatively charged viruses and PEI, even at low PEI concentration, probably governed by strong electrostatic attractive interactions. This result explains the remarkable improvement of the affinity of medical masks for virus droplets when one of their cellulose layers was changed by two-PEI-functionalized cellulose-based filters.

  2. Hydration Dependence of Energy Relaxation Time for Cytochrome C

    Science.gov (United States)

    Ye, Shuji; Chen, Jing-Yin; Knab, Joseph R.; Markelz, Andrea

    2006-03-01

    Hydration plays a critical role in protein dynamics. Here we consider the effects of hydration on energy relaxation for an electronically excited heme protein cytochrome c. We measure the hydration dependence of energy relaxation time of cytochrome C films after photoexcitation in the Soret regionusing two-color pump/probe time resolved transmission measurements. Thin films were prepared from cytochrome C/ Trizma buffer solutions and mounted in a hydration controlled cell. We used 400nm (˜3 mW) to pump the B band and 800 nm (˜1 mW) to probe the III band. The III band corresponds to the charge-transfer transition between heme π and iron d orbital, and is assigned to the ground electronic state of the heme. Therefore this band can be used to probe the ground state population. Three separate dynamic components were observed: a very fast transient τ1 ˜ 200 fs; a several hundred femtosecond component (τ2); and a recovery of the ground state absorption(τ3). We find τ3 apparently decreases with decreasing hydration while τ1 and τ2 are independent of hydration.

  3. PART II. HYDRATED CEMENTS

    Directory of Open Access Journals (Sweden)

    Milan Drabik

    2014-09-01

    Full Text Available Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - ΔH, of technological materials based on two types of Portland cements. The values of thermoanalytical events and also ΔH of probes of technological compositions, if related with the data of a choice of minerals of calcium-silicate-sulfate-aluminate hydrates, served as a valued input for the assessment of phases present and phase changes due to the topical hydraulic processes. The results indicate mainly the effects of "standard humidity" or "wet storage" of the entire hydration/hydraulic treatment, but also the presence of cement residues alongside calcium-silicate-sulfate-aluminate hydrates (during the tested period of treatment. "A diluting" effect of unhydrated cement residues upon the values of decomposition enthalpies in the studied multiphase system is postulated and discussed

  4. Fulton Cellulosic Ethanol Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Sumait, Necy [BlueFire Ethanol, Irvine, CA (United States); Cuzens, John [BlueFire Ethanol, Irvine, CA (United States); Klann, Richard [BlueFire Ethanol, Irvine, CA (United States)

    2015-07-24

    Final report on work performed by BlueFire on the deployment of acid hydrolysis technology to convert cellulosic waste materials into renewable fuels, power and chemicals in a production facility to be located in Fulton, Mississippi.

  5. State of the Art in the Development and Properties of Protein-Based Films and Coatings and Their Applicability to Cellulose Based Products: An Extensive Review

    Directory of Open Access Journals (Sweden)

    Maria-Beatrice Coltelli

    2015-12-01

    Full Text Available There is increasing research towards the substitution of petrochemicals by sustainable components. Biopolymers such as proteins, polysaccharides, and lipids derive from a variety of crop sources and most promisingly from waste streams generated during their processing by the agro food industry. Among those, proteins of different types such as whey, casein, gelatin, wheat gluten, soy protein or zein present a potential beyond the food and feed industry for the application in packaging. The general protein hydrophilicity promotes a good compatibility to polar surfaces, such as paper, and a good barrier to apolar gases, such as oxygen and carbon dioxide. The present review deals with the development of protein-based coatings and films. It includes relevant discussion for application in paper or board products, as well as an outlook on its future industrial potential. Proteins with suitable functionalities as food packaging materials are described as well as the different technologies for processing the coatings and the current state of the art about the coating formulations for selectively modulating barrier, mechanical, surface and end of life properties. Some insights onto regulations about packaging use, end of life and perspectives of such natural coating for decreasing the environmental impact of packages are given.

  6. Influence of Water on the Structure and Dielectric Properties of the Microcrystalline and Nano-Cellulose

    Science.gov (United States)

    Kovalov, Kostiantyn M.; Alekseev, Olexander M.; Lazarenko, Maxim M.; Zabashta, Yu F.; Grabovskii, Yurii E.; Tkachov, Sergii Yu

    2017-07-01

    Influence of water in the different states on a structure and dielectric properties of microcrystalline cellulose were studied by of X-ray, thermogravimetry, and dielectric spectroscopy. At research of microcrystalline cellulose (MCC) with different content of water, it is shown that the molecules of water are located in the macropores of MCC and in multimolecular hydrated layers. It is shown that at the increase of concentration of water in a hydrated shell, the reorganization of molecules of cellulose in the surface of crystallites takes place, and as a result, their transversal size and crystallinity increase. It is shown that during the concentration of water, more than 13% in a continuous hydrated shell of crystallites appears. Temperature dependences of actual and imaginary parts of complex dielectric permittivity were studied in the interval of temperatures [-180 ÷ 120] °C on frequencies of f = 5, 10, 20, and 50 kHz. A low-temperature relaxation process and high-temperature transition were observed. Low-temperature relaxation process which is related to transition of surface methylol groups of molecules of cellulose conformation from tg to tt is shifted toward low temperatures at the increase of concentration of water in microcrystalline cellulose.

  7. Using ion-selective electrodes to study the drug release from porous cellulose matrices

    DEFF Research Database (Denmark)

    Vakili, Hossein; Genina, Natalja; Ehlers, Henrik;

    2012-01-01

    -polymer solutions were prepared with the model drugs, using different blend ratios of ethylcellulose (EC) and hydroxypropyl cellulose (HPC). Two different solid dosage forms were used. Polymer films were produced by solvent casting method and drug containing porous cellulose samples were prepared by depositing...... method \\r\

  8. Mechanical and microstructural properties of "wet" alginate and composite films containing various carbohydrates.

    Science.gov (United States)

    Harper, B Allison; Barbut, Shai; Smith, Alexandra; Marcone, Massimo F

    2015-01-01

    Composite "wet" alginate films were manufactured from alginate-carbohydrate solutions containing 5% alginate and 0.25% pectin, carrageenan (kappa or iota), potato starch (modified or unmodified), gellan gum, or cellulose (extracted or commercial). The "wet" alginate films were used as a model to understand co-extruded alginate sausage casings that are currently being used by several sausage manufacturers. The mechanical, optical, and microstructural properties of the calcium cross-linked composite films were explored. In addition, the water holding capacity and textural profile analysis properties of the alginate-carbohydrate gels were studied. The results indicate that the mechanical properties of "wet" alginate films/casings can be modified by adding various carbohydrates to them. Alginate films with pectin, carrageenan, and modified potato starch had significantly (P alginate films. The alginate-pectin films also had greater (P alginate films. Alginate films with extracted cellulose, commercial cellulose, and modified potato starch had lower (P alginate control films. Transmission electron microscopy images showed a very uniform alginate network in the control films. Several large cellulose fibers were visible in the films with extracted cellulose, while the cellulose fibers in the films with commercial cellulose were difficult to distinguish. Despite these apparent differences in cellulose fiber length, the 2 cellulose films had similar puncture and tensile properties.

  9. [Hydration in clinical practice].

    Science.gov (United States)

    Maristany, Cleofé Pérez-Portabella; Segurola Gurruchaga, Hegoi

    2011-01-01

    Water is an essential foundation for life, having both a regulatory and structural function. The former results from active and passive participation in all metabolic reactions, and its role in conserving and maintaining body temperature. Structurally speaking it is the major contributer to tissue mass, accounting for 60% of the basis of blood plasma, intracellular and intersticial fluid. Water is also part of the primary structures of life such as genetic material or proteins. Therefore, it is necessary that the nurse makes an early assessment of patients water needs to detect if there are signs of electrolyte imbalance. Dehydration can be a very serious problem, especially in children and the elderly. Dehydrations treatment with oral rehydration solution decreases the risk of developing hydration disorders, but even so, it is recommended to follow preventive measures to reduce the incidence and severity of dehydration. The key to having a proper hydration is prevention. Artificial nutrition encompasses the need for precise calculation of water needs in enteral nutrition as parenteral, so the nurse should be part of this process and use the tools for calculating the patient's requirements. All this helps to ensure an optimal nutritional status in patients at risk. Ethical dilemmas are becoming increasingly common in clinical practice. On the subject of artificial nutrition and hydration, there isn't yet any unanimous agreement regarding hydration as a basic care. It is necessary to take decisions in consensus with the health team, always thinking of the best interests of the patient.

  10. Polysaccharide Thin Films – Buildup and Hydration

    Science.gov (United States)

    Plating, painting and the application of enamel are common anti-corrosion treatments by providing a barrier of resistant material between the damaging environment and the structural material. Coatings start failing rapidly if scratched or damaged because “pitting” occurs at high rates in cracks or p...

  11. Photoresponsive Cellulose Nanocrystals

    Directory of Open Access Journals (Sweden)

    Dimitris S Argyropoulos

    2011-07-01

    Full Text Available In this communication a method for the creation of fluorescent cellulose nanoparticles using click chemistry and subsequent photodimerization of the installed side‐ chains is demonstrated. In the first step, the primary hydroxyl groups on the surface of the CNCs were converted to carboxylic acids by using TEMPO‐mediated hypohalite oxidation. The alkyne groups, essential for the click reaction, were introduced into the surface of TEMPO‐ oxidized CNCs via carbodiimide‐mediated formation of an amide linkage between monomers carrying an amine functionality and carboxylic acid groups on the surface of the TEMPO‐oxidized CNCs. Finally, the reaction of surface‐modified TEMPO‐oxidized cellulose nanocrystals and azido‐bearing coumarin and anthracene monomers were carried out by means of a click chemistry, i.e., Copper(I‐catalyzed Azide‐Alkyne Cycloaddition (CuAAC to produce highly photo‐responsive and fluorescent cellulose nanoparticles. Most significantly, the installed coumarin and/or anthracene side‐chains were shown to undergo UV‐induced [2+2] and [4+4] cycloaddition reactions, bringing and locking the cellulose nanocrystals together. This effort paves the way towards creating, cellulosic photo responsive nano‐arrays with the potential of photo reversibility since these reactions are known to be reversible at varying wavelengths.

  12. Cellulosic fibril–rubber nanocomposites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2010-06-01

    Full Text Available Cellulose is the most abundant polymer on earth- has emerged as an ideal candidate for providing nanoparticles as reinforcing agents. There is a growing interest in cellulose nanocomposites within the research community and especially...

  13. Acid hydrolysis of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  14. The cellulose resource matrix.

    Science.gov (United States)

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  15. Nanocrystalline cellulose with various contents of sulfate groups.

    Science.gov (United States)

    Voronova, M I; Surov, O V; Zakharov, A G

    2013-10-15

    Properties of films derived from aqueous nanocrystalline cellulose dispersions by water evaporation depend on concentration of sulfate groups. Namely type of thermodestruction and surface morphology change as a function of contents of sulfate groups. Surface roughness increases and water adsorption enhances with increasing sulfate groups content particularly at high relative pressure.

  16. Modeling Hydrates and the Gas Hydrate Markup Language

    Directory of Open Access Journals (Sweden)

    Weihua Wang

    2007-06-01

    Full Text Available Natural gas hydrates, as an important potential fuels, flow assurance hazards, and possible factors initiating the submarine geo-hazard and global climate change, have attracted the interest of scientists all over the world. After two centuries of hydrate research, a great amount of scientific data on gas hydrates has been accumulated. Therefore the means to manage, share, and exchange these data have become an urgent task. At present, metadata (Markup Language is recognized as one of the most efficient ways to facilitate data management, storage, integration, exchange, discovery and retrieval. Therefore the CODATA Gas Hydrate Data Task Group proposed and specified Gas Hydrate Markup Language (GHML as an extensible conceptual metadata model to characterize the features of data on gas hydrate. This article introduces the details of modeling portion of GHML.

  17. Overview: Nucleation of clathrate hydrates

    Science.gov (United States)

    Warrier, Pramod; Khan, M. Naveed; Srivastava, Vishal; Maupin, C. Mark; Koh, Carolyn A.

    2016-12-01

    Molecular level knowledge of nucleation and growth of clathrate hydrates is of importance for advancing fundamental understanding on the nature of water and hydrophobic hydrate formers, and their interactions that result in the formation of ice-like solids at temperatures higher than the ice-point. The stochastic nature and the inability to probe the small length and time scales associated with the nucleation process make it very difficult to experimentally determine the molecular level changes that lead to the nucleation event. Conversely, for this reason, there have been increasing efforts to obtain this information using molecular simulations. Accurate knowledge of how and when hydrate structures nucleate will be tremendously beneficial for the development of sustainable hydrate management strategies in oil and gas flowlines, as well as for their application in energy storage and recovery, gas separation, carbon sequestration, seawater desalination, and refrigeration. This article reviews various aspects of hydrate nucleation. First, properties of supercooled water and ice nucleation are reviewed briefly due to their apparent similarity to hydrates. Hydrate nucleation is then reviewed starting from macroscopic observations as obtained from experiments in laboratories and operations in industries, followed by various hydrate nucleation hypotheses and hydrate nucleation driving force calculations based on the classical nucleation theory. Finally, molecular simulations on hydrate nucleation are discussed in detail followed by potential future research directions.

  18. A study on gas hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Byoung Jae; Jung, Tae Jin; Sunwoo, Don [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1996-12-01

    Sufficient documents were reviewed to understand solid components of water and gaseous hydrocarbon known as gas hydrates, which represent an important potential energy resource of the future. The review provides us with valuable information on crystal structures, kinetics, origin and distribution of gas hydrates. In addition, the review increased our knowledge of exploration and development methods of gas hydrates. Large amounts of methane, the principal component of natural gas, in the form of solid gas hydrate are found mainly offshore in outer continental margin sediment and, to a lesser extent, in polar regions commonly associated with permafrost. Natural gas hydrates are stable in some environments where the hydrostatic pressure exerted by overlying water column is sufficient for hydrate formation and stability. The required high pressures generally restrict gas hydrate to sediments beneath water of approximately 400 m. Higher sediment temperatures at greater subbottom depths destabilize gas hydrates. Based on the pressure- temperature condition, the outer continental margin of East Sea where water depth is deep enough to form gas hydrate is considered to have high potential of gas hydrate accumulations. (author). 56 refs., tabs., figs.

  19. Hybrid nanocomposite based on cellulose and tin oxide: growth, structure, tensile and electrical characteristics

    Directory of Open Access Journals (Sweden)

    Suresha K Mahadeva and Jaehwan Kim

    2011-01-01

    Full Text Available A highly flexible nanocomposite was developed by coating a regenerated cellulose film with a thin layer of tin oxide (SnO2 by liquid-phase deposition. Tin oxide was crystallized in solution and formed nanocrystal coatings on regenerated cellulose. The nanocrystalline layers did not exfoliate from cellulose. Transmission electron microscopy and energy dispersive x-ray spectroscopy suggest that SnO2 was not only deposited over the cellulose surface, but also nucleated and grew inside the cellulose film. Current–voltage characteristics of the nanocomposite revealed that its electrical resistivity decreases with deposition time, with the lowest value obtained for 24 h of deposition. The cellulose–SnO2 hybrid nanocomposite can be used for biodegradable and disposable chemical, humidity and biosensors.

  20. Possibility of cellulose-based electro-active paper energy scavenging transducer.

    Science.gov (United States)

    Abas, Zafar; Kim, Heung Soo; Zhai, Lindong; Kim, Jaehwan; Kim, Joo Hyung

    2014-10-01

    In this paper, a cellulose-based Electro-Active Paper (EAPap) energy scavenging transducer is presented. Cellulose is proven as a smart material, and exhibits piezoelectric effect. Specimens were prepared by coating gold electrodes on both sides of cellulose film. The fabricated specimens were tested by a base excited aluminum cantilever beam at resonant frequency. Different tests were performed with single and multiple parallel connected electrodes coated on the cellulose film. A maximum of 131 mV output voltage was measured, when three electrodes were connected in parallel. It was observed that voltage output increases significantly with the area of electrodes. From these results, it can be concluded that the piezoelectricity of cellulose-based EAPap can be used in energy transduction application.

  1. Development of wet-dry reversible reverse osmosis membrane with high performance from cellulose acetate and cellulose triactate blend

    NARCIS (Netherlands)

    Vasarhelyi, K.; Ronner, J.A.; Mulder, M.H.V.; Smolders, C.A.

    1987-01-01

    Wet-dry reversible membrane were prepared bt a two-step coagulation procedure. A cast film containing a blend of cellulose triacetate as polymers, dioxane and acetone as solvents and maleic acid and methanol as additives was immersed consecutively in two aqueous coagulation baths, the first bath bei

  2. Drilling Gas Hydrates on hydrate Ridge, Oregon continental margin

    Science.gov (United States)

    Trehu, A. M.; Bohrmann, G.; Leg 204 Science Party

    2002-12-01

    During Leg 204, we cored and logged 9 sites on the Oregon continental margin to determine the distribution and concentration of gas hydrates in an accretionary ridge and adjacent slope basin, investigate the mechanisms that transport methane and other gases into the gas hydrate stability zone (GHSZ), and obtain constraints on physical properties of hydrates in situ. A 3D seismic survey conducted in 2000 provided images of potential subsurface fluid conduits and indicated the position of the GHSZ throughout the survey region. After coring the first site, we acquired Logging-While-Drilling (LWD) data at all but one site to provide an overview of downhole physical properties. The LWD data confirmed the general position of key seismic stratigraphic horizons and yielded an initial estimate of hydrate concentration through the proxy of in situ electrical resistivity. These records proved to be of great value in planning subsequent coring. The second new hydrate proxy to be tested was infrared thermal imaging of cores on the catwalk as rapidly as possible after retrieval. The thermal images were used to identify hydrate samples and to estimate the distribution and texture of hydrate within the cores. Geochemical analyses of interstitial waters and of headspace and void gases provide additional information on the distribution and concentration of hydrate within the stability zone, the origin and pathway of fluids into and through the GHSZ, and the rates at which gas hydrate is forming. Bio- and lithostratigraphic description of cores, measurement of physical properties, and in situ pressure core sampling and thermal measurements complement the data set, providing ground-truth tests of inferred physical and sedimentological properties. Among the most interesting preliminary results are: 1) that gas hydrates are distributed through a broad depth range within the GHSZ and that different physical and chemical proxies for hydrate distribution and concentration give generally

  3. Rapid gas hydrate formation process

    Science.gov (United States)

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  4. CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE

    Institute of Scientific and Technical Information of China (English)

    Yun Chen; Xiao-peng Xiong; Guang Yang; Li-na Zhang; Sen-lin Lei; Hui Lianga

    2002-01-01

    A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzedin 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree ofsubstitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration,Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differentialscanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes wasslightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability weresignificantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept thegood pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity andthermostability. Therefore, the application range of cellulose acetate membranes can be expanded.

  5. The cellulose resource matrix

    NARCIS (Netherlands)

    Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G.

    2013-01-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where

  6. Calculating cellulose diffraction patterns

    Science.gov (United States)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  7. The cellulose resource matrix

    NARCIS (Netherlands)

    Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G.

    2013-01-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where

  8. Preparation of High Quality Indium Tin Oxide Film on a Microbial Cellulose Membrane Using Radio Frequency Magnetron Sputtering%采用磁控溅射法在细菌纤维素膜上制备高性能的铟锡氧化物薄膜

    Institute of Scientific and Technical Information of China (English)

    杨加志; 赵成刚; 刘晓丽; 于俊伟; 孙东平; 唐卫华

    2011-01-01

    Microbial cellulose (MC) membranes produced by Acetobacterxylinumn NUST4.1, were used as flexible substrates for the fabrication of transparent indium tin oxide (ITO) electrodes. Transparent and conductive ITO thin films were deposited on MC membrane at room temperature using radio frequency (RF) magnetron sputtering. The optimum ITO deposition conditions were achieved by examining crystalline structure, surface morphology and optoelectrical characteristics with X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV spectroscopy. The sheet resistance of the samples was measured with a four-point probe and the resistivity of the film was calculated. The results reveal that the preferred orientation of the deposited ITO crystals is strongly dependent upon with oxygen content (O2/Ar, volume ratio) in the sputtering chamber. And the ITO crystalline structure directly determines the conductivity of ITO-deposited films. High conductive [sheet resistance -120 Ω·square-1 (Ω·sq-1)] and transparent (above 76%) ITO thin films (240 nm thick) were obtained with a moderate sputtering power (about 60 W) and with an oxygen flow rate of 0.25 ml.min-1(sccm) during the deposition. These results show that the ITO-MC electrodes can find their potential application in optoelectrical devices.

  9. 13C MAS NMR studies of the effects of hydration on the cell walls of potatoes and Chinese water chestnuts.

    Science.gov (United States)

    Tang, H; Belton, P S; Ng, A; Ryden, P

    1999-02-01

    13C NMR with magic angle spinning (MAS) has been employed to investigate the cell walls of potatoes and Chinese water chestnuts over a range of hydration levels. Both single-pulse excitation (SPEMAS) and cross-polarization (CPMAS) experiments were carried out. Hydration led to a substantial increase in signal intensities of galactan and galacturonan in the SPEMAS spectra and a decrease in line width, implying mobilization in the backbone and side chains of pectin. In CPMAS spectra of both samples, noncellulose components showed signal loss as hydration increased. However, the signals of some galacturonan in the 3(1) helix configuration remained in the spectra even when the water content was as high as 110%. Cellulose was unaffected. It is concluded that the pectic polysaccharides experience a distribution of molecular conformations and mobility, whereas cellulose remained as typical rigid solid.

  10. Effect of the hydration state of supports before lyophilization on subtilisin-A activity in organic media.

    Science.gov (United States)

    Kim, J; Kim, B G

    1996-06-20

    Subtilisin-A was colyophilized with various types of support materials, such as Amberlite IRC-50, Celite545, chitosan, DEAE-cellulose, DOWEX-1, zeolite, glass bead, and polystyrene. The colyophilized enzyme was used for the optical resolution of racemic 1-phenylethylamine with 2,2,2-trifluoroethylbutyrate in 3-methyl-3-pentanol. The enzyme activity in organic media changed dramatically according to the hydration state of the support materials before lyophilization. This effect was especially marked with supports of high water capacity (aquaphilicity), such as chitosan and DEAE-cellulose. By hydrating these supports of high aquaphilicity prior to lyophilization, subtilisin-A activity in organic media increased ca. 4-8 times, depending upon the supports used. This result suggests that the hydration state of aquaphilic support materials for colyophilization is critical to determining enzyme activity in organic solvents.

  11. FORMULATION AND EVALUATION OF FAST DISSOLVING FILMS OF ZOLMITRIPTAN

    OpenAIRE

    2012-01-01

    The present study was aimed to formulate and evaluate fast dissolving films of Zolmitriptan using hydroxyl propyl methyl cellulose. 5-HT1B and 5-HT1D antagonist which is an antimigraine. Hydroxyl propyl methyl cellulose is used as film forming agent. Fast dissolving films are meant to be dissolved in saliva and remain in oral cavity until swallowed. Hence taste masking becomes critically important. The films are prepared by solvent evaporation method and characterized by UV, FTIR studies. The...

  12. Hydration and physical performance.

    Science.gov (United States)

    Murray, Bob

    2007-10-01

    There is a rich scientific literature regarding hydration status and physical function that began in the late 1800s, although the relationship was likely apparent centuries before that. A decrease in body water from normal levels (often referred to as dehydration or hypohydration) provokes changes in cardiovascular, thermoregulatory, metabolic, and central nervous function that become increasingly greater as dehydration worsens. Similarly, performance impairment often reported with modest dehydration (e.g., -2% body mass) is also exacerbated by greater fluid loss. Dehydration during physical activity in the heat provokes greater performance decrements than similar activity in cooler conditions, a difference thought to be due, at least in part, to greater cardiovascular and thermoregulatory strain associated with heat exposure. There is little doubt that performance during prolonged, continuous exercise in the heat is impaired by levels of dehydration >or= -2% body mass, and there is some evidence that lower levels of dehydration can also impair performance even during relatively short-duration, intermittent exercise. Although additional research is needed to more fully understand low-level dehydration's effects on physical performance, one can generalize that when performance is at stake, it is better to be well-hydrated than dehydrated. This generalization holds true in the occupational, military, and sports settings.

  13. Ductile flow of methane hydrate

    Science.gov (United States)

    Durham, W.B.; Stern, L.A.; Kirby, S.H.

    2003-01-01

    Compressional creep tests (i.e., constant applied stress) conducted on pure, polycrystalline methane hydrate over the temperature range 260-287 K and confining pressures of 50-100 MPa show this material to be extraordinarily strong compared to other icy compounds. The contrast with hexagonal water ice, sometimes used as a proxy for gas hydrate properties, is impressive: over the thermal range where both are solid, methane hydrate is as much as 40 times stronger than ice at a given strain rate. The specific mechanical response of naturally occurring methane hydrate in sediments to environmental changes is expected to be dependent on the distribution of the hydrate phase within the formation - whether arranged structurally between and (or) cementing sediments grains versus passively in pore space within a sediment framework. If hydrate is in the former mode, the very high strength of methane hydrate implies a significantly greater strain-energy release upon decomposition and subsequent failure of hydrate-cemented formations than previously expected.

  14. Some thermodynamical aspects of protein hydration water

    Energy Technology Data Exchange (ETDEWEB)

    Mallamace, Francesco, E-mail: francesco.mallamace@unime.it [Dipartimento di Fisica e Scienze della Terra, Università di Messina and CNISM, I-98168 Messina (Italy); Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Corsaro, Carmelo [Dipartimento di Fisica e Scienze della Terra, Università di Messina and CNISM, I-98168 Messina (Italy); CNR-IPCF, Viale F. Stagno D’Alcontres 37, I-98158 Messina (Italy); Mallamace, Domenico [Dipartimento SASTAS, Università di Messina, I-98166 Messina (Italy); Vasi, Sebastiano [Dipartimento di Fisica e Scienze della Terra, Università di Messina and CNISM, I-98168 Messina (Italy); Vasi, Cirino [CNR-IPCF, Viale F. Stagno D’Alcontres 37, I-98158 Messina (Italy); Stanley, H. Eugene [Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Chen, Sow-Hsin [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-06-07

    We study by means of nuclear magnetic resonance the self-diffusion of protein hydration water at different hydration levels across a large temperature range that includes the deeply supercooled regime. Starting with a single hydration shell (h = 0.3), we consider different hydrations up to h = 0.65. Our experimental evidence indicates that two phenomena play a significant role in the dynamics of protein hydration water: (i) the measured fragile-to-strong dynamic crossover temperature is unaffected by the hydration level and (ii) the first hydration shell remains liquid at all hydrations, even at the lowest temperature.

  15. Cellulose Isolation Methodology for NMR Analysis of Cellulose Ultrastructure

    Directory of Open Access Journals (Sweden)

    Art J. Ragauskas

    2011-11-01

    Full Text Available In order to obtain accurate information about the ultrastructure of cellulose from native biomass by 13C cross polarization magic angle spinning (CP/MAS NMR spectroscopy the cellulose component must be isolated due to overlapping resonances from both lignin and hemicellulose. Typically, cellulose isolation has been achieved via holocellulose pulping to remove lignin followed by an acid hydrolysis procedure to remove the hemicellulose components. Using 13C CP/MAS NMR and non-linear line-fitting of the cellulose C4 region, it was observed that the standard acid hydrolysis procedure caused an apparent increase in crystallinity of ~10% or less on the cellulose isolated from Populus holocellulose. We have examined the effect of the cellulose isolation method, particularly the acid treatment time for hemicellulose removal, on cellulose ultrastructural characteristics by studying these effects on cotton, microcrystalline cellulose (MCC and holocellulose pulped Populus. 13C CP/MAS NMR of MCC indicated that holocellulose pulping and acid hydrolysis has little effect on the crystalline ultrastructural components of cellulose. Although any chemical method to isolate cellulose from native biomass will invariably alter substrate characteristics, especially those related to regions accessible to solvents, we found those changes to be minimal and consistent in samples of typical crystallinity and lignin/hemicellulose content. Based on the rate of the hemicellulose removal, as determined by HPLC-carbohydrate analysis and magnitude of cellulose ultrastructural alteration, the most suitable cellulose isolation methodology utilizes a treatment of 2.5 M HCl at 100 °C for a standard residence time between 1.5 and 4 h. However, for the most accurate crystallinity results this residence time should be determined empirically for a particular sample.

  16. Flow assurance intervention, hydrates remediation

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, Christopher S. [Oceaneering International Inc., Houston, TX (United States)

    2012-07-01

    This paper addresses the issues of removing hydrates in sub sea flow lines and associated equipment with an Remotely Operated Vehicle (ROV) of opportunity and a multi-service-vessel (MSV). The paper is split into three topics: the equipment used with the ROV, assessing the interface points and handling fluids produced from drawing down the pressure. Each section is explained thoroughly and backed up with real world experience. The equipment section details information from actual jobs performed and why the particular components were utilized. The system is generally contained in an ROV mounted skid. Pumps are utilized to draw down the pressure inside the hydrated section of equipment, removing one of the three necessary components for hydrates formation. Once the section is pumped down, several options exist for handling the fluids pumped out of the system: pumping to surface, re-injection into the well, or injection into an operating flow line. This method of hydrates remediation is both economical and timely. Hydrate blockages form in low temperatures and high pressures. Reducing the pressure or increasing the temperature so the conditions lie to the right of the hydrate dissociation curve will slowly decompose the blockage. Depressurization and the use of MEG or methanol will give favorable conditions to remove the hydrate plug. Oceaneering has the capabilities to remove hydrates using the FRS in conjunction with an installation vessel to dispose of the gas and fluid removed from the flow line. Hydrate remediation techniques should be implemented into the initial design to reduce costs later. The cost of stopped production combined with the day rate for equipment needed for hydrate removal outweighs the costs if no technique is utilized. (author)

  17. Enhanced enzymatic hydrolysis of cellulose in microgels.

    Science.gov (United States)

    Chang, Aiping; Wu, Qingshi; Xu, Wenting; Xie, Jianda; Wu, Weitai

    2015-07-04

    A cellulose-based microgel, where an individual microgel contains approximately one cellulose chain on average, is synthesized via free radical polymerization of a difunctional small-molecule N,N'-methylenebisacrylamide in cellulose solution. This microgelation leads to a low-ordered cellulose, favoring enzymatic hydrolysis of cellulose to generate glucose.

  18. Investigation on Gas Storage in Methane Hydrate

    Institute of Scientific and Technical Information of China (English)

    Zhigao Sun; Rongsheng Ma; Shuanshi Fan; Kaihua Guo; Ruzhu Wang

    2004-01-01

    The effect of additives (anionic surfactant sodium dodecyl sulfate (SDS), nonionic surfactant alkyl polysaccharide glycoside (APG), and liquid hydrocarbon cyclopentane (CP)) on hydrate induction time and formation rate, and storage capacity was studied in this work. Micelle surfactant solutions were found to reduce hydrate induction time, increase methane hydrate formation rate and improve methane storage capacity in hydrates. In the presence of surfactant, hydrate could form quickly in a quiescent system and the energy costs of hydrate formation were reduced. The critical micelle concentrations of SDS and APG water solutions were found to be 300× 10-6 and 500× 10-6 for methane hydrate formation system respectively. The effect of anionic surfactant (SDS) on methane storage in hydrates is more pronounced compared to a nonionic surfactant (APG). CP also reduced hydrate induction time and improved hydrate formation rate, but could not improve methane storage in hydrates.

  19. Atomic-scale modeling of cellulose nanocrystals

    Science.gov (United States)

    Wu, Xiawa

    Cellulose nanocrystals (CNCs), the most abundant nanomaterials in nature, are recognized as one of the most promising candidates to meet the growing demand of green, bio-degradable and sustainable nanomaterials for future applications. CNCs draw significant interest due to their high axial elasticity and low density-elasticity ratio, both of which are extensively researched over the years. In spite of the great potential of CNCs as functional nanoparticles for nanocomposite materials, a fundamental understanding of CNC properties and their role in composite property enhancement is not available. In this work, CNCs are studied using molecular dynamics simulation method to predict their material' behaviors in the nanoscale. (a) Mechanical properties include tensile deformation in the elastic and plastic regions using molecular mechanics, molecular dynamics and nanoindentation methods. This allows comparisons between the methods and closer connectivity to experimental measurement techniques. The elastic moduli in the axial and transverse directions are obtained and the results are found to be in good agreement with previous research. The ultimate properties in plastic deformation are reported for the first time and failure mechanism are analyzed in details. (b) The thermal expansion of CNC crystals and films are studied. It is proposed that CNC film thermal expansion is due primarily to single crystal expansion and CNC-CNC interfacial motion. The relative contributions of inter- and intra-crystal responses to heating are explored. (c) Friction at cellulose-CNCs and diamond-CNCs interfaces is studied. The effects of sliding velocity, normal load, and relative angle between sliding surfaces are predicted. The Cellulose-CNC model is analyzed in terms of hydrogen bonding effect, and the diamond-CNC model compliments some of the discussion of the previous model. In summary, CNC's material properties and molecular models are both studied in this research, contributing to

  20. Property evaluations of dry-cast reconstituted bacterial cellulose/tamarind xyloglucan biocomposites.

    Science.gov (United States)

    de Souza, Clayton F; Lucyszyn, Neoli; Woehl, Marco A; Riegel-Vidotti, Izabel C; Borsali, Redouane; Sierakowski, Maria Rita

    2013-03-01

    We describe the mechanical defibrillation of bacterial cellulose (BC) followed by the dry-cast generation of reconstituted BC films (RBC). Xyloglucan (XGT), extracted from tamarind seeds, was incorporated into the defibrillated cellulose at various compositions, and new films were created using the same process. Microscopy and contact angle analyses of films revealed an increase in the microfibre adhesion, a reduced polydispersity in the diameters of the microfibrils and increased hydrophobic behaviour as a function of %XGT. X-ray diffraction analysis revealed changes to the crystallographic planes of the RBC and the biocomposite films with preferential orientation along the (110) plane. Compared with BC, RBC/XGT biocomposite with 10% XGT exhibited improvement in its thermal properties and in Young's modulus. These results indicated a reorganisation of the microfibres with mechanical treatment, which when combined with hydrocolloids, can create cellulose-based materials that could be applied as scaffolding for tissue engineering and drug release.

  1. Manufacturing of robust natural fiber preforms utilizing bacterial cellulose as binder.

    Science.gov (United States)

    Lee, Koon-Yang; Shamsuddin, Siti Rosminah; Fortea-Verdejo, Marta; Bismarck, Alexander

    2014-05-22

    A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, holding the loose natural fibers together. Our method is specially suited for the manufacturing of rigid and robust preforms of hydrophilic fibers. The porous and hydrophilic nature of such fibers results in significant water uptake, drawing in the bacterial cellulose dispersed in the suspension. The bacterial cellulose will then be filtered against the surface of these fibers, forming a bacterial cellulose coating. When the loose fiber-bacterial cellulose suspension is filtered and dried, the adjacent bacterial cellulose forms a network and hornified to hold the otherwise loose fibers together. The introduction of bacterial cellulose into the preform resulted in a significant increase of the mechanical properties of the fiber preforms. This can be attributed to the high stiffness and strength of the bacterial cellulose network. With this preform, renewable high performance hierarchical composites can also be manufactured by using conventional composite production methods, such as resin film infusion (RFI) or resin transfer molding (RTM). Here, we also describe the manufacturing of renewable hierarchical composites using double bag vacuum assisted resin infusion.

  2. Hydration-controlled bacterial motility and dispersal on surfaces

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Wang, G.; Gulez, Gamze

    2010-01-01

    hydrated habitats, where water dynamics result in fragmented aquatic habitats connected by micrometric films, is debated. Here, we quantify the spatial dynamics of Pseudomonas putida KT2440 and its nonflagellated isogenic mutant as affected by the hydration status of a rough porous surface using......Flagellar motility, a mode of active motion shared by many prokaryotic species, is recognized as a key mechanism enabling population dispersal and resource acquisition in microbial communities living in marine, freshwater, and other liquid-replete habitats. By contrast, its role in variably...... an experimental system that mimics aquatic habitats found in unsaturated soils. The flagellar motility of the model soil bacterium decreased sharply within a small range of water potential (0 to −2 kPa) and nearly ceased in liquid films of effective thickness smaller than 1.5 μm. However, bacteria could rapidly...

  3. Biocomposites reinforced with cellulose nanocrystals derived from potato peel waste.

    Science.gov (United States)

    Chen, D; Lawton, D; Thompson, M R; Liu, Q

    2012-09-01

    This study investigated the effectiveness of cellulose nanocrystals derived from potato peel waste as a reinforcement and vapor barrier additive. The nanocrystals were derived from cellulosic material in the potato peel by alkali treatment and subsequently acid hydrolysis. TEM images revealed the average fiber length of the nanocrystals was 410 nm with an aspect ratio of 41; its aspect ratio being considerably larger than cotton-derived nanocrystals prepared using similar reaction conditions. Cellulose nanocrystals (CNC)-filled polyvinyl alcohol (PVA) and thermoplastic starch (TPS) films were prepared by solution casting method to maintain uniform dispersion of the 1-2% (w/w) filler content. An increase of 19% and 33% (starch composite) and 38% and 49% (PVA composite) in tensile modulus was observed for the 1% and 2% CNC-reinforced composites, respectively. Water vapor transmission measurements showed a marginal reduction of water permeability for the PVA composite, whereas no effect was observed for the thermoplastic starch composite.

  4. Synthesis of cellulose methylcarbonate in ionic liquids using dimethylcarbonate.

    Science.gov (United States)

    Labafzadeh, Sara R; Helminen, K Juhani; Kilpeläinen, Ilkka; King, Alistair W T

    2015-01-01

    Dialkylcarbonates are viewed as low-cost, low-toxicity reagents, finding application in many areas of green chemistry. Homogeneous alkoxycarbonylation of cellulose was accomplished by applying dialkycarbonates (dimethyl and diethyl carbonate) in the ionic liquid-electrolyte trioctylphosphonium acetate ([P8881 ][OAc])/DMSO or 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). Cellulose dialkylcarbonates with a moderate degree of substitution (DS∼1) are accessible via this procedure and cellulose methylcarbonate was thoroughly characterized for its chemical and physical properties after regeneration. This included HSQC & HMBC NMR, ATR-IR, molecular weight distribution, morphology, thermal properties, and barrier properties after film formation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Effects of a cellulose mask synthesized by a bacterium on facial skin characteristics and user satisfaction

    Directory of Open Access Journals (Sweden)

    Amnuaikit T

    2011-06-01

    Full Text Available Thanaporn Amnuaikit, Toon Chusuit, Panithi Raknam, Prapaporn BoonmeDepartment of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Songkhla, ThailandBackground: Cellulose masks obtained from natural sources such as bacteria are of interest as cosmetic devices for the treatment of dry skin because they not only improve hydration of the skin, but have low toxicity and are biodegradable. The aims of this study were to determine the in vivo effects of a cellulose mask obtained from Acetobacter xylinum on skin characteristics and to evaluate user satisfaction with the product.Methods: Thirty healthy Thai volunteers aged 21–40 years participated in the study. The volunteers were randomly separated into a control group and an experimental group. For the control group, volunteers were assigned to apply moist towels to the face for 25 minutes. For the experimental group, the volunteers were assigned to apply the masks, ie, translucent patches which could be fitted onto the face for the same period. The following week, the groups were changed over to the alternative treatment. Skin moisture, sebum, elasticity, texture, dullness, and desquamation levels were assessed using a system used for routine skin counseling before applying the trial product and five minutes after its removal. Degree of satisfaction with use of the cellulose mask was investigated using a five-point rating scale.Results: The cellulose mask increased moisture levels in the skin significantly more than moist towels (P < 0.05 after a single application. No obvious effects on other skin characteristics were found. The cellulose mask product rated around 4/5 on the satisfaction rating scale.Conclusions: A single application of the trial cellulose mask enhanced moisture uptake by facial skin. Users also reported being satisfied with the trial product.Keywords: bacterial cellulose, facial mask, skin characteristics, skin hydration, user

  6. Cellulose biogenesis in Dictyostelium discoideum

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, R.L.

    1993-12-31

    Organisms that synthesize cellulose can be found amongst the bacteria, protistans, fungi, and animals, but it is in plants that the importance of cellulose in function (as the major structural constituent of plant cell walls) and economic use (as wood and fiber) can be best appreciated. The structure of cellulose and its biosynthesis have been the subjects of intense investigation. One of the most important insights gained from these studies is that the synthesis of cellulose by living organisms involves much more than simply the polymerization of glucose into a (1{r_arrow}4)-{beta}-linked polymer. The number of glucoses in a polymer (the degree of polymerization), the crystalline form assumed by the glucan chains when they crystallize to form a microfibril, and the dimensions and orientation of the microfibrils are all subject to cellular control. Instead of cellulose biosynthesis, a more appropriate term might be cellulose biogenesis, to emphasize the involvement of cellular structures and mechanisms in controlling polymerization and directing crystallization and deposition. Dictyostelium discoideum is uniquely suitable for the study of cellulose biogenesis because of its amenability to experimental study and manipulation and the extent of our knowledge of its basic cellular mechanisms (as will be evident from the rest of this volume). In this chapter, I will summarize what is known about cellulose biogenesis in D. discoideum, emphasizing its potential to illuminate our understanding both of D. discoideum development and plant cellulose biogenesis.

  7. Investigation of hydrate formation and transportability in multiphase flow systems

    Science.gov (United States)

    Grasso, Giovanny A.

    cohesion force (3.32 mN/m). These measurements prove the importance of natural surfactants in crude oil for particle dispersion. An experimental methodology was provided to determine the effectiveness of asphaltenes as a dispersant. Even though hydrate deposition was inferred from the flowloop tests, it could not be verified from these measurements. Custom-made experimental set-ups (a recirculation liquid system, a rocking cell and a lab-scale mini-loop) were used to isolate the hydrate deposi- tion investigation. Besides water, mineral oil 70T and King Ranch condensate were used in combination with water for the deposition investigation. One of the most important deliverables of this thesis was the construction of a lab-scale flowloop that provides insight on deposition phenomenon in multiphase flow, representing the only set-up, reported in the literature, suitable for this investigation. The miniloop can handle gas-liquid flow (maximum flow rates of 10 Nm3/m for gas and 22 GPM for liquid) through a 10 ft. long straight section (2 in. standard tubing). The testing section (30 in. long) was designed to observe hydrate deposition on the wall. Three mechanisms of hydrate deposition were identified: film growth, particles adhering and particle bedding. The maximum water conversions were: 27.5 ml in the rocking cell, 2400 ml in the miniloop with 100 % WC and 250 ml in the miniloop for dispersed water in mineral oil 70T. The measured DP across to the testing section ranged from 0 to 8 in. H2O. Deposits were obtained for different flow regimes, including 100 % LL, stratified, stratified- wavy and slug flow. The maximum deposit thickness was 1.5 in., obtained in the gas flowing section. When deposits form from particle cohesion, they were easy to slough. From all the experimental worked in this thesis, hydrates accumulated depending on the degrees of subcooling of the bulk fluid, film growth (between 3 to 5 F), deposition from a combination of film growth and particle cohesion

  8. Determination of membrane hydration numbers of alkali metal ions by insertion in a conducting polymer

    DEFF Research Database (Denmark)

    Skaarup, Steen; Junaid Mohamed Jafeen, Mohamed; Careem, M.A.

    2010-01-01

    , and a secondary (or outer) solvation shell, consisting of all other water molecules whose properties are still influenced significantly by the cation. Knowing the hydration number is important when considering, for instance, the transport of Na+ and K+ in biological cell membranes, since their different behavior...... of the number of M+ ions entering the film, and therefore the inserted M+ mass. The mass of the water molecules can then be calculated as a difference. The values determined this way may be called membrane hydration numbers. The results yield the following membrane hydration numbers: Li+: 5.3-5.5; Na+ 4...... membrane....

  9. Hydrates fighting tools; Des outils de lutte contre les hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-04-01

    Shell Exploration and Production company (SEPCo) is the operator of the 'Popeye' deep offshore field in the Gulf of Mexico. Thanks to the introduction of a low dosing hydrates inhibitor (LDHI) elaborated by Shell Global Solutions, the company has added a 7.5 Gpc extra volume of gas to its recoverable reserves. This new technology avoids the plugging of pipes by hydrates formation. (J.S.)

  10. Effects of excipients on hydrate formation in wet masses containing theophylline

    DEFF Research Database (Denmark)

    Airaksinen, Sari; Luukkonen, Pirjo; Jørgensen, Anna

    2003-01-01

    its dissolution rate. The aim of this study was to investigate whether excipients, such as alpha-lactose monohydrate or the highly water absorbing silicified microcrystalline cellulose (SMCC) can influence the hydrate formation of theophylline. In particular, the aim was to study if SMCC offers...... protection against the formation of theophylline monohydrate relative to alpha-lactose monohydrate in wet masses after an overnight equilibration and the stability of final granules during controlled storage. In addition, the aim was to study the use of spectroscopic methods to identify hydrate formation...... in the formulations containing excipients. Off-line evaluation of materials was performed using X-ray powder diffractometry, near infrared and Raman spectroscopy. alpha-Lactose monohydrate with minimal water absorbing potential was not able to prevent but enhanced hydrate formation of theophylline. Even though SMCC...

  11. Preparation and characterization of transparent PMMA-cellulose-based nanocomposites.

    Science.gov (United States)

    Kiziltas, Esra Erbas; Kiziltas, Alper; Bollin, Shannon C; Gardner, Douglas J

    2015-01-01

    Nanocomposites of polymethylmethacrylate (PMMA) and cellulose were made by a solution casting method using acetone as the solvent. The nanofiber networks were prepared using three different types of cellulose nanofibers: (i) nanofibrillated cellulose (NFC), (ii) cellulose nanocrystals (CNC) and (iii) bacterial cellulose from nata de coca (NDC). The loading of cellulose nanofibrils in the PMMA varied between 0.25 and 0.5 wt%. The mechanical properties of the composites were evaluated using a dynamic mechanical thermal analyzer (DMTA). The flexural modulus of the nanocomposites reinforced with NDC at the 0.5 wt% loading level increased 23% compared to that of pure PMMA. The NFC composite also exhibited a slightly increased flexural strength around 60 MPa while PMMA had a flexural strength of 57 MPa. The addition of NDC increased the storage modulus (11%) compared to neat PMMA at room temperature while the storage modulus of PPMA/CNC nanocomposite containing 0.25 and 0.5 wt% cellulose increased about 46% and 260% to that of the pure PMMA at the glass transition temperature, respectively. Thermogravimetric analysis (TGA) indicated that there was no significant change in thermal stability of the composites. The UV-vis transmittance of the CNF nanocomposites decreased by 9% and 27% with the addition of 0.25 wt% CNC and NDC, respectively. This work is intended to spur research and development activity for application of CNF reinforced PMMA nanocomposites in applications such as: packaging, flexible screens, optically transparent films and light-weight transparent materials for ballistic protection.

  12. Surface-type humidity sensor based on cellulose-PEPC for telemetry systems

    Institute of Scientific and Technical Information of China (English)

    Kh. S. Karimov; M.Saleem; T. A. Qasuria; M. Farooq

    2011-01-01

    Au/cellulose-PEPC/Au surface-type humidity sensors were fabricated by drop-casting cellulose and poly-N-epoxypropylcarbazole (PEPC) blend thin films. A blend of 2wt% of each cellulose and PEPC in benzol was used for the deposition of humidity sensing films. Blend films were deposited on glass substrates with preliminary deposited surface-type gold electrodes. Films of different thicknesses of cellulose and PEPC composite were deposited by drop-casting technique. A change in electrical resistance and capacitance of the fabricated devices was observed by increasing the relative humidity in the range of 0-95% RH. It was observed that the capacitances of the sensors increase, while their resistances decrease with increasing the relative humidity. The sensors were connected to op-amp square wave oscillators. It was observed that with increasing the relative humidity, the oscillator's frequencies were also increased in the range of 4.2-12.0 kHz for 65/μm thick film sample, 4.1-9.0 kHz for 88 μm thick film sample, and 4.2-9.0 kHz for 210 μm sample. Effects of film thickness on the oscillator's frequency with respect to humidity were also investigated. This polymer humidity sensor controlled oscillator can be used for short-range and long-range remote systems at environmental monitoring and assessment of the humidity level.

  13. Acetoacetylation of Hydroxyethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    陈晓锋; 高彦芳; 杜奕; 刘德山

    2002-01-01

    The acetoacetyl group can be used to improve superabsorbent resins since it is more active than the hydroxyethyl group. The acetoacetyl group can be introduced into the side group of hydroxyethyl cellulose (HEC) to activate HEC using the ester exchange reaction between HEC and ethyl acetoacetate (EAA) to improve HEC grafting. This paper discusses the main factors affecting the reaction, such as the amount of EAA and catalyzer, the reaction temperature, and the reaction time. The acetoacetyl group was successfully introduced into HEC. Within specified ranges, increasing the amount of EAA, the reaction temperature and the reaction time will increase the acetoacetylation.

  14. Obsidian Hydration: A New Paleothermometer

    Energy Technology Data Exchange (ETDEWEB)

    Anovitz, Lawrence {Larry} M [ORNL; Riciputi, Lee R [ORNL; Cole, David R [ORNL; Fayek, Mostafa [ORNL; Elam, J. Michael [University of Tennessee, Knoxville (UTK)

    2006-01-01

    The natural hydration of obsidian was first proposed as a dating technique for young geological and archaeological specimens by Friedman and Smith (1960), who noted that the thickness of the hydrated layer on obsidian artifacts increases with time. This approach is, however, sensitive to temperature and humidity under earth-surface conditions. This has made obsidian hydration dating more difficult, but potentially provides a unique tool for paleoclimatic reconstructions. In this paper we present the first successful application of this approach, based on combining laboratory-based experimental calibrations with archaeological samples from the Chalco site in the Basin of Mexico, dated using stratigraphically correlated 14C results and measuring hydration depths by secondary ion mass spectrometry. The resultant data suggest, first, that this approach is viable, even given the existing uncertainties, and that a cooling trend occurred in the Basin of Mexico over the past 1450 yr, a result corroborated by other paleoclimatic data.

  15. Obsidian hydration: A new paleothermometer

    Science.gov (United States)

    Anovitz, Lawrence M.; Riciputi, Lee R.; Cole, David R.; Fayek, Mostafa; Elam, J. Michael

    2006-07-01

    The natural hydration of obsidian was first proposed as a dating technique for young geological and archaeological specimens by Friedman and Smith (1960), who noted that the thickness of the hydrated layer on obsidian artifacts increases with time. This approach is, however, sensitive to temperature and humidity under earth-surface conditions. This has made obsidian hydration dating more difficult, but potentially provides a unique tool for paleoclimatic reconstructions. In this paper we present the first successful application of this approach, based on combining laboratory-based experimental calibrations with archaeological samples from the Chalco site in the Basin of Mexico, dated using stratigraphically correlated 14C results and measuring hydration depths by secondary ion mass spectrometry. The resultant data suggest, first, that this approach is viable, even given the existing uncertainties, and that a cooling trend occurred in the Basin of Mexico over the past 1450 yr, a result corroborated by other paleoclimatic data.

  16. Obsidian hydration dates glacial loading?

    Science.gov (United States)

    Friedman, I; Pierce, K L; Obradovich, J D; Long, W D

    1973-05-18

    Three different groups of hydration rinds have been measured on thin sections of obsidian from Obsidian Cliff, Yellowstone National Park, Wyoming. The average thickness of the thickest (oldest) group of hydration rinds is 16.3 micrometers and can be related to the original emplacement of the flow 176,000 years ago (potassium-argon age). In addition to these original surfaces, most thin sections show cracks and surfaces which have average hydration rind thicknesses of 14.5 and 7.9 micrometers. These later two hydration rinds compare closely in thickness with those on obsidian pebbles in the Bull Lake and Pinedale terminal moraines in the West Yellowstone Basin, which are 14 to 15 and 7 to 8 micrometers thick, respectively. The later cracks are thought to have been formed by glacial loading during the Bull Lake and Pinedale glaciations, when an estimated 800 meters of ice covered the Obsidian Cliff flow.

  17. Cellulose binding domain fusion proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  18. Cellulose Synthesis in Agrobacterium tumefaciens

    Energy Technology Data Exchange (ETDEWEB)

    Alan R. White; Ann G. Matthysse

    2004-07-31

    We have cloned the celC gene and its homologue from E. coli, yhjM, in an expression vector and expressed the both genes in E. coli; we have determined that the YhjM protein is able to complement in vitro cellulose synthesis by extracts of A. tumefaciens celC mutants, we have purified the YhjM protein product and are currently examining its enzymatic activity; we have examined whole cell extracts of CelC and various other cellulose mutants and wild type bacteria for the presence of cellulose oligomers and cellulose; we have examined the ability of extracts of wild type and cellulose mutants including CelC to incorporate UDP-14C-glucose into cellulose and into water-soluble, ethanol-insoluble oligosaccharides; we have made mutants which synthesize greater amounts of cellulose than the wild type; and we have examined the role of cellulose in the formation of biofilms by A. tumefaciens. In addition we have examined the ability of a putative cellulose synthase gene from the tunicate Ciona savignyi to complement an A. tumefaciens celA mutant. The greatest difference between our knowledge of bacterial cellulose synthesis when we started this project and current knowledge is that in 1999 when we wrote the original grant very few bacteria were known to synthesize cellulose and genes involved in this synthesis were sequenced only from Acetobacter species, A. tumefaciens and Rhizobium leguminosarum. Currently many bacteria are known to synthesize cellulose and genes that may be involved have been sequenced from more than 10 species of bacteria. This additional information has raised the possibility of attempting to use genes from one bacterium to complement mutants in another bacterium. This will enable us to examine the question of which genes are responsible for the three dimensional structure of cellulose (since this differs among bacterial species) and also to examine the interactions between the various proteins required for cellulose synthesis. We have carried out one

  19. Evaluation of thermal gelation behavior of different cellulose ether polymers by rheology

    Science.gov (United States)

    Balaghi, S.; Edelby, Y.; Senge, B.

    2014-05-01

    Hydroxypropylmethylcellulose (HPMC) and Methylcellulose (MC) are cellulose ethers which can be dispersed in water and used as thickeners, emulsifiers, binders, film formers, and water-retention agents due to their hydrophilic and hydrophobic characteristics. In this study, various types of HPMCs, in comparison with two types of MCs were examined. The formed gels of the different cellulose ethers showed specific and various structural formation and network properties. The degree of methylation (Meth.) and hydroxypropylation (HyPr.) affected drastically the heat-induced gelation of the examined cellulose ethers.

  20. Storing natural gas as frozen hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Gudmundsson, J.S.; Khokhar, A.A. (Univ. of Trondheim (Norway)); Parlaktuna, M. (Middle East Technical Univ., Ankara (Turkey))

    1994-02-01

    The formation of natural gas hydrates is a well-known problem in the petroleum and natural gas industries. Hydrates are solid materials that form when liquid water and natural gas are brought in contact under pressure. Hydrate formation need not be a problem. On the contrary, it can be an advantage. The volume of hydrates is much less than that of natural gas. At standard conditions, hydrates occupy 150 to 170 times less volume than the corresponding gas. Typically, natural gas hydrates contain 15% gas and 85% water by mass. It follows that hydrates can be used for large-scale storage of natural gas. Benesh proposed using hydrates to improve the load factor of natural gas supply systems. The author suggested that hydrates could be produced by bringing liquid water into contact with natural gas at the appropriate temperature and high pressure. The hydrate then would be stored at a temperature and pressure where it was stable. When gas was needed for the supply system, the hydrate would be melted at low pressure. The stability of a natural gas hydrate during storage at atmospheric pressure and below-freezing temperatures was studied in the laboratory. The gas hydrate was produced in a stirred vessel at 2- to 6-MPa pressure and temperatures from 0 to 20 C. The hydrate was refrigerated and stored in deep freezers at [minus]5, [minus]10, and [minus]18 C for up to 10 days. The natural gas hydrate remained stable when kept frozen at atmospheric pressure.

  1. Ultrasonic dyeing of cellulose nanofibers.

    Science.gov (United States)

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

  2. Airway Hydration and COPD

    Science.gov (United States)

    Ghosh, Arunava; Boucher, R.C.; Tarran, Robert

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is one of the prevalent causes of worldwide mortality and encompasses two major clinical phenotypes, i.e., chronic bronchitis (CB) and emphysema. The most common cause of COPD is chronic tobacco inhalation. Research focused on the chronic bronchitic phenotype of COPD has identified several pathological processes that drive disease initiation and progression. For example, the lung’s mucociliary clearance (MCC) system performs the critical task of clearing inhaled pathogens and toxic materials from the lung. MCC efficiency is dependent on: (i) the ability of apical plasma membrane ion channels such as the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na+ channel (ENaC) to maintain airway hydration; (ii) ciliary beating; and, (iii) appropriate rates of mucin secretion. Each of these components is impaired in CB and likely contributes to the mucus stasis/accumulation seen in CB patients. This review highlights the cellular components responsible for maintaining MCC and how this process is disrupted following tobacco exposure and with CB. We shall also discuss existing therapeutic strategies for the treatment of chronic bronchitis and how components of the MCC can be used as biomarkers for the evaluation of tobacco or tobacco-like-product exposure. PMID:26068443

  3. Mechanism of gypsum hydration

    Directory of Open Access Journals (Sweden)

    Pacheco, G.

    1991-06-01

    Full Text Available There is an hypothesis that the mechanism o f gypsum hydration and dehydration is performed through two simultaneous phenomena. In this study we try to clear up this phenomenon using chlorides as accelerators or a mixture of ethanol-methanol as retarders to carry out the gypsum setting. Natural Mexican gypsum samples and a hemihydrate prepared in the laboratory are used. The following analytical techniques are used: MO, DRX, DTA, TG and DTG. In agreement with the obtained results, it can be concluded: that colloid formation depends on the action of accelerators or retarders and the crystals are a consequence of the quantity of hemihydrate formed.

    En el mecanismo de hidratación y deshidratación del yeso existe la hipótesis de que éste se efectúa por dos fenómenos simultáneos. Este estudio intenta esclarecer estos fenómenos, empleando: cloruros como aceleradores o mezcla etanol-metanol como retardadores para efectuar el fraguado del yeso. Se emplean muestras de yeso de origen natural mexicano y hemihydrate preparado en laboratorio; se utilizan técnicas analíticas: MO, DRX, DTA, TG y DTG. De acuerdo a los resultados obtenidos se puede deducir: que la formación del coloide depende de la acción de los agentes aceleradores o retardadores y que los cristales son consecuencia de la cantidad de hemihidrato formado.

  4. Morphological structure of Gluconacetobacter xylinus cellulose and cellulose-based organic-inorganic composite materials

    Science.gov (United States)

    Smyslov, R. Yu; Ezdakova, K. V.; Kopitsa, G. P.; Khripunov, A. K.; Bugrov, A. N.; Tkachenko, A. A.; Angelov, B.; Pipich, V.; Szekely, N. K.; Baranchikov, A. E.; Latysheva, E.; Chetverikov, Yu O.; Haramus, V.

    2017-05-01

    Scanning electron microscopy, ultra-small-angle neutron scattering (USANS), small-angle neutron and X-ray scattering (SANS and SAXS), as well as low-temperature nitrogen adsorption, were used in the studies of micro- and mesostructure of polymer matrix prepared from air-dry preliminarily disintegrated cellulose nano-gel film (synthesized by Gluconacetobacter xylinus) and the composites based on this bacterial cellulose. The composites included ZrO2 nanoparticles, Tb3+ in the form of low molecular weight salt and of metal-polymer complex with poly(vinylpyrrolydone)-poly(methacryloyl-o-aminobenzoic acid) copolymer. The combined analysis of the data obtained allowed revealing three levels of fractal organization in mesostructure of G. xylinus cellulose and its composites. It was shown that both the composition and an aggregation state of dopants have a significant impact on the structural characteristics of the organic-inorganic composites. The composites containing Tb3+ ions demonstrate efficient luminescence; its intensity is an order of magnitude higher in the case of the composites with the metal-polymer complex. It was found that there is the optimal content of ZrO2 nanoparticles in composites resulting in increased Tb3+ luminescence.

  5. Impact of CO{sub 2} hydrates on ocean carbon dioxide deposition options

    Energy Technology Data Exchange (ETDEWEB)

    Lund, P.C.

    1995-04-01

    The objective of the research project described in this report was to contribute to the research on greenhouse gases and the global environment. The focus is on the concept of storing large amounts of CO{sub 2} in the ocean. The project was divided into three subtasks: (1) a comprehensive study of the thermodynamic, physical and chemical properties of the seawater/CO{sub 2}/hydrate system, (2) establishment of a micro-scale kinetic model for CO{sub 2} hydrate formation and stability, based on (1), and (3) establishment of macro-scale models for various ocean deposition options based on (2). A database of selected thermodynamic functions has been set up. A large database of oceanic data has also been made; for any given coordinates at sea a computer program provides the temperature, salinity and oxygen profiles from the sea surface to the sea floor. The kinetic model predicts the formation and pseudo-stability of a very thin hydrate film which acts as an inhibitor for diffusion of CO{sub 2} into the sea water. The model predicts that the hydrate film reduces the overall flux from a liquid CO{sub 2} source with about 90%. Thermodynamically, pure CO{sub 2} in contact with water might form hydrates at depths below about 400 m, which would indicate that hydrate formation could play a role for all ocean CO{sub 2} deposition options. However, this study shows that other mechanisms significantly reduce the role of hydrate formation. It is finally concluded that although more modelling and experimental work is required within this field of research, the hydrate film may play an important role for all options except from shallow water injection. 86 refs., 32 figs., 16 tabs.

  6. Approaching zero cellulose loss in cellulose nanocrystal (CNC) production: recovery and characterization of cellulosic solid residues (CSR) and CNC

    Science.gov (United States)

    Q.Q. Wang; J.Y. Zhu; R.S. Reiner; S.P. Verrill; U. Baxa; S.E. McNeil

    2012-01-01

    This study demonstrated the potential of simultaneously recovering cellulosic solid residues (CSR) and producing cellulose nanocrystals (CNCs) by strong sulfuric acid hydrolysis to minimize cellulose loss to near zero. A set of slightly milder acid hydrolysis conditions than that considered as “optimal” were used to significantly minimize the degradation of cellulose...

  7. Dispersion of cellulose nanofibers in biopolymer based nanocomposites

    Science.gov (United States)

    Wang, Bei

    The focus of this work was to understand the fundamental dispersion mechanism of cellulose based nanofibers in bionanocomposites. The cellulose nanofibers were extracted from soybean pod and hemp fibers by chemo-mechanical treatments. These are bundles of cellulose nanofibers with a diameter ranging between 50 to 100 nm and lengths of thousands of nanometers which results in very high aspect ratio. In combination with a suitable matrix polymer, cellulose nanofiber networks show considerable potential as an effective reinforcement for high quality specialty applications of bio-based nanocomposites. Cellulose fibrils have a high density of --OH groups on the surface, which have a tendency to form hydrogen bonds with adjacent fibrils, reducing interaction with the surrounding matrix. The use of nanofibers has been mostly restricted to water soluble polymers. This thesis is focused on synthesizing the nanocomposite using a solid phase matrix polypropylene (PP) or polyethylene (PE) by hot compression and poly (vinyl alcohol) (PVA) in an aqueous phase by film casting. The mechanical properties of nanofiber reinforced PVA film demonstrated a 4-5 fold increase in tensile strength, as compared to the untreated fiber-blend-PVA film. It is necessary to reduce the entanglement of the fibrils and improve their dispersion in the matrix by surface modification of fibers without deteriorating their reinforcing capability. Inverse gas chromatography (IGC) was used to explore how various surface treatments would change the dispersion component of surface energy and acid-base character of cellulose nanofibers and the effect of the incorporation of these modified nanofibers into a biopolymer matrix on the properties of their nano-composites. Poly (lactic acid) (PLA) and polyhydroxybutyrate (PHB) based nanocomposites using cellulose nanofibers were prepared by extrusion, injection molding and hot compression. The IGC results indicated that styrene maleic anhydride coated and ethylene

  8. New insight into hydration and aging mechanisms of paper by the line shape analysis of proton NMR spectra

    Science.gov (United States)

    Mallamace, D.; Vasi, S.; Missori, M.; Corsaro, C.

    2016-05-01

    The action of water within biological systems is strictly linked either with their physical chemical properties and with their functions. Cellulose is one of the most studied biopolymers due to its biological importance and its wide use in manufactured products. Among them, paper is mainly constituted by an almost equimolar ratio of cellulose and water. Therefore the study of the behavior of water within pristine and aged paper samples can help to shed light on the degradation mechanisms that irremediably act over time and spoil paper. In this work we present Nuclear Magnetic Resonance (NMR) experiments on modern paper samples made of pure cellulose not aged and artificially aged as well as on ancient paper samples made in 1413 in Perpignan (France). The line shape parameters of the proton NMR spectra were studied as a function of the hydration content. Results indicate that water in aged samples is progressively involved in the hydration of the byproducts of cellulose degradation. This enhances the degradation process itself through the progressive consumption of the cellulose amorphous regions.

  9. Micromechanics of TEMPO-oxidized fibrillated cellulose composites.

    Science.gov (United States)

    Bulota, Mindaugas; Tanpichai, Supachok; Hughes, Mark; Eichhorn, Stephen J

    2012-01-01

    Composites of poly(lactic) acid (PLA) reinforced with TEMPO-oxidized fibrillated cellulose (TOFC) were prepared to 15, 20, 25, and 30% fiber weight fractions. To aid dispersion and to improve stress transfer, we acetylated the TOFC prior to the fabrication of TOFC-PLA composite films. Raman spectroscopy was employed to study the deformation micromechanics in these systems. Microtensile specimens were prepared from the films and deformed in tension with Raman spectra being collected simultaneously during deformation. A shift in a Raman peak initially located at ~1095 cm(-1), assigned to C-O-C stretching of the cellulose backbone, was observed upon deformation, indicating stress transfer from the matrix to the TOFC reinforcement. The highest band shift rate, with respect to strain, was observed in composites having a 30% weight fraction of TOFC. These composites also displayed a significantly higher strain to failure compared to pure acetylated TOFC film, and to the composites having lower weight fractions of TOFC. The stress-transfer processes that occur in microfibrillated cellulose composites are discussed with reference to the micromechanical data presented. It is shown that these TOFC-based composite materials are progressively dominated by the mechanics of the networks, and a shear-lag type stress transfer between fibers.

  10. Tetrahydrofuran hydrate decomposition characteristics in porous media

    Science.gov (United States)

    Song, Yongchen; Wang, Pengfei; Wang, Shenglong; Zhao, Jiafei; Yang, Mingjun

    2016-12-01

    Many tetrahydrofuran (THF) hydrate properties are similar to those of gas hydrates. In the present work THF hydrate dissociation in four types of porous media is studied. THF solution was cooled to 275.15 K with formation of the hydrate under ambient pressure, and then it dissociated under ambient conditions. THF hydrate dissociation experiments in each porous medium were conducted three times. Magnetic resonance imaging (MRI) was used to obtain images. Decomposition time, THF hydrate saturation and MRI mean intensity (MI) were measured and analyzed. The experimental results showed that the hydrate decomposition time in BZ-4 and BZ-3 was similar and longer than that in BZ-02. In each dissociation process, the hydrate decomposition time of the second and third cycles was shorter than that of the first cycle in BZ-4, BZ-3, and BZ-02. The relationship between THF hydrate saturation and time is almost linear.

  11. 21 CFR 172.868 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl cellulose. 172.868 Section 172.868 Food and... Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance with the following prescribed conditions: (a) The food additive is a cellulose...

  12. 21 CFR 573.420 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and... Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether...

  13. Cellulose Nanomaterials in Water Treatment Technologies

    OpenAIRE

    Carpenter, Alexis Wells; de Lannoy, Charles François; Mark R. Wiesner

    2015-01-01

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials’ potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials’ beneficial role in environmental remediation and membranes for water filtration, ...

  14. Cellulose nanocrystals: synthesis, functional properties, and applications

    OpenAIRE

    George J.; Sabapathi SN

    2015-01-01

    Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers...

  15. Mechanical and microstructure studies on the modification of CA film by blending with PS

    Indian Academy of Sciences (India)

    P Meenakshi; S E Noorjahan; R Rajini; U Venkateswarlu; C Rose; T P Sastry

    2002-02-01

    Dried Musa paradiciaca (banana) stem and veins of the leaves, which were hitherto discarded as a waste, were collected and used as starting material for the preparation of cellulose and cellulose acetate. This cellulose acetate was mixed with polystyrene to form blend of cellulose acetate–polystyrene in order to provide enhanced stability and extended utility to the end products. The films of these composites or their individual partners were made separately and studied for their mechanical properties, chemical modification and morphological changes. We report here that banana stem is good source of cellulose and that cellulose completely undergoes modification upon esterification.

  16. Modeling of CO{sub 2}-hydrate formation at the gas-water interface in sand sediment

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T.; Sato, T.; Hirabayashi, S.; Brumby, P.E. [University of Tokyo, Department of Ocean Technology, Policy, and Environment, Kashiwa (Japan); Inui, M. [Mitsubishi Heavy Industries America, Inc., Environmental Systems Division, Austin, TX (United States)

    2012-10-15

    Sub-seabed geological storage of CO{sub 2} in the form of gas hydrate is attractive because clathrate hydrate stably exists at low temperature and high pressure, even if a fault occurs by diastrophism like a big earthquake. For the effective design of the storage system it is necessary to model the formation of CO{sub 2}-hydrate. Here, it is assumed that the formation of gas hydrate on the interface between gas and water consists of two stages: gas diffusion through the CO{sub 2}-hydrate film and consequent CO{sub 2}-hydrate formation on the interface, between film and water. Also proposed is the presence of a fresh reaction interface, which is part of the interface between the gas and aqueous phases and not covered with CO{sub 2}-hydrate. Parameters necessary to model the hydrate formation in sand sediment are derived by comparing the results of the present numerical simulations and the measurements in the literature. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Clinker mineral hydration at reduced relative humidities

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Lachowski, Eric E.;

    1999-01-01

    Vapour phase hydration of purl cement clinker minerals at reduced relative humidities is described. This is relevant to modern high performance concrete that may self-desiccate during hydration and is also relevant to the quality of the cement during storage. Both the oretical considerations...... and experimental data are presented showing that C(3)A can hydrate at lower humidities than either C3S or C2S. It is suggested that the initiation of hydration during exposure to water vapour is nucleation controlled. When C(3)A hydrates at low humidity, the characteristic hydration product is C(3)AH(6...

  18. Progress of Gas Hydrate Studies in China

    Institute of Scientific and Technical Information of China (English)

    樊栓狮; 汪集旸

    2006-01-01

    A brief overview is given on the gas hydrate-related research activities carried out by Chinese researchers in the past 15 years. The content involves: (1) Historical review. Introducing the gas hydrate research history in China; (2) Gas hydrate research groups in China. There are nearly 20 groups engaged in gas hydrate research now; (3) Present studies.Including fundamental studies, status of the exploration of natural gas hydrate resources in the South China Sea region, and development of hydrate-based new techniques; (4) Future development.

  19. Hydration of fly ash cement

    Energy Technology Data Exchange (ETDEWEB)

    Etsuo Sakai; Shigeyoshi Miyahara; Shigenari Ohsawa; Seung-Heun Lee; Masaki Daimon [Tokyo Institute of Technology, Tokyo (Japan). Department of Metallurgy and Ceramics Science, Graduate School of Science and Engineering

    2005-06-01

    It is necessary to establish the material design system for the utilization of large amounts of fly ash as blended cement instead of disposing of it as a waste. Cement blended with fly ash is also required as a countermeasure to reduce the amount of CO{sub 2} generation. In this study, the influences of the glass content and the basicity of glass phase on the hydration of fly ash cement were clarified and hydration over a long curing time was characterized. Two kinds of fly ash with different glass content, one with 38.2% and another with 76.6%, were used. The hydration ratio of fly ash was increased by increasing the glass content in fly ash in the specimens cured for 270 days. When the glass content of fly ash is low, the basicity of glass phase tends to decrease. Reactivity of fly ash is controlled by the basicity of the glass phase in fly ash during a period from 28 to 270 days. However, at an age of 360 days, the reaction ratios of fly ash show almost identical values with different glass contents. Fly ash also affected the hydration of cement clinker minerals in fly ash cement. While the hydration of alite was accelerated, that of belite was retarded at a late stage.

  20. Starch composites reinforced by bamboo cellulosic crystals.

    Science.gov (United States)

    Liu, Dagang; Zhong, Tuhua; Chang, Peter R; Li, Kaifu; Wu, Qinglin

    2010-04-01

    Using a method of combined HNO(3)-KClO(3) treatment and sulfuric acid hydrolysis, bamboo cellulose crystals (BCCs) were prepared and used to reinforce glycerol plasticized starch. The structure and morphology of BCCs were investigated using X-ray diffraction, electron microscopy, and solid-state (13)C NMR. Results showed that BCCs were of typical cellulose I structure, and the morphology was dependent on its concentration in the suspension. BCC of 50-100 nm were assembled into leaf nervations at low concentration (i.e. 0.1 wt.% of solids), but congregated into a micro-sized "flower" geometry at high concentration (i.e. 10.0 wt.% of solids). Tensile strength and Young's modulus of the starch/BCC composite films (SBC) were enhanced by the incorporation of the crystals due to reinforcement of BCCs and reduction of water uptake. BCCs at the optimal 8% loading level exhibited a higher reinforcing efficiency for plasticized starch plastic than any other loading level.

  1. Cellulose-Based Membranes for Solutes Fractionation

    Science.gov (United States)

    Anokhina, T. S.; Yushkin, A. A.; Volkov, V. V.; Antonov, S. V.; Volkov, A. V.

    This work was focused on investigation of industrial cellophane film as a membrane material for solvent nanofiltration. The effect of conditioning of cellophane membranes by stepwise changing of composition of ethanol-water binary mixtures (from ethanol to water and from water to ethanol) was studied. It was shown that such treatment leads to an increase of ethanol permeability more than two orders of magnitude over initial untreated film samples. Treated cellophane membranes possess the ethanol permeability coefficient comparable with the values for highly permeability glassy polymers. Investigation of cellophane swelling in water ethanol solutions allowed to conclude that during the treatment formation of porous in the film takes place due to increase of inter chain distances. Observed high ethanol permeability connected with the fact that formed porous structure remains after the replacement of water with ethanol. Also it was shown that rejection coefficients of a number of dyes (MW 350) were in good agreement with the degree of hydrophobicity/hydrophilicity and ability of the solvent to form hydrogen bonding with the solute molecules. It was demonstrated that cellulose-based membranes can be complimentary for other type of the membranes in fractionation of multi-components solutions.

  2. Methane fermentation of cellulose and ligno-cellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Bachman, J.S.; Villermaux, S.; Prost, C. (Laboratoire des Sciences du Genie Chimique, 54 - Nancy (France))

    1985-01-01

    Study of the methane fermentation of two simple substrates i.e. pure cellulose and oat straw. Experiments have been carried out in laboratory fermentors with several initial cellulose concentrations and different straw particle sizes. The results show the effect of adding nutrients and enriched seedings with pure cellulolytic or methanogenic bacteria. In each case, the rate limiting step is defined and the degradation kinetics of the two substrates are compared.

  3. Correlation Between Chain Architecture and Hydration Water Structure in Polysaccharides.

    Science.gov (United States)

    Grossutti, Michael; Dutcher, John R

    2016-03-14

    The physical properties of confined water can differ dramatically from those of bulk water. Hydration water associated with polysaccharides provides a particularly interesting example of confined water, because differences in polysaccharide structure provide different spatially confined environments for water sorption. We have used attenuated total reflection infrared (ATR-IR) spectroscopy to investigate the structure of hydration water in films of three different polysaccharides under controlled relative humidity (RH) conditions. We compare the results obtained for films of highly branched, dendrimer-like phytoglycogen nanoparticles to those obtained for two unbranched polysaccharides, hyaluronic acid (HA), and chitosan. We find similarities between the water structuring in the two linear polysaccharides and significant differences for phytoglycogen. In particular, the results suggest that the high degree of branching in phytoglycogen leads to a much more well-ordered water structure (low density, high connectivity network water), indicating the strong influence of chain architecture on the structuring of water. These measurements provide unique insight into the relationship between the structure and hydration of polysaccharides, which is important for understanding and exploiting these sustainable nanomaterials in a wide range of applications.

  4. Comparison of stromal hydration techniques for clear corneal cataract incisions: conventional hydration versus anterior stromal pocket hydration.

    Science.gov (United States)

    Mifflin, Mark D; Kinard, Krista; Neuffer, Marcus C

    2012-06-01

    Anterior stromal pocket hydration was compared with conventional hydration for preventing wound leak after 2.8 mm uniplanar clear corneal incisions (CCIs) in patients having routine cataract surgery. Conventional hydration involves hydration of the lateral walls of the main incision with visible whitening of the stroma. The anterior stromal pocket hydration technique involves creation of an additional supraincisional stromal pocket overlying the main incision, which is then hydrated instead of the main incision. Sixty-six eyes of 48 patients were included in the data analysis with 33 assigned to each study group. The anterior stromal pocket hydration technique was significantly better than conventional hydration in preventing wound leak due to direct pressure on the posterior lip of the incision. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  5. Cellulose nanocrystal reinforced oxidized natural rubber nanocomposites.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-02-10

    Natural rubber (NR) latex particles were oxidized using KMnO4 as oxidant to promote the insertion of hydroxyl groups in the surface polyisoprene chains. Different degrees of oxidation were investigated. Both unoxidized and oxidized NR (ONR) latex were used to prepare nanocomposite films reinforced with cellulose nanocrystals (CNCs) by casting/evaporation. The oxidation of NR was carried out to promote chemical interactions between the hydroxyl groups of ONR with those of CNCs through hydrogen bonding. The effect of the degree of oxidation of the NR latex on the rheological behavior of CNC/NR and CNC/ONR suspensions, as well as on the mechanical, swelling and thermal properties of ensuing nanocomposites was investigated. Improved properties were observed for intermediate degrees of oxidation but they were found to degrade for higher oxidation levels.

  6. Inclusion of solid particles in bacterial cellulose.

    Science.gov (United States)

    Serafica, G; Mormino, R; Bungay, H

    2002-05-01

    Depending upon the strain and the method of cultivation, bacterial cellulose can be reticulated filaments, pellets, or a dense, tough gel called a pellicle. The pellicular form is commonly made by surface culture, but a rotating disk bioreactor is more efficient and reduces the time of a run to about 3.5 days instead of the usual 12-20 days. Particles added to the medium as the gel is forming are trapped to form a new class of composite materials. Particles enter the films that are forming on the disks at rates depending on the size and geometry of the particle, as well as the rotational speed and concentration of the suspension.

  7. Gas hydrates forming and decomposition conditions analysis

    Directory of Open Access Journals (Sweden)

    А. М. Павленко

    2017-07-01

    Full Text Available The concept of gas hydrates has been defined; their brief description has been given; factors that affect the formation and decomposition of the hydrates have been reported; their distribution, structure and thermodynamic conditions determining the gas hydrates formation disposition in gas pipelines have been considered. Advantages and disadvantages of the known methods for removing gas hydrate plugs in the pipeline have been analyzed, the necessity of their further studies has been proved. In addition to the negative impact on the process of gas extraction, the hydrates properties make it possible to outline the following possible fields of their industrial use: obtaining ultrahigh pressures in confined spaces at the hydrate decomposition; separating hydrocarbon mixtures by successive transfer of individual components through the hydrate given the mode; obtaining cold due to heat absorption at the hydrate decomposition; elimination of the open gas fountain by means of hydrate plugs in the bore hole of the gushing gasser; seawater desalination, based on the hydrate ability to only bind water molecules into the solid state; wastewater purification; gas storage in the hydrate state; dispersion of high temperature fog and clouds by means of hydrates; water-hydrates emulsion injection into the productive strata to raise the oil recovery factor; obtaining cold in the gas processing to cool the gas, etc.

  8. WOOD CELLULOSE ACETATE MEMBRANE 179

    African Journals Online (AJOL)

    DR. AMINU

    2013-06-01

    Jun 1, 2013 ... process. The harnessed cellulose was acetylated by the process of step-wise acetylation to a degree of acetylation (DA) of ... several fields including oil recovery (Heinrich and ..... removed by filtration using the membrane was.

  9. Direct measurements of non-ionic attraction and nanoscaled lubrication in biomimetic composites from nanofibrillated cellulose and modified carboxymethylated cellulose

    Science.gov (United States)

    Olszewska, Anna; Valle-Delgado, Juan José; Nikinmaa, Miika; Laine, Janne; Österberg, Monika

    2013-11-01

    There is a growing interest to design biomimetic self-assembled composite films from renewable resources aimed at a combination of high toughness, strength and stiffness. However, the relationship between interfacial interactions of the components and the mechanical performance of the composite is still poorly understood. In this work we present evidence of the link between mechanical performance of carbohydrate-based composites with nanolubrication and with direct surface forces between the hard and soft domain in the system. Our approach was to use nanofibrillated cellulose (NFC) as the major reinforcing domain and to modify it by adsorption of a small amount of soft polyethylene glycol grafted carboxymethyl cellulose (CMC-g-PEG). The effect of the soft polymer on direct normal and friction forces in air between cellulose surfaces was evaluated using colloidal probe microscopy. The fibrillar structure of the NFC thin film affected the frictional behaviour; when decreasing load, the friction between pure cellulose surfaces increased, suggesting partial pull-out of fibrils, a phenomenon not observed for non-fibrillar cellulose substrates. Adsorption of CMC-g-PEG on both surfaces decreased the friction considerably but adhesion was still high. The symmetric system, having both cellulose substrates covered with the polymer, was compared to asymmetric systems where only one surface was covered with the polymer. Furthermore, a free standing composite film was prepared by non-ionic self-assembly of NFC and CMC-g-PEG with 99 : 1 weight-ratio; the mechanical properties of the macroscopic films were related to the nanoscaled interactions between the components. The composition studied showed excellent mechanical properties which do not follow the simple rule of mixture. Thus, a synergy in the direct surface forces and mechanical properties was found. This approach offers a robust path to aid in the efficient design of next generation biomimetic composites.There is a

  10. Hydration of highly charged ions.

    Science.gov (United States)

    Hofer, Thomas S; Weiss, Alexander K H; Randolf, Bernhard R; Rode, Bernd M

    2011-08-01

    Based on a series of ab initio quantum mechanical charge field molecular dynamics (QMCF MD) simulations, the broad spectrum of structural and dynamical properties of hydrates of trivalent and tetravalent ions is presented, ranging from extreme inertness to immediate hydrolysis. Main group and transition metal ions representative for different parts of the periodic system are treated, as are 2 threefold negatively charged anions. The results show that simple predictions of the properties of the hydrates appear impossible and that an accurate quantum mechanical simulation in cooperation with sophisticated experimental investigations seems the only way to obtain conclusive results.

  11. Bacterial cellulose/boehmite composites

    Energy Technology Data Exchange (ETDEWEB)

    Salvi, Denise T.B. de; Barud, Hernane S.; Messaddeq, Younes; Ribeiro, Sidney J.L. [Universidade Estadual Paulista Julio de Mesquita Filho. UNESP. Instituto de Quimica de Araraquara, SP (Brazil); Caiut, Jose Mauricio A. [Universidade de Sao Paulo. Departamento de Quimica - FFCLRP/USP, Ribeirao Preto, SP (Brazil)

    2011-07-01

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  12. Great Market Potential of Hydrazine Hydrate

    Institute of Scientific and Technical Information of China (English)

    Shi Yuying

    2007-01-01

    @@ Stable consumption growth worldwide Hydrazine hydrate is an organic chemical raw material with extensive applications. The world's capacity to produce hydrazine hydrate has reached more than 200 thousand t/atoday (based on 100% hydrazine content).

  13. Methods to determine hydration states of minerals and cement hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Baquerizo, Luis G., E-mail: luis.baquerizoibarra@holcim.com [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Matschei, Thomas [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Scrivener, Karen L. [Laboratory of Construction Materials, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Saeidpour, Mahsa; Thorell, Alva; Wadsö, Lars [Building Materials, Lund University, Box 124, 221 000 Lund (Sweden)

    2014-11-15

    This paper describes a novel approach to the quantitative investigation of the impact of varying relative humidity (RH) and temperature on the structure and thermodynamic properties of salts and crystalline cement hydrates in different hydration states (i.e. varying molar water contents). The multi-method approach developed here is capable of deriving physico-chemical boundary conditions and the thermodynamic properties of hydrated phases, many of which are currently missing from or insufficiently reported in the literature. As an example the approach was applied to monosulfoaluminate, a phase typically found in hydrated cement pastes. New data on the dehydration and rehydration of monosulfoaluminate are presented. Some of the methods used were validated with the system Na{sub 2}SO{sub 4}–H{sub 2}O and new data related to the absorption of water by anhydrous sodium sulfate are presented. The methodology and data reported here should permit better modeling of the volume stability of cementitious systems exposed to various different climatic conditions.

  14. Novel understanding of calcium silicate hydrate from dilute hydration

    KAUST Repository

    Zhang, Lina

    2017-05-13

    The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10 was conducted for tricalcium silicate (C3S) to interpret long-term hydration process and investigate the formation, structure and properties of C-S-H. Based on results from XRD, IR, SEM, NMR and so forth, loose and dense clusters of C-S-H with analogous C/S ratio were obtained along with the corresponding chemical formulae proposed as Ca5Si4O13∙6.2H2O. Crystalline structure inside C-S-H was observed by TEM, which was allocated at the foil-like proportion as well as the edge of wrinkles of the product. The long-term hydration process of C3S in dilute suspension could be sketchily described as migration of calcium hydroxide and in-situ growth of C-S-H with equilibrium silicon in aqueous solution relatively constant and calcium varied.

  15. Surface modification of cellulose nanocrystals

    Science.gov (United States)

    Eyley, Samuel; Thielemans, Wim

    2014-06-01

    Chemical modification of cellulose nanocrystals is an increasingly popular topic in the literature. This review analyses the type of cellulose nanocrystal modification reactions that have been published in the literature thus far and looks at the steps that have been taken towards analysing the products of the nanocrystal modifications. The main categories of reactions carried out on cellulose nanocrystals are oxidations, esterifications, amidations, carbamations and etherifications. More recently nucleophilic substitutions have been used to introduce more complex functionality to cellulose nanocrystals. Multi-step modifications are also considered. This review emphasizes quantification of modification at the nanocrystal surface in terms of degree of substitution and the validity of conclusions drawn from different analysis techniques in this area. The mechanisms of the modification reactions are presented and considered with respect to the effect on the outcome of the reactions. While great strides have been made in the quality of analytical data published in the field of cellulose nanocrystal modification, there is still vast scope for improvement, both in data quality and the quality of analysis of data. Given the difficulty of surface analysis, cross-checking of results from different analysis techniques is fundamental for the development of reliable cellulose nanocrystal modification techniques.

  16. Molecular Dynamics Modeling of Hydrated Calcium-Silicate-Hydrate (CSH) Cement Molecular Structure

    Science.gov (United States)

    2014-08-30

    properties of key hydrated cement constituent calcium-silicate-hydrate (CSH) at the molecular, nanometer scale level. Due to complexity, still unknown...public release; distribution is unlimited. Molecular Dynamics Modeling of Hydrated Calcium-Silicate- Hydrate (CSH) Cement Molecular Structure The views... Cement Molecular Structure Report Title Multi-scale modeling of complex material systems requires starting from fundamental building blocks to

  17. Metal nanoparticle/ionic liquid/cellulose: new catalytically active membrane materials for hydrogenation reactions.

    Science.gov (United States)

    Gelesky, Marcos A; Scheeren, Carla W; Foppa, Lucas; Pavan, Flavio A; Dias, Silvio L P; Dupont, Jairton

    2009-07-13

    Transition metal-containing membrane films of 10, 20, and 40 μm thickness were obtained by the combination of irregularly shaped nanoparticles with monomodal size distributions of 4.8 ± 1.1 nm (Rh(0)) and 3.0 ± 0.4 nm (Pt(0)) dispersed in the ionic liquid (IL) 1-n-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (BMI·(NTf)(2)) with a syrup of cellulose acetate (CA) in acetone. The Rh(0) and Pt(0) metal concentration increased proportionally with increases in film thickness up to 20 μm, and then the material became metal saturated. The presence of small and stable Rh(0) or Pt(0) nanoparticles induced an augmentation in the CA/IL film surface areas. The augmentation of the IL content resulted in an increase of elasticity and decrease in tenacity and toughness, whereas the stress at break was not influenced. The introduction of IL probably causes an increase in the separation between the cellulose macromolecules that results in a higher flexibility, lower viscosity, and better formability of the cellulose material. The nanoparticle/IL/CA combinations exhibit an excellent synergistic effect that enhances the activity and durability of the catalyst for the hydrogenation of cyclohexene. The nanoparticle/IL/cellulose acetate film membranes display higher catalytic activity (up to 7353 h(-1) for the 20 μm film of CA/IL/Pt(0)) and stability than the nanoparticles dispersed only in the IL.

  18. Hydration and Thermal Expansion in Anatase Nanoparticles.

    Science.gov (United States)

    Zhu, He; Li, Qiang; Ren, Yang; Fan, Longlong; Chen, Jun; Deng, Jinxia; Xing, Xianran

    2016-08-01

    A tunable thermal expansion is reported in nanosized anatase by taking advantage of surface hydration. The coefficient of thermal expansion of 4 nm TiO2 along a-axis is negative with a hydrated surface and is positive without a hydrated surface. High-energy synchrotron X-ray pair distribution function analysis combined with ab initio calculations on the specific hydrated surface are carried out to reveal the local structure distortion that is responsible for the unusual negative thermal expansion.

  19. Hydration and Thermal Expansion in Anatase Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, He [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 China; Li, Qiang [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 China; Ren, Yang [Argonne National Laboratory, X-Ray Science Division, Argonne IL 60439 USA; Fan, Longlong [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 China; Chen, Jun [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 China; Deng, Jinxia [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 China; Xing, Xianran [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 China

    2016-06-06

    A tunable thermal expansion is reported in nanosized anatase by taking advantage of surface hydration. The coefficient of thermal expansion of 4 nm TiO2 along a-axis is negative with a hydrated surface and is positive without a hydrated surface. High-energy synchrotron X-ray pair distribution function analysis combined with ab initio calculations on the specific hydrated surface are carried out to reveal the local structure distortion that is responsible for the unusual negative thermal expansion.

  20. Methane-propane hydrate crystal growth in the presence of nanosized materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.S.; Ryu, Y.B.; Kim, Y.S.; Lee, J.D. [Korea Inst. of Industrial Technology, Busan (Korea, Republic of). Busan Research Center; Park, Y.H. [Pusan National Univ., Busan (Korea, Republic of)

    2008-07-01

    The impact of nano-sized titanium dioxide, silver, and silica (TiO{sub 2}-Ag-SiO{sub 2}) sols on the gas hydrate formation morphology within an enclosed cell partially filled with liquid water was investigated. The nano-sized particles were synthesized suing a modified sol-gel method with a reduction agent added to eliminate the need for auxiliary dispersants or surfactants. Structure 2 (s2) hydrates were synthesized using a gas mixture of 90.1 per cent methane and propane as guest molecules. Small amounts of the nano-sized sols were added to the liquid water. The aim of the study was to determine methods of ensuring the stability of methane hydrates in storage facilities and during transport using gas to solids technology (GTS). Nucleation, hydrate crystal growth, and the migration of the gas hydrate were studied in relation to the stationary interface between the liquid water and the gas. Results of the study showed that the hydrate's growth phase started with the formation of a film at the upper surface of the liquid water pool. Crystals then grew in a downward manner from the hydrate film. Video images of the crystals showed that the downward crystals grown in the presence of the nano-sized particles occurred at a faster rate and with finer arm spacing. It was concluded that the addition of the nano-particles provided a larger specific surface area and larger nucleation sides so that more gas was absorbed into the water. The TiO{sub 2}-Ag-SiO{sub 2} sols acted as a promoter for methane-propane hydrate formation. 5 refs., 4 figs.

  1. Preparation and properties of biodegradable films from Sterculia urens short fiber/celluose green composites

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2013-04-01

    Full Text Available of the composites films is discussed. This paper presents the developments made in the area of biodegradable S. urens short fiber/cellulose (SUSF/cellulose) composite films, buried in the soil and later investigated by the (POM), before and after biodegradation has...

  2. Miniaturization of cellulose fibers and effect of addition on the mechanical and barrier properties of hydroxypropyl methylcellulose

    Science.gov (United States)

    Cellulose fibers were miniaturized by microfluidics technology and incorporated in hydroxypropyl methylcellulose (HPMC) films to study the effect of the addition of such fibers on the mechanical and barrier properties of HPMC films suitable for food packaging applications. The particle size of the f...

  3. Nanomechanics of cellulose crystals and cellulose-based polymer composites

    Science.gov (United States)

    Pakzad, Anahita

    Cellulose-polymer composites have potential applications in aerospace and transportation areas where lightweight materials with high mechanical properties are needed. In addition, these economical and biodegradable composites have been shown to be useful as polymer electrolytes, packaging structures, optoelectronic devices, and medical implants such as wound dressing and bone scaffolds. In spite of the above mentioned advantages and potential applications, due to the difficulties associated with synthesis and processing techniques, application of cellulose crystals (micro and nano sized) for preparation of new composite systems is limited. Cellulose is hydrophilic and polar as opposed to most of common thermoplastics, which are non-polar. This results in complications in addition of cellulose crystals to polymer matrices, and as a result in achieving sufficient dispersion levels, which directly affects the mechanical properties of the composites. As in other composite materials, the properties of cellulose-polymer composites depend on the volume fraction and the properties of individual phases (the reinforcement and the polymer matrix), the dispersion quality of the reinforcement through the matrix and the interaction between CNCs themselves and CNC and the matrix (interphase). In order to develop economical cellulose-polymer composites with superior qualities, the properties of individual cellulose crystals, as well as the effect of dispersion of reinforcements and the interphase on the properties of the final composites should be understood. In this research, the mechanical properties of CNC polymer composites were characterized at the macro and nano scales. A direct correlation was made between: - Dispersion quality and macro-mechanical properties - Nanomechanical properties at the surface and tensile properties - CNC diameter and interphase thickness. Lastly, individual CNCs from different sources were characterized and for the first time size-scale effect on

  4. From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

    Directory of Open Access Journals (Sweden)

    Maria Helena Godinho

    2014-06-01

    Full Text Available Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR, Rheology coupled with NMR (Rheo-NMR, rheology, optical methods, Magnetic Resonance Imaging (MRI, Wide Angle X-rays Scattering (WAXS, were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

  5. Direct-Write Fabrication of Cellulose Nano-Structures via Focused Electron Beam Induced Nanosynthesis

    Science.gov (United States)

    Ganner, Thomas; Sattelkow, Jürgen; Rumpf, Bernhard; Eibinger, Manuel; Reishofer, David; Winkler, Robert; Nidetzky, Bernd; Spirk, Stefan; Plank, Harald

    2016-09-01

    In many areas of science and technology, patterned films and surfaces play a key role in engineering and development of advanced materials. Here, we introduce a new generic technique for the fabrication of polysaccharide nano-structures via focused electron beam induced conversion (FEBIC). For the proof of principle, organosoluble trimethylsilyl-cellulose (TMSC) thin films have been deposited by spin coating on SiO2 / Si and exposed to a nano-sized electron beam. It turns out that in the exposed areas an electron induced desilylation reaction takes place converting soluble TMSC to rather insoluble cellulose. After removal of the unexposed TMSC areas, structured cellulose patterns remain on the surface with FWHM line widths down to 70 nm. Systematic FEBIC parameter sweeps reveal a generally electron dose dependent behavior with three working regimes: incomplete conversion, ideal doses and over exposure. Direct (FT-IR) and indirect chemical analyses (enzymatic degradation) confirmed the cellulosic character of ideally converted areas. These investigations are complemented by a theoretical model which suggests a two-step reaction process by means of TMSC → cellulose and cellulose → non-cellulose material conversion in excellent agreement with experimental data. The extracted, individual reaction rates allowed the derivation of design rules for FEBIC parameters towards highest conversion efficiencies and highest lateral resolution.

  6. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    Science.gov (United States)

    Meirovitch, Sigal; Shtein, Zvi; Ben-Shalom, Tal; Lapidot, Shaul; Tamburu, Carmen; Hu, Xiao; Kluge, Jonathan A.; Raviv, Uri; Kaplan, David L.; Shoseyov, Oded

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites. PMID:27649169

  7. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly.

    Science.gov (United States)

    Meirovitch, Sigal; Shtein, Zvi; Ben-Shalom, Tal; Lapidot, Shaul; Tamburu, Carmen; Hu, Xiao; Kluge, Jonathan A; Raviv, Uri; Kaplan, David L; Shoseyov, Oded

    2016-09-18

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites.

  8. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    Directory of Open Access Journals (Sweden)

    Sigal Meirovitch

    2016-09-01

    Full Text Available The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs and recombinant spider silk protein fused to a cellulose binding domain (CBD is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS, small angle X-ray scattering (SAXS and cryo-transmission electron microscopy (TEM indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites.

  9. Cellulose Fibre-Reinforced Biofoam for Structural Applications

    Directory of Open Access Journals (Sweden)

    Jasmina Obradovic

    2017-06-01

    Full Text Available Traditionally, polymers and macromolecular components used in the foam industry are mostly derived from petroleum. The current transition to a bio-economy creates demand for the use of more renewable feedstocks. Soybean oil is a vegetable oil, composed mainly of triglycerides, that is suitable material for foam production. In this study, acrylated epoxidized soybean oil and variable amounts of cellulose fibres were used in the production of bio-based foam. The developed macroporous bio-based architectures were characterised by several techniques, including porosity measurements, nanoindentation testing, scanning electron microscopy, and thermogravimetric analysis. It was found that the introduction of cellulose fibres during the foaming process was necessary to create the three-dimensional polymer foams. Using cellulose fibres has potential as a foam stabiliser because it obstructs the drainage of liquid from the film region in these gas-oil interfaces while simultaneously acting as a reinforcing agent in the polymer foam. The resulting foams possessed a porosity of approximately 56%, and the incorporation of cellulose fibres did not affect thermal behaviour. Scanning electron micrographs showed randomly oriented pores with irregular shapes and non-uniform pore size throughout the samples.

  10. Terahertz sensing of corneal hydration.

    Science.gov (United States)

    Singh, Rahul S; Tewari, Priyamvada; Bourges, Jean Louis; Hubschman, Jean Pierre; Bennett, David B; Taylor, Zachary D; Lee, H; Brown, Elliott R; Grundfest, Warren S; Culjat, Martin O

    2010-01-01

    An indicator of ocular health is the hydrodyanmics of the cornea. Many corneal disorders deteriorate sight as they upset the normal hydrodynamics of the cornea. The mechanisms include the loss of endothelial pump function of corneal dystophies, swelling and immune response of corneal graft rejection, and inflammation and edema, which accompany trauma, burn, and irritation events. Due to high sensitivity to changes of water content in materials, a reflective terahertz (300 GHz and 3 THz) imaging system could be an ideal tool to measure the hydration level of the cornea. This paper presents the application of THz technology to visualize the hydration content across ex vivo porcine corneas. The corneas, with a thickness variation from 470 - 940 µm, were successfully imaged using a reflective pulsed THz imaging system, with a maximum SNR of 50 dB. To our knowledge, no prior studies have reported on the use of THz in measuring hydration in corneal tissues or other ocular tissues. These preliminary findings indicate that THz can be used to accurately sense hydration levels in the cornea using a pulsed, reflective THz imaging system.

  11. Physical properties of gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Kliner, J.T.R.; Grozic, J.L.H. [Calgary Univ., AB (Canada)

    2003-07-01

    Gas hydrates are naturally occurring, solid crystalline compounds (clathrates) that encapsulate gas molecules inside the lattices of hydrogen bonded water molecules within a specific temperature-pressure stability zone. Estimates of the total quantity of available methane gas in natural occurring hydrates are based on twice the energy content of known conventional fossil fuels reservoirs. Accurate and reliable in-situ quantification techniques are essential in determining the economic viability of this potential energy yield, which is dependent upon several factors such as sensitivity of the temperature-pressure stability zone, sediment type, porosity, permeability, concentration/abundance of free gas, spatial distribution in pore spaces, specific cage occupancy, and the influence of inhibitors. Various techniques like acoustic P and S waves, time domain reflectometry, and electrical resistance have been used to analyze the quantity and spatial distribution of the gas hydrate samples. These techniques were reviewed and the results obtained in the course of gas hydrate research were presented. 34 refs., 8 figs.

  12. Hydration kinetics of transgenic soybeans

    Directory of Open Access Journals (Sweden)

    Aline Francielle Fracasso

    2015-01-01

    Full Text Available The kinetic and experimental analyses of the hydration process of transgenic soybeans (BRS 225 RR are provided. The importance of the hydration process consists of the grain texture modifications which favor grinding and extraction of soybeans. The soaking isotherms were obtained for four different temperatures. Results showed that temperature affected transgenic soybeans´ hydration rate and time. Moisture content d.b. of the soybeans increased from 0.12 ± 0.01 kg kg-1 to 1.45 ± 0.19 kg kg-1 during 270 min. of process. Two models were used to fit the kinetic curves: an empirical model developed by Peleg (1988 and a phenomenological one, proposed by Omoto et al. (2009. The two models adequately represented the hydration kinetics. Peleg model was applied to the experimental data and the corresponding parameters were obtained and correlated to temperature. The model by Omoto et al. (2009 showed a better statistical fitting. Although Ks was affected by temperature (Ks = 0.38079 exp (-2289.3 T-1, the equilibrium concentration remained practically unchanged.

  13. Development and characterization of hybrid materials based on biodegradable PLA matrix, microcrystalline cellulose and organophilic silica

    Directory of Open Access Journals (Sweden)

    Fernanda Abbate dos Santos

    2014-10-01

    Full Text Available The goal of this work was to investigate the production and properties of hybrid materials based on poly(lactic acid (PLA, employing microcrystalline cellulose (MCC and organophilic silica (R972 as fillers. The composites were obtained by solution casting to form films. Each nanoparticle was incorporated at 3 wt. %, relative to the polymer matrix. In this experiment, four films were obtained (PLA, PLA/MCC, PLA/R972 and PLA/MCC/R972. The films properties were evaluated by X-ray diffractometry, nuclear magnetic resonance, Fourier transform infrared spectroscopy and mechanical properties. The results showed that each nanoparticle, added individually or both combined, had different effect on the final properties of the films. Microcrystalline cellulose can act as nucleating agent for the crystallization of PLA. Silica promoted an increase in rigidity, due to the strong intermolecular forces, while MCC addition promoted an increase in the molecular mobility of the polymeric chains. The PLA/MCC/R972 film showed the highest crystallinity degree and tensile modulus. This film presented a T1H value between both values found for PLA/MCC and PLA/R972 films. The results indicated that silica R972 could promote a decrease of the surface tension between PLA and cellulose.

  14. Structure-activity relationships in carbohydrates revealed by their hydration.

    Science.gov (United States)

    Maugeri, Laura; Busch, Sebastian; McLain, Sylvia E; Pardo, Luis Carlos; Bruni, Fabio; Ricci, Maria Antonietta

    2016-12-21

    One of the more intriguing aspects of carbohydrate chemistry is that despite having very similar molecular structures, sugars have very different properties. For instance, there is a sensible difference in sweet taste between glucose and trehalose, even though trehalose is a disaccharide that comprised two glucose units, suggesting a different ability of these two carbohydrates to bind to sweet receptors. Here we have looked at the hydration of specific sites and at the three-dimensional configuration of water molecules around three carbohydrates (glucose, cellobiose, and trehalose), combining neutron diffraction data with computer modelling. Results indicate that identical chemical groups can have radically different hydration patterns depending on their location on a given molecule. These differences can be linked with the specific activity of glucose, cellobiose, and trehalose as a sweet substance, as building block of cellulose fiber, and as a bioprotective agent, respectively. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editors: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader.

  15. Cellulose Nanofibers as a Modifier for Rheology, Curing and Mechanical Performance of Oil Well Cement

    Science.gov (United States)

    Sun, Xiuxuan; Wu, Qinglin; Lee, Sunyoung; Qing, Yan; Wu, Yiqiang

    2016-08-01

    The influence of nanocellulose on oil well cement (OWC) properties is not known in detail, despite recent advances in nanocellulose technology and its related composite materials. The effect of cellulose nanofibers (CNFs) on flow, hydration, morphology, and strength of OWC was investigated using a range of spectroscopic methods coupled with rheological modelling and strength analysis. The Vom-Berg model showed the best fitting result of the rheology data. The addition of CNFs increased the yield stress of OWC slurry and degree of hydration value of hydrated CNF-OWC composites. The flexural strength of hydrated OWC samples was increased by 20.7% at the CNF/OWC ratio of 0.04 wt%. Excessive addition of CNFs into OWC matrix had a detrimental effect on the mechanical properties of hydrated CNF-OWC composites. This phenomenon was attributed to the aggregation of CNFs as observed through coupled morphological and elemental analysis. This study demonstrates a sustainable reinforcing nano-material for use in cement-based formulations.

  16. Cellulose acetate from oil palm empty fruit bunch via a one step heterogeneous acetylation.

    Science.gov (United States)

    Wan Daud, Wan Rosli; Djuned, Fauzi Muhammad

    2015-11-05

    Acetone soluble oil palm empty fruit bunch cellulose acetate (OPEFB-CA) of DS 2.52 has been successfully synthesized in a one-step heterogeneous acetylation of OPEFB cellulose without necessitating the hydrolysis stage. This has only been made possible by the mathematical modeling of the acetylation process by manipulating the variables of reaction time and acetic anhydride/cellulose ratio (RR). The obtained model was verified by experimental data with an error of less than 2.5%. NMR analysis showed that the distribution of the acetyl moiety among the three OH groups of cellulose indicates a preference at the C6 position, followed by C3 and C2. XRD revealed that OPEFB-CA is highly amorphous with a degree of crystallinity estimated to be ca. 6.41% as determined from DSC. The OPEFB-CA films exhibited good mechanical properties being their tensile strength and Young's modulus higher than those of the commercial CA.

  17. Eggshell and Bacterial Cellulose Composite Membrane as Absorbent Material in Active Packaging

    Directory of Open Access Journals (Sweden)

    S. Ummartyotin

    2016-01-01

    Full Text Available Bacterial cellulose and eggshell composite was successfully developed. Eggshell was mixed with bacterial cellulose suspension and it was casted as a composite film. CaCO3 derived from eggshell was compared with its commercial availability. It can be noted that good dispersion of eggshell particle was prepared. Eggshell particle was irregular in shape with a variation in size. It existed in bacterial cellulose network. Characterization on composite was focused on thermal and mechanical properties. It showed that flexibility and thermal stability of composite were enhanced. No significant effect of mechanical properties was therefore observed. The thermal stability of composite was stable up to 300°C. The adsorption experiment on water and vegetable oil capacity was performed. The enhancement on adsorption was due to the existence of eggshell in bacterial cellulose composite. It exhibited the potential to be a good candidate for absorbent material in active packaging.

  18. Biocomposites of cellulose reinforced starch: improvement of properties by photo-induced crosslinking.

    Science.gov (United States)

    Kumar, Annamalai Pratheep; Singh, Raj Pal

    2008-12-01

    In the present study, the composite films have been prepared from the aqueous dispersions of starch with microcrystalline cellulose using glycerol as plasticizer and irradiated under ultraviolet (UV) light using sodium benzoate as photo-sensitizer. Photo-crosslinking was characterized by measuring the water absorption under 100% relative humidity, swelling degree and gel fraction in dimethylsulphoxide (DMSO), upon irradiation time. Both, the incorporation of cellulose and photo-irradiation were found to decrease the water absorption, swelling in DMSO and increase the gel fraction. Thermal transitions indicated the anti-plasticization of amylopectin chains at the fiber/matrix interface. With increasing content of cellulose and photo-irradiation time, the tensile modulus and strength were found to improve. It is summarized that the combination of cellulose reinforcement and photo-crosslinking of matrix has improved the physical and mechanical properties.

  19. Ionic liquid processing of cellulose.

    Science.gov (United States)

    Wang, Hui; Gurau, Gabriela; Rogers, Robin D

    2012-02-21

    Utilization of natural polymers has attracted increasing attention because of the consumption and over-exploitation of non-renewable resources, such as coal and oil. The development of green processing of cellulose, the most abundant biorenewable material on Earth, is urgent from the viewpoints of both sustainability and environmental protection. The discovery of the dissolution of cellulose in ionic liquids (ILs, salts which melt below 100 °C) provides new opportunities for the processing of this biopolymer, however, many fundamental and practical questions need to be answered in order to determine if this will ultimately be a green or sustainable strategy. In this critical review, the open fundamental questions regarding the interactions of cellulose with both the IL cations and anions in the dissolution process are discussed. Investigations have shown that the interactions between the anion and cellulose play an important role in the solvation of cellulose, however, opinions on the role of the cation are conflicting. Some researchers have concluded that the cations are hydrogen bonding to this biopolymer, while others suggest they are not. Our review of the available data has led us to urge the use of more chemical units of solubility, such as 'g cellulose per mole of IL' or 'mol IL per mol hydroxyl in cellulose' to provide more consistency in data reporting and more insight into the dissolution mechanism. This review will also assess the greenness and sustainability of IL processing of biomass, where it would seem that the choices of cation and anion are critical not only to the science of the dissolution, but to the ultimate 'greenness' of any process (142 references).

  20. Physical activity, hydration and health

    Directory of Open Access Journals (Sweden)

    Ascensión Marcos

    2014-06-01

    Full Text Available Since the beginning of mankind, man has sought ways to promote and preserve health as well as to prevent disease. Hydration, physical activity and exercise are key factors for enhancing human health. However, either a little dose of them or an excess can be harmful for health maintenance at any age. Water is an essential nutrient for human body and a major key to survival has been to prevent dehydration. However, there is still a general controversy regarding the necessary amount to drink water or other beverages to properly get an adequate level of hydration. In addition, up to now the tools used to measure hydration are controversial. To this end, there are several important groups of variables to take into account such as water balance, hydration biomarkers and total body water. A combination of methods will be the most preferred tool to find out any risk or situation of dehydration at any age range. On the other hand, physical activity and exercise are being demonstrated to promote health, avoiding or reducing health problems, vascular and inflammatory diseases and helping weight management. Therefore, physical activity is also being used as a pill within a therapy to promote health and reduce risk diseases, but as in the case of drugs, dose, intensity, frequency, duration and precautions have to be evaluated and taken into account in order to get the maximum effectiveness and success of a treatment. On the other hand, sedentariness is the opposite concept to physical activity that has been recently recognized as an important factor of lifestyle involved in the obesogenic environment and consequently in the risk of the non-communicable diseases. In view of the literature consulted and taking into account the expertise of the authors, in this review a Decalogue of global recommendations is included to achieve an adequate hydration and physical activity status to avoid overweight/obesity consequences.

  1. Rheological and mechanical study of regenerated cellulose/multi-walled carbon nanotube composites

    Science.gov (United States)

    Shao, Wei; Wang, Shuxia; Liu, Hui; Wu, Jimin; Huang, Min; Ma, Wenjing; Huang, Chaobo

    2016-09-01

    Regenerated cellulose (RC)-based composites reinforced with multi-walled carbon nanotubes (MWCNTs) were prepared by a facile casting method. The morphology and microstructure of the fabricated composites were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Thermogravimetry and derivative thermogravimetric analysis were conducted to investigate the effect of MWCNTs on the thermal behaviors of the RC. The results showed that the introduction of MWCNTs enhanced the thermal stability of the RC. Moreover, the effect of the dispersion state of MWCNTs in microcrystalline cellulose/ZnCl2 solutions with varying MWCNT loadings was studied by rheological tests. The mechanical properties of composite films were remarkably improved compared to those of pure RC film. Specifically, the composite film containing 3 wt% of MWCNTs exhibits a 123% enhancement in tensile strength and a 163% enhancement in the Young’s modulus compared with the pure RC film.

  2. Seismic reflections associated with submarine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, K.

    1995-12-31

    Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

  3. Handbook of gas hydrate properties and occurrence

    Energy Technology Data Exchange (ETDEWEB)

    Kuustraa, V.A.; Hammershaimb, E.C.

    1983-12-01

    This handbook provides data on the resource potential of naturally occurring hydrates, the properties that are needed to evaluate their recovery, and their production potential. The first two chapters give data on the naturally occurring hydrate potential by reviewing published resource estimates and the known and inferred occurrences. The third and fourth chapters review the physical and thermodynamic properties of hydrates, respectively. The thermodynamic properties of hydrates that are discussed include dissociation energies and a simplified method to calculate them; phase diagrams for simple and multi-component gases; the thermal conductivity; and the kinetics of hydrate dissociation. The final chapter evaluates the net energy balance of recovering hydrates and shows that a substantial positive energy balance can theoretically be achieved. The Appendices of the Handbook summarize physical and thermodynamic properties of gases, liquids and solids that can be used in designing and evaluating recovery processes of hydrates. 158 references, 67 figures, 47 tables.

  4. Separation of water through gas hydrate formation

    DEFF Research Database (Denmark)

    Boch Andersen, Torben; Thomsen, Kaj

    2009-01-01

    Gas hydrate is normally recognized as a troublemaker in the oil and gas industry. However, gas hydrate has some interesting possibilities when used in connection with separation of water. Nordic Sugar has investigated the possibility of using gas hydrates for concentration of sugar juice. The goa...... volumes and the needs for high pressure. The process could be interesting for concentration of heat sensitive, high value products......Gas hydrate is normally recognized as a troublemaker in the oil and gas industry. However, gas hydrate has some interesting possibilities when used in connection with separation of water. Nordic Sugar has investigated the possibility of using gas hydrates for concentration of sugar juice. The goal...... of the project was to formulate an alternative separation concept, which can replace the traditional water evaporation process in the sugar production. Work with the separation concept showed that gas hydrates can be used for water separation. The process is not suitable for sugar production because of large...

  5. Development of 500-kV AC cable employing laminar insulation of other than conventional cellulosic paper

    Science.gov (United States)

    Bahder, G.; Eager, G. S., Jr.; Walker, J. J.; Dima, A. F.

    1980-09-01

    The results of an investigation to develop a 500 kV ac laminar dielectric power cable and joint having insulation with lower losses than conventional cellulosic paper insulation are presented. Background information is presented on proposed low loss synthetic and composite synthetic/cellulosic paper insulations. From these studies, fibrous polypropylene paper tape and cellulosic paper-polypropylene film-cellulosic paper composite paper (PPP) were chosen. Extensive testing of handwrapped cable models fabricated with each type of tape served to eliminate the fibrous polypropylene paper tape from further consideration. Cable model tests indicate that the PPP tape is satisfactory for insulation in 500 kV ac cable, and that oil impregnants now used in conventional cellulosic paper insulated cables are unsuitable, but that silicone oil with an additive is satisfactory for PPP tapes.

  6. Isolation and recovery of cellulose from waste nylon/cotton blended fabrics by 1-allyl-3-methylimidazolium chloride.

    Science.gov (United States)

    Lv, Fangbing; Wang, Chaoxia; Zhu, Ping; Zhang, Chuanjie

    2015-06-05

    Development of a simple process for separating cellulose and nylon 6 from their blended fabrics is indispensable for recycling of waste mixed fabrics. An efficient procedure of dissolution of the fabrics in an ionic liquid 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) and subsequent filtration separation has been demonstrated. Effects of treatment temperature, time and waste fabrics ratio on the recovery rates were investigated. SEM images showed that the cotton cellulose dissolved in [AMIM]Cl while the nylon 6 fibers remained. The FTIR spectrum of regenerated cellulose (RC) was similar with that of virgin cotton fibers, which verified that no other chemical reaction occurred besides breakage of hydrogen bonds during the processes of dissolution and separation. TGA curves indicated that the regenerated cellulose possessed a reduced thermal stability and was effectively removed from waste nylon/cotton blended fabrics (WNCFs). WNCFs were sufficiently reclaimed with high recovery rate of both regenerated cellulose films and nylon 6 fibers.

  7. Biodegradable packaging materials conception based on starch and polylactic acid (PLA) reinforced with cellulose.

    Science.gov (United States)

    Masmoudi, Fatma; Bessadok, Atef; Dammak, Mohamed; Jaziri, Mohamed; Ammar, Emna

    2016-10-01

    The plastic materials used for packaging are increasing leading to a considerable amount of undegradable solid wastes. This work deals with the reduction of conventional plastics waste and the natural resources preservation by using cellulosic polymers from renewable resources (alfa and luffa). Plasticized starch films syntheses were achieved at a laboratory scale. These natural films showed some very attractive mechanical properties at relatively low plasticizers levels (12 to 17 % by weight). Furthermore, mixtures including polylactic acid polymer (PLA) and cellulose fibers extracted from alfa and luffa were investigated by melt extrusion technique. When used at a rate of 10 %, these fibers improved the mixture mechanical properties. Both developed materials were biodegradable, but the plasticized starch exhibited a faster biodegradation kinetic compared to the PLA/cellulose fibers. These new materials would contribute to a sustainable development and a waste reduction.

  8. Regenerated Cellulose Capsules for Controlled Drug Delivery, Part 2: Modulating Membrane Permeability by Incorporation of Depolymerized Cellulose and Altering Membrane Thickness.

    Science.gov (United States)

    Bhatt, Bhavik; Kumar, Vijay

    2015-12-01

    For application of regenerated cellulose (RC) membranes in capsule dosage forms, the methods to modify drug release from these membranes are described. Membranes were fabricated by blending native and depolymerized celluloses dissolved in dimethyl sulfoxide and paraformaldehyde solvent system, prior to casting on molds, precipitation in water, and thermal annealing. The effect of laminating layers of RC to fabricate membranes with increasing thickness was also investigated. Solute diffusion studies using ionic and hydrophobic solutes, as well as large protein molecules, were conducted in side-by-side diffusion cells. Microscopic as well as physiological evaluation of these membranes indicated that pore size, porosity, and water uptake decreased as the fraction of depolymerized cellulose increased in the membranes. Permeability analysis of small ionic and hydrophobic solutes indicated that the solute transport across the hydrated membrane occurs through diffusion in the water-filled pores that are formed in situ. The apparent path for solute diffusion increases as the fraction of depolymerized cellulose increases. Permeability analysis of large protein molecules indicated that the pore sizes and distribution in these membranes is heterogeneous. Increasing the membrane thickness by lamination of RC does not influence porosity but causes formation of dead-end pores because of blocking by subsequent laminate layers.

  9. Hybrid HPMC nanocomposites containing bacterial cellulose nanocrystals and silver nanoparticles.

    Science.gov (United States)

    George, Johnsy; Kumar, Ranganathan; Sajeevkumar, Vallayil Appukuttan; Ramana, Karna Venkata; Rajamanickam, Ramalingam; Abhishek, Virat; Nadanasabapathy, Shanmugam; Siddaramaiah

    2014-05-25

    Hydroxypropyl methyl cellulose (HPMC) based hybrid nanocomposites reinforced with bacterial cellulose nanocrystals (BCNC) and silver nanoparticles (AgNPs) had been prepared and characterised. BCNC was capable of improving the tensile strength and modulus of HPMC, but they made the film more brittle. The addition of AgNPs along with BCNC, helped to regain some of the lost elongation properties without affecting other properties. Moisture sorption analysis proved that the hydrophilicity of the nanocomposite decreased considerably by the addition of these nanomaterials. Several mathematical models were also used to fit the experimental sorption results. A unique combination of two nanomaterials was highly effective in overcoming certain limitations of nanocomposites which uses only one type of nanomaterial. This type of hybrid nanocomposites with superior properties is expected to be useful in eco-friendly food packaging applications.

  10. Role of excipients in hydrate formation kinetics of theophylline in wet masses studied by near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Jørgensen, Anna C; Airaksinen, Sari; Karjalainen, Milja

    2004-01-01

    . Anhydrous theophylline was chosen as the hydrate-forming model drug compound and two excipients, silicified microcrystalline cellulose (SMCC) and alpha-lactose monohydrate, with different water absorbing properties, were used in formulation. An early stage of wet massing was studied with anhydrous...... theophylline and its 1:1 (w/w) mixtures with alpha-lactose monohydrate and SMCC with 0.1g/g of purified water. The changes in the state of water were monitored using near-infrared spectroscopy, and the conversion of the crystal structure was verified using X-ray powder diffraction (XRPD). SMCC decreased...... the hydrate formation rate by absorbing water, but did not inhibit it. The results suggest that alpha-lactose monohydrate slightly increased the hydrate formation rate in comparison with a mass comprising only anhydrous theophylline....

  11. Well log characterization of natural gas hydrates

    Science.gov (United States)

    Collett, Timothy S.; Lee, Myung W.

    2011-01-01

    In the last 25 years we have seen significant advancements in the use of downhole well logging tools to acquire detailed information on the occurrence of gas hydrate in nature: From an early start of using wireline electrical resistivity and acoustic logs to identify gas hydrate occurrences in wells drilled in Arctic permafrost environments to today where wireline and advanced logging-while-drilling tools are routinely used to examine the petrophysical nature of gas hydrate reservoirs and the distribution and concentration of gas hydrates within various complex reservoir systems. The most established and well known use of downhole log data in gas hydrate research is the use of electrical resistivity and acoustic velocity data (both compressional- and shear-wave data) to make estimates of gas hydrate content (i.e., reservoir saturations) in various sediment types and geologic settings. New downhole logging tools designed to make directionally oriented acoustic and propagation resistivity log measurements have provided the data needed to analyze the acoustic and electrical anisotropic properties of both highly inter-bedded and fracture dominated gas hydrate reservoirs. Advancements in nuclear-magnetic-resonance (NMR) logging and wireline formation testing have also allowed for the characterization of gas hydrate at the pore scale. Integrated NMR and formation testing studies from northern Canada and Alaska have yielded valuable insight into how gas hydrates are physically distributed in sediments and the occurrence and nature of pore fluids (i.e., free-water along with clay and capillary bound water) in gas-hydrate-bearing reservoirs. Information on the distribution of gas hydrate at the pore scale has provided invaluable insight on the mechanisms controlling the formation and occurrence of gas hydrate in nature along with data on gas hydrate reservoir properties (i.e., permeabilities) needed to accurately predict gas production rates for various gas hydrate

  12. Thermal conductivity of hydrate-bearing sediments

    Science.gov (United States)

    Cortes, Douglas D.; Martin, Ana I.; Yun, Tae Sup; Francisca, Franco M.; Santamarina, J. Carlos; Ruppel, Carolyn

    2009-11-01

    A thorough understanding of the thermal conductivity of hydrate-bearing sediments is necessary for evaluating phase transformation processes that would accompany energy production from gas hydrate deposits and for estimating regional heat flow based on the observed depth to the base of the gas hydrate stability zone. The coexistence of multiple phases (gas hydrate, liquid and gas pore fill, and solid sediment grains) and their complex spatial arrangement hinder the a priori prediction of the thermal conductivity of hydrate-bearing sediments. Previous studies have been unable to capture the full parameter space covered by variations in grain size, specific surface, degree of saturation, nature of pore filling material, and effective stress for hydrate-bearing samples. Here we report on systematic measurements of the thermal conductivity of air dry, water- and tetrohydrofuran (THF)-saturated, and THF hydrate-saturated sand and clay samples at vertical effective stress of 0.05 to 1 MPa (corresponding to depths as great as 100 m below seafloor). Results reveal that the bulk thermal conductivity of the samples in every case reflects a complex interplay among particle size, effective stress, porosity, and fluid-versus-hydrate filled pore spaces. The thermal conductivity of THF hydrate-bearing soils increases upon hydrate formation although the thermal conductivities of THF solution and THF hydrate are almost the same. Several mechanisms can contribute to this effect including cryogenic suction during hydrate crystal growth and the ensuing porosity reduction in the surrounding sediment, increased mean effective stress due to hydrate formation under zero lateral strain conditions, and decreased interface thermal impedance as grain-liquid interfaces are transformed into grain-hydrate interfaces.

  13. Thermal conductivity of hydrate-bearing sediments

    Science.gov (United States)

    Cortes, D.D.; Martin, A.I.; Yun, T.S.; Francisca, F.M.; Santamarina, J.C.; Ruppel, C.

    2009-01-01

    A thorough understanding of the thermal conductivity of hydrate-bearing sediments is necessary for evaluating phase transformation processes that would accompany energy production from gas hydrate deposits and for estimating regional heat flow based on the observed depth to the base of the gas hydrate stability zone. The coexistence of multiple phases (gas hydrate, liquid and gas pore fill, and solid sediment grains) and their complex spatial arrangement hinder the a priori prediction of the thermal conductivity of hydrate-bearing sediments. Previous studies have been unable to capture the full parameter space covered by variations in grain size, specific surface, degree of saturation, nature of pore filling material, and effective stress for hydrate-bearing samples. Here we report on systematic measurements of the thermal conductivity of air dry, water- and tetrohydrofuran (THF)-saturated, and THF hydrate-saturated sand and clay samples at vertical effective stress of 0.05 to 1 MPa (corresponding to depths as great as 100 m below seafloor). Results reveal that the bulk thermal conductivity of the samples in every case reflects a complex interplay among particle size, effective stress, porosity, and fluid-versus-hydrate filled pore spaces. The thermal conductivity of THF hydrate-bearing soils increases upon hydrate formation although the thermal conductivities of THF solution and THF hydrate are almost the same. Several mechanisms can contribute to this effect including cryogenic suction during hydrate crystal growth and the ensuing porosity reduction in the surrounding sediment, increased mean effective stress due to hydrate formation under zero lateral strain conditions, and decreased interface thermal impedance as grain-liquid interfaces are transformed into grain-hydrate interfaces. Copyright 2009 by the American Geophysical Union.

  14. The effect of hydrate saturation on water retention curves in hydrate-bearing sediments

    Science.gov (United States)

    Mahabadi, Nariman; Zheng, Xianglei; Jang, Jaewon

    2016-05-01

    The experimental measurement of water retention curve in hydrate-bearing sediments is critically important to understand the behavior of hydrate dissociation and gas production. In this study, tetrahydrofuran (THF) is selected as hydrate former. The pore habit of THF hydrates is investigated by visual observation in a transparent micromodel. It is confirmed that THF hydrates are not wetting phase on the quartz surface of the micromodel and occupy either an entire pore or part of pore space resulting in change in pore size distribution. And the measurement of water retention curves in THF hydrate-bearing sediments with hydrate saturation ranging from Sh = 0 to Sh = 0.7 is conducted for excess water condition. The experimental results show that the gas entry pressure and the capillary pressure increase with increasing hydrate saturation. Based on the experimental results, fitting parameters for van Genuchten equation are suggested for different hydrate saturation conditions.

  15. Plant cellulose synthesis: CESA proteins crossing kingdoms.

    Science.gov (United States)

    Kumar, Manoj; Turner, Simon

    2015-04-01

    Cellulose is a biopolymer of considerable economic importance. It is synthesised by the cellulose synthase complex (CSC) in species ranging from bacteria to higher plants. Enormous progress in our understanding of bacterial cellulose synthesis has come with the recent publication of both the crystal structure and biochemical characterisation of a purified complex able to synthesis cellulose in vitro. A model structure of a plant CESA protein suggests considerable similarity between the bacterial and plant cellulose synthesis. In this review article we will cover current knowledge of how plant CESA proteins synthesise cellulose. In particular the focus will be on the lessons learned from the recent work on the catalytic mechanism and the implications that new data on cellulose structure has for the assembly of CESA proteins into the large complex that synthesis plant cellulose microfibrils.

  16. Characterization of Cellulose Synthesis in Plant Cells

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Maleki

    2016-01-01

    Full Text Available Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4 D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family.

  17. Development of nonflammable cellulosic foams

    Science.gov (United States)

    Luttinger, M.

    1972-01-01

    The development of a moldable cellulosic foam for use in Skylab instrument storage cushions is considered. Requirements include density of 10 lb cu ft or less, minimal friability with normal handling, and nonflammability in an atmosphere of 70 percent oxygen and 30 percent nitrogen at 6.2 psia. A study of halogenated foam components was made, including more highly chlorinated binders, halogen-containing additives, and halogenation of the cellulose. The immediate objective was to reduce the density of the foam through reduction in inorganic phosphate without sacrificing flame-retarding properties of the foams. The use of frothing techniques was investigated, with particular emphasis on a urea-formaldehyde foam. Halogen-containing flame retardants were deemphasized in favor of inorganic salts and the preparation of phosphate and sulphate esters of cellulose. Utilization of foam products for civilian applications was also considered.

  18. A comparative study of cellulose nanofibrils disintegrated via multiple processing approaches

    Science.gov (United States)

    Yan Qing; Ronald Sabo; J.Y. Zhu; Umesh Agarwal; Zhiyong Cai; Yiqiang Wu

    2013-01-01

    Various cellulose nanofibrils (CNFs) created by refining and microfluidization, in combination withenzymatic or 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized pretreatment were compared. Themorphological properties, degree of polymerization, and crystallinity for the obtained nanofibrils, aswell as physical and mechanical properties of the corresponding films...

  19. Biocompatibility of Bacterial Cellulose Based Biomaterials

    OpenAIRE

    2012-01-01

    Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC) has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received...

  20. The trafficking and behavior of cellulose synthase and a glimpse of potential cellulose synthesis regulators

    Institute of Scientific and Technical Information of China (English)

    Logan BASHLINE; Juan DU; Ying GU

    2011-01-01

    Cellulose biosynthesis is a topic of intensive research not only due to the significance of cellulose in the integrity of plant cell walls,but also due to the potential of using cellulose,a natural carbon source,in the production ot biofuels.Characterization of the composition,regulation,and trafficking of cellulose synthase complexes (CSCs) is critical to an understanding of cellulose biosynthesis as well as the characterization of additional proteins that contribute to the production of cellulose either through direct interactions with CSCs or through indirect mechanisms.In this review,a highlight of a few proteins that appear to affect cellulose biosynthesis,which includes:KORRIGAN (KOR),Cellulose Synthase-Interactive Protein 1 (CSI1),and the poplar microtubule-associated protein,PttMAP20,will accompany a description of cellulose synthase (CESA) behavior and a discussion of CESA trafficking compartments that might act in the regulation of cellulose biosynthesis.

  1. Effect of Urea Concentration on the Viscosity and Thermal Stability of Aqueous NaOH/Urea Cellulose Solutions

    Directory of Open Access Journals (Sweden)

    Tim Huber

    2016-01-01

    Full Text Available Aqueous solutions of sodium hydroxide (NaOH and urea are a known and versatile solvent for cellulose. The dissolution of cellulose occurs at subambient temperatures through the formation of a cellulose-NaOH-urea “inclusion complex” (IC. NaOH and urea form a hydrate layer around the cellulose chains preventing chain agglomeration. Urea is known to stabilize the solution but its direct role is unknown. Using viscometry and quartz crystal microbalance with dissipation monitoring (QCM-D it could be shown that the addition of urea reduced the solutions viscosity of the tested solutions by almost 40% and also increased the gelation temperature from approximately 40°C to 90°C. Both effects could also be observed in the presence of additional cellulose powder serving as a physical cross-linker. Using Fourier transform infrared (FTIR spectroscopy during heating, it could be shown that a direct interaction occurs between urea and the cellulose molecules, reducing their ability to form hydrogen bonds with neighbouring chains.

  2. Synthesis of hydrated lutetium carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Song Liu [South China Univ. of Technology, Dept. of Applied Chemistry, Guangdong (China); Rong-jun Ma [Changsha Research Institute of Minig and Metallurgy, Hunan (China)

    1997-09-01

    Crystalline lutetium carbonate was synthesized for the corresponding chloride using ammonium bicarbonate as precipitant. The chemical analyses suggest that the synthesized lutetium carbonate is a hydrated basic carbonate or oxycarbonate. The X-ray powder diffraction data are presented. The IR data for the compound show the presence of two different carbonate groups. There is no stable intermediate carbonate in the process of thermal decomposition of the lutetium carbonate. (au) 15 refs.

  3. Cellulose nanomaterials review: structure, properties and nanocomposites

    Science.gov (United States)

    Robert J. Moon; Ashlie Martini; John Nairn; John Simonsen; Jeff Youngblood

    2011-01-01

    This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The...

  4. Bioengineering cellulose-hemicellulose networks in plants

    NARCIS (Netherlands)

    Obembe, O.

    2006-01-01

    The interactions between cellulose and hemicellulose in the cell walls are important in the industrial application of the cellulose (natural) fibres. We strive to modify these interactions (i) by interfering with cellulose biosynthesis and (ii) by direct interference of the

  5. Adsorption and desorption of cellulose derivatives

    NARCIS (Netherlands)

    Hoogendam, C.W.

    1998-01-01

    Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.

    In chapter 1

  6. Adsorption and desorption of cellulose derivatives.

    NARCIS (Netherlands)

    Hoogendam, C.W.

    1998-01-01

    Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.In chapter 1 of this thesis we discuss some appl

  7. Crystallite size distributions of marine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Klapp, S.A.; Bohrmann, G.; Abegg, F. [Bremen Univ., Bremen (Germany). Research Center of Ocean Margins; Hemes, S.; Klein, H.; Kuhs, W.F. [Gottingen Univ., Gottingen (Germany). Dept. of Crystallography

    2008-07-01

    Experimental studies were conducted to determine the crystallite size distributions of natural gas hydrate samples retrieved from the Gulf of Mexico, the Black Sea, and a hydrate ridge located near offshore Oregon. Synchrotron radiation technology was used to provide the high photon fluxes and high penetration depths needed to accurately analyze the bulk sediment samples. A new beam collimation diffraction technique was used to measure gas hydrate crystallite sizes. The analyses showed that gas hydrate crystals were globular in shape. Mean crystallite sizes ranged from 200 to 400 {mu}m for hydrate samples taken from the sea floor. Larger grain sizes in the hydrate ridge samples suggested differences in hydrate formation ages or processes. A comparison with laboratory-produced methane hydrate samples showed half a lognormal curve with a mean value of 40{mu}m. Results of the study showed that a cautious approach must be adopted when transposing crystallite-size sensitive physical data from laboratory-made gas hydrates to natural settings. It was concluded that crystallite size information may also be used to resolve the formation ages of gas hydrates when formation processes and conditions are constrained. 48 refs., 1 tab., 9 figs.

  8. IMPORTANCE OF HYDRATION IN SPORTS

    Directory of Open Access Journals (Sweden)

    Goran Vasić

    2008-08-01

    Full Text Available Importance of hydration is detrmined by importance of functions of water in the human organism: i.e. regulation of body temperature, transport, excretion of waste materials through urine, digestion of food which is facilititated by saliva and gastric juices, maintenance of flexibility of organs and tissues About 60 % body mass of an adult person (males: 61 %, females: 54 % is made up of water. Water content of a newly born baby reaches 77 %, and it is up to 50 % in adults. It is very important for sportsmen to provide adequate hydration during and after the time of bodily activities. A symptom of water shortage is thirst. However, thirst is a late response of an organism and it occurs when dehydration has already taken place. Minimum in take of fluids in humans should range between one-and-half to two liters. It has been known for a long time that there is no success in sport without proper hydration in a sportsman.

  9. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Directory of Open Access Journals (Sweden)

    Mehmet Isik

    2014-07-01

    Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels.

  10. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did...

  11. Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

    OpenAIRE

    Chukwuemeka P. Azubuike; Jimson O. Odulaja; Augustine O Okhamafe

    2012-01-01

    α-Cellulose and microcrystalline cellulose powders, derived from agricultural waste products, that have for thepharmaceutical industry, desirable physical (flow) properties were investigated. α–Cellulose (GCN) wasextracted from groundnut shell (an agricultural waste product) using a non-dissolving method based oninorganic reagents. Modification of this α -cellulose was carried out by partially hydrolysing it with 2Nhydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN). Th...

  12. Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

    OpenAIRE

    Nigmatullin, R.; Lovitt, R.; Wright, C; Linder, M.; Nakari-Setälä, T; Gama, F. M.

    2004-01-01

    Colloidal probe microscopy has been used to study the interaction between model cellulose surfaces and the role of cellulose binding domain (CBD), peptides specifically binding to cellulose, in interfacial interaction of cellulose surfaces modified with CBDs. The interaction between pure cellulose surfaces in aqueous electrolyte solution is dominated by double layer repulsive forces with the range and magnitude of the net force dependent on electrolyte concentration. AFM imaging reve...

  13. 抗菌纤维素/纤维素纤维的研究进展%Research progress of antibacterial cellulose/cellulose fiber

    Institute of Scientific and Technical Information of China (English)

    徐永建; 左磊刚

    2014-01-01

    介绍了常用的无机抗菌剂和有机抗菌剂的种类及其抗菌机理,阐述了载银抗菌纤维素、纳米TiO2抗菌纤维素、季铵盐类抗菌纤维素、壳聚糖改性抗菌纤维素等抗菌纤维素及其在纺织工业、膜材料等方面的应用。指出了根据所选抗菌剂的不同,通过化学或物理方法可对纤维素和纤维素纤维进行抗菌改性。绒毛浆是一次性卫生用品吸水性垫层用绒毛化的纤维素纤维,对绒毛浆进行抗菌性改性能够提高绒毛浆的品质和功能。提出了可用于绒毛浆纤维抗菌性改性的抗菌剂和可能的方法,抗菌纤维素纤维改性在绒毛浆生产和应用中存在潜在应用前景。同时,提出了抗菌纤维素/纤维素纤维在生产和应用中存在的问题和解决办法。%The commonly used inorganic antibacterial agent and organic antibacterial agent , and their types and antibacterial mechanism were introduced .Silver antibacterial cellulose , nano TiO2 antibacterial cellulose , quaternary ammonium antibacterial cellulose , chitosan modified bacterial cellulose and other antimicrobial cellulose and its application in the textile industry ,film material and other applications were elaborated .According to the selected type of antibacterial agent ,cellulose and cellulose fibers can be modified by chemical or physical method ,fluff pulp is fluffed cellulose fibers used in disposable sanitary absorbent mat ,and fluff pulp can improve its quality and function by antibacterial modified .Paper introduced the possible antimicrobial agent and methods can be used in the antibacterial modified of fluff pulp fibers ,and the potential prospect of antibacterial modified of cellulose fibers in the pro-duction and application fluff pulp .Meanwhile the problems and solutions were presented in the production and application of antibacterial cellulose and cellulose fiber .

  14. Cholesteric liquid crystal formation in suspensions of cellulose nanocrystals

    Science.gov (United States)

    Honorato-Rios, Camilla; Bruckner, Johanna; Schütz, Christina; Wagner, Sammy; Tosheva, Zornitza; Bergström, Lennart; Lagerwall, Jan P. F.

    With the strong current trend in nanotechnology to focus on sustainably produced nanomaterials, cellulose nanocrystals (CNC) are emerging as a particularly interesting candidate. They are mechanically strong, optically transparency and birefringent, have low weight and low thermal expansion coefficient. A most desirable feature of CNC is that aqueous suspensions form cholesteric liquid crystal phases already at low concentration, and when dried into thin solid films, the periodicity of the helical structure can be reduced to the range of visible selective reflection, in practice making the film a photonic crystal paper. We begin the chapter by briefly explaining how CNC is extracted from cellulose-rich bioresources, followed by a summary of the typical characteristics in terms of dimensions and surface charge, and how these depend on the production method. The current understanding of the phase diagram of CNC suspensions is then discussed, from the low-concentration regime around the isotropic-cholesteric transition to the less well understood regime where the system is kinetically arrested in a non-equilibrium state. We discuss the influences on phase behavior and cholesteric pitch of the solvent and its ionic strength. Finally, we discuss the production of photonic crystal films and we give a brief outlook.

  15. Study of Formation Mechanisms of Gas Hydrate

    Science.gov (United States)

    Yang, Jia-Sheng; Wu, Cheng-Yueh; Hsieh, Bieng-Zih

    2015-04-01

    Gas hydrates, which had been found in subsurface geological environments of deep-sea sediments and permafrost regions, are solid crystalline compounds of gas molecules and water. The estimated energy resources of hydrates are at least twice of that of the conventional fossil fuel in the world. Gas hydrates have a great opportunity to become a dominating future energy. In the past years, many laboratory experiments had been conducted to study chemical and thermodynamic characteristics of gas hydrates in order to investigate the formation and dissociation mechanisms of hydrates. However, it is difficult to observe the formation and dissociation of hydrates in a porous media from a physical experiment directly. The purpose of this study was to model the dynamic formation mechanisms of gas hydrate in porous media by reservoir simulation. Two models were designed for this study: 1) a closed-system static model with separated gas and water zones; this model was a hydrate equilibrium model to investigate the behavior of the formation of hydrates near the initial gas-water contact; and 2) an open-system dynamic model with a continuous bottom-up gas flow; this model simulated the behavior of gas migration and studied the formation of hydrates from flowed gas and static formation water in porous media. A phase behavior module was developed in this study for reservoir simulator to model the pressure-volume-temperature (PVT) behavior of hydrates. The thermodynamic equilibriums and chemical reactions were coupled with the phase behavior module to have functions modelling the formation and dissociation of hydrates from/to water and gas. The simulation models used in this study were validated from the code-comparison project proposed by the NETL. According to the modelling results of the closed-system static model, we found that predominated location for the formation of hydrates was below the gas-water contact (or at the top of water zone). The maximum hydrate saturation

  16. Foaming of Ethyl Hydroxyethyl Cellulose

    OpenAIRE

    Carrillo Agilera, Marc

    2015-01-01

    The current depletion of petroleum resources together with environmental issues have led to new approaches in plastic manufacturing. This trend involves using ecofriendly materials coming from renewable resources. Good candidates for this, due to their properties and availability, are the cellulose derivatives. Some of them, such as hydroxypropyl methylcellulose (HPMC), showed in previous studies a promising behavior when making polymeric foams. Unfortunately, the corresponding...

  17. The use of sodium alginate-based coating and cellulose acetate in papaya post-harvest preservation

    Directory of Open Access Journals (Sweden)

    Denise Andrade Silva

    2014-02-01

    Full Text Available This study aimed to evaluate the ripening of papaya fruit (Carica papaya L. at room temperature (±25°C and10°C with 80% relative humidity, coated with edible film based on sodium alginate (1% and cellulose acetate film (3% by dipping the fruit in the suspensions for 1 min. On the application of the treatment and every three days during 12 days of storage, fruit were evaluated for weight loss, firmness, total carotenoid content, lycopene content and vitamin C content of the pulp. The cellulose acetate film extended the shelf-life of papayas, without affecting their quality. This treatment delayed fruit ripening, whose changes in all the parameters analyzed were significantly slower than fruit treated with sodium alginate-based coating. The coating with cellulose acetate at 3% was more effective in the preservation of papaya stored for 12 days under both temperatures.

  18. Cellulose nanomaterials review: structure, properties and nanocomposites.

    Science.gov (United States)

    Moon, Robert J; Martini, Ashlie; Nairn, John; Simonsen, John; Youngblood, Jeff

    2011-07-01

    This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

  19. SEISMIC STUDIES OF MARINE GAS HYDRATES

    Institute of Scientific and Technical Information of China (English)

    SONG Haibin

    2003-01-01

    We give a brief introduction of developments of seismic methods in the studies of marine gas hydrates. Then we give an example of seismic data processing for BSRs in western Nankai accretionary prism, a typical gas hydrate distribution region. Seismic data processing is proved to be important to obtain better images of BSRs distribution. Studies of velocity structure of hydrated sediments are useful for better understanding the distribution of gas hydrates. Using full waveform inversion, we successfully derived high-resolution velocity model of a double BSR in eastern Nankai Trough area. Recent survey and research show that gas hydrates occur in the marine sediments of the South China Sea and East China Sea.But we would like to say seismic researches on gas hydrate in China are very preliminary.

  20. Development of Alaskan gas hydrate resources

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, V.A.; Sharma, G.D.; Patil, S.L.

    1991-06-01

    The research undertaken in this project pertains to study of various techniques for production of natural gas from Alaskan gas hydrates such as, depressurization, injection of hot water, steam, brine, methanol and ethylene glycol solutions through experimental investigation of decomposition characteristics of hydrate cores. An experimental study has been conducted to measure the effective gas permeability changes as hydrates form in the sandpack and the results have been used to determine the reduction in the effective gas permeability of the sandpack as a function of hydrate saturation. A user friendly, interactive, menu-driven, numerical difference simulator has been developed to model the dissociation of natural gas hydrates in porous media with variable thermal properties. A numerical, finite element simulator has been developed to model the dissociation of hydrates during hot water injection process.

  1. Bioelectrodes based on pseudocapacitive cellulose/polypyrrole composite improve performance of biofuel cell.

    Science.gov (United States)

    Kizling, Michal; Stolarczyk, Krzysztof; Tammela, Petter; Wang, Zhaohui; Nyholm, Leif; Golimowski, Jerzy; Bilewicz, Renata

    2016-12-01

    Enzymatic electrodes with high internal capacitance, based on cellulose/polypyrrole composite were optimized and utilized to design improved enzymatic fuel cell. Fructose dehydrogenase Gluconobacter sp. specifically adsorbed on the cellulose/polypyrrole matrix and electrophoretically immobilized and electrochemically entrapped Laccase Trametes versicolor, were used as the anode and cathode bioelectrocatalysts, respectively. The cellulose/polypyrrole composite film exhibited pseudocapacitive properties under mild pH conditions. Following modification with carboxylic groups the composite material enabled highly efficient adsorption of enzyme and provided good electrical contact between the enzymatic active sites and the electrode surface. The modified cellulose/polypyrrole composite based electrode was used for the anode leading to mediatorless fructose oxidation giving large catalytic current density, 12.8mAcm(-2). Laccase and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) as the mediator entrapped in the cellulose/polypyrrole composite film generated dioxygen reduction current density of 2mAcm(-2). Application of pseudocapacitive matrix and decreasing the distance between electrodes to 1mm lead to improvement of the biofuel cell power output and its regeneration ability. The power of the cell was found to increase by introduction of a preconditioning step during which the cell was kept at open circuit voltage under fuel flow. After 24h of preconditioning the matrix was recharged and the device output reached the power, 2.1mWcm(-2) and OCV, 0.59V. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Terahertz Time Domain Spectroscopy for Structure-II Gas Hydrates

    DEFF Research Database (Denmark)

    Takeya, Kei; Zhang, Caihong; Kawayama, Iwao

    2009-01-01

    For the nondestructive inspection of gas hydrates, terahertz (THz) time-domain spectroscopy (TDS) was applied to tetrahydrofuran (THF) hydrate and propane hydrate. The absorption of propane hydrate monotonically increases with frequency, similar to the case of ice, while THF hydrate has a charact...

  3. Clinker mineral hydration at reduced relative humidities

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    1998-01-01

    This report deals with gas phase hydration of pure cement clinker minerals at reduced relative humidities. This is an important subject in relation to modern high performance concrete which may self-desiccate during hydration. In addition the subject has relevance to storage stability where...... prehydration may occur. In the report both theoretical considerations and experimental data are presented. It is suggested that the initiation of hydration during water vapour exposure is nucleation controlled....

  4. Structure and engineering of celluloses.

    Science.gov (United States)

    Pérez, Serge; Samain, Daniel

    2010-01-01

    This chapter collates the developments and conclusions of many of the extensive studies that have been conducted on cellulose, with particular emphasis on the structural and morphological features while not ignoring the most recent results derived from the elucidation of unique biosynthetic pathways. The presentation of structural and morphological data gathered together in this chapter follows the historical development of our knowledge of the different structural levels of cellulose and its various organizational levels. These levels concern features such as chain conformation, chain polarity, chain association, crystal polarity, and microfibril structure and organization. This chapter provides some historical landmarks related to the evolution of concepts in the field of biopolymer science, which parallel the developments of novel methods for characterization of complex macromolecular structures. The elucidation of the different structural levels of organization opens the way to relating structure to function and properties. The chemical and biochemical methods that have been developed to dissolve and further modify cellulose chains are briefly covered. Particular emphasis is given to the facets of topochemistry and topoenzymology where the morphological features play a key role in determining unique physicochemical properties. A final chapter addresses what might be considered tomorrow's goal in amplifying the economic importance of cellulose in the context of sustainable development. Selected examples illustrate the types of result that can be obtained when cellulose fibers are no longer viewed as inert substrates, and when the polyhydroxyl nature of their surfaces, as well as their entire structural complexity, are taken into account. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Cellulose nanomaterials in water treatment technologies.

    Science.gov (United States)

    Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R

    2015-05-05

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization.

  6. Hierarchical-structured anatase-titania/cellulose composite sheet with high photocatalytic performance and antibacterial activity.

    Science.gov (United States)

    Luo, Yan; Huang, Jianguo

    2015-02-02

    Bulk hierarchical anatase-titania/cellulose composite sheets were fabricated by subjecting an ultrathin titania gel film pre-deposited filter paper to a solvo-co-hydrothermal treatment by using titanium butoxide as the precursor to grow anatase-titania nanocrystallites on the cellulose nanofiber surfaces. The titanium butoxide specie is firstly absorbed onto the nanofibers of the cellulose substance through a solvothermal process, which was thereafter hydrolyzed and crystallized upon the subsequent hydrothermal treatment, leading to the formation of fine anatase-titania nanoparticles with sizes of 2-5 nm uniformly anchored on the cellulose nanofibers. The resulting anatase-titania/cellulose composite sheet shows a significant photocatalytic performance towards degradation of a methylene blue dye, and introduction of silver nanoparticles into the composite sheet yields an Ag-NP/anatase-titania/cellulose composite material possessing excellent antibacterial activity against both Gram-positive and Gram-negative bacteria. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Preparation and characterization of regenerated cellulose membranes from natural cotton fiber

    Directory of Open Access Journals (Sweden)

    Yanjuan CAO

    2015-06-01

    Full Text Available A series of organic solutions with different cellulose concentrations are prepared by dissolving natural cotton fibers in lithium chloride/dimethyl acetamide (LiCl/DMAC solvent system after the activation of cotton fibers. Under different coagulating bath, the regenerated cellulose membranes are formed in two kinds of coagulation baths, and two coating methods including high-speed spin technique (KW-4A spin coating machine and low-speed scraping (AFA-Ⅱ Film Applicator are selected in this paper. The macromolecular structure, mechanical properties, crystallinity, thermal stability and wetting property of the regenerated cellulose membrane are characterized by Scanning Electron Microscope(SEM, Fourier Transform Infrared Spectroscopy (FT-IR,X-ray diffraction (XRD, Thermogravimetric analysis (TG and contacting angle tester. The effects of mass fraction, coagulation bath type, membrane forming process on the regenerated membrane properties are investigated. Experimental results show that the performance of regenerated cellulose membrane is relatively excellent under the condition of using the KW-4A high-speed spin method, water coagulation bath, and when mass fraction of cellulose is 3.5%. The crystallinity of the regenerated cellulose membrane changes a lot compared with natural cotton fibers. The variation trend of thermal stability is similar with that of cotton fiber. But thermal stability is reduced to some degree, while the wetting ability is improved obviously.

  8. Prediction of Refrigerant Gas Hydrates Formation Conditions

    Institute of Scientific and Technical Information of China (English)

    Deqing Liang; Ruzhu Wang; Kaihua Guo; Shuanshi Fan

    2001-01-01

    A fugacity model was developed for prediction of mixed refrigerant gas hydrates formation conditions based on the molecule congregation and solution theories. In this model, g as hydrates were regarded as non-ideal solid solution composed of water groups and guest molecules, and the expressions of fugacity of guest molecules in hydrate phase was proposed accordingly. It has been shown that the developed model can indicate successfully the effect of guest-guest molecule interaction. The results showed that the model can describe better the characteristics of phase equilibrium of mixed refrigerant gas hydrates and predictions are in good agreement with experimental data.

  9. Desalination utilizing clathrate hydrates (LDRD final report).

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Blake Alexander; Bradshaw, Robert W.; Dedrick, Daniel E.; Cygan, Randall Timothy (Sandia National Laboratories, Albuquerque, NM); Greathouse, Jeffery A. (Sandia National Laboratories, Albuquerque, NM); Majzoub, Eric H. (University of Missouri, Columbia, MO)

    2008-01-01

    Advances are reported in several aspects of clathrate hydrate desalination fundamentals necessary to develop an economical means to produce municipal quantities of potable water from seawater or brackish feedstock. These aspects include the following, (1) advances in defining the most promising systems design based on new types of hydrate guest molecules, (2) selection of optimal multi-phase reactors and separation arrangements, and, (3) applicability of an inert heat exchange fluid to moderate hydrate growth, control the morphology of the solid hydrate material formed, and facilitate separation of hydrate solids from concentrated brine. The rate of R141b hydrate formation was determined and found to depend only on the degree of supercooling. The rate of R141b hydrate formation in the presence of a heat exchange fluid depended on the degree of supercooling according to the same rate equation as pure R141b with secondary dependence on salinity. Experiments demonstrated that a perfluorocarbon heat exchange fluid assisted separation of R141b hydrates from brine. Preliminary experiments using the guest species, difluoromethane, showed that hydrate formation rates were substantial at temperatures up to at least 12 C and demonstrated partial separation of water from brine. We present a detailed molecular picture of the structure and dynamics of R141b guest molecules within water cages, obtained from ab initio calculations, molecular dynamics simulations, and Raman spectroscopy. Density functional theory calculations were used to provide an energetic and molecular orbital description of R141b stability in both large and small cages in a structure II hydrate. Additionally, the hydrate of an isomer, 1,2-dichloro-1-fluoroethane, does not form at ambient conditions because of extensive overlap of electron density between guest and host. Classical molecular dynamics simulations and laboratory trials support the results for the isomer hydrate. Molecular dynamics simulations

  10. Waters of Hydration of Cupric Hydrates: A Comparison between Heating and Absorbance Methods

    Science.gov (United States)

    Barlag, Rebecca; Nyasulu, Frazier

    2011-01-01

    The empirical formulas of four cupric hydrates are determined by measuring the absorbance in aqueous solution. The Beer-Lambert Law is verified by constructing a calibration curve of absorbance versus known Cu[superscript 2+](aq) concentration. A solution of the unknown hydrate is prepared by using 0.2-0.3 g of hydrate, and water is added such…

  11. Measurements of water content in hydroxypropyl-methyl-cellulose based hydrogels via texture analysis.

    Science.gov (United States)

    Lamberti, Gaetano; Cascone, Sara; Cafaro, Maria Margherita; Titomanlio, Giuseppe; d'Amore, Matteo; Barba, Anna Angela

    2013-01-30

    In this work, a fast and accurate method to evaluate the water content in a cellulose derivative-based matrix subjected to controlled hydration was proposed and tuned. The method is based on the evaluation of the work of penetration required in the needle compression test. The work of penetration was successfully related to the hydrogel water content, assayed by a gravimetric technique. Moreover, a fitting model was proposed to correlate the two variables (the water content and the work of penetration). The availability of a reliable tool is useful both in the quantification of the water uptake phenomena, both in the management of the testing processes of novel pharmaceutical solid dosage forms.

  12. Hydration in soccer: a review

    Directory of Open Access Journals (Sweden)

    Monteiro Cristiano Ralo

    2003-01-01

    Full Text Available Hydration should be considered before, during and after the exercise. This review intends to approach the main points of hydration process in soccer. The replacement of fluids during exercise is proportional to some factors, such as: exercise intensity; climatic conditions; the athlete's acclimatization; the athlete's physical conditioning; physiologic individual characteristics and the player's biomechanics. Performance is improved when players ingest not only water but also carbohydrate. The rates that carbohydrate and water are absorbed by the organism are limited by the rates of gastric emptying and intestinal absorption. The composition of drinks offered to the players should be influenced by the relative importance of the need of supplying carbohydrates or water; it should be remembered that the depletion of carbohydrate can result in fatigue and decrease of performance, but it is not usually a life-threatening condition. The addition of carbohydrate in these drinks increases the concentrations of blood glucose, increases the use of external fuel through the increase of the glucose oxidation in the muscles and it spares muscle glycogen. So, the ingestion of carbohydrate before and during the exercise can delay the emergence of fatigue and increase the players' performance. Several tactics can be used to avoid dehydration, like hyperhydration before exercise and player's acclimatization. The ideal situation to restore the player's fluid losses is between the sessions of exercises. Since soccer is a sport with quite peculiar characteristics related to hydration, the players should be concerned and educated about the importance of fluid ingestion before, during and after the exercise.

  13. Hydration behaviour of polyhydroxylated fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Zavala, J G [Departamento de Ciencias Exactas y Tecnologicas, Centro Universitario de Los Lagos, Universidad de Guadalajara, Enrique Diaz de Leon S/N, 47460 Jalisco (Mexico); Barajas-Barraza, R E [Departamento de Matematicas y Fisica, Instituto Tecnologico y de Estudios Superiores de Occidente, Periferico Sur, Manuel Gomez MorIn No 8585, 45604 Jalisco (Mexico); Padilla-Osuna, I; Guirado-Lopez, R A, E-mail: jgrz@culagos.udg.mx, E-mail: ebarajas@iteso.mx, E-mail: ismael@ifisica.uaslp.mx, E-mail: guirado@ifisica.uaslp.mx [Instituto de Fisica ' Manuel Sandoval Vallarta' , Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi (Mexico)

    2011-10-28

    We have performed semi-empirical as well as density functional theory calculations in order to analyse the hydration properties of both bare C{sub 60} and highly hydroxylated C{sub 60}(OH){sub 26} fullerenes. In all of our calculations, a total of 42 and 98 water molecules are always surrounding our here-considered carbon nanostructures. We found different wetting properties as a function of the chemical composition and structure of the OH-molecular over-layer covering the fullerene surface. In the case of bare C{sub 60}, water adsorption reveals that the H{sub 2}O species are not uniformly arranged around the carbon network but rather forms water droplets of different sizes, clearly revealing the hydrophobic nature of the C{sub 60} structure. In contrast, in the polyhydroxylated C{sub 60}(OH){sub 26} fullerenes, the degree of wetting is strongly influenced by the precise location of the hydroxyl groups. We found that different adsorbed configurations for the OH-molecular coating can lead to the formation of partially hydrated or completely covered C{sub 60}(OH){sub 26} compounds, a result that could be used to synthesize fullerene materials with different degrees of wettability. By comparing the relative stability of our hydroxylated structures in both bare and hydrated conditions we obtain that the energy ordering of the C{sub 60}(OH){sub 26} isomers can change in the presence of water. The radial distribution function of our hydrated fullerenes reveals that water near these kinds of surfaces is densely packed. In fact, by counting the number of H{sub 2}O molecules which are adsorbed, by means of hydrogen bonds, to the surface of our more stable C{sub 60}(OH){sub 26} isomer, we found that it varies in the range of 5-10, in good agreement with experiments. Finally, by comparing the calculated optical absorption spectra of various C{sub 60}(OH){sub 26} structures in the presence and absence of water molecules, we note that only slight variations in the position and

  14. Protein dynamics: hydration and cavities

    Directory of Open Access Journals (Sweden)

    K. Heremans

    2005-08-01

    Full Text Available The temperature-pressure behavior of proteins seems to be unique among the biological macromolecules. Thermodynamic as well as kinetic data show the typical elliptical stability diagram. This may be extended by assuming that the unfolded state gives rise to volume and enthalpy-driven liquid-liquid transitions. A molecular interpretation follows from the temperature and the pressure dependence of the hydration and cavities. We suggest that positron annihilation spectroscopy can provide additional quantitative evidence for the contributions of cavities to the dynamics of proteins. Only mature amyloid fibrils that form from unfolded proteins are very resistant to pressure treatment.

  15. Ultrasound mediated enzymatic hydrolysis of cellulose and carboxymethyl cellulose.

    Science.gov (United States)

    Sulaiman, Ahmad Ziad; Ajit, Azilah; Chisti, Yusuf

    2013-01-01

    A recombinant Trichoderma reesei cellulase was used for the ultrasound-mediated hydrolysis of soluble carboxymethyl cellulose (CMC) and insoluble cellulose of various particle sizes. The hydrolysis was carried out at low intensity sonication (2.4-11.8 W cm(-2) sonication power at the tip of the sonotrode) using 10, 20, and 40% duty cycles. [A duty cycle of 10%, for example, was obtained by sonicating for 1 s followed by a rest period (no sonication) of 9 s.] The reaction pH and temperature were always 4.8 and 50°C, respectively. In all cases, sonication enhanced the rate of hydrolysis relative to nonsonicated controls. The hydrolysis of CMC was characterized by Michaelis-Menten kinetics. The Michaelis-Menten parameter of the maximum reaction rate Vmax was enhanced by sonication relative to controls, but the value of the saturation constant Km was reduced. The optimal sonication conditions were found to be a 10% duty cycle and a power intensity of 11.8 W cm(-2) . Under these conditions, the maximum rate of hydrolysis of soluble CMC was nearly double relative to control. In the hydrolysis of cellulose, an increasing particle size reduced the rate of hydrolysis. At any fixed particle size, sonication at a 10% duty cycle and 11.8 W cm(-2) power intensity improved the rate of hydrolysis relative to control. Under the above mentioned optimal sonication conditions, the enzyme lost about 20% of its initial activity in 20 min. Sonication was useful in accelerating the enzyme catalyzed saccharification of cellulose. © 2013 American Institute of Chemical Engineers.

  16. Formation rate of natural gas hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Mork, Marit

    2002-07-01

    The rate of methane hydrate and natural gas hydrate formation was measured in a 9.5 litre stirred tank reactor of standard design. The experiments were performed to better understand the performance and scale-up of a reactor for continuous production of natural gas hydrates. The hydrate formation rate was measured at steady-state conditions at pressures between 70 and 90 bar and temperatures between 7 and 15 deg C. Between 44 and 56 % of the gas continuously supplied to the reactor was converted to hydrate. The experimental results show that the rate of hydrate formation is strongly influenced by gas injection rate and pressure. The effect of stirring rate is less significant and subcooling has no observable effect on the formation rate. Hydrate crystal concentration and gas composition do not influence the hydrate formation rate. Observations of produced hydrate crystals indicate that the crystals are elongated, about 5 micron in diameter and 10 micron long. Analysis of the results shows that the rate of hydrate formation is dominated by gas-liquid mass transfer. A mass transfer model, the bubble-to-crystal model, was developed for the hydrate formation rate in a continuous stirred tank reactor, given in terms of concentration driving force and an overall mass transfer coefficient. The driving force is the difference between the gas concentration at the gas-liquid interface and at the hydrate crystal surface. These concentrations correspond to the solubility of gas in water at experimental temperature and pressure and the solubility of gas at hydrate equilibrium temperature and experimental pressure, respectively. The overall mass transfer coefficient is expressed in terms of superficial gas velocity and impeller power consumption, parameters commonly used in study of stirred tank reactors. Experiments and modeling show that the stirred tank reactor has a considerable potential for increased production capacity. However, at higher hydrate production rates the

  17. Biosynthesis and Characterization of Nanocellulose-Gelatin Films

    Directory of Open Access Journals (Sweden)

    Muenduen Phisalaphong

    2013-02-01

    Full Text Available A nanocellulose-gelatin (bacterial cellulose gelatin (BCG film was developed by a supplement of gelatin, at a concentration of 1%–10% w/v, in a coconut-water medium under the static cultivation of Acetobacter xylinum. The two polymers exhibited a certain degree of miscibility. The BCG film displayed dense and uniform homogeneous structures. The Fourier transform infrared spectroscopy (FTIR results demonstrated interactions between the cellulose and gelatin. Incorporation of gelatin into a cellulose nanofiber network resulted in significantly improved optical transparency and water absorption capacity of the films. A significant drop in the mechanical strengths and a decrease in the porosity of the film were observed when the supplement of gelatin was more than 3% (w/v. The BCG films showed no cytotoxicity against Vero cells.

  18. Transparent Flexible Conductive Thin Films Based on Cellulose Nanofibers by Layer-by-layer Assembly Method and Its Fabricated Electrochromic Flexible Supercapacitors%纤维素纳米纤维基层层自组装透明柔性导电膜及其电致变色柔性超级电容器

    Institute of Scientific and Technical Information of China (English)

    郝红英; 王茜; 邵自强; 杨荣杰

    2015-01-01

    以纤维素纳米纤维(CNFs)膜为基材,通过层层自组装法设计并制备了 CNFs/[Cu2+-GO]5/[PANI-PEDOT:PSS]10复合膜(CGPP膜),经过除铜,将氧化石墨烯(GO)还原为还原氧化石墨烯(RGO),得到CNFs/RGO5/[ PANI-PEDOT: PSS ]10复合导电膜( CRGPP-10膜),并以 H2 SO4-PVA 凝胶为电解质,双片CRGPP-10膜为电极,组装了双电极体系的柔性超级电容器S-RGPP.对CGPP膜和CRGPP-10膜进行紫外-可见光谱、结晶特性和形态表征,并对S-RGPP的循环伏安( CV)曲线、恒电流充放电性能( GCD)及电化学阻抗谱( EIS)等电化学性能进行分析.结果表明,通过层层自组装法制备的CRGPP-10膜具有均匀和透明度可控的优点.柔性超级电容器S-RGPP的内阻较小,同时具有双电层( EDL)电容和赝电容性能,表现出良好的柔性和一定的电致变色性. RGO的加入使S-RGPP的循环稳定性得到改善.%The cellulose nanofibers ( CNFs) film exhibit high visible light transmittance, high mechanical strength, and excellent flexibility. Therefore, CNFs film may be an excellent substrate material for flexible transparent electronic devices. In this paper, we endeavor to prepare the CNFs-based hybrid multilayer thin film CNFs/[ Cu2+-GO ] 5/[ PANI-PEDOT: PSS ] 10 by layer-by-layer assembly method using divalent copper ions( Cu2+) as the crosslinking agent. Then the conductive thin film of CRGPP-10 was got by removing copper ions with solution and using reduction reaction of graphene oxide( GO) with hydroiodic acid solution for reduc-tion of oxide graphene( RGO) from CNFs/[ Cu2+-GO] 5/[ PANI-PEDOT:PSS] 10 film. After that, the superca-pacitor fabricated S-RGPP was fabricated using double CRGPP-10 films as electrode when H2 SO4-PVA gel was used as the electrolyte. The crystalline characteristic and configuration of CRGPP thin films, along with the absorbency characteristics of CRGPP thin films, were analyzed. Meanwhile, the electrochemical characters of the

  19. Polyimide Cellulose Nanocrystal Composite Aerogels

    Science.gov (United States)

    Nguyen, Baochau N.; Meador, Mary Ann; Rowan, Stuart; Cudjoe, Elvis; Sandberg, Anna

    2014-01-01

    Polyimide (PI) aerogels are highly porous solids having low density, high porosity and low thermal conductivity with good mechanical properties. They are ideal for various applications including use in antenna and insulation such as inflatable decelerators used in entry, decent and landing operations. Recently, attention has been focused on stimuli responsive materials such as cellulose nano crystals (CNCs). CNCs are environmentally friendly, bio-renewable, commonly found in plants and the dermis of sea tunicates, and potentially low cost. This study is to examine the effects of CNC on the polyimide aerogels. The CNC used in this project are extracted from mantle of a sea creature called tunicates. A series of polyimide cellulose nanocrystal composite aerogels has been fabricated having 0-13 wt of CNC. Results will be discussed.

  20. CELLULOSE DEGRADATION BY OXIDATIVE ENZYMES

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  1. Cellulose degradation by oxidative enzymes

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  2. Dynamics of a photoexcited hydrated electron

    NARCIS (Netherlands)

    Pshenichnikov, M.S.; Baltuška, A.; Wiersma, D.A.; Kärtner, F.X.

    2004-01-01

    Combining photon-echo and frequency-resolved pump-probe techniques with extremely short laser pulses that consist of only few optical cycles, we investigate the dynamics of the equilibrated hydrated electron. The pure dephasing time of the hydrated electron deduced from the photon-echo measurements

  3. Gas hydrate inhibition of drilling fluid additives

    Energy Technology Data Exchange (ETDEWEB)

    Xiaolan, L.; Baojiang, S.; Shaoran, R. [China Univ. of Petroleum, Dongying (China). Inst. of Petroleum Engineering

    2008-07-01

    Gas hydrates that form during offshore well drilling can have adverse impacts on well operational safety. The hydrates typically form in the risers and the annulus between the casing and the drillstring, and can stop the circulation of drilling fluids. In this study, experiments were conducted to measure the effect of drilling fluid additives on hydrate inhibition. Polyalcohols, well-stability control agents, lubricating agents, and polymeric materials were investigated in a stirred tank reactor at temperatures ranging from -10 degree C to 60 degrees C. Pressure, temperature, and torque were used to detect onset points of hydrate formation and dissociation. The inhibitive effect of the additives on hydrate formation was quantified. Phase boundary shifts were measured in terms of temperature difference or sub-cooling gained when chemicals were added to pure water. Results showed that the multiple hydroxyl groups in polyalcohol chemicals significantly inhibited hydrate formation. Polymeric and polyacrylamide materials had only a small impact on hydrate formation, while sulfonated methyl tannins were found to increase hydrate formation. 6 refs., 1 tab., 4 figs.

  4. Hydration shells exchange charge with their protein

    DEFF Research Database (Denmark)

    Abitan, Haim; Lindgård, Per-Anker; Nielsen, Bjørn Gilbert;

    2010-01-01

    Investigation of the interaction between a protein and its hydration shells is an experimental and theoretical challenge. Here, we used ultrasonic pressure waves in aqueous solutions of a protein to explore the conformational states of the protein and its interaction with its hydration shells. In...

  5. A new geotechnical gas hydrates research laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Grozic, J.L.H. [Calgary Univ., AB (Canada)

    2003-07-01

    Gas hydrates encapsulate natural gas molecules in a very compact form, as ice-like compounds composed of water molecules. Permafrost environments and offshore areas contain vast quantities of gas hydrates within soil and rock. This paper describes the role played by gas hydrates in submarine slope instability, their potential as a sustainable energy source, and their effects on global climate change. A new state-of-the-art laboratory located at the University of Calgary, which was developed to study the geomechanical behaviour of gas hydrate-sediment mixtures, was also presented. A specialized high pressure low temperature triaxial apparatus capable of performing a suite of tests on gas hydrate-sediment mixtures is housed in this laboratory. Extensive renovations were required in order to enable the use of methane gas to simulate natural hydrate formation conditions. The laboratory is specifically designed to examine the properties and behaviour of reconstituted gas hydrate-sediment mixtures and natural gas hydrate core samples. 26 refs., 9 figs.

  6. Investigations into surfactant/gas hydrate relationship

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Rudy; Zhang, Guochang; Dearman, Jennifer; Woods, Charles [Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS 39762 (United States)

    2007-03-15

    Gas hydrates have unique physical properties portending useful industrial applications of gas storage, gas separation, or water desalination. When gas hydrates were found in the early 1990s to occur naturally and abundantly in seafloors, three other primary interests and concerns emerged: potential new energy source, climate threat from their greenhouse gases, and seafloor instabilities. This paper presents research showing how anionic synthetic surfactants helped develop an industrial gas hydrate storage process for natural gas and how naturally-occurring in-situ anionic biosurfactants influence the formation and placement of gas hydrates in ocean sediments. The catalytic effects, mechanisms, and surface specificities imparted by synthetic surfactants in the gas storage process and imparted by biosurfactants in porous media are discussed. The Bacillus subtilis bacterium that is indigenous to gas hydrate mounds in the Gulf of Mexico was cultured in the laboratory. Its biosurfactant was separated and found to catalyze gas hydrates in porous media. The experiments indicate that seafloor-biosurfactants can be produced rapidly in-situ to achieve threshold concentrations whereby hydrates are promoted. The biosurfactants accumulate and promote hydrate formation on specific mineral surfaces such as sodium montmorillonite. (author)

  7. Raman Spectroscopic Studies of Methane Gas Hydrates

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.

    2009-01-01

    A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory.......A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory....

  8. Bacterial cellulose in biomedical applications: A review.

    Science.gov (United States)

    Picheth, Guilherme Fadel; Pirich, Cleverton Luiz; Sierakowski, Maria Rita; Woehl, Marco Aurélio; Sakakibara, Caroline Novak; de Souza, Clayton Fernandes; Martin, Andressa Amado; da Silva, Renata; de Freitas, Rilton Alves

    2017-11-01

    Bacterial cellulose (BC) derived materials represents major advances to the current regenerative and diagnostic medicine. BC is a highly pure, biocompatible and versatile material that can be utilized in several applications - individually or in the combination with different components (e.g. biopolymers and nanoparticles) - to provide structural organization and flexible matrixes to distinct finalities. The wide application and importance of BC is described by its common utilization as skin repair treatments in cases of burns, wounds and ulcers. BC membranes accelerate the process of epithelialization and avoid infections. Furthermore, BC biocomposites exhibit the potential to regulate cell adhesion, an important characteristic to scaffolds and grafts; ultra-thin films of BC might be also utilized in the development of diagnostic sensors for its capability in immobilizing several antigens. Therefore, the growing interest in BC derived materials establishes it as a great promise to enhance the quality and functionalities of the current generation of biomedical materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Preparation of 14C Radiolabelled Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    CHEN; Bao-jun; YANG; Hong-wei; LI; Shuai

    2013-01-01

    Carboxymethyl cellulose(CMC)is a kind of cellulose derivative.CMC has wide applications,including food,daily chemicals,pharmaceutical industry and chemical industry,etc.In order to study the metabolism of CMC,the sodium carboxymethyl cellulose was labelled with 14C.The carboxymethyl cellulose was labelled with 14C by treatment with alkalized cellulose and 14C-

  10. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Donn McGuire; Steve Runyon; Richard Sigal; Bill Liddell; Thomas Williams; George Moridis

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. Hot Ice No. 1 was planned to test the Ugnu and West Sak sequences for gas hydrates and a concomitant free gas accumulation on Anadarko's 100% working interest acreage in section 30 of Township 9N, Range 8E of the Harrison Bay quadrangle of the North Slope of Alaska. The Ugnu and West Sak intervals are favorably positioned in the hydrate-stability zone over an area extending from Anadarko's acreage westward to the vicinity of the aforementioned gas-hydrate occurrences. This suggests that a large, north-to-south trending gas-hydrate accumulation may exist in that area. The presence of gas shows in the Ugnu and West Sak reservoirs in wells situated eastward and down dip of the Hot Ice location indicate that a free-gas accumulation may be trapped by gas hydrates. The Hot Ice No. 1 well was designed to core from the surface to the base of the West Sak interval using the

  11. Bacterial Cellulose (BC) as a Functional Nanocomposite Biomaterial

    Science.gov (United States)

    Nandgaonkar, Avinav Ghanashyam

    compressive tests. In our second study, we developed a one-pot in-situ biosynthetic method to fabricate structurally controllable bacterial cellulose (BC)/reduced graphene oxide (RGO) composites. The graphene oxide (GO) was highly reduced during a standard autoclave process using a traditional mannitol culture medium as the reducing agent. The electrical conductivity of the RGO was found to be 23.75 S m-1. The final BC/RGO composites were developed in three distinct forms: 1) sealed structures in the water, 2) aerogels characterized by a porous cross section and aligned longitudinal structure, and 3) films embedded within the RGO sheets. Because of the simplicity and non-toxic nature of this work, it can be used in biomedical and bioelectronics applications. The last study was on dye degradation using BC as the substrate. The surface of the BC was chemically oxidized to produce aldehyde groups to successfully covalently crosslink laccase. TiO2 and laccase (Lac) were co-immobilized on the surface of OBC and the dye degradation process was carried out under specific conditions. Compared with free laccase, the optimum pH of the immobilized laccase system shifted to lower pH, while the optimum temperature decreased from 55 °C to 50 °C. The dye degradation experiments showed that the optimum pH for dye degradation was pH 5.0-6.0, while the optimum temperature was ca. 40 ºC. Under UV illumination, the dye degradation efficiency significantly improved characteristic of a synergy in the system. This dissertation contributes to the basic research of bacterial cellulose which will result in novel ideas that can possibly result in future industrial applications. The research provides a fundamental underpinning of specialized structure-property relationships between BC and the materials used to fabricate the BC nanocomposites that have value-added applications that are environmentally safe and eco-friendly.

  12. Conversion of an electrospun nanofibrous cellulose acetate mat from a super-hydrophilic to super-hydrophobic surface

    Science.gov (United States)

    Ding, Bin; Li, Chunrong; Hotta, Yoshio; Kim, Jinho; Kuwaki, Oriha; Shiratori, Seimei

    2006-09-01

    We report a new approach to convert an electrospun nanofibrous cellulose acetate mat surface from super-hydrophilic to super-hydrophobic. Super-hydrophilic cellulose acetate nanofibrous mats can be obtained by electrospinning hydrophilic cellulose acetate. The surface properties of the fibrous mats were modified from super-hydrophilic to super-hydrophobic with a simple sol-gel coating of decyltrimethoxysilane (DTMS) and tetraethyl orthosilicate (TEOS). The resultant samples were characterized by field emission scanning electron microscopy (FE-SEM), x-ray photoelectron spectroscopy (XPS), water contact angle, Brunauer-Emmett-Teller (BET) surface area, atomic force microscopy (AFM), and UV-visible measurements. The results of FE-SEM and XPS showed that the sol-gel (I) films were formed on the rough fibrous mats only after immersion in sol-gel. After the sol-gel (I) coating, the cellulose acetate fibrous mats formed in both 8 and 10 wt% cellulose acetate solutions showed the super-hydrophobic surface property. Additionally, the average sol-gel film thickness coated on 10 wt% cellulose acetate fibrous mats was calculated to be 80 nm. The super-hydrophobicity of fibrous mats was attributed to the combined effects of the high surface roughness of the electrospun nanofibrous mats and the hydrophobic DTMS sol-gel coating. Additionally, hydrophobic sol-gel nanofilms were found to be transparent according to UV-visible measurements.

  13. Compound Natural Gas Hydrate: A Natural System for Separation of Hydrate-Forming Gases

    Science.gov (United States)

    Max, M. D.; Osegovic, J. P.

    2007-12-01

    Natural processes that separate materials from a mixture may exert a major influence on the development of the atmospheres and surfaces of planets, moons, and other planetary bodies. Natural distillation and gravity separation, amongst others, are well known means of differentiating materials through liquid-gas partitioning. One of the least known attributes of clathrate (gas) hydrates is their potential effect on the evolution of planetary system oceans and atmospheres. Gas hydrates separate gases from mixtures of gases by concentrating preferred hydrate-forming materials (HFM) guests within the water-molecule cage structure of crystalline hydrate. Different HFMs have very different fields of stability. When multiple hydrate formers are present, a preference series based on their selective uptake exists. Compound hydrate, which is formed from two or more species of HFM, extract preferred HFM from a mixture in very different proportions to their relative percentages of the original mixture. These compound hydrates can have different formation and dissociation conditions depending on the evolution of the environment. That is, the phase boundary of the compound hydrate that is required for dissociation lies along a lower pressure - higher temperature course. Compound hydrates respond to variations in temperature, pressure, and HFM composition. On Earth, the primary naturally occurring hydrate of interest to global climate modeling is methane hydrate. Oceanic hydrate on Earth is the largest store of carbon in the biosphere that is immediately reactive to environmental change, and is capable of releasing large amounts of methane into the atmosphere over a short geological time span. Hydrate formation is essentially metastable and is very sensitive to environmental change and to gas flux. Where natural variations in temperature and pressure varies so that hydrate will form and dissociate in some cyclical manner, such as in oceans where sea level is capable of rising and

  14. Effects of reaction conditions on cellulose structures synthesized in vitro by bacterial cellulose synthases.

    Science.gov (United States)

    Penttilä, Paavo A; Sugiyama, Junji; Imai, Tomoya

    2016-01-20

    Cellulose was synthesized by cellulose synthases extracted from the Komagataeibacter xylinus (formerly known as Gluconacetobacter xylinus). The effects of temperature and centrifugation of the reaction solution on the synthesis products were investigated. Cellulose with number-average degree of polymerization (DPn) roughly in the range 60-80 and cellulose II crystal structure was produced under all conditions. The amount of cellulose varied with temperature and centrifugation, and the centrifugation at 2000 × g also slightly reduced the DPn. Cellulose production was maximal around the temperature 35 °C and without centrifugation. At higher temperatures and during centrifugation at 2000 × g the proteins started to denature, causing differences also in the morphology of the cellulosic aggregates, as seen with electron microscopy. These observations serve as a basis for discussions about the factors affecting the structure formation and chain length of in vitro synthesized cellulose.

  15. Overview on Hydrate Coring, Handling and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jon Burger; Deepak Gupta; Patrick Jacobs; John Shillinglaw

    2003-06-30

    Gas hydrates are crystalline, ice-like compounds of gas and water molecules that are formed under certain thermodynamic conditions. Hydrate deposits occur naturally within ocean sediments just below the sea floor at temperatures and pressures existing below about 500 meters water depth. Gas hydrate is also stable in conjunction with the permafrost in the Arctic. Most marine gas hydrate is formed of microbially generated gas. It binds huge amounts of methane into the sediments. Worldwide, gas hydrate is estimated to hold about 1016 kg of organic carbon in the form of methane (Kvenvolden et al., 1993). Gas hydrate is one of the fossil fuel resources that is yet untapped, but may play a major role in meeting the energy challenge of this century. In June 2002, Westport Technology Center was requested by the Department of Energy (DOE) to prepare a ''Best Practices Manual on Gas Hydrate Coring, Handling and Analysis'' under Award No. DE-FC26-02NT41327. The scope of the task was specifically targeted for coring sediments with hydrates in Alaska, the Gulf of Mexico (GOM) and from the present Ocean Drilling Program (ODP) drillship. The specific subjects under this scope were defined in 3 stages as follows: Stage 1: Collect information on coring sediments with hydrates, core handling, core preservation, sample transportation, analysis of the core, and long term preservation. Stage 2: Provide copies of the first draft to a list of experts and stakeholders designated by DOE. Stage 3: Produce a second draft of the manual with benefit of input from external review for delivery. The manual provides an overview of existing information available in the published literature and reports on coring, analysis, preservation and transport of gas hydrates for laboratory analysis as of June 2003. The manual was delivered as draft version 3 to the DOE Project Manager for distribution in July 2003. This Final Report is provided for records purposes.

  16. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2005-03-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Oil-field engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in Arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrates agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored the HOT ICE No. 1 on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was designed, constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. Unfortunately, no gas hydrates were encountered in this well; however, a wealth of information was generated

  17. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-07-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope drilled and cored a well The HOT ICE No.1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report.

  18. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-06-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope drilled and cored a well The HOT ICE No.1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report.

  19. Cellulose Synthases and Synthesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Anne Endler; Staffan Persson

    2011-01-01

    Plant cell walls are complex structures composed of high-molecular-weight polysaccharides,proteins,and lignins. Among the wall polysaccharides,cellulose,a hydrogen-bonded β-1,4-linked glucan microfibril,is the main load-bearing wall component and a key precursor for industrial applications. Cellulose is synthesized by large multi-meric cellulose synthase (CesA) complexes,tracking along cortical microtubules at the plasma membrane. The only known components of these complexes are the cellulose synthase proteins. Recent studies have identified tentative interaction partners for the CesAs and shown that the migratory patterns of the CesA complexes depend on phosphorylation status. These advances may become good platforms for expanding our knowledge about cellulose synthesis in the near future. In addition,our current understanding of cellulose chain polymerization in the context of the CesA complex is discussed.

  20. Assessment of solvents for cellulose dissolution.

    Science.gov (United States)

    Ghasemi, Mohammad; Tsianou, Marina; Alexandridis, Paschalis

    2017-03-01

    A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.