Diffusion and saponification inside porous cellulose triacetate fibers.

Science.gov (United States)

Braun, Jennifer L; Kadla, John F

2005-01-01

Cellulose triacetate (CTA) fibers were partially hydrolyzed in 0.054 N solutions of NaOH/H(2)O and NaOMe/MeOH. The surface concentration of acetyl groups was determined using ATR-FTIR. Total acetyl content was determined by the alkaline hydrolysis method. Fiber cross-sections were stained with Congo red in order to examine the interface between reacted and unreacted material; these data were used to estimate the rate constant k and effective diffusivity D(B) for each reagent during the early stages of reaction by means of a volume-based unreacted core model. For NaOH/H(2)O, k = 0.37 L mol(-1) min(-1) and D(B) = 6.2 x 10(-7) cm(2)/sec; for NaOMe/MeOH, k = 4.0 L mol(-1) min(-1) and D(B) = 5.7 x 10(-6) cm(2)/sec. The NaOMe/MeOH reaction has a larger rate constant due to solvent effects and the greater nucleophilicity of MeO(-) as compared to OH(-); the reaction has a larger effective diffusivity because CTA swells more in MeOH than it does in water. Similarities between calculated concentration profiles for each case indicate that the relatively diffuse interface seen in fibers from the NaOMe/MeOH reaction results from factors not considered in the model; shrinkage of stained fiber cross-sections suggests that increased disruption of intermolecular forces may be the cause.

Poly(3`,4`-dibutyl-{alpha}-terthiophene-phenylene-vinylene): a new soluble and dopable phenylene-vinylene-based conjugated polymer

Energy Technology Data Exchange (ETDEWEB)

Chenggang, Wang [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry; Xusheng, Xie [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry; LeGoff, E [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry; Albritton-Thomas, J [Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208-3118 (United States); Kannewurf, C R [Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208-3118 (United States); Kanatzidis, M G [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry

1995-09-01

A new soluble and dopable copolymer consisting of 3`,4`-dibutyl-2,2`:5`,2``-terthiophene and phenylene-vinylene units has been designed and prepared via a Wittig reaction. This title copolymer is soluble in common organic solvents such as THF and CHCl{sub 3}, and can be doped with iodine achieving an electrical conductivity of about 3.2x10{sup -2} S/cm at room temperature. Films of this copolymer are electroactive and turn reversibly and rapidly from red to green-blue upon doping and undoping electrochemically. (orig.)

Localization of alpha emitters by damage production in a thin film. Application to the study of alpha emitter diffusion in irradiated samples; Localisation des emetteurs alpha par creation de dommages dans un film mince. Application a l'etude de la diffusion des emetteurs alpha dans des echantillons irradies

Energy Technology Data Exchange (ETDEWEB)

Houdaille, B; Perrot, M [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

1968-07-01

The process of recording {alpha} particles on cellulose nitrate films, called alpha-graphy, is applied to the study of the diffusion of {alpha}-emitting elements in irradiated alloys. The existence of diffusion is shown by attacking the film with concentrated caustic soda after exposition. The insensitivity of the recorder to {beta} {gamma} radiation emitted by the sample after passing in the reactor makes it possible to operate with long exposure times and to detect small diffusions. The concentration-penetration curves are drawn up after carrying out a densitometric analysis of the alpha-graphies. - As the cellulose nitrate is affected only by {alpha} particles of energies of between 0.5 and 4 MeV, it was first necessary to determine the yield of the recorder for {alpha} particles emitted by a thick source, i.e. whose energy varies between 0 and E{sub 0}, E{sub 0} being the energy of the alpha emitter. - The concentration C of the {alpha}-emitter, as a function of the optical density D of the alpha-graphy, and of the exposure time t is given by a simple relationship: C = D/at where a is an experimental constant determined by calibration. It depends on the nature of the cellulose nitrate, of the {alpha}-emitting element and of the alloy studied. (authors) [French] Le procede d'enregistrement des particules alpha sur film de nitrate de cellulose, ou alphagraphie, est applique a l'etude de la diffusion d'elements emetteurs alpha dans des alliages irradies. La diffusion est mise en evidence par une attaque du film de nitrate, apres exposition, dans de la soude concentree. L'insensibilite de l'enregistreur au rayonnement {beta} {gamma}, emis par l'echantillon apres son sejour en pile, permet d'operer sur de longs temps de pose et de detecter des diffusions faibles. Les courbes concentration - penetration sont etablies par exploitation densitometrique des alphagraphies. - Comme le nitrate de cellulose n'est impressionne que par des particules alpha dont l'energie est

Evaluation of microcrystalline cellulose modifed from alpha ...

African Journals Online (AJOL)

Alpha cellulose was obtained from Costus afer and part of it was modified to microcrystalline cellulose (CAMCC). The physicochemical properties of the microcrystalline cellulose were determined and compared with those of commercial microcrystalline cellulose (Avicel 101). The swelling capacity, hydration capacity, loss ...

Drug-loaded Cellulose Acetate and Cellulose Acetate Butyrate Films ...

African Journals Online (AJOL)

The purpose of this research work was to evaluate the contribution of formulation variables on release properties of matrix type ocular films containing chloramphenicol as a model drug. This study investigated the use of cellulose acetate and cellulose acetate butyrate as film-forming agents in development of ocular films.

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

International Nuclear Information System (INIS)

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

1976-01-01

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-μ optimum mylar film thickness, while experimental results indicated a 22.8-μ 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 3 for up to 15-hr exposure was also investigated. An average TSEE/β ratio of 0.02 was obtained

Evaluation of LR-115 cellulose nitrate film for use in bone autoradiography

International Nuclear Information System (INIS)

Harris, M.J.; Schlenker, R.A.

1977-01-01

An evaluation of Kodak LR-115 cellulose nitrate (CN) film for alpha autoradiography of radium-burdened bone was undertaken. Comparison of the registration efficiency between a plaster of Paris radiator and bone samples on NTA nuclear track emulsion and on the CN film is presented. CN film was observed to record as etched-through holes 11 percent and as tracks only 32 percent of the events detected by NTA emulsion. Potential advantages and disadvantages of using CN film in microdosimetry and for adapting it to automated analysis are discussed

Production of Cellulosic Polymers from Agricultural Wastes

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A. U. Israel

2008-01-01

Full Text Available Cellulosic polymers namely cellulose, di-and triacetate were produced from fourteen agricultural wastes; Branch and fiber after oil extraction from oil palm (Elais guineensis, raffia, piassava, bamboo pulp, bamboo bark from raphia palm (Raphia hookeri, stem and cob of maize plant (Zea mays, fruit fiber from coconut fruit (Cocos nucifera, sawdusts from cotton tree (Cossypium hirsutum, pear wood (Manilkara obovata, stem of Southern gamba green (Andropogon tectorus, sugarcane baggase (Saccharium officinarum and plantain stem (Musa paradisiaca. They were subjected to soda pulping and hypochlorite bleaching system. Results obtained show that pulp yield from these materials were: 70.00, 39.59, 55.40, 86.00, 84.60, 80.00, 40.84, 81.67, 35.70, 69.11, 4.54, 47.19, 31.70 and 52.44% respectively. The pulps were acetylated with acetic anhydride in ethanoic acid catalyzed by conc. H2SO4 to obtain cellulose derivatives (Cellulose diacetate and triacetate. The cellulose diacetate yields were 41.20, 17.85, 23.13, 20.80, 20.23, 20.00, 39.00, 44.00, 18.80, 20.75, 20.03, 41.20, 44.00, and 39.00% respectively while the results obtained as average of four determinations for cellulose triacetate yields were: 52.00, 51.00, 43.10, 46.60, 49.00, 35.00, 40.60, 54.00, 57.50, 62.52, 35.70. 52.00, 53.00 and 38.70% respectively for all the agricultural wastes utilized. The presence of these cellulose derivatives was confirmed by a solubility test in acetone and chloroform.

Method of producing thin cellulose nitrate film

International Nuclear Information System (INIS)

Lupica, S.B.

1975-01-01

An improved method for forming a thin nitrocellulose film of reproducible thickness is described. The film is a cellulose nitrate film, 10 to 20 microns in thickness, cast from a solution of cellulose nitrate in tetrahydrofuran, said solution containing from 7 to 15 percent, by weight, of dioctyl phthalate, said cellulose nitrate having a nitrogen content of from 10 to 13 percent

Preparation of cellulose II and IIII films by allomorphic conversion of bacterial cellulose I pellicles

International Nuclear Information System (INIS)

Faria-Tischer, Paula C.S.; Tischer, Cesar A.; Heux, Laurent; Le Denmat, Simon; Picart, Catherine; Sierakowski, Maria-R.

2015-01-01

The structural changes resulting from the conversion of native cellulose I (Cel I) into allomorphs II (Cel II) and III I (Cel III 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 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 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

Spectroelectrochemical and electrochromic behaviors of newly synthesized poly[3′-(2-aminopyrimidyl)-2,2′:5′,2″-terthiophene

International Nuclear Information System (INIS)

Kim, Dong-Min; Shim, Kyu-Bin; Son, Jung Ik; Reddy, Sanapalli S.; Shim, Yoon-Bo

2013-01-01

The functionalized conductive polymer precursor of the terthiophene derivative, 3′-(2-aminopyrimidyl)-2,2′:5′,2″-terthiophene (PATT) was firstly synthesized and confirmed with FT-IR, 1 H NMR, 13 C NMR, and mass spectroscopy. The electrochemical and electronic properties of polyPATT film are investigated and compared with that of poly(2,2′:5′,2″-terthiophene-3′-p-benzoic acid) (polyTTBA), which has an electron-accepting group. The cyclic voltammograms (CVs) recorded for electrochemically grown polyPATT reveal the redox peaks at +1.1/+0.96 V, and the conductivity increases monotonically as the applying potential goes to the positive direction (0.11 S cm −1 at +1.4 V). The spectroelectrochemical analysis of polyPATT reveals the absorption bands at 456, 825 and 643 nm corresponding to the π–π* transition, polaron, and bipolaron formations, respectively. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the polyPATT film bearing an electron donating group are to be 3.60 and 5.54 eV, respectively. The polyPATT film shows reversible multiple color transition within 0.6 s (from brownish-yellow (at 0.0 V) to blue (at +1.4 V)) when the potential switches between the reduced and oxidized states

Films based on oxidized starch and cellulose from barley.

Science.gov (United States)

El Halal, Shanise Lisie Mello; Colussi, Rosana; Deon, Vinícius Gonçalves; Pinto, Vânia Zanella; Villanova, Franciene Almeida; Carreño, Neftali Lenin Villarreal; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2015-11-20

Starch and cellulose fibers were isolated from grains and the husk from barley, respectively. Biodegradable films of native starch or oxidized starches and glycerol with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. Cellulose fibers isolated from the barley husk were obtained with 75% purity and high crystallinity. The morphology of the films of the oxidized starches, regardless of the fiber addition, was more homogeneous as compared to the film of the native starch. The addition of cellulose fibers in the films increased the tensile strength and decreased elongation. The water vapor permeability of the film of oxidized starch with 20% of cellulose fibers was lower than the without fibers. However the films with cellulose fibers had the highest decomposition with the initial temperature and thermal stability. The oxidized starch and cellulose fibers from barley have a good potential for use in packaging. The addition of cellulose fibers in starch films can contribute to the development of films more resistant that can be applied in food systems to maintain its integrity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of Aldehyde Crosslinked Kenaf Regenerated Cellulose Film

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Hatika Kaco

2015-08-01

Full Text Available Regenerated cellulose film with better mechanical properties was successfully produced by introducing aldehyde crosslinker during the regeneration process. The cellulose source material was derived from kenaf core powder and dissolved in LiOH/urea solvent at −13 °C to form a cellulose solution. The cellulose solution was cast and coagulated in a crosslinker bath at different percentages of glutaraldehyde (GA and glyoxal (GX to form a regenerated cellulose film. According to Fourier transform infrared spectroscopy (FTIR spectra, the hydroxyl group of the cellulose was reduced, reducing the percentage of swelling as the percentage of crosslinker was increased. X-ray diffraction (XRD patterns showed that the crystallinity index of the crosslinked film was decreased. The pore size of the films decreased as the percentage of crosslinker was increased, resulting in decreased film transparency. The pore volume and percentage of swelling in water of the films also increased with decreases in the pore size as the percentage of crosslinker was increased. The tensile strengths of the GA- and GX-crosslinked films increased by 20 and 15% with the addition of 20% of each crosslinker, respectively.

Cellulose ionics: switching ionic diode responses by surface charge in reconstituted cellulose films.

Science.gov (United States)

Aaronson, Barak D B; Wigmore, David; Johns, Marcus A; Scott, Janet L; Polikarpov, Igor; Marken, Frank

2017-09-25

Cellulose films as well as chitosan-modified cellulose films of approximately 5 μm thickness, reconstituted from ionic liquid media onto a poly(ethylene-terephthalate) (PET, 6 μm thickness) film with a 5, 10, 20, or 40 μm diameter laser-drilled microhole, show significant current rectification in aqueous NaCl. Reconstituted α-cellulose films provide "cationic diodes" (due to predominant cation conductivity) whereas chitosan-doped cellulose shows "anionic diode" effects (due to predominant anion conductivity). The current rectification, or "ionic diode" behaviour, is investigated as a function of NaCl concentration, pH, microhole diameter, and molecular weight of the chitosan dopant. Future applications are envisaged exploiting the surface charge induced switching of diode currents for signal amplification in sensing.

Characterisation of cellulose films regenerated from acetone/water coagulants.

Science.gov (United States)

Geng, Hongjuan; Yuan, Zaiwu; Fan, Qingrui; Dai, Xiaonan; Zhao, Yue; Wang, Zhaojiang; Qin, Menghua

2014-02-15

A precooled aqueous solution of 7 wt% NaOH/12 wt% urea was used to dissolve cellulose up to a concentration of 2 wt%, which was then coagulated in an acetone/water mixture to regenerate cellulose film. The volume ratio of acetone to water (φ) had a dominant influence on film dimensional stability, film-forming ability, micromorphology, and mechanical strength. The film regenerated at φ=2.0 showed excellent performance in both dimensional stability and film-forming ability. Compared to that from pure acetone, the cellulose film from the acetone/water mixture with φ=2.0 was more densely interwoven, since the cellulosic fibrils formed during regeneration had pores with smaller average diameter. The alkali capsulated in the film during film formation could be released at quite a slow rate into the surrounding aqueous solution. The regenerated cellulose film with adjustable structure and properties may have potential applications in drug release and ultra filtration. Copyright © 2013 Elsevier Ltd. All rights reserved.

Transparent and Printable Regenerated Kenaf Cellulose/PVA Film

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Hatika Kaco

2014-02-01

Full Text Available Cellulose was extracted from kenaf core powder by a series of bleaching processes and subsequently dissolved using an alkaline LiOH/urea solvent at low temperatures. The produced cellulose solution was mixed with polyvinyl alcohol (PVA with different ratios of cellulose/PVA and coagulated to produce regenerated transparent films. The films were then air dried to produce transparent film. The effects of PVA content on tensile index, transparency, pore size, and printability of the films were studied. A slight reduction of 7% on the tensile index of the film was observed when the content of PVA increased to 10%. Nevertheless, the addition of 10% of PVA increased the porosity of the regenerated cellulose/PVA film, while the transparency of the film increased by 10%. The films were color-printed using a laser printer and can be recycled, in which the printed ink can be removed easily from the films with higher amount of PVA content. In addition, the films can be reprinted repeatedly several times.

Blood compatibility of AAc, HEMA, and PEGMA-grafted cellulose film

International Nuclear Information System (INIS)

Nho, Young Chang.; Kwon, Oh Hyun

2003-01-01

To improve surface blood compatibility on cellulose film for hemodialysis, acrylic acid, 2-hydroxyethyl methacrylate and three kinds of polyethylene glycol methacrylates were grafted onto the cellulose film surface by radiation grafting technique. Heparin was introduced onto the grafted cellulose film surfaces. The grafting and heparinization were confirmed by Fourier transform infrared spectroscopy in the attenuated total reflectance mode and electron spectroscopy for chemical analysis. The blood compatibility of the modified cellulose film was examined by the determination of platelet adhesion and thrombus formation

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.

Ductile all-cellulose nanocomposite films fabricated from core-shell structured cellulose nanofibrils.

Science.gov (United States)

Larsson, Per A; Berglund, Lars A; Wågberg, Lars

2014-06-09

Cellulosic materials have many desirable properties such as high mechanical strength and low oxygen permeability and will be an important component in a sustainable biomaterial-based society, but unfortunately they often lack the ductility and formability offered by petroleum-based materials. This paper describes the fabrication and characterization of nanocomposite films made of core-shell modified cellulose nanofibrils (CNFs) surrounded by a shell of ductile dialcohol cellulose, created by heterogeneous periodate oxidation followed by borohydride reduction of the native cellulose in the external parts of the individual fibrils. The oxidation with periodate selectively produces dialdehyde cellulose, and the process does not increase the charge density of the material. Yet the modified cellulose fibers could easily be homogenized to CNFs. Prior to film fabrication, the CNF was shown by atomic force microscopy to be 0.5-2 μm long and 4-10 nm wide. The films were fabricated by filtration, and besides uniaxial tensile testing at different relative humidities, they were characterized by scanning electron microscopy and oxygen permeability. The strength-at-break at 23 °C and 50% RH was 175 MPa, and the films could, before rupture, be strained, mainly by plastic deformation, to about 15% and 37% at 50% RH and 90% RH, respectively. This moisture plasticization was further utilized to form a demonstrator consisting of a double-curved structure with a nominal strain of 24% over the curvature. At a relative humidity of 80%, the films still acted as a good oxygen barrier, having an oxygen permeability of 5.5 mL·μL/(m(2)·24 h·kPa). These properties indicate that this new material has a potential for use as a barrier in complex-shaped structures and hence ultimately reduce the need for petroleum-based plastics.

Electrically aligned cellulose film for electro-active paper and its piezoelectricity

International Nuclear Information System (INIS)

Yun, Sungryul; Jang, Sangdong; Yun, Gyu-Young; Kim, Jaehwan

2009-01-01

Electrically aligned regenerated cellulose films were fabricated and the effect of applied electric field was investigated for the piezoelectricity of electro-active paper (EAPap). The EAPap was fabricated by coating gold electrodes on both sides of regenerated cellulose film. The cellulose film was prepared by dissolving cotton pulp in LiCl/N,N-dimethylacetamide solution followed by a cellulose chain regeneration process. During the regeneration process an external electric field was applied in the direction of mechanical stretching. Alignment of cellulose fiber chains was investigated as a function of applied electric field. The material characteristics of the cellulose films were analyzed by using an x-ray diffractometer, a field emission scanning electron microscope and a high voltage electron microscope. The application of external electric fields was found to induce formation of nanofibers in the cellulose, resulting in an increase in the crystallinity index (CI) values. It was also found that samples with higher CI values showed higher in-plane piezoelectric constant, d 31 , values. The piezoelectricity of the current EAPap films was measured to be equivalent or better than that of ordinary PVDF films. Therefore, an external electric field applied to a cellulose film along with a mechanical stretching during the regeneration process can enhance the piezoelectricity. (technical note)

A new generation of cellulose triacetate suitable for online haemodiafiltration

Directory of Open Access Journals (Sweden)

Francisco Maduell

2018-03-01

Full Text Available Background: Online haemodiafiltration (OL-HDF is currently the most effective dialysis technique that also improves survival. To date, high permeability membranes with low albumin loss, such as polysulfone, polyamide and polyacrylonitrile membranes have been the most widely used. However, the initially restricted use of cellulose triacetate (CTA membranes in OL-HDF has expanded. The aim of the study was to ascertain whether the latest generation asymmetric CTA membranes are more effective in obtaining high convective transport. Patients and methods: A total of 16 patients (10 males and 6 females undergoing OL-HDF were studied. Each patient underwent 4 different sessions, with haemodialysis or OL-HDF, and/or with CTA or asymmetric CTA 1.9 m2 membranes. Each session was assigned in a randomised order. Serum levels of urea, creatinine, β2-microglobulin, myoglobin, prolactin, α1-microglobulin, α1-acid glycoprotein and albumin where measured at the beginning and end of each session to obtain the reduction rate. The loss of solutes and albumin was quantified from the dialysate. Results: A significantly greater replacement volume in OL-HDF (32.1 ± 3.1 vs. 19.7 ± 4.5 l, p < 0.001 was obtained by using asymmetrical CTA membranes compared to conventional CTA membranes. Regarding uraemic toxin removal, both membranes obtained similar results for small molecules, whereas asymmetric CTA membranes achieved better results for large molecules, increasing the reduction ratio by 29% for β2-microglobulin, 27.7% for myoglobin, 19.5% for prolactin, 49% for α1-microglobulin and double for α1-acid glycoprotein (p < 0.01 in all situations. The loss of albumin was less than 2 g for all treatment sessions. Conclusion: Latest-generation asymmetric CTA have proven to be effective in attaining OL-HDF objectives without increased albumin loss. Resumen: Antecedentes: La hemodiafiltración on-line (HDF-OL es actualmente

Electrochemical Characterization of a Polymer Inclusion Membrane Made of Cellulose Triacetate and Aliquat 336 and Its Application to Sulfonamides Separation

Directory of Open Access Journals (Sweden)

Juana Benavente

2018-01-01

Full Text Available An electrochemical characterization of a polymer inclusion membrane (PIM fabricated with the ionic liquid (IL Aliquat 336 (26% and the polymer cellulose triacetate (CTA (76% is presented. Considering the use of PIMs in separation systems to remove pollutants from water, the characterization was performed with NaCl solutions by measuring membrane potential, electrochemical impedance spectroscopy, and salt diffusion and results were compared with those obtained from dry membranes. Results showed a significant reduction in the membrane diffusive permeability and electrical conductivity as well as the transport number of cation Na+ across the PIM when compared with solution values, which could be mainly related to the dense character of the membrane. Membrane application in the separation of different sulfonamides (sulfathiazole, sulfapyridine, sulfamethazine, and sulfamethoxazole from water, with 1 M NaCl solution as striping phase, was also considered. These results indicated that the different chemical characteristics of the compounds, as well as the compact structure of the PIM, limited the transport of the organic molecules though it.

Adsorption of Saccharomyces cerevisiae onto cellulose and ecteola-cellulose films for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Lueng, K.L.; Joshi, S.; Yamazaki, H.

1983-05-01

Epichlorohydrin-triethanolamine (ECTEOLA)-cellulose films (paper and cloth) have been found to bind Saccharomyces cerevisiae cells which were able to develop metabolically active colonies on the surface of the films. Umodified cellulose films also bound the yeast but to a lesser extent. Film fermenters were constructed by coiling a double layer of the cloth and copper screen and vertically placing the resulting cartridge into a column. These film fermenters were able to convert the sugars (14%) in the hydrolysate of a Jerusalem artichoke tuber into ethanol, with 90% of the theoretical yield after 6 hours of fermentation. The bound yeast produced ethanol at a specific rate of 1.0 g ethanol per g cell per hour. (Refs. 4).

High magnetic field quantum transport in Au nanoparticle–cellulose films

International Nuclear Information System (INIS)

Turyanska, L; Makarovsky, O; Patanè, A; Kozlova, N V; Liu, Z; Li, M; Mann, S

2012-01-01

We report the magneto-transport properties of cellulose films comprising interconnected networks of gold nanoparticles (Au NPs). Cellulose is a biopolymer that can be made electrically conducting by cellulose regeneration in Au NP dispersions. The mechanism of electronic conduction in the Au–cellulose films changes from variable range hopping to metallic-like conduction with decreasing resistivity. Our experiments in high magnetic fields (up to 45 T) reveal negative magnetoresistance in the highly resistive films. This is attributed to the spin polarization of the Au NPs and the magnetic field induced suppression of electron spin flips during spin-polarized tunneling in the NP network. (paper)

Radon and radon-daughter exposure measurements by through-etched track registration in cellulose nitrate

International Nuclear Information System (INIS)

Knoefell, T.M.J.; Silva Estrada, J.J. da; Tavares, O.A.P.; Martins, J.B.

1981-01-01

The use of cellulose nitrate films LR-115 type II (Kodak-Pathe) as a practical, exposure integrating device to measure the level of exposure to alpha particles in atmospheres which contain radon and radon-daughter products is investigated. The analysis of a number of cellulose nitrate films that have been exposed to calibrated radon test-chamber atmospheres has indicated good correlations between through-etched track density p and integrated alpha-particle exposure Σa (Working-Level-Hour). It is shown that the response of the cellulose nitrate detector to radon-daughter alpha-particle exposures is linear, and that reliable conservative estimations of the Working-Level-Hour can be obtained from Σa = 3.0(p-b), where p is expressed in tracks/mm 2 (b is the background level). These results recommend the use of the special red cellulose nitrate films as a convenient dosimeter for monitoring radioactive contaminants in mine atmospheres. (Author) [pt

Experimental determination of alpha particle threshold detection in cellulose nitrate

International Nuclear Information System (INIS)

Knoefell, T.M.J.

1978-01-01

LR 115, type II, Kodak-Pathe cellulose nitrate pellicles were irradiated perpendicularly with monoenergetic alpha bemas in the energy range 2,5-5,5 Mev. The alpha particle beams were produced by an intense Am 241 source using Argon as energy attenuating. After irradiations, samples were etched with NaOH solutions without agitation at 60 0 C, by different time periods varying from 15 minutes to 3,5 hours. Measurements of density and track diameter were done using optical microscopy. The sample compositions were done by CHN method of combustion gas analysis showing good agreement with the composition of cellulose trinitrate. From detection threshold and from obtained results, the development of latent tracks only occur for alpha particles with stopping power superior to 0,87 +- 0,06 MeV.cm -2 .mg -1 , was verified. (M.C.K.) [pt

A new terthiophene derivative as a fluorescent sensor for protein detection

International Nuclear Information System (INIS)

Hu, Jingqiu; Xia, Bing; Elioff, Michael S.

2016-01-01

A terthiophene carboxylic derivative, 3,3″-dihexyl-2,2′:5′,2″-terthiophene-5-carboxylic acid (3TC6A), was synthesized and its application as fluorescent biosensor was investigated using Bovine Serum Albumin (BSA) and Lectin from Triticum as the target proteins. The photophysical properties of terthiophene carboxylic acid depend on the solvent polarity and the pH of the solution. At low concentrations, the dye exhibits monomer emission in organic solvents. In acidic and neutral aqueous solutions, it displays dimer emission (490–500 nm). The emission can be completely quenched by heptyl viologen in aqueous solutions due to intermolecular electron transfer. While no emission enhancement was observed in the presence of cytochrome C, hemoglobin, or lysozyme, upon binding to trace amounts of BSA, the dye displayed strongly enhanced monomer emission at 450 nm. Upon binding to Lectin from Triticum vulgaris, the dye displayed enhanced dimer emission at 490 nm. In both cases, the fluorescence intensity is proportional to the concentration of proteins, making this organic dye a promising reagent for protein analysis.

A new terthiophene derivative as a fluorescent sensor for protein detection

Energy Technology Data Exchange (ETDEWEB)

Hu, Jingqiu [Department of Chemistry, West Chester University of Pennsylvania, West Chester, PA 19383 (United States); Xia, Bing [RD Platform Technology & Science, GlaxoSmithKline, Waltham, MA 02451 (United States); Elioff, Michael S., E-mail: melioff@millersville.edu [Department of Chemistry, Millersville University of Pennsylvania, Millersville, PA 17551 (United States)

2016-05-15

A terthiophene carboxylic derivative, 3,3″-dihexyl-2,2′:5′,2″-terthiophene-5-carboxylic acid (3TC6A), was synthesized and its application as fluorescent biosensor was investigated using Bovine Serum Albumin (BSA) and Lectin from Triticum as the target proteins. The photophysical properties of terthiophene carboxylic acid depend on the solvent polarity and the pH of the solution. At low concentrations, the dye exhibits monomer emission in organic solvents. In acidic and neutral aqueous solutions, it displays dimer emission (490–500 nm). The emission can be completely quenched by heptyl viologen in aqueous solutions due to intermolecular electron transfer. While no emission enhancement was observed in the presence of cytochrome C, hemoglobin, or lysozyme, upon binding to trace amounts of BSA, the dye displayed strongly enhanced monomer emission at 450 nm. Upon binding to Lectin from Triticum vulgaris, the dye displayed enhanced dimer emission at 490 nm. In both cases, the fluorescence intensity is proportional to the concentration of proteins, making this organic dye a promising reagent for protein analysis.

Surface analysis of the selective excimer laser patterning of a thin PEDOT:PSS film on flexible polymer films

Science.gov (United States)

Schaubroeck, David; De Smet, Jelle; Willems, Wouter; Cools, Pieter; De Geyter, Nathalie; Morent, Rino; De Smet, Herbert; Van Steenbeerge, Geert

2016-07-01

Fast patterning of highly conductive polymers like PEDOT:PSS (poly (3,4-ethylene dioxythiophene): polystyrene sulfonate) with lasers can contribute to the development of industrial production of liquid crystal displays on polymer foils. In this article, the selective UV laser patterning of a PEDOT:PSS film on flexible polymer films is investigated. Based on their optical properties, three polymer films are investigated: polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and cellulose triacetate (TAC). Ablation parameters for a 110 nm PEDOT:PSS film on these polymer films are optimized. A detailed study of the crater depth, topography and surface composition are provided using optical profilometry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The electrical insulation of the lines is measured and correlated to the crater analyses for different laser settings. Finally, potential ablation parameters for each of the polymer films are derived.

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.

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

Self-assembly behaviour of conjugated terthiophene surfactants in water

NARCIS (Netherlands)

van Rijn, Patrick; Janeliunas, Dainius; Brizard, Aurelie M.; Stuart, Marc C. A.; Koper, Ger J. M.; Eelkema, Rienk; van Esch, Jan H.

2011-01-01

Conjugated self-assembled systems in water are of great interest because of their potential application in biocompatible supramolecular electronics, but so far their supramolecular chemistry remains almost unexplored. Here we present amphiphilic terthiophenes as a general self-assembling platform

Bionanocomposite films based on plasticized PLA-PHB/cellulose nanocrystal blends.

Science.gov (United States)

Arrieta, M P; Fortunati, E; Dominici, F; López, J; Kenny, J M

2015-05-05

Optically transparent plasticized poly(lactic acid) (PLA) based bionanocomposite films intended for food packaging were prepared by melt blending. Materials were plasticized with 15wt% of acetyl(tributyl citrate) (ATBC) to improve the material processability and to obtain flexibile films. Poly(hydroxybutyrate) (PHB) was used to increase PLA crystallinity. The thermal stability of the PLA-PHB blends was improved by the addition of 5 wt% of cellulose nanocrystals (CNC) or modified cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose. The combination of ATBC and cellulose nanocrystals, mainly the better dispersed CNCs, improved the interaction between PLA and PHB. Thus, an improvement on the oxygen barrier and stretchability was achieved in PLA-PHB-CNCs-ATBC which also displayed somewhat UV light blocking effect. All bionanocomposite films presented appropriate disintegration in compost suggesting their possible applications as biodegradable packaging materials. Copyright © 2014 Elsevier Ltd. All rights reserved.

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...

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.

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

International Nuclear Information System (INIS)

Soheilmoghaddam, Mohammad; Wahit, Mat Uzir; Mahmoudian, Shaya; Hanid, Nurbaiti Abdul

2013-01-01

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

Determination of the optimum concentration cellulose baggase in making film bioplastic

Science.gov (United States)

Chadijah, S.; Rustiah, W. O.; Munir, M. I. D.

2018-03-01

The hoarding rubbish synthetic plastic caused pollution and demage in life circles, to cope it can be done with synthesizing the plastic from agriculture substance or called biopolymer (bioplastic). It was that potentially as bioplastic was biopolymer from agriculture substance baggase that contain cellulose 40 %. This research aimed to determine the optimum concentration cellulose baggase in making bioplastic film with adding chitosan and sorbitol plasticizer and also to know the result of characterization film bioplastic. The steps in this research were; the extraction of cellulose, making film bioplastic, tensile strenght test and used characterization spectrofotometer FTIR. In this research showed that optimum concentration cellulose baggase in making film bioplastic was 2% with adding chitosan and sorbitol plasticizer. The optimal result of tensile strenght test was 0,089 Kgf/cm2 with elongation percent 15,90 %. The analyzing FTIR in all of variation that looked almost same with characterization with tapes -OH, -NH and C-O.

Hybrid composite thin films composed of tin oxide nanoparticles and cellulose

International Nuclear Information System (INIS)

Mahadeva, Suresha K; Nayak, Jyoti; Kim, Jaehwan

2013-01-01

This paper reports the preparation and characterization of hybrid thin films consisting of tin oxide (SnO 2 ) nanoparticles and cellulose. SnO 2 nanoparticle loaded cellulose hybrid thin films were fabricated by a solution blending technique, using sodium dodecyl sulfate as a dispersion agent. Scanning and transmission electron microscopy studies revealed uniform dispersion of the SnO 2 nanoparticles in the cellulose matrix. Reduction in the crystalline melting transition temperature and tensile properties of cellulose was observed due to the SnO 2 nanoparticle loading. Potential application of these hybrid thin films as low cost, flexible and biodegradable humidity sensors is examined in terms of the change in electrical resistivity of the material exposed to a wide range of humidity as well as its response–recovery behavior. (paper)

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.

Development of regenerated cellulose/halloysite nanotube bionanocomposite films with ionic liquid.

Science.gov (United States)

Soheilmoghaddam, Mohammad; Wahit, Mat Uzir

2013-07-01

In this study, novel nanocomposite films based on regenerated cellulose/halloysite nanotube (RC/HNT) have been prepared using an environmentally friendly ionic liquid 1-butyl-3-methylimidazolium chloride (BMIMCl) through a simple green method. The structural, morphological, thermal and mechanical properties of the RC/HNT nanocomposites were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), thermal analysis and tensile strength measurements. The results obtained revealed interactions between the halloysite nanotubes and regenerated cellulose matrix. The thermal stability and mechanical properties of the nanocomposite films, compared with pure regenerated cellulose film, were significantly improved When the halloysite nanotube (HNT) loading was only 2 wt.%, the 20% weight loss temperature (T20) increased 20°C. The Young's modulus increased from 1.8 to 4.1 GPa, while tensile strength increased from 35.30 to 60.50 MPa when 8 wt.% halloysite nanotube (HNT) was incorporated, interestingly without loss of ductility. The nanocomposite films exhibited improved oxygen barrier properties and water absorption resistance compared to regenerated cellulose. Copyright © 2013 Elsevier B.V. All rights reserved.

The sonochemical arylation of malonic esters mediated by manganese triacetate.

Science.gov (United States)

Meciarova, M; Toma, S; Luche, J L

2001-04-01

The intermolecular arylation of malonate esters in acetic acid solution in the presence of manganese(III) triacetate is known to proceed via an Electron Transfer mechanism. Under sonication, this reaction undergoes only minor changes. In contrast, the intramolecular reaction of dimethyl alpha-(3-phenylpropyl)malonate provides a new case of sonochemical switching, with the formation of compounds 7-9, while conventional thermal conditions generate only the bicyclic compound 6. Reactions using the more powerful oxidant, cerium ammonium nitrate are governed by the formation of the nitrate ester 11. Compounds 7-9 are isolated in yields lower than with MnTA, and in proportions depending on the conditions, thermal or sonochemical.

Embedding and electropolymerization of terthiophene derivatives in porous n-type silicon

Energy Technology Data Exchange (ETDEWEB)

Badeva, Diyana, E-mail: diyana.badeva@cnrs-imn.fr [Equipe Physique des Materiaux et Nanostructures, IMN, B.P. 32229, 44322 Nantes cedex 3 (France); Tran-Van, Francois, E-mail: francois.tran@univ-tours.fr [Laboratoire de Physico-Chimie des Materiaux et des Electrolytes pour l' Energie (PCM2E), E.A 6299, Universite de Tours, Faculte des Sciences et Techniques, Parc de Grandmont, 37200 Tours (France); Beouch, Layla, E-mail: layla.beouch@u-cergy.fr [Laboratoire de Physicochimie des Polymeres et des Interfaces, 5, mail Gay-Lussac, F-95031 Cergy-Pontoise Cedex (France); Chevrot, Claude, E-mail: claude.chevrot@u-cergy.fr [Laboratoire de Physicochimie des Polymeres et des Interfaces, 5, mail Gay-Lussac, F-95031 Cergy-Pontoise Cedex (France); Markova, Ivania, E-mail: vania@uctm.edu [Laboratory of Nanomaterials and Nanotechnologies, University of Chemical Technology and Metallurgy, 8 St. Kliment Ohridski blvd., 1756 Sofia (Bulgaria); Racheva, Todora, E-mail: todora@uctm.edu [Laboratory of Nanomaterials and Nanotechnologies, University of Chemical Technology and Metallurgy, 8 St. Kliment Ohridski blvd., 1756 Sofia (Bulgaria); Froyer, Gerard, E-mail: gerard.froyer@cnrs-imn.fr [Equipe Physique des Materiaux et Nanostructures, IMN, B.P. 32229, 44322 Nantes cedex 3 (France)

2012-04-16

Highlights: Black-Right-Pointing-Pointer Development of a mesoporous silicon with special morphological and chemical properties. Black-Right-Pointing-Pointer Successful embedding of carboxylic-acid terthiophenic monomer in porous silicon. Black-Right-Pointing-Pointer In situ electrochemical polymerization. Black-Right-Pointing-Pointer Polarized IRTF scattering provides the tendency to preferential organization. - Abstract: A mesoporous n-type silicon/poly (3 Prime -acetic acid-2,2 Prime -5 Prime ,2 Prime Prime terthiophene)-(Poly (3TAA) nanocomposite was elaborated in order to realize new components for optoelectronics. Non-oxidized and oxidized porous silicon substrates is used and their physical and chemical properties have been studied by different techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR). Terthiophene based conjugated structure has been successfully incorporated inside the pores by capillarity at the melting temperature of the monomer. The filling of the monomer into the porous volume was probed by energy dispersive X-ray spectroscopy (EDX). Polarized infrared absorption spectroscopy results indicated that the monomer molecules show preferential orientation along the pore axis, due to hydrogen bonding, in particular that of the carboxylic groups with silanol-rich oxidized porous silicon surface. The 3TAA monomer molecules embedded in porous silicon matrix were electrochemically polymerized in situ and resonance Raman scattering spectroscopy proved the above-mentioned polymerization.

Effect of DS Concentration on the PRO Performance Using a 5-Inch Scale Cellulose Triacetate-Based Hollow Fiber Membrane Module

Directory of Open Access Journals (Sweden)

Masahiro Yasukawa

2018-05-01

Full Text Available In this study, pressure-retarded osmosis (PRO performance of a 5-inch scale cellulose triacetate (CTA-based hollow fiber (HF membrane module was evaluated under a wide range of operating conditions (0.0–6.0 MPa of applied pressure, 0.5–2.0 L/min feed solution (FS inlet flow rate, 1.0–6.0 L/min DS inlet flow rate and 0.1–0.9 M draw solution (DS concentration by using a PRO/reverse osmosis (RO hybrid system. The subsequent RO system for DS regeneration enabled the evaluation of the steady-stated module performance. In the case of pilot-scale module operation, since the DS dilution and the feed solution (FS up-concentration had occurred and was not negligible, unlike the lab-scale experiment, PRO performance strongly depended on operating conditions such as inlet flow rates of both the DS and FS concentration. To compare the module performance with different configurations, we proposed a converted parameter in which a difference of the packing density between the spiral wound (SW and the HF module was fairly considered. In the case of HF configuration, because of high packing density, volumetric-based performance was higher than that of SW module, that is, the required number of the module would be less than that of SW module in a full-scale PRO plant.

Preliminary study on biosynthesis and characterization of bacteria cellulose films from coconut water

Science.gov (United States)

Indrianingsih, A. W.; Rosyida, V. T.; Jatmiko, T. H.; Prasetyo, D. J.; Poeloengasih, C. D.; Apriyana, W.; Nisa, K.; Nurhayati, S.; Hernawan; Darsih, C.; Pratiwi, D.; Suwanto, A.; Ratih, D.

2017-12-01

Bacterial cellulose produced by Acetobacter xylinum is a unique type of bacterial cellulose. It contains more than 90% of water. A preliminary study had shown that bacterial cellulose films has remarkable mechanical properties. The aim of this study was to investigate the optimum condition such as percentage of carbon source, time of cultivation, and pH to produce bacterial cellulose films from local coconut water, and its characterization on morphology, swelling ability and tensile strength of dried bacterial cellulose. A. xylinum was grown on coconut water culture medium with addition of 3%, 5%, and 7% of sugar, while the cultivation time was vary from 3 days, 5 days and 7 days. pH condition was conducted in pH 3, pH 5 and pH 7. Bacterial cellulose samples were dried using oven with temperature of 100°C until the moisture content reached 4-5%. This study showed that several parameters for optimum condition to produce bacterial cellulose films from local waste of coconut water had been obtained (5% of carbon source; pH 5; and 7 day of incubation period). The electron microscopy also showed that dried bacterial cellulose films had pores covered by fibrils on the surface. Therefore, the present work proposes the optimum formula and condition that can be used based on properties of end product needed.

Conformations and Intermolecular Interactions in Cellulose/Silk Fibroin Blend Films: A Solid-State NMR Perspective.

Science.gov (United States)

Tian, Donglin; Li, Tao; Zhang, Rongchun; Wu, Qiang; Chen, Tiehong; Sun, Pingchuan; Ramamoorthy, Ayyalusamy

2017-06-29

Fabricating materials with excellent mechanical performance from the natural renewable and degradable biopolymers has drawn significant attention in recent decades due to the environmental concerns and energy crisis. As two of the most promising substitutes of synthetic polymers, silk fibroin (SF), and cellulose, have been widely used in the field of textile, biomedicine, biotechnology, etc. Particularly, the cellulose/SF blend film exhibits better strength and toughness than that of regenerated cellulose film. Herein, this study is aimed to understand the molecular origin of the enhanced mechanical properties for the cellulose/SF blend film, using solid-state NMR as a main tool to investigate the conformational changes, intermolecular interactions between cellulose and SF and the water organization. It is found that the content of the β-sheet structure is increased in the cellulose/SF blend film with respect to the regenerated SF film, accompanied by the reduction of the content of random coil structures. In addition, the strong hydrogen bonding interaction between the SF and cellulose is clearly elucidated by the two-dimensional (2D) 1 H- 13 C heteronuclear correlation (HETCOR) NMR experiments, demonstrating that the SF and cellulose are miscible at the molecular level. Moreover, it is also found that the -NH groups of SF prefer to form hydrogen bonds with the hydroxyl groups bonded to carbons C2 and C3 of cellulose, while the hydroxyl groups bonded to carbon C6 and the ether oxygen are less favorable for hydrogen bonding interactions with the -NH groups of SF. Interestingly, bound water is found to be present in the air-dried cellulose/SF blend film, which is predominantly associated with the cellulose backbones as determined by 2D 1 H- 13 C wide-line-separation (WISE) experiments with spin diffusion. This clearly reveals the presence of nanoheterogeneity in the cellulose/SF blend film, although cellulose and SF are miscible at a molecular level. Without doubt

Bond scission cross sections for alpha-particles in cellulose nitrate (LR115)

CERN Document Server

Barillon, R; Chambaudet, A; Katz, R; Stoquert, J P; Pape, A

1999-01-01

Chemical damage created by alpha-particles in cellulose nitrate (LR115) have been studied by infrared spectroscopy. This technique enables identifying the sensitive bonds and giving an order of magnitude of their scission cross sections for given alpha-particle energies. The high cross sections observed suggest a new description of the track etch velocity in this material.

Mueller matrix spectroscopic ellipsometry study of chiral nanocrystalline cellulose films

Science.gov (United States)

Mendoza-Galván, Arturo; Muñoz-Pineda, Eloy; Ribeiro, Sidney J. L.; Santos, Moliria V.; Järrendahl, Kenneth; Arwin, Hans

2018-02-01

Chiral nanocrystalline cellulose (NCC) free-standing films were prepared through slow evaporation of aqueous suspensions of cellulose nanocrystals in a nematic chiral liquid crystal phase. Mueller matrix (MM) spectroscopic ellipsometry is used to study the polarization and depolarization properties of the chiral films. In the reflection mode, the MM is similar to the matrices reported for the cuticle of some beetles reflecting near circular left-handed polarized light in the visible range. The polarization properties of light transmitted at normal incidence for different polarization states of incident light are discussed. By using a differential decomposition of the MM, the structural circular birefringence and dichroism of a NCC chiral film are evaluated.

Morphological, mechanical, barrier and properties of films based on acetylated starch and cellulose from barley.

Science.gov (United States)

El Halal, Shanise Lisie Mello; Colussi, Rosana; Biduski, Bárbara; Evangelho, Jarine Amaral do; Bruni, Graziella Pinheiro; Antunes, Mariana Dias; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2017-01-01

Biodegradable films of native or acetylated starches with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. The tensile strength of the acetylated starch film was lower than those of the native starch film, without fibers. The addition of fibers increased the tensile strength and decreased the elongation and the moisture of native and acetylated starches films. The acetylated starch film showed higher water solubility when compared to native starch film. The addition of cellulose fibers reduced the water solubility of the acetylated starch film. The films reinforced with cellulose fiber exhibited a higher initial decomposition temperature and thermal stability. The mechanical, barrier, solubility, and thermal properties are factors which direct the type of the film application in packaging for food products. The films elaborated with acetylated starches of low degree of substitution were not effective in a reduction of the water vapor permeability. The addition of the cellulose fiber in acetylated and native starches films can contribute to the development of more resistant films to be applied in food systems that need to maintain their integrity. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Characterization of the microporous HDPE film with alpha alumina

International Nuclear Information System (INIS)

Park, Jong Seok; Sung, Hae Jun; Gwon, Hui Jeong; Lim, Youn Mook; Nho, Young Chang

2010-01-01

The effects of the addition of the alpha alumina on the properties of the microporous high density polyethylene (HDPE) films were investigated. The particle size and the specific surface area of alpha alumina were 400 nm and 7.3 m 2 g -1 . The HDPE and the alpha alumina were mixed to obtain the precursor film in the twin extruder. The precursor films were uni-axially stretched up to 600% in oven 120 .deg. C and then the stretched HDPE films were irradiated by gamma rays. The pore volume of the microporous HDPE films was increased with an increasing content of the alpha alumina. The mechanical characteristics of the microporous HDPE films were increased with a content of alpha alumina up to 15%, but decreased at 20%. The electrochemical stability of the microporous HDPE film containing alpha alumia was increased with an increased irradiation dose up ti 50 kGy

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.

Surface analysis of the selective excimer laser patterning of a thin PEDOT:PSS film on flexible polymer films

Energy Technology Data Exchange (ETDEWEB)

Schaubroeck, David, E-mail: David.Schaubroeck@elis.ugent.be [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 15, B-9052 Ghent (Belgium); De Smet, Jelle; Willems, Wouter [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 15, B-9052 Ghent (Belgium); Cools, Pieter; De Geyter, Nathalie; Morent, Rino [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); De Smet, Herbert; Van Steenbeerge, Geert [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 15, B-9052 Ghent (Belgium)

2016-07-15

Highlights: • Laser patterning of thin film PEDOT:PSS on polymer foils is characterized in great detail. • PEDOT:PSS does not need to be fully removed to create electrically insulating patterns. • The underlying polymer foil influences the ablation behavior. - Abstract: Fast patterning of highly conductive polymers like PEDOT:PSS (poly (3,4-ethylene dioxythiophene): polystyrene sulfonate) with lasers can contribute to the development of industrial production of liquid crystal displays on polymer foils. In this article, the selective UV laser patterning of a PEDOT:PSS film on flexible polymer films is investigated. Based on their optical properties, three polymer films are investigated: polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and cellulose triacetate (TAC). Ablation parameters for a 110 nm PEDOT:PSS film on these polymer films are optimized. A detailed study of the crater depth, topography and surface composition are provided using optical profilometry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The electrical insulation of the lines is measured and correlated to the crater analyses for different laser settings. Finally, potential ablation parameters for each of the polymer films are derived.

Bioinspired lubricating films of cellulose nanofibrils and hyaluronic acid.

Science.gov (United States)

Valle-Delgado, Juan José; Johansson, Leena-Sisko; Österberg, Monika

2016-02-01

The development of materials that combine the excellent mechanical strength of cellulose nanofibrils (CNF) with the lubricating properties of hyaluronic acid (HA) is a new, promising approach to cartilage implants not explored so far. A simple, solvent-free method to produce a very lubricating, strong cellulosic material by covalently attaching HA to the surface of CNF films is described in this work. A detailed analysis of the tribological properties of the CNF films with and without HA is also presented. Surface and friction forces at micro/nanoscale between model hard surfaces (glass microspheres) and the CNF thin films were measured using an atomic force microscope and the colloid probe technique. The effect of HA attachment, the pH and the ionic strength of the aqueous medium on the forces was examined. Excellent lubrication was observed for CNF films with HA attached in conditions where the HA layer was highly hydrated. These results pave the way for the development of new nanocellulose-based materials with good lubrication properties that could be used in biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Fabrication and characterization of regenerated cellulose films obtained from oil palm empty fruit bunch

Science.gov (United States)

Nor Amalini, A.; Melina Cheah, M. Y.; Wan Rosli, W. D.; Hayati, S.; Mohamad Haafiz, M. K.

2017-12-01

Development of regenerated cellulose (RC) derived from underutilized cellulosic biomass has recently gained attention as potential petroleum-based polymer replacers. The objective of this current work is to evaluate the properties of RC films obtained from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) through environmental process. The RC films were fabricated by using different amounts of OPEFB-MCC (4, 6 and 8 %) and 1-butyl-3-methylimidazolium chloride (BMIMCl) was used as green OPEFB-MCC dissolving medium. The resultant RC films were then characterized by means of Fourier transform infrared (FTIR) spectroscopy, mechanical, thermal and morphological properties by using tensile test, differential scanning colorimetry (DSC), and scanning electron microscopy (SEM) respectively. Increase in OPEFB-MCC amounts from 4 to 8 % enhanced the tensile strength and elongation at break of RC by 101 and 78 %, respectively, indicating stronger and more flexible films were formed. It is interesting to note that the Tg (101-154 °C) and Tm(130-187 °C) were found shifted to higher temperature with higher proportions of OPEFB-MCC in RC films. Meanwhile, FTIR analysis showed no new peak presented in RC films, suggesting that BMIMCl is a non-derivatizing solvent to OPEFB-MCC. Conspicuous changes in the spectra of RC films compared to OPEFB-MCC at 3200-3600 cm-1, 1430 cm-1, 1162 cm-1, 1111 cm-1, 1020-1040 cm-1 and 896 cm-1 were associated with transformation of cellulose I to cellulose II structure or/and decrease in crystallinity occurred after regeneration process. SEM micrographs of the RC films revealed that higher OPEFB-MCC contents exhibited smoother and more homogeneous surfaces morphology. Overall, OPEFB-MCC exhibited good film forming ability for RC production and may offer potential application in various industries including food packaging, medical goods and electronic devices.

Cellulose/poly-(m-phenylene isophthalamide) porous film as a tissue-engineered skin bioconstruct

Science.gov (United States)

Lee, Jae Woong; Han, Sung Soo; Zo, Sum Mi; Choi, Soon Mo

2018-06-01

Regarding the porous structure, coagulated cellulose may not provide sufficient voids for cell proliferation, resulting in tissue growth. For this reason, it was blended with poly(m-phenylene isophthalamide) (PMIA), which could produce a porous structure in the resulting construct. The aim of this study was to confirm the potential of a novel cellulose/PMIA porous film as a tissue-engineered bioconstruct for impaired skin. The films were fabricated by a coagulation process added with a peel-off method, and the structural, mechanical properties were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and capillary flow porometry. CRL-2310 human keratinocytes were used to determine the biocompatibility of the prepared films. The attachment and proliferation of cells were investigated by scanning electron microscopy, DAPI staining, and a cell viability assay. The results show that cellulose/PMIA porous films have potential use as wound matrices for skin tissue genesis.

Characterization of cellulose acetate obtained from sugarcane bagasse by 1H-NMR

International Nuclear Information System (INIS)

Cerqueira, Daniel A.; Rodrigues Filho, Guimes; Carvalho, Rui A.; Valente, Artur J.M.

2009-01-01

Cellulose from sugarcane bagasse was used for synthesizing cellulose acetate with different degrees of substitution, which were characterized by 1 H-NMR through the relationship between the peak areas of the hydrogen atoms present at the acetate groups (-(C=O)OCH 3 ) and the peaks of the hydrogen bonded to the carbon atoms of the glycosidic rings. Suppression was carried out in order to remove the peak of residual water in the materials and the peak related to impurities in cellulose triacetate. Degree of substitution values obtained through the resonance deconvolution were compared to those obtained by chemical determination through an acid-base titration. The determined degrees of substitution of the cellulose samples were 2.94 and 2.60. (author)

Improved Properties of Coconut Shell Regenerated Cellulose Biocomposite Films using Butyl Methacrylate

Directory of Open Access Journals (Sweden)

Farah Norain Hahary

2015-11-01

Full Text Available Butyl methacrylate acid (BMA was used to enhance the properties of coconut shell (CS and regenerated cellulose (RC biocomposite films. The effects of coconut shell content and BMA on the tensile properties, crystallinity index (CrI, thermal properties, and morphology of biocomposite films were investigated. An increase in CS content, up to 3 wt.%, increased the tensile strength and modulus of elasticity, but decreased the elongation at break. The CS-RC biocomposite films treated with BMA exhibited higher tensile strength and modulus of elasticity but lower elongation at break. The crystallinity index (CrI and thermal stability of CS-RC biocomposite films increased with increasing CS up to 3 wt.%. Treated CS biocomposite films had better thermal stability than untreated CS biocomposite films. The presence of BMA increased the crystallinity of CS regenerated cellulose biocomposite films. Enhancement of the interfacial interaction of CS-RC biocomposite films was revealed by morphological study.

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 °...

Novel Terthiophene-Substituted Fullerene Derivatives as Easily Accessible Acceptor Molecules for Bulk-Heterojunction Polymer Solar Cells

Directory of Open Access Journals (Sweden)

Filippo Nisic

2014-01-01

Full Text Available Five fulleropyrrolidines and methanofullerenes, bearing one or two terthiophene moieties, have been prepared in a convenient way and well characterized. These novel fullerene derivatives are characterized by good solubility and by better harvesting of the solar radiation with respect to traditional PCBM. In addition, they have a relatively high LUMO level and a low band gap that can be easily tuned by an adequate design of the link between the fullerene and the terthiophene. Preliminary results show that they are potential acceptors for the creation of efficient bulk-heterojunction solar cells based on donor polymers containing thiophene units.

Calcinated tea and cellulose composite films and its dielectric and lead adsorption properties.

Science.gov (United States)

Jayaramudu, Tippabattini; Varaprasad, Kokkarachedu; Kim, Hyun Chan; Kafy, Abdullahil; Kim, Jung Woong; Kim, Jaehwan

2017-09-01

In this paper, calcinated tea and cellulose composite (CTCC) films were fabricated via solution casting method. Chemical structure, morphology, crystallinity and thermal stability of the fabricated films were characterized by using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. The effect of calcinated tea loading on the properties of the prepared CTCC films was studied. The results suggest that the prepared CTCC films show higher mechanical properties, thermal stability and dielectric constant than the neat cellulose film. In addition, the CTCC films adsorb Pb 2+ ions and its adsorption performance depends on the calcinated tea content and pH level. The CTCC films are useful for sensors, flexible capacitor as well as lead adsorption applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of Carboxymethyl Cellulose (CMC on Mechanical Properties of Cold Water Fish Gelatin Biodegradable Edible Films

Directory of Open Access Journals (Sweden)

Mahsa Tabari

2017-05-01

Full Text Available The tendency to use biocompatible packages, such as biodegradable films, is growing since they contain natural materials, are recyclable and do not cause environmental pollution. In this research, cold water fish gelatin and carboxymethyl cellulose were combined for use in edible films. Due to its unique properties, gelatin is widely used in creating gel, and in restructuring, stabilizing, emulsifying, and forming foam and film in food industries. This research for the first time modified and improved the mechanical properties of cold water fish gelatin films in combination with carboxymethyl cellulose. Cold water fish gelatin films along with carboxymethyl cellulose with concentrations of 0%, 5%, 10%, 20% and 50% were prepared using the casting method. The mechanical properties were tested by the American National Standard Method. Studying the absorption isotherm of the resulting composite films specified that the humidity of single-layer water decreased (p < 0.05 and caused a reduction in the equilibrium moisture of these films. In the mechanical testing of the composite films, the tensile strength and Young’s modulus significantly increased and the elongation percent significantly decreased with the increase in the concentration of carboxymethyl cellulose. Considering the biodegradability of the films and the improvement of their mechanical properties by carboxymethyl cellulose, this kind of packaging can be used in different industries, especially the food industry, as an edible coating for packaging food and agricultural crops.

Nanocomposite film prepared by depositing xylan on cellulose nanowhiskers matrix

Science.gov (United States)

Qining Sun; Anurag Mandalika; Thomas Elder; Sandeep S. Nair; Xianzhi Meng; Fang Huang; Art J. Ragauskas

2014-01-01

Novel bionanocomposite films have been prepared by depositing xylan onto cellulose nanowhiskers through a pH adjustment. Analysis of strength properties, water vapour transmission, transparency, surface morphology and thermal decomposition showed the enhancement of film performance. This provides a new green route to the utilization of biomass for sustainable...

Optimization of some electrochemical etching parameters for cellulose derivatives

International Nuclear Information System (INIS)

Chowdhury, Annis; Gammage, R.B.

1978-01-01

Electrochemical etching of fast neutron induced recoil particle tracks in cellulose derivatives and other polymers provides an inexpensive and sensitive means of fast neutron personnel dosimetry. A study of the shape, clarity, and size of the tracks in Transilwrap polycarbonate indicated that the optimum normality of the potassium hydroxide etching solution is 9 N. Optimizations have also been attempted for cellulose nitrate, triacetate, and acetobutyrate with respect to such electrochemical etching parameters as frequency, voltage gradient, and concentration of the etching solution. The measurement of differential leakage currents between the undamaged and the neutron damaged foils aided in the selection of optimum frequencies. (author)

Fabrication of transparent cellulose acetate/graphene oxide nanocomposite film for UV shielding

Energy Technology Data Exchange (ETDEWEB)

Jahan, Nusrat; Khan, Wasi, E-mail: wasiamu@gmail.com; Azam, Ameer; Naqvi, A. H. [Department of Applied Physics, Z.H. College of Engineering & Technology, Aligarh Muslim University, Aligarh - 202002 (India)

2016-05-23

In this work, we have fabricated transparent cellulose acetate/graphene oxide nanocomposite (CAGONC) films for ultraviolet radiations (UVR) shielding. Graphene oxide (GO) was synthesized by modified Hummer’s method and CAGONC films were fabricated by solvent casting method. The films were analyzed using characterization techniques like x-ray diffraction (XRD), energy dispersive x-ray (EDX) equipped scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and ultra-violet visible (UV-VIS) spectroscopy. Four films were prepared by varying the wt% of GO (0.1wt%, 0.2wt% and 0.3wt%) with respect to cellulose acetate (CA). UV-vis measurements exhibit optical transparency in the range of 76-99% for visible light while ultra-violet radiation was substantially shielded.

High oxygen nanocomposite barrier films based on xylan and nanocrystalline cellulose

Science.gov (United States)

Amit Saxena; Thomas J. Elder; Jeffrey Kenvin; Arthur J. Ragauskas

2010-01-01

The goal of this work is to produce nanocomposite film with low oxygen permeability by casting an aqueous solution containing xylan, sorbitol and nanocrystalline cellulose. The morphology of the resulting nanocomposite films was examined by scanning electron microscopy and atomic force microscopy which showed that control films containing xylan and sorbitol had a more...

Three-Dimensional Microstructural Properties of Nanofibrillated Cellulose Films

Directory of Open Access Journals (Sweden)

Arttu Miettinen

2014-04-01

Full Text Available Nanofibrillated cellulose (NFC films have potential as oxygen barriers for, e.g., food packaging applications, but their use is limited by their hygroscopic characteristics. The three-dimensional microstructure of NFC films made of Pinus radiata (Radiata Pine kraft pulp fibres has been assessed in this study, considering the structural development as a function of relative humidity (RH. The surface roughness, micro-porosity, thickness and their correlations were analyzed using X-ray microtomography (X–μCT and computerized image analysis. The results are compared to those from scanning electron microscopy and laser profilometry. Based on a series of films having varying amounts of 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO-mediated oxidated nanofibrils, it was demonstrated that X–μCT is suitable for assessing the surface and bulk 3D microstructure of the cellulose films. Additionally, one of the series was assessed at varying humidity levels, using the non-destructive capabilities of X–μCT and a newly developed humidity chamber for in-situ characterization. The oxygen transmission rate (OTR of the films (20 g=m2 was below 3:7mLm-2 day-1 at humidity levels below 60% RH. However, the OTR increased considerably to 12:4mLm-2 day-1 when the humidity level increased to 80% RH. The increase in OTR was attributed to a change of the film porosity, which was reflected as an increase in local thickness. Hence, the characterization techniques applied in this study shed more light on the structures of NFC films and how they are affected by varying humidity levels. It was demonstrated that in increasing relative humidity the films swelled and the oxygen barrier properties decreased.

Thermal Conductivity in Nanostructured Films: From Single Cellulose Nanocrystals to Bulk Films

Science.gov (United States)

Jairo A. Diaz; Zhijiang Ye; Xiawa Wu; Arden L. Moore; Robert J. Moon; Ashlie Martini; Dylan J. Boday; Jeffrey P. Youngblood

2014-01-01

We achieved a multiscale description of the thermal conductivity of cellulose nanocrystals (CNCs) from single CNCs (~­0.72−5.7 W m−1 K−1) to their organized nanostructured films (~­0.22−0.53 W m−1 K−1) using...

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 chemically unstable and highly flammable. Agencies must handle nitrocellulose-base film (used in the...

Preparation and properties of silk sericin/cellulose cross-linking films

Directory of Open Access Journals (Sweden)

Wang Kunyan

2017-01-01

Full Text Available Silk sericin/cellulose cross-linked films were successfully prepared using glutaraldehyde as cross-linkinger. FTIR was applied to characterize the chemical structure of films. Cross-linked silk sericin film was found the peak intensity of FTIR for cross-linked film decreased markedly compared to pure silk sericin, which indicating cross-linking reaction has been occurred. The increasing value of swelling ratio also indicated the cross-linking has been happened. The cross-linking reaction increased the thermal decomposition temperature.

Status of Electron and Gamma Dosimetry

DEFF Research Database (Denmark)

Miller, Arne

1985-01-01

Several dosimetric systems have gained acceptance mainly for use in radiation sterilization or in plastic processing. They include: Perspex, radiochromic dye films, cellulose triacetate films, ceric-cerous liquid ampules, ethanol-chlorobenzene liquid ampules, ferrous-sulfate (Fricke) liquid ampules...... of light upon dissolution of amino acids and sugars, measurement of optical density of polyethylene film, and measurement of optical density in potassium dichromate solution....

Diazaisoindigo bithiophene and terthiophene copolymers for application in field-effect transistors and solar cells

KAUST Repository

Yue, Wan; Li, Cheng; Tian, Xuelin; Li, Weiwei; Neophytou, Marios; Chen, Hu; Du, Weiyuan; Jellett, Cameron; Chen, Hung-Yang; Onwubiko, Ada; McCulloch, Iain

2017-01-01

Two donor–acceptor conjugated polymers with azaisoindigo as acceptor units and bithiophene and terthiophene as donor units have been synthesized by Stille polymerization. These two polymers have been successfully applied in field-effect transistors

A Facile Pathway to Modify Cellulose Composite Film by Reducing Wettability and Improving Barrier towards Moisture

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Xiaorong Hu

2017-01-01

Full Text Available The hydrophilic property of cellulose is a key limiting factor for its wide application. Here, a novel solution impregnation pathway was developed to increase the hydrophobic properties of cellulose. When compared with the regenerated cellulose (RC, the composite films showed a decrease in water uptake ability towards water vapor, and an increase of the water contact angle from 29° to 65° with increasing resin content in the composites, with only a slight change in the transmittance. Furthermore, the Young’s modulus value increased from 3.2 GPa (RC film to 5.1 GPa (RCBEA50 film. The results indicated that the composites had combined the advantages of cellulose and biphenyl A epoxy acrylate prepolymer (BEA resin. The presented method has great potential for the preparation of biocomposites with improved properties. The overall results suggest that composite films can be used as high-performance packaging materials.

Investigation of size effect on film type haptic actuator made with cellulose acetate

International Nuclear Information System (INIS)

Kim, Sang-Youn; Kim, Jaehwan; Kim, Ki-Baek

2014-01-01

The most important factor in haptic interaction with hand-held devices is to develop a thin film type actuator which can be easily inserted into the devices and create vibrotactile signals with wide frequency bandwidth. This paper reports a film type vibrotactile actuator which is tiny enough to be embedded into small hand-held devices. The vibration mechanism and experiment results for the suggested vibrotactile actuator are explained. The aim of the actuator is to convey a vibrotactile force greater than a human’s vibrotactile threshold with broad frequency bandwidth to users. To achieve the requirement, we fabricate a film type vibrotactile actuator with cellulose acetate. When an AC voltage is applied to the actuator, the cellulose acetate film gets charged and then generates vibration. The suggested vibrotactile actuator is fabricated in two sizes: 50 mm × 25 mm and 25 mm × 25 mm. For each size of actuator, three kinds of actuator are fabricated with different pillar materials to support the cellulose acetate films. An experiment for measuring vibrational amplitude is conducted over a wide frequency range of actuation voltage. It is known that the proposed film type actuator is feasible for haptic application in the small hand-held devices. (paper)

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, ...

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....... Tensile testing revealed that MFC 2-reinforced films exhibited a more ductile behavior and that MFC 1-reinforced films had higher modulus of elasticity (E-modulus) at MFC loadings of 50 wt % or higher. Pure MFC films had relatively low oxygen permeability values when data were compared with those...

Versatile High-Performance Regenerated Cellulose Membranes Prepared using Trimethylsilyl Cellulose as a Precursor

KAUST Repository

Puspasari, Tiara

2018-01-01

(TMSC), a highly soluble cellulose derivative, as a precursor for the fabrication of cellulose thin film composite membranes. TMSC is an attractive precursor to assemble thin cellulose films with good deposition behavior and film morphology; cumbersome

Enhanced mechanical properties of hydrothermal carbamated cellulose nanocomposite film reinforced with graphene oxide.

Science.gov (United States)

Gan, Sinyee; Zakaria, Sarani; Syed Jaafar, Sharifah Nabihah

2017-09-15

Cellulose carbamate (CC) was synthesized via hydrothermal process and mixed with graphene oxide (GO) to form a homogeneous cellulose matrix nanocomposite films. The properties of CC/GO nanocomposite films fabricated using simple solution-mixing method with different GO loadings were studied. Transmission electron microscope analysis showed the exfoliation of self-synthesized GO nanosheets within the CC matrix. X-ray diffraction results confirmed the crystalline structure of CC/GO films as the CC/GO mass ratio increased from 100/0 to 100/4. The mechanical properties of CC/GO film were significantly improved as compared to neat CC film. From thermogravimetric analysis result, the introduction of GO enhanced the thermal stability and carbon yields. The 3D homogeneous porous structures of the CC/GO films were observed under Field emission scanning electron microscope. These improvements in nanocomposite film properties could be confirmed by Fourier transform infrared spectroscopy due to the strong and good interactions between CC and GO. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances... packaging food in accordance with the following prescribed conditions: (a) Water-insoluble hydroxyethyl...

Tunable d-Limonene Permeability in Starch-Based Nanocomposite Films Reinforced by Cellulose Nanocrystals.

Science.gov (United States)

Liu, Siyuan; Li, Xiaoxi; Chen, Ling; Li, Lin; Li, Bing; Zhu, Jie

2018-01-31

In order to control d-limonene permeability, cellulose nanocrystals (CNC) were used to regulate starch-based film multiscale structures. The effect of sphere-like cellulose nanocrystal (CS) and rod-like cellulose nanocrystal (CR) on starch molecular interaction, short-range molecular conformation, crystalline structure, and micro-ordered aggregated region structure were systematically discussed. CNC aspect ratio and content were proved to be independent variables to control d-limonene permeability via film-structure regulation. New hydrogen bonding formation and increased hydroxypropyl starch (HPS) relative crystallinity could be the reason for the lower d-limonene permeability compared with tortuous path model approximation. More hydrogen bonding formation, higher HPS relative crystallinity and larger size of micro-ordered aggregated region in CS0.5 and CR2 could explain the lower d-limonene permeability than CS2 and CR0.5, respectively. This study provided new insight for the control of the flavor release from starch-based films, which favored its application in biodegradable food packaging and flavor encapsulation.

Effects of Two Different Cellulose Nanofiber Types on Properties of Poly(vinyl alcohol Composite Films

Directory of Open Access Journals (Sweden)

Kitti Yuwawech

2015-01-01

Full Text Available This work concerns a study on the effects of fiber types and content of cellulose nanofiber on mechanical, thermal, and optical properties polyvinyl alcohol (PVA composites. Two different types of cellulose nanofibers, which are nanofibrillated cellulose (NFC and bacterial cellulose (BC, were prepared under various mechanical treatment times and then incorporated into the PVA prior to the fabrication of composite films. It was found that tensile modulus of the PVA film increased with nanofibers content at the expense of its percentage elongation value. DSC thermograms indicate that percentage crystallinity of PVA increased after adding 2–4 wt% of the fibers. This contributed to the better mechanical properties of the composites. Tensile toughness values of the PVA/BC nanocomposite films were also superior to those of the PVA/NFC system containing the same fiber loading. SEM images of the composite films reveal that tensile fractured surface of PVA/BC experienced more ductile deformation than the PVA/NFC analogue. The above discrepancies were discussed in the light of differences between the two types of fibers in terms of diameter and their intrinsic properties. Lastly, percentage total visible light transmittance values of the PVA composite films were greater than 90%, regardless of the fiber type and content.

Asymmetric oxidation of vinyl- and ethynyl terthiophene ligands in triruthenium complexes.

Science.gov (United States)

Zhang, Jing; Sun, Chao-Fang; Zhang, Ming-Xing; Hartl, František; Yin, Jun; Yu, Guang-Ao; Rao, Li; Liu, Sheng Hua

2016-01-14

A series of ruthenium(ii) complexes [{RuCl(CO)(PMe3)3(-CH[double bond, length as m-dash]CH-)}nX], (: n = 3, X = 3,3''-dimethyl-2,2':3',2''-terthiophene; : n = 2, X = 2,2'-bithiophene; : n = 2, X = 2,3-bis(3-methylthiophen-2-yl)benzothiophene) and [{Cp*(dppe)2Ru(-C[triple bond, length as m-dash]C-)}3X], (X = 3,3''-dimethyl-2,2':3',2''-terthiophene), were prepared and characterized by (1)H, (13)C and (31)P NMR. Their redox, spectroscopic and bonding properties were studied with a range of spectro-electrochemical methods in combination with density functional theory calculations. The first two anodic steps observed for and are largely localized on the lateral frameworks of the molecular triangle, the direct conjugation between them being precluded due to the photostable open form of the dithienyl ethene moiety. The third anodic step is then mainly localized on the centerpiece of the triangular structure, affecting both bithiophene laterals. The experimental IR and UV-vis-NIR spectroelectrochemical data and, largely, also DFT calculations account for this explanation, being further supported by direct comparison with the anodic behavior of reference diruthenium complexes and .

Au-pattern fabrication on a cellulose film using a polyurethane acrylate mold

International Nuclear Information System (INIS)

Han, Kwangjoon; Kang, Kwang-Sun; Kim, Jaehwan

2009-01-01

This paper deals with a gold micro-patterning process on a cellulose film using a polyurethane acrylate (PUA) mold. Recently, cellulose electro-active paper (EAPap) has been found to be a smart material that can be used for biodegradable sensors, actuators and MEMS devices. However, the hydrophilic and flexible characteristics of cellulose EAPap are major drawbacks for applying a conventional lithography process to fabricate MEMS devices. To overcome these drawbacks, an unconventional lithography process, the so-called micro-transfer printing technique based on a PUA mold, was employed. A master pattern for the PUA mold was fabricated using the conventional photolithography process with an SU-8 photoresist, and the replica of the master pattern was fabricated using PUA. Gold was deposited onto the PUA mold, and a mercaptopropyltrimethoxysilane (MPTMS) self-assembly monolayer was made on the gold surface to securely transfer the gold layer onto the cellulose film. The effect of MPTMS was investigated. Further investigation of the factors to optimize the repeated stamping process will lead to a practical, reusable mold

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...

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.

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.

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. Copyright © 2016 Elsevier B.V. All rights reserved.

Realization and characterization of a cellulose and conducting polymer-based ultrathin films composite material

International Nuclear Information System (INIS)

Henry, Christelle

1998-01-01

This work was dedicated to the realization and the characterization of an organic composite material in order to obtain organized ultrathin films with high conductivity and good mechanical properties. In this purpose, the Langmuir-Blodgett (LB) film of a crosslinked alkyl cellulose (rigid-rod polymer) was used as a host matrix for the electro-polymerization of alkyl thiophene and pyrrole. The first interesting result was the synthesis of a bigger amount of conducting alkyl polymer in the presence of cellulose. With the help of a photo-patterning technique, we were able to form contacts more or less conducting on the substrate. We have also shown that the conducting polymer grows beyond the electrode area until distances never described up to now in the literature. A preferential orientation of the conducting polymer chains along the LB dipping direction of the cellulose has been observed in some cases. Even for the films without molecular orientation, we have systematically observed a microscopic or macroscopic anisotropy. This phenomenon appears as domains concentrated in conducting polymers with anisotropic shapes oriented along the dipping direction. Finally, we have noticed that cellulose doesn't change the conductivity and the electrochromic properties of the conducting polymer. Beyond the keeping of these intrinsic properties, the matrix allows to stabilize the film when it is in contact with an organic solvent. (author) [fr

Triacetic acid lactone production from Saccharomyces cerevisiae

Science.gov (United States)

Triacetic acid lactone (TAL) is a potential platform chemical produced from acetyl-CoA and malonyl-CoA by the Gerbera hybrida 2-pyrone synthase (2PS) gene. Studies are ongoing to optimize production, purification, and chemical modification of TAL, which can be used to create the commercial chemicals...

Method of 10B determination in biological specimens

International Nuclear Information System (INIS)

Nikitina, R.G.; Frolova, E.I.

1981-01-01

The paper is concerned with the methods of 10 B determination in biological specimens (blood, skin and tissues of rats). On the basis of investigations conducted there have been proposed films based on cellulose triacetate with optimal characteristics in terms of their possible utilization as solid detectors to record α-particles and recoil nuclei. The conditions of film staining are also discussed

Packaging properties and control of Listeria monocytogenes in bologna by cellulosic films incorporated with pediocin

Directory of Open Access Journals (Sweden)

Paula Judith Pérez Espitia

2013-09-01

Full Text Available Listeria monocytogenes is a foodborne pathogen, able to survive and proliferate at refrigeration temperatures. As a result, ready-to-eat meat products have been associated with major outbreaks. Producing meat products involves lethal preservation treatments, e.g. thermal treatments. Listeria contamination, however, may be introduced when products are sliced and packaged at retail businesses or delicatessens. In Brazil, sliced bologna is very popular at retail markets. After slicing, however, bologna has a short shelf-life. The aim of this work was to study the effects of pediocin incorporation on the load at break, water vapor permeability rate and structure, by microscopic analysis, of antimicrobial cellulosic packaging. The potential application of the developed packaging for the preservation of bologna and inhibition of Listeria biofilm formation was also studied. Cellulosic antimicrobial packaging films were produced with cellulose acetate and acetone. Pediocin (commercially available concentrate ALTA TM 2341 was incorporated at 30, 40 and 50 % w/w. The load at break of films was studied using the Universal Testing Machine (Instron at 10 °C and 25 °C. The water vapor permeability was determined by gravimetric method. A scanning electron microscope was used to study the developed packaging structure. Antimicrobial activity of films against Listeria innoucua and L. monocytogenes was tested both in vitro and in bologna samples. Results showed that values of load at break decreased with increasing concentrations of pediocin at 10 °C and 25 °C. Regarding water vapor permeability, only the control and 50 % pediocin films presented statistical difference, with the 50 % pediocin film being more permeable. In vitro tests showed antimicrobial activity against L. innocua. Cellulosic film with 50 % pediocin reduced L. monocytogenes growth on sliced bologna by 1.2 log cycles after 9 days and prevented biofilm formation on packaging and bologna

Utilization of flax (Linum usitatissimum) cellulose nanocrystals as reinforcing material for chitosan films.

Science.gov (United States)

Mujtaba, Muhammad; Salaberria, Asier M; Andres, María A; Kaya, Murat; Gunyakti, Ayse; Labidi, Jalel

2017-11-01

Use of plastic based packaging tools is causing both health and economic problems. To overcome this situation, researchers are focusing on the use of different biomaterials such as chitosan and cellulose. The current study was conducted to check the effect of flax (Linum usitatissimum) cellulose nanocrystals (CNC) on mechanical and barrier properties of chitosan-based films. CNC was incorporated in different concentrations (5, 10, 20 and 30%). CNC was isolated from flax fiber using acid hydrolysis method. Tensile strength (TS) and young modulus (YM) values increased with the increase of CNC concentration. Chitosan film with 20% CNC revealed the highest YM value as 52.35MPa. No significant improvement was recorded in water vapor permeability due to overall lower film crystallinity. All the films were observed to be transparent up to an acceptable level. SEM and AFM analysis confirmed the homogeneity of films. A gradual enhancement was recorded in the antimicrobial activity of chitosan/CNC composite films. No significant improvement revealed in the thermal stability of composites. Copyright © 2017 Elsevier B.V. All rights reserved.

Neutron Reflectometry and QCM-D Study of the Interaction of Cellulase Enzymes with Films of Amorphous Cellulose

International Nuclear Information System (INIS)

Halbert, Candice E.; Ankner, John Francis; Kent, Michael S.; Jaclyn, Murton K.; Browning, Jim; Cheng, Gang; Liu, Zelin; Majewski, Jaroslaw; Supratim, Datta; Michael, Jablin; Bulent, Akgun; Alan, Esker; Simmons, Blake

2011-01-01

Improving the efficiency of enzymatic hydrolysis of cellulose is one of the key technological hurdles to reduce the cost of producing ethanol and other transportation fuels from lignocellulosic material. A better understanding of how soluble enzymes interact with insoluble cellulose will aid in the design of more efficient enzyme systems. We report a study involving neutron reflectometry (NR) and quartz crystal microbalance with dissipation (QCM-D) of the interaction of a commercial fungal enzyme extract (T. viride), two purified endoglucanses from thermophilic bacteria (Cel9A from A. acidocaldarius and Cel5A from T. maritima), and a mesophilic fungal endoglucanase (Cel45A from H. insolens) with amorphous cellulose films. The use of amorphous cellulose is motivated by the promise of ionic liquid pretreatment as a second generation technology that disrupts the native crystalline structure of cellulose. NR reveals the profile of water through the film at nm resolution, while QCM-D provides changes in mass and film stiffness. At 20 C and 0.3 mg/ml, the T. viride cocktail rapidly digested the entire film, beginning from the surface followed by activity throughout the bulk of the film. For similar conditions, Cel9A and Cel5A were active for only a short period of time and only at the surface of the film, with Cel9A releasing 40 from the ∼ 700 film and Cel5A resulting in only a slight roughening/swelling effect at the surface. Subsequent elevation of the temperature to the Topt in each case resulted in a very limited increase in activity, corresponding to the loss of an additional 60 from the film for Cel9A and 20 from the film for Cel5A, and very weak penetration into and digestion within the bulk of the film, before the activity again ceased. The results for Cel9A and Cel5A contrast sharply with results for Cel45A where very rapid and extensive penetration and digestion within the bulk of the film was observed at 20 C. We speculate that the large differences are due

A novel method for alpha dosimetry using peeled-off Gafchromic EBT3 films

Energy Technology Data Exchange (ETDEWEB)

Lee, Kwang-Ho; Kim, Eun-Hee [Seoul National University, Seoul (Korea, Republic of)

2016-10-15

One can estimate dose imposed to film by measuring the optical density of film. EBT3 film has been used in dose measurement for photon, proton, and electron beams but not for alpha particles. Both sides of diacetylene monomer layer are covered with 100 μm-thick polyester coating layers, through which alpha particles even at several MeV cannot penetrate. A recent study demonstrated the use of EBT3 film in alpha dosimetry by peeling off one side of polyester coating layer. Their study did not inform the reliability of measurement using the peeled-off films. In this study, we evaluated the feasibility of EBT3 film as a substitute for conventional alpha dosimeters and checked the uncertainty of dose measurements obtained with peeled-off EBT3 films. We also applied this film dosimeter to measuring of the fluence distribution at cell targets in a culture dish set in the alpha irradiation chamber of the Radiation Bioengineering Laboratory (RadBio Lab) at Seoul National University (SNU). In this work, we confirmed the feasibility of using Gafchromic EBT3 films for alpha dosimetry. The peeled-off EBT3 films can make a convenient alpha dosimeter by carrying an uncertainty less than 9 %.

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.

Eco-friendly biorefractory films of gelatin and TEMPO-oxidized cellulose ester for food packaging application.

Science.gov (United States)

Zhuang, Chen; Tao, Furong; Cui, Yuezhi

2017-08-01

In recent years, many types of food-packaging films and composites have been prepared using gelatin because of its good film-forming ability, non-toxic nature and cost-effectiveness. However, the relatively weak thermal stability, poor mechanical properties and easily-degradable quality limit the potential application of gelatin as a practical material. Microcrystalline cellulose (MCC), which comprises one of the most abundant biomass resources, has been regarded as a safe and reliable food additive because it has the same ingredients as the cellulose in people's daily intake. Food-packaging films with the excellent properties provided by gelatin and oxidized-cellulose represent a topic of great interest. MCC was modified by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation and chosen as the base of the macromolecule cross-linker (TMN). After modification of gelatin film by TMN, the minimum amount of free -NH 2 in solution was 4.8 × 10 -4  mol g -1 ). The thermal property obviously increased (from 322.31  o C to 352.63  o C) and was crucial for usage in the food industry. The highest water contact value 123.09° (η = 25%) indicated a better surface hydrophobicity. The higher E ab (58.88%) and lower E m (77.16%) demonstrated that a more flexible and shatter-proof material was obtained. Water vapor uptake studies suggested increased moisture absorption and greater swelling ability. The film material obtained in the present study was safe, stable, eco-friendly and biorefractory and could also be decomposed completely by the environment after disposal as a result of the properties of the ingredients gelatin and cellulose. The incorporation of a cellulosic cross-linker to gelatin-based films was an ideal choice with respect to developing a packaging for the food industry. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

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.

Biotransformation of Stypotriol triacetate by Aspergillus niger

Science.gov (United States)

Areche, Carlos; Vaca, Inmaculada; Labbe, Pamela; Soto-Delgado, Jorge; Astudillo, Luis; Silva, Mario; Rovirosa, Juana; San-Martin, Aurelio

2011-07-01

Biological transformation of the meroditerpenoid, stypotriol triacetate ( 1) by the fungi Aspergillus niger, Cunninghamella elegans, Gibberella fujikuroi and Mucor plumbeus was studied. The incubation of 1 with A. niger yielded the new compound 6',14-diacetoxy-stypol-4,5-dione ( 2) whose structure was established by 1H, 13C and 2D NMR and supported by DFT/GIAO.

Preparation and Characterization of Polyvinyl Alcohol-Chitosan Composite Films Reinforced with Cellulose Nanofiber

Science.gov (United States)

Choo, Kaiwen; Ching, Yern Chee; Chuah, Cheng Hock; Julai, Sabariah; Liou, Nai-Shang

2016-01-01

In this study microcrystalline cellulose (MCC) was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. The treated cellulose slurry was mechanically homogenized to form a transparent dispersion which consisted of individual cellulose nanofibers with uniform widths of 3–4 nm. Bio-nanocomposite films were then prepared from a polyvinyl alcohol (PVA)-chitosan (CS) polymeric blend with different TEMPO-oxidized cellulose nanofiber (TOCN) contents (0, 0.5, 1.0 and 1.5 wt %) via the solution casting method. The characterizations of pure PVA/CS and PVA/CS/TOCN films were performed in terms of field emission scanning electron microscopy (FESEM), tensile tests, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results from FESEM analysis justified that low loading levels of TOCNs were dispersed uniformly and homogeneously in the PVA-CS blend matrix. The tensile strength and thermal stability of the films were increased with the increased loading levels of TOCNs to a maximum level. The thermal study indicated a slight improvement of the thermal stability upon the reinforcement of TOCNs. As evidenced by the FTIR and XRD, PVA and CS were considered miscible and compatible owing to hydrogen bonding interaction. These analyses also revealed the good dispersion of TOCNs within the PVA/CS polymer matrix. The improved properties due to the reinforcement of TOCNs can be highly beneficial in numerous applications. PMID:28773763

Cellulose nanocomposite films with in situ generated silver nanoparticles using Cassia alata leaf extract as a reducing agent.

Science.gov (United States)

Sivaranjana, P; Nagarajan, E R; Rajini, N; Jawaid, M; Rajulu, A Varada

2017-06-01

Cotton linters were dissolved in aq. (8% LiOH+15% urea) that was pre-cooled to -12.5°C. Using this solution cellulose gel films were prepared by regeneration method with ethyl alcohol as a coagulant. These wet films were diffused with 10wt% Cassia alata leaf extract that acted as a reducing agent. The leaf extract diffused cellulose wet films were used as the matrix. The wet matrix films were dipped individually in lower concentrated 1-5mM aq.AgNO 3 source solutions in the presence of sunlight and allowed the solutions to react with the diffused leaf extract reducing agent which in situ generated the silver nanoparticles (AgNPs) inside the films as well as in the source solution. The AgNPs formed in the source solution were observed by transmission electron microscope (TEM) and scanning electron microscope (SEM) while those formed in situ the films were observed by SEM and the particle size distribution was determined. The cellulose/AgNP composite films showed good antibacterial activity against Escherichia coli bacteria. These nanocomposite films were also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and tensile tests. At temperatures below 300°C, the thermal stability of the nanocomposite films was lower than that of the matrix due to the catalytic effect of AgNPs. The nanocomposite films also possessed good tensile properties. The ecofriendly cellulose/AgNP composite films with good antibacterial activity and tensile properties can be considered for medical applications like dressing materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Spark counting technique of alpha tracks on an aluminium oxide film

International Nuclear Information System (INIS)

Morishima, Hiroshige; Koga, Taeko; Niwa, Takeo; Kawai, Hiroshi

1984-01-01

We have tried to use aluminium oxide film as a neutron detector film with a spark counter for neutron monitoring in the mixed field of neutron and gamma-rays near a reactor. The merits of this method are that (1) aluminium oxide is good electric insulator, (2) any desired thickness of the film can be prepared, (3) chemical etching of the thin film can be dispensed with. The relation between spark counts and numbers of alpha-particles which entered the aluminium oxide film 1 μm thick was linear in the range of 10 5 -10 7 alpha-particles. The sensitivity(ratio of the spark counts to irradiated numbers of alpha-particles) was approximately 10 -3 . (author)

Effect of Punica granatum peel extracts on antimicrobial properties in Walnut shell cellulose reinforced Bio-thermoplastic starch films from cashew nut shells.

Science.gov (United States)

Harini, K; Chandra Mohan, C; Ramya, K; Karthikeyan, S; Sukumar, M

2018-03-15

The main aim of the present study is to extract and characterize cashew nut shell (CNS) starch and walnut shell cellulose (WNC) for development of cellulose reinforced starch films. Moreover, the extraction and characterization of pomegranate peel extract, for incorporation with CNS-WNC films, was investigated. CNS starch was examined to be a moderate amylose starch with 26.32 ± 0.43% amylose content. Thermal degradation temperature of CNS starch was found to be 310 °C. Walnut shell cellulose was found to have high crystallinity index of 72%, with two thermal degradation temperatures of 319 °C and 461 °C. 2% WN cellulose reinforced CNS starch films were examined to have good oxygen transfer rate, mechanical and physical properties. Thermal degradation temperature of CNS-WNC starch films were found to be at the range of 298-302 °C. Surface roughness of CNS-WNC starch films were found to be increasing with increase in concentration of cellulose in films. Hydroxymethylfurfurole, Benzene, 2-methoxy-1,3,4-trimethyl and 1,2,3-Propanetriol, 1-acetate were found to be major active compounds present in hydrophilic extracts of Punica granatum peels. 2% WN cellulose reinforced starch films infused with hydrophilic active compounds of pomegranate peel was examined to be having good active package properties. Copyright © 2018 Elsevier Ltd. All rights reserved.

Creep behavior of starch-based nanocomposite films with cellulose nanofibrils.

Science.gov (United States)

Li, Meng; Li, Dong; Wang, Li-jun; Adhikari, Benu

2015-03-06

Nanocomposite films were successfully prepared by incorporating cellulose nanofibrils (CNFs) from sugar beet pulp into plasticized starch (PS) at CNFs concentration of 5-20%. The storage (G') and loss (G″) moduli, creep and creep-recovery behavior of these films were studied. The creep behavior of these films at long time frame was studied using time-temperature superposition (TTS). The CNFs were uniformly distributed within these films up to 15% of CNFs. The PS-only and the PS/CNFs nanocomposite films exhibited dominant elastic behavior. The incorporation of CNFs increased both the G' and G″. The CNFs improved the creep resistance and reduced the creep recovery rate of the PS/CNFs nanocomposite films. TTS method was successfully used to predict the creep behavior of these films at longer time frame. Power law and Burgers model were capable (R(2)>0.98) of fitting experimental G' versus angular frequency and creep strain versus time data, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation of Surlyn films reinforced with cellulose nanofibres and feasibility of applying the transparent composite films for organic photovoltaic encapsulation

Science.gov (United States)

Lertngim, Anantaya; Phiriyawirut, Manisara; Wootthikanokkhan, Jatuphorn; Yuwawech, Kitti; Sangkhun, Weradesh; Kumnorkaew, Pisist; Muangnapoh, Tanyakorn

2017-10-01

This research concerns the development of Surlyn film reinforced with micro-/nanofibrillated celluloses (MFC) for use as an encapsulant in organic photovoltaic (OPV) cells. The aim of this work was to investigate the effects of fibre types and the mixing methods on the structure-properties of the composite films. Three types of cellulose micro/nanofibrils were prepared: the as-received MFC, the dispersed MFC and the esterified MFC. The fibres were mixed with Surlyn via an extrusion process, using two different mixing methods. It was found that the extent of fibre disintegration and tensile modulus of the composite films prepared by the master-batching process was superior to that of the composite system prepared by the direct mixing method. Using the esterified MFC as a reinforcement, compatibility between polymer and the fibre increased, accompanied with the improvement of the percentage elongation of the Surlyn composite film. The percentage of light transmittance of the Surlyn/MFC films was above 88, regardless of the fibre types and fibre concentrations. The water vapour transmission rate of the Surlyn/esterified MFC film was 65% lower than that of the neat Surlyn film. This contributed to the longer lifetime of the OPV encapsulated with the Surlyn/esterified MFC film.

Effect of cellulose nanocrystals from corn cob with dispersion agent polyvinyl pyrrolidone in natural rubber latex film after aging treatment

Science.gov (United States)

Harahap, H.; Ridha, M.; Halimatuddahliana; Taslim; Iriany

2018-02-01

This study about the resistance of natural rubber latex films using nanocrystals cellulose filler from corn cob waste by aging treatment. Corn cob used as organic filler composed of cellulose, hemicellulose, and lignin. Each component has a potential for reuse, such as cellulose. Cellulose from corn cob has potential application as a filler prepared by hydrolysis process using a strong acid. The producing of natural rubber latex films through coagulant dowsing process. This research started with the pre-vulcanization process of natural rubber latex at 70 °C and followed by process of vulcanization at 110 °C for 20 minutes. Natural rubber latex films that have been produced continued with the aging treatment at 70 °C for 168 hours. The mechanical properties of natural rubber latex films after aging treatment are the tensile strength, elongation at break, M100 and M300 have performed.

Calibration of cellulose nitrate film for measurement of time-integrated concentration of radon-222 in air

International Nuclear Information System (INIS)

Jha, G.; Raghavayya, M.

1986-01-01

Measurement of time-integrated concentration of 222 Rn in air by using solid-state nuclear track detectors (SSNTD) is finding increasing application in such diverse fields as radiation protection, exploration of radioactive minerals, prediction of earthquakes etc. While there are several types of SSNTDs sensitive to specific types of particulate radiation, films made from cellulose nitrate (CN) are found to be the best suited for quick and quantitative measurement of alpha radiation. This is because CN films are available in small thicknesses, of the order of 10-12 μm, which can be suitably evaluated by spark counting technique. This report describes the use of a sensitive thin film of CN (Kodak LR 115, Type II) for quantitative estimation of 222 Rn. The film (along with the base is exposed in a cylindrical plastic cup closed at one end with a special rubber membrane which permits discrimination of 222 Rn against 220 Rn, which is also present in air to varying extents. The calibration procedure, including etching and evaluation of track registration efficiency, are described in detail. The mean track registration efficiency works out to 41.9 per cent and the sensitivity of the system is found to be 58.92 tracks cm -2 per (Bq.litre -1 ) day. The report lists the advantages and limitations of the system for measurement of time-integrated concentration of 222 Rn in air. (author)

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.

2018-01-01

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...

Cytocompatible cellulose hydrogels containing trace lignin

International Nuclear Information System (INIS)

Nakasone, Kazuki; Kobayashi, Takaomi

2016-01-01

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 12 h. 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 0.43 N/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. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

Cytocompatible cellulose hydrogels containing trace lignin

Energy Technology Data Exchange (ETDEWEB)

Nakasone, Kazuki; Kobayashi, Takaomi, E-mail: takaomi@nagaoakut.ac.jp

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 12 h. 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 0.43 N/mm{sup 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. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

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.

Biodegradable Composite Films based on κ-carrageenan Reinforced by Cellulose Nanocrystal from Kenaf Fibers

Directory of Open Access Journals (Sweden)

Siti Zarina

2014-11-01

Full Text Available Through alkali treatment, bleaching, and sulfuric acid hydrolysis, cellulose nanocrystals (CNCs were prepared from kenaf fibers and were used as reinforcement materials in biocomposites based on κ-carrageenan. Biocomposites in the form of films were prepared by solution casting of a mixture of κ-carrageenan, glycerol, and various amounts of CNCs (0 to 8 wt%. Fourier transform infrared spectroscopy (FTIR revealed that alkali treatment followed by bleaching totally removed lignin and hemicellulose from the kenaf. Morphological analysis of the fibers, cellulose, and κ-carrageenan of biocomposite films were carried out using field emission scanning electron microscopy (FESEM and transmission electron microscopy (TEM. The effects of filler content on the mechanical and thermal stability of the k-carrageenan biocomposite films were analyzed through tensile strength measurements and thermogravimetric analysis (TGA. At an optimum CNC content of 4%, the κ-carrageenan biocomposite films showed good dispersion, superior mechanical properties, and improved thermal stability.

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of halloysite content on carboxymethyl cellulose/halloysite nanotube bio-nanocomposite films

Science.gov (United States)

Suppiah, Kathiravan; Leng, Teh Pei; Husseinsyah, Salmah; Rahman, Rozyanty; Keat, Yeoh Cheow

2017-04-01

Carboxymethyl cellulose/halloysite nanotube (CMC/HNT) bio-nanocomposite films were prepared by solution casting method. The effect of HNT content on tensile properties and morphology were studied. The results showed that the tensile strength of the CMC/HNT bio-nanocomposite films achieved optimum at 10 wt% of HNT content. The elongation at break and modulus of elasticity increased with increasing HNT content. The morphology of CMC/HNT bio-nanocomposite films showed that the poor distribution of HNT filler was observed at 20 wt% of HNT content.

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.

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Bulk etch rate of LR-115 cellulose nitrate film

International Nuclear Information System (INIS)

Harris, M.J.; Schlenker, R.A.

1977-01-01

Bulk etch rate (V/sub b/) of Kodak LR-115 cellulose nitrate film has been studied, and values for the parameter are presented. An interesting variability of V/sub b/ has been found which has implications for microdosimetry using this type of integrating nuclear track detector. Short-term and longer-term thickness changes have been observed which may increase the uncertainty in estimations of dose using this type of detector

Poly(vinyl alcohol) films reinforced with nanofibrillated cellulose (NFC) isolated from corn husk by high intensity ultrasonication.

Science.gov (United States)

Xiao, Shaoliang; Gao, Runan; Gao, LiKun; Li, Jian

2016-01-20

This work was aimed at fabricating and characterizing poly(vinyl alcohol) films that were reinforced by nanofibrillated corn husk celluloses using a combination of chemical pretreatments and ultrasonication. The obtained nanofibrillated celluloses (NFCs) possessed a narrow width ranging from 50 to 250 nm and a high aspect ratio (394). The crystalline type of NFC was cellulose I type. Compared with the original corn husks, the NCF crystallinity and thermal stability increased due to the removal of the hemicelluloses and lignin. PVA films containing different NFC concentrations (0.5%, 1%, 3%, 5%, 7% and 9%, w/w, dry basis) were examined. The 1% PVA/NFC reinforced films exhibited a highly visible light transmittance of 80%, and its tensile strength and the tensile strain at break were increased by 1.47 and 1.80 times compared to that of the pure PVA film, respectively. The NFC with high aspect ratio and high crystallinity is beneficial to the improvement of the mechanical strength and thermal stability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biodegradable films containing {alpha}-tocopherol/{beta}-cyclodextrin complex; Filmes biodegradaveis contendo {alpha}-tocoferol complexado em {beta}-ciclodextrina

Energy Technology Data Exchange (ETDEWEB)

Motta, Caroline; Martelli, Silvia M.; Soldi, Valdir, E-mail: vsoldi@qmc.ufsc.br [Lab. de Materiais Polimericos (POLIMAT), Dept. de Quimica, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil); Barreto, Pedro L.M. [Lab. de Reologia (REOLAB), Dept. de Ciencia e Tecnologia de Alimentos, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil)

2011-07-01

The growing environmental concern about pollution and the need to reduce dependence of plastic industry in relation to non-renewable resources has increased the interest of both researchers and industry in the use of biopolymers. In this work {beta}-cyclodextrin/{alpha}-tocopherol complexes were prepared and characterized. In order to obtain polymeric active biofilms, the {beta}-cyclodextrin/{alpha}-tocopherol complex was incorporated into a polymeric matrix of carboxymethylcellulose. The {beta}-cyclodextrin/{alpha}-tocopherol complex was characterized through of X-ray diffraction and thermogravimetric analysis. The physicochemical properties of the films incorporated with the complex were evaluated through mechanical and colorimetric analysis and moisture sorption isotherm. (author)

Facile preparation of optically transparent and hydrophobic cellulose nanofibril composite films

Science.gov (United States)

Yan Qing; Zhiyong Cai; Yiqiang Wu; Chunhua Yao; Qinglin Wu; Xianjun Li

2015-01-01

Cellulose nanofibril (CNF) and epoxy nanocomposites with high visible light transmittance and low watersensitivity were manufactured by laminating thin layers of epoxy resin onto CNF films prepared through,pressurized filtration in combination with oven drying. Scanning Electron Microscopy (SEM) studiessuggest that the resin component bonded to the CNF substrate well....

Triacetic acid lactone production in industrial Saccharomyces yeast strains

Science.gov (United States)

Triacetic acid lactone (TAL) is a potential platform chemical that can be produced in yeast. To evaluate the potential for industrial yeast strains to produce TAL, the g2ps1 gene encoding 2-pyrone synthase was transformed into thirteen industrial yeast strains of varied genetic background. TAL produ...

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).

Characterizations of biodegradable epoxy-coated cellulose nanofibrils (CNF) thin film for flexible microwave applications

Science.gov (United States)

Hongyi Mi; Chien-Hao Liu; Tzu-Husan Chang; Jung-Hun Seo; Huilong Zhang; Sang June Cho; Nader Behdad; Zhenqiang Ma; Chunhua Yao; Zhiyong Cai; Shaoqin Gong

2016-01-01

Wood pulp cellulose nanofibrils (CNF) thin film is a novel recyclable and biodegradable material. We investigated the microwave dielectric properties of the epoxy coated-CNF thin film for potential broad applications in flexible high speed electronics. The characterizations of dielectric properties were carried out in a frequency range of 1–10 GHz. The dielectric...

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

OpenAIRE

Galina Rodionova,; Solenne Roudot; , Øyvind Eriksen,; Ferdinand Männle,; Øyvind Gregersen

2012-01-01

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...

Structure and properties of hydroxyapatite/hydroxyethyl cellulose acetate composite films.

Science.gov (United States)

Azzaoui, K; Mejdoubi, E; Lamhamdi, A; Zaoui, S; Berrabah, M; Elidrissi, A; Hammouti, B; Fouda, Moustafa M G; Al-Deyab, Salem S

2015-01-22

The main aim of this research work was to develop a new inorganic-organic film. Hydroxyapaptite (HAp) particles that represent the inorganic phase was mixed well with hydroxyethyl cellulose acetate (HECA), which representing the organic phase and then the inorganic-organic films were fabricated by evaporating of the solvent. The structure as well as the properties of the formed films were characterized using different analytical tools such as field emission scanning electron microscopy (FEG-SEM), thermo-gravimetric analysis (TGA), Fourier transform infra-red (FT-IR) spectroscopy. The obtained results revealed that, the HAp nanoparticles was well dispersed and well immobilized throughout the formed films. This can be attributed to the role of the nano- and micropores in the HECA substrate. In addition, a strong interaction occurred between HAp and HECA matrix. The results showed also good thermal stability and miscibility as well. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

DEFF Research Database (Denmark)

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

2010-01-01

, confirming the existence of complex structures below the film surface. In contrast, the diffusion coefficient was definitely affected by plasticization, being higher for glycerol-containing samples and showing in all cases an exponential increase when water was added to the system. Similar behavior...... the existence of complex structures in the different samples. A porous, closely packed fiber network, more homogeneous in the samples containing glycerol, was characteristic of the surface of MFC films; while film cross-sections presented a dense layered structure with no evidence of porosity. Water vapor...... 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...

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

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...... in plasticized films increased with glycerol content but was independent of xylan:NFC ratio in unplasticized films. Sorbitol- and MPEG-plasticized films showed equilibrium moisture contents of approximately 10 wt% independent of plasticizer content. Tensile testing revealed increases in tensile strength...... with increased NFC content in the xylan:NFC composition range from 50:50 to 80:20 and plasticizer addition generally provided less brittle films. The oxygen permeability of unplasticized xylan-NFC films fell into a range which was similar to that for previously measured pure NFC films and was statistically...

Multifunctional PLA-PHB/cellulose nanocrystal films: processing, structural and thermal properties.

Science.gov (United States)

Arrieta, M P; Fortunati, E; Dominici, F; Rayón, E; López, J; Kenny, J M

2014-07-17

Cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose by acid hydrolysis were added into poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends to improve the final properties of the multifunctional systems. CNC were also modified with a surfactant (CNCs) to increase the interfacial adhesion in the systems maintaining the thermal stability. Firstly, masterbatch pellets were obtained for each formulation to improve the dispersion of the cellulose structures in the PLA-PHB and then nanocomposite films were processed. The thermal stability as well as the morphological and structural properties of nanocomposites was investigated. While PHB increased the PLA crystallinity due to its nucleation effect, well dispersed CNC and CNCs not only increased the crystallinity but also improved the processability, the thermal stability and the interaction between both polymers especially in the case of the modified CNCs based PLA-PHB formulation. Likewise, CNCs were better dispersed in PLA-CNCs and PLA-PHB-CNCs, than CNC. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dispersion Process and Effect of Oleic Acid on Properties of Cellulose Sulfate- Oleic Acid Composite Film

Science.gov (United States)

Chen, Guo; Zhang, Bin; Zhao, Jun

2015-01-01

The cellulose sulfate (CS) is a newly developed cellulose derivative. The work aimed to investigate the effect of oleic acid (OA) content on properties of CS-OA film. The process of oleic acid dispersion into film was described to evaluate its effect on the properties of the film. Among the formulations evaluated, the OA addition decreased the solubility and water vapor permeability of the CS-OA film. The surface contact angle changed from 64.2° to 94.0° by increasing CS/OA ratio from 1:0 to 1:0.25 (w/w). The TS increased with OA content below 15% and decreased with OA over 15%, but the ε decreased with higher OA content. The micro-cracking matrices and micro pores in the film indicated the condense structure of the film destroyed by the incorporation of oleic acid. No chemical interaction between the OA and CS was observed in the XRD and FTIR spectrum. Film formulation containing 2% (w/w) CS, 0.3% (w/w) glycerol and 0.3% (w/w) OA, showed good properties of mechanic, barrier to moisture and homogeneity.

An application of 222Rn alpha particle's tracks to uranium exploration

International Nuclear Information System (INIS)

Aguilar H, F.

1981-01-01

The uranium exploration method is based on the register of 222 Rn alpha particles; 222 Rn gas is generated in the chain 238 U desintegration. The detection of alpha particles was performed with cellulose nitrate films (NTC), located in a grid at the region in study. The alpha particles produce latent tracks in the NTC films; these tracks may be enlarged by chemical etching and are observed with an ordinary optic microscope, ninety seven NTC films were used, these were distributed in an area of approximately seventeen square kilometers, located in the municipalities of Granados and Huasabas in Sonora Mexico, the detectors remain in the ground for a thirty days mean period. The results obtained show an area with high 222 Rn concentration, this can be related with an underground uranium ore deposit. The more important conclusion is that the results obtained in this work can be used as preliminary results for other prospection methods in this particular area. (author)

Films of chitin, chitosan and cellulose obtained from aqueous suspension treated by irradiation of high intensity ultrasound

International Nuclear Information System (INIS)

Almeida, Erika V.R.; Mariano, Mario S.; Campana-Filho, Sergio P.

2011-01-01

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)

Characterization of cinematographic films by Laser Induced Breakdown Spectroscopy

International Nuclear Information System (INIS)

Gaspard, S.; Oujja, M.; Rebollar, E.; Abrusci, C.; Catalina, F.; Castillejo, M.

2007-01-01

The emulsion-coated transparent plastic-base film has been the main carrier for production and preservation of motion picture contents since the 19th century. The knowledge of the composition of black and white silver gelatine cinematographic films is of great importance for the characterization of the photographic process and for identifying the optimum conditions for conservation. A cinematographic film is a multi-component system that consists of a layer of photographic emulsion overcoating a polymeric support (plasticized cellulose triacetate) and a protective transparent cross-linked gelatine layer coating the emulsion. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) is used to characterize the composition of the materials of cinematographic films. LIB spectra of film samples and of different individual film components, polymeric support and reference gelatines, were acquired in vacuum by excitation at 266 nm (Q-switched Nd:YAG laser, 6 ns, 10 Hz). In the cinematographic film, silver lines from the light-sensitive silver halide salts of the photographic emulsion are accompanied by iron, lead, chrome and phosphorus lines. Iron and lead are constituents of film developers, chrome is included in the composition of the hardening agents and phosphorus has its origin in the plasticizer used in the polymeric support. By applying successive pulses on the same spot of the film sample, it was possible to observe through stratigraphic analysis the different layers composition. Additionally, the results obtained reveal the analytical capacity of LIBS for the study and classification of the different gelatine types and qualities used for the protecting layer and the photographic emulsion

Preparation of cellulose nitrate films using a spinning disc for solid state nuclear track detection (SSNTD) applications

International Nuclear Information System (INIS)

Raghunath, B.; Iyer, M.R.; Samant, S.D.

1995-01-01

Solid state nuclear track detectors (SSNTD) are widely used in the detection and measurement of ionizing particles. Cellulose nitrate (CN) films are commonly used as SSNTD for the measurement of radon/thoron gases and their decay products. A simple method for making uniform thin CN films of various thickness has been developed. Performance of these films is compared with commercially available film. (Author)

Preparation of cellulose nitrate films using a spinning disc for solid state nuclear track detection (SSNTD) applications

Energy Technology Data Exchange (ETDEWEB)

Raghunath, B.; Iyer, M.R. [Bhabha Atomic Research Centre, Bombay (India); Samant, S.D. [Bombay Univ. (India). Dept. of Chemical Technology

1995-01-01

Solid state nuclear track detectors (SSNTD) are widely used in the detection and measurement of ionizing particles. Cellulose nitrate (CN) films are commonly used as SSNTD for the measurement of radon/thoron gases and their decay products. A simple method for making uniform thin CN films of various thickness has been developed. Performance of these films is compared with commercially available film. (Author).

Quality assurance of alpha-particle dosimetry using peeled-off Gafchromic EBT3® film

International Nuclear Information System (INIS)

Ng, C.Y.P.; Chun, S.L.; Yu, K.N.

2016-01-01

A novel alpha-particle dosimetry technique using Gafchromic EBT3 film has recently been proposed for calibrating the activity of alpha-emitting radiopharmaceuticals. In the present paper, we outlined four measures which could further help assure the quality of the method. First, we suggested an alternative method in fabricating the peeled-off EBT3 film. Films with a chosen size were cut from the original films and all the edges were sealed with silicone. These were immersed into deionized water for 19 d and the polyester covers of the EBT3 films could then be easily peeled off. The active layers in these peeled-off EBT3 films remained intact, and these films could be prepared reproducibly with ease. Second, we proposed a check on the integrity of the peeled-off film by comparing the responses of the pristine and peeled-off EBT3 films to the same X-ray irradiation. Third, we highlighted the importance of scanning directions of the films. The “landscape” and “portrait” scanning directions were defined as the scanning directions perpendicular and parallel to the long edge of the original EBT3 films, respectively. Our results showed that the responses were different for different scanning directions. As such, the same scanning direction should be used every time. Finally, we cautioned the need to confirm the uniformity of the alpha-particle source used for calibration. Radiochromic films are well known for their capability of providing two-dimensional dosimetric information. As such, EBT3 films could also be conveniently used to check the uniformity of the alpha-particle source. - Highlights: • Proposed method to fabricate peeled-off EBT3 films for alpha dosimetry. • Proposed integrity check of peeled-off EBT3 films using X-ray irradiation. • Highlighted importance of scanning directions of EBT3 films. • Cautioned the need for uniformity check on alpha-particle source.

Mode and polarization state selected guided wave spectroscopy of orientational anisotrophy in model membrane cellulosic polymer films: relevance to lab-on-a-chip

Science.gov (United States)

Andrews, Mark P.; Kanigan, Tanya

2007-06-01

Orientation anisotropies in structural properties relevant to the use of cellulosic polymers as membranes for lab-on-chips were investigated for cellulose acetate (CA) and regenerated cellulose (RC) films deposited as slab waveguides. Anisotropy was probed with mode and polarization state selected guided wave Raman spectroscopy. CA exhibits partial chain orientation in the plane of the film, and this orientation is independent of sample substrate and film preparation conditions. RC films also show in-plane anisotropy, where the hexose sugar rings lie roughly in the plane of the film. Explanations are given of the role of artifacts in interpreting waveguide Raman spectra, including anomalous contributions to Raman spectra that arise from deviations from right angle scattering geometry, mode-dependent contributions to longitudinal electric field components and TETM mode conversion. We explore diffusion profiles of small molecules in cellulosic films by adaptations of an inverse-Wentzel-Kramers-Brillouin (iWKB) recursive, noninteger virtual mode index algorithm. Perturbations in the refractive index distribution, n(z), are recovered from the measured relative propagation constants, neffective,m, of the planar waveguide. The refractive index distribution then yields the diffusion profile.

Enzymatic Systems for Cellulose Acetate Degradation

Directory of Open Access Journals (Sweden)

Oskar Haske-Cornelius

2017-09-01

Full Text Available Cellulose acetate (CA-based materials, like cigarette filters, contribute to landscape pollution challenging municipal authorities and manufacturers. This study investigates the potential of enzymes to degrade CA and to be potentially incorporated into the respective materials, enhancing biodegradation. Deacetylation studies based on Liquid Chromatography-Mass Spectrometry-Time of Flight (LC-MS-TOF, High Performance Liquid Chromatography (HPLC, and spectrophotometric analysis showed that the tested esterases were able to deacetylate the plasticizer triacetin (glycerol triacetate and glucose pentaacetate (cellulose acetate model compound. The most effective esterases for deacetylation belong to the enzyme family 2 (AXE55, AXE 53, GAE, they deacetylated CA with a degree of acetylation of up to 1.8. A combination of esterases and cellulases showed synergistic effects, the absolute glucose recovery for CA 1.8 was increased from 15% to 28% when an enzymatic deacetylation was performed. Lytic polysaccharide monooxygenase (LPMO, and cellobiohydrolase were able to cleave cellulose acetates with a degree of acetylation of up to 1.4, whereas chitinase showed no activity. In general, the degree of substitution, chain length, and acetyl group distribution were found to affect CA degradation. This study shows that, for a successful enzyme-based deacetylation system, a cocktail of enzymes, which will randomly cleave and generate shorter CA fragments, is the most suitable.

Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films

Science.gov (United States)

Paribok, I. V.; Solomyanskii, A. E.; Zhavnerko, G. K.

2016-02-01

Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films are studied by means of microcontact printing, atomic force microscopy, and quartz crystal microbalance. It is shown that both the charge of polysaccharide macromolecules and the technique for deposition of their films onto the surface (via adsorption from a solution or covalent cross-linking) are factors that determine the degree of nonspecific adsorption of the protein on such films.

Composite Films Formed by Cellulose nanocrystals and Latex Nanoparticles: Optical, Structural, and Mechanical Properties

Science.gov (United States)

Vollick, Brandon McRae

This thesis describes the preparation of iridescent, birefringent, composite films composed of cellulose nanocrystals (CNCs), latex nanoparticles (NPs) and a NP crosslinker; hexanediamine (HDA). First, aqueous suspensions were prepared with varying quantities of CNCs, NPs and HDA before equilibrating for one week. The cholesteric (Ch) phase was then cast and dried into a film. The optical, structural and mechanical properties of the film was analyzed. Second, films with identical compositions of CNCs, NPs, and HDA were fabricated in three different ways to yield films of different morphology, (i) fast drying of an isotropic suspension, yielding an isotropic film, (ii) slow drying of an isotropic suspension, yielding a partially Ch films, (iii) slow drying of an equilibrated suspension, yielding a highly Ch film. The optical and mechanical properties of the films was analyzed.

A monolithic functional film of nanotubes/cellulose/ionic liquid for high performance supercapacitors

Science.gov (United States)

Basiricò, Lucia; Lanzara, Giulia

2014-12-01

A novel monolithic, pre-fabricated, fully functional film made of a nanostructured free-standing layer is presented for a new and competitive class of easy-to-assemble flexible supercapacitors whose design is in-between the all solid state and the traditional liquid electrolyte. The film is made of two vertically aligned multi-walled carbon nanotube (VANT) electrodes that store ions, embedded-in, and monolithically interspaced by a solution of microcrystalline cellulose in a room temperature ionic liquid (RTIL) electrolyte (1-ethyl-3-methylimidazolium acetate-EMIM Ac). The fine tuning of VANTs length and electrolyte/cellulose amount leads, in a sole and continuous block, to ions storage and physical separation between the electrodes without the need of the additional separator layer that is typically used in supercapacitors. Thus, physical discontinuities that can induce disturbances to ions mobility, are fully eliminated significantly reducing the equivalent series resistance and increasing the knee frequency, hence outclassing the best supercapacitors based on VANTs and non-aqueous electrolytes. The excellent electrochemical response can also be addressed to the chosen electrolyte that, not only has the advantage of leading to a significantly simpler and more affordable fabrication procedure, but has higher ionic conductivity, lower viscosity and higher ions mobility than other electrolytes capable of dissolving cellulose.

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%. Copyright © 2013 Elsevier B.V. All rights reserved.

Water-Triggered Dimensional Swelling of Cellulose Nanofibril Films: Instant Observation Using Optical Microscope

International Nuclear Information System (INIS)

Qing, Y.; Wu, Y.; Li, X.; Qing, Y.; Cai, Z.

2013-01-01

To understand the swelling behavior of cellulose nano fibril (CNF) films, the dimensional variation of untreated and phenol formaldehyde modified CNF (CNF/PF) films soaked in distilled water was examined in situ with microscopic image recording combined with pixel calculation. Results showed that a dramatic thickness increase exhibited in both CNF and CNF/PF films, despite being at different swelling levels. Compared to thickness swelling, however, the width expansion for these films is negligible. Such significant difference in dimensional swelling for CNF and PF modified films is mainly caused by nano fibril deposition and their meso structure. However, addition of PF modifier has a positive effect on the constraint of water absorption and thickness swelling, which is strongly dependent on PF loadings

Plot of charged nuclear particles in polymers

International Nuclear Information System (INIS)

Gallardo H, J.I.L.

1975-01-01

Experiments were made in order to obtain particle tracks and fission fragments in polymers. To increase the damage the polymer is attacked chemically with a solution of KOH, NaOH or other chemical agent, whose concentration depends of the polymer to be treated, maintaining a constant temperature during the process. To count the tracks which perforate the film, a spark counter with controlled nitrogen atmosphere was constructed. In the experiments which were made in order to detect particles, films of cellulose nitrate known as xylonite, daicel and red paper were used. For the detection of fission products, cellulose triacetate and cellulose polycarbonate films, known as kodacel and kimfol were used. The particle tracks on the treated films were optically counted with a microscope. They had a diameter between 12 and 30 microns, and when the thickness of the film permitted it the tracks consisted in perforations from one to another side of the film. The obtained results have permitted to have the necessary reproducibility for the realization of quantitative analysis of irradiations which can be applied to neutron dosimetry. (author)

International Geophysical Year, 1957-1958: Drifting Station Alpha Documentary Film

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This film documents the activities that occurred on Drifting Station Alpha in the Arctic Ocean during the International Geophysical Year, 1957 to 1958. The film is...

Comparison of fast neutron-induced tracks in plastics using the electrochemical etching method

International Nuclear Information System (INIS)

Cotter, S.J.; Gammage, R.B.; Thorngate, J.H.; Ziemer, P.L.

1979-01-01

Four plastics were examined by the electrochemical etching method for their suitability in registering fast neutron-induced recoil particle tracks. The plastics were cellulose acetate, cellulose triacetate, cellulose acetobutyrate and polycarbonate. Cellulose acetate and triacetate displayed high levels of water absorptivity during etching while the acetobutyrate foils cracked due to electromechanical stresses at high frequencies (>500 Hz). The clarity of the etched track was superior in the polycarbonate foils, suggesting the latter as the generally preferred dosimeter for fast neutrons. (author)

Nuclear rich alpha cellulosic waste management experiments by acid digestion

International Nuclear Information System (INIS)

Arnal; Cousinou; Desille; Maigret.

1985-03-01

At Cadarache, where the French plutonium fuel fabrication plant is located, the strategy used for the management of rich alpha waste (superior to accepted level for storage) consist in incinerating the wastes, crushed and washed by cryogenic crushing and soda-nitric solutions. Although all ''technological'' wastes could be processed this way, the cellulosic are sorted and treated separately by the sulfuric acid digestion process. This process has definite advantages, particularly since it is specific to cellulosis, which dissolves easily at low temperature, i-e under the boiling point of H 2 SO 4 . Except for this aspect, of great importance for the gaz treatment operations and the resistance of material to corrosion, the process is identical to the one given in the literature: dehydration of cellulosis by H 2 SO 4 72% and carbon oxydation by HNO 3 13N. The apparatus used hold in a small volume (10 m 3 ); the gloves-box in which the dissolver and the filtration treatments (insoluble Pu sulfate for one part, and reaction gas for the other) are placed is in stainless steel coated with corrosion proof paint; the equipments are made of glass (dissolver) teflon (flanges) PVDF (pipes) hastelloy (pompes). A general balance is given for the recuperated nuclear materials, as well as for the mass and volumes of input and output cellulosic wastes

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.

Diazaisoindigo bithiophene and terthiophene copolymers for application in field-effect transistors and solar cells

KAUST Repository

Yue, Wan

2017-06-10

Two donor–acceptor conjugated polymers with azaisoindigo as acceptor units and bithiophene and terthiophene as donor units have been synthesized by Stille polymerization. These two polymers have been successfully applied in field-effect transistors and polymer solar cells. By changing the donor component of the conjugated polymer backbone from bithiophene to terthiophene, the density of thiophene in the backbone is increased, manifesting as a decrease in both ionization potential and in electron affinity. Therefore, the charge transport in field-effect transistors switches from ambipolar to predominantly hole transport behavior. PAIIDTT exhibits hole mobility up to 0.40 cm2/Vs and electron mobility of 0.02 cm2/Vs, whereas PAIIDTTT exhibits hole mobility of 0.62 cm2/Vs. Polymer solar cells were fabricated based on these two polymers as donors with PC61BM and PC71BM as acceptor where PAIIDTT shows a modest efficiency of 2.57% with a very low energy loss of 0.55 eV, while PAIIDTTT shows a higher efficiency of 6.16% with a higher energy loss of 0.74 eV. Our results suggest that azaisoindgo is a useful building block for the development of efficient polymer solar cells with further improvement possibility by tuning the alternative units on the polymer backbone. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017

Versatile High-Performance Regenerated Cellulose Membranes Prepared using Trimethylsilyl Cellulose as a Precursor

KAUST Repository

Puspasari, Tiara

2018-05-01

Cellulose has emerged as an indispensable membrane material due to its abundant availability, low cost, fascinating physiochemical properties and environment benignancy. However, it is believed that the potential of this polymer is not fully explored yet due to its insolubility in the common organic solvents, encouraging the use of derivatization-regeneration method as a viable alternative to the direct dissolution in exotic or reactive solvents. In this work, we use trimethylsilyl cellulose (TMSC), a highly soluble cellulose derivative, as a precursor for the fabrication of cellulose thin film composite membranes. TMSC is an attractive precursor to assemble thin cellulose films with good deposition behavior and film morphology; cumbersome solvents used in the one step cellulose processing are avoided. This derivative is prepared from cellulose by the known silylation reaction. The complete transformation of TMSC back into cellulose after the membrane formation is carried out by vapor-phase acid treatment, which is simple, scalable and reproducible. This process along with the initial TMSC concentration determines the membrane sieving characteristics. Unlike the typical regenerated cellulose membranes with meso- or macropores, membranes regenerated from TMSC display micropores suitable for the selective separation of nanomolecules in aqueous and organic solvent nanofiltration. The membranes introduced in this thesis represent the first polymeric membranes ever reported for highly selective separation of similarly sized small organic molecules based on charge and size differences with outstanding fluxes. Owing to its strong hydrophilic and amorphous character, the membranes also demonstrate excellent air-dehumidification performance as compared to previously reported thin film composite membranes. Moreover, the use of TMSC enables the creation of the previously unfeasible cellulose–polydimethylsiloxane (PDMS) and cellulose–polyethyleneimine (PEI) blend membranes

Development of alpha spectroscopy method with solid state nuclear track detector using aluminium thin films

International Nuclear Information System (INIS)

Dwaikat, N.

2015-10-01

This work presents the development of alpha spectroscopy method with Solid-state nuclear track detectors using aluminum thin films. The resolution of this method is high, and it is able to discriminate between alpha particles at different incident energy. It can measure the exact number of alpha particles at specific energy without needing a calibration of alpha track diameter versus alpha energy. This method was tested by using Cf-252 alpha standard source at energies 5.11 MeV, 3.86 MeV and 2.7 MeV, which produced by the variation of detector -standard source distance. On front side, two detectors were covered with two Aluminum thin films and the third detector was kept uncovered. The thickness of Aluminum thin films was selected carefully (using SRIM 2013) such that one of the films will block the lower two alpha particles (3.86 MeV and 2.7 MeV) and the alpha particles at higher energy (5.11 MeV) can penetrate the film and reach the detectors surface. The second thin film will block alpha particles at lower energy of 2.7 MeV and allow alpha particles at higher two energies (5.11 MeV and 3.86 MeV) to penetrate and produce tracks. For uncovered detector, alpha particles at three different energies can produce tracks on it. For quality assurance and accuracy, the detectors were mounted on thick enough copper substrates to block exposure from the backside. The tracks on the first detector are due to alpha particles at energy of 5.11 MeV. The difference between the tracks number on the first detector and the tracks number on the second detector is due to alpha particles at energy of 3.8 MeV. Finally, by subtracting the tracks number on the second detector from the tracks number on the third detector (uncovered), we can find the tracks number due to alpha particles at energy 2.7 MeV. After knowing the efficiency calibration factor, we can exactly calculate the activity of standard source. (Author)

Development of alpha spectroscopy method with solid state nuclear track detector using aluminium thin films

Energy Technology Data Exchange (ETDEWEB)

Dwaikat, N., E-mail: ndwaikat@kfupm.edu.sa [King Fahd University of Petroleum and Minerals, College of Sciences, Department of Physics, Dhahran 31261 (Saudi Arabia)

2015-10-15

This work presents the development of alpha spectroscopy method with Solid-state nuclear track detectors using aluminum thin films. The resolution of this method is high, and it is able to discriminate between alpha particles at different incident energy. It can measure the exact number of alpha particles at specific energy without needing a calibration of alpha track diameter versus alpha energy. This method was tested by using Cf-252 alpha standard source at energies 5.11 MeV, 3.86 MeV and 2.7 MeV, which produced by the variation of detector -standard source distance. On front side, two detectors were covered with two Aluminum thin films and the third detector was kept uncovered. The thickness of Aluminum thin films was selected carefully (using SRIM 2013) such that one of the films will block the lower two alpha particles (3.86 MeV and 2.7 MeV) and the alpha particles at higher energy (5.11 MeV) can penetrate the film and reach the detectors surface. The second thin film will block alpha particles at lower energy of 2.7 MeV and allow alpha particles at higher two energies (5.11 MeV and 3.86 MeV) to penetrate and produce tracks. For uncovered detector, alpha particles at three different energies can produce tracks on it. For quality assurance and accuracy, the detectors were mounted on thick enough copper substrates to block exposure from the backside. The tracks on the first detector are due to alpha particles at energy of 5.11 MeV. The difference between the tracks number on the first detector and the tracks number on the second detector is due to alpha particles at energy of 3.8 MeV. Finally, by subtracting the tracks number on the second detector from the tracks number on the third detector (uncovered), we can find the tracks number due to alpha particles at energy 2.7 MeV. After knowing the efficiency calibration factor, we can exactly calculate the activity of standard source. (Author)

Improved lifetime of chitosan film in converting water vapor to electrical power by adding carboxymethyl cellulose

Science.gov (United States)

Nasution, T. I.; Balyan, M.; Nainggolan, I.

2018-02-01

A Water vapor cell based on chitosan film has been successfully fabricated in film form to convert water vapor to electrical power. In order to improve the lifetime of water vapor cell, Carboxymethyl Cellulose (CMC) was added into 1% chitosan solution within concentration variations of 0.01, 0.05, 0.1 and 0.5%. The result showed that the lifetime of water vapor cell increased higher by adding the higher concentration of Carboxymethyl cellulose. The highest lifetime was evidenced by adding 0.5%CMC which maintained for 48 weeks. However, the average electrical power became lower to 4.621 µW. This electrical power lower than the addition of 0.1%CMC which maintained for 5.167 µW. While, the lifetime of chitosan-0.1%CMC film of 44 weeks is shorter compared to chitosan-0.5%CMC film. Based on FTIR characterization, it was founded that the chitosan structure did not change until the addition of 0.1%CMC. This caused the electrical power of water vapor cell degenerated. Therefore, chitosan-0.5%CMC film has excellent lifetime in converting water vapor to electrical power.

Quality assurance of alpha-particle dosimetry using peeled-off Gafchromic EBT3® film

Science.gov (United States)

Ng, C. Y. P.; Chun, S. L.; Yu, K. N.

2016-08-01

A novel alpha-particle dosimetry technique using Gafchromic EBT3 film has recently been proposed for calibrating the activity of alpha-emitting radiopharmaceuticals. In the present paper, we outlined four measures which could further help assure the quality of the method. First, we suggested an alternative method in fabricating the peeled-off EBT3 film. Films with a chosen size were cut from the original films and all the edges were sealed with silicone. These were immersed into deionized water for 19 d and the polyester covers of the EBT3 films could then be easily peeled off. The active layers in these peeled-off EBT3 films remained intact, and these films could be prepared reproducibly with ease. Second, we proposed a check on the integrity of the peeled-off film by comparing the responses of the pristine and peeled-off EBT3 films to the same X-ray irradiation. Third, we highlighted the importance of scanning directions of the films. The ;landscape; and ;portrait; scanning directions were defined as the scanning directions perpendicular and parallel to the long edge of the original EBT3 films, respectively. Our results showed that the responses were different for different scanning directions. As such, the same scanning direction should be used every time. Finally, we cautioned the need to confirm the uniformity of the alpha-particle source used for calibration. Radiochromic films are well known for their capability of providing two-dimensional dosimetric information. As such, EBT3 films could also be conveniently used to check the uniformity of the alpha-particle source.

Ignition inhibitors for cellulosic materials

International Nuclear Information System (INIS)

Alvares, N.J.

1976-01-01

By exposing samples to various irradiance levels from a calibrated thermal radiation source, the ignition responses of blackened alpha-cellulose and cotton cloth with and without fire-retardant additives were compared. Samples treated with retardant compounds which showed the most promise were then isothermally pyrolyzed in air for comparisons between the pyrolysis rates. Alpha-cellulose samples containing a mixture of boric acid, borax, and ammonium di-hydrogen phosphate could not be ignited by irradiances up to 4.0 cal cm -2 s-1 (16.7 W/cm 2 ). At higher irradiances the specimens ignited, but flaming lasted only until the flammable gases were depleted. Cotton cloth containing a polymeric retardant with the designation THPC + MM was found to be ignition-resistant to all irradiances below 7.0 cal cm -2 s -1 (29.3 W/cm 2 ). Comparison of the pyrolysis rates of the retardant-treated alpha-cellulose and the retardant-treated cotton showed that the retardant mechanism is qualitatively the same. Similar ignition-response measurements were also made with specimens exposed to ionizing radiation. It was observed that gamma radiation results in ignition retardance of cellulose, while irradiation by neutrons does not

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.

Preparation Nano-Structure Polytetrafluoroethylene (PTFE Functional Film on the Cellulose Insulation Polymer and Its Effect on the Breakdown Voltage and Hydrophobicity Properties

Directory of Open Access Journals (Sweden)

Jian Hao

2018-05-01

Full Text Available Cellulose insulation polymer is an important component of oil-paper insulation, which is widely used in power transformer. The weight of the cellulose insulation polymer materials is as high as tens of tons in the larger converter transformer. Excellent performance of oil-paper insulation is very important for ensuring the safe operation of larger converter transformer. An effective way to improve the insulation and the physicochemical property of the oil impregnated insulation pressboard/paper is currently a popular research topic. In this paper, the polytetrafluoroethylene (PTFE functional film was coated on the cellulose insulation pressboard by radio frequency (RF magnetron sputtering to improve its breakdown voltage and the hydrophobicity properties. X-ray photoelectron spectroscopy (XPS results show that the nano-structure PTFE functional film was successfully fabricated on the cellulose insulation pressboard surface. The scanning electron microscopy (SEM and X-ray diffraction (XRD present that the nanoscale size PTFE particles were attached to the pressboard surface and it exists in the amorphous form. Atomic force microscopy (AFM shows that the sputtered pressboard surface is still rough. The rough PTFE functional film and the reduction of the hydrophilic hydroxyl of the surface due to the shielding effect of PTFE improve the breakdown and the hydrophobicity properties of the cellulose insulation pressboard obviously. This paper provides an innovative way to improve the performance of the cellulose insulation polymer.

Vacuum-assisted bilayer PEDOT:PSS/cellulose nanofiber composite film for self-standing, flexible, conductive electrodes.

Science.gov (United States)

Ko, Youngsang; Kim, Dabum; Kim, Ung-Jin; You, Jungmok

2017-10-01

Sustainable cellulose nanofiber (CNF)-based composites as functional conductive materials have garnered considerable attention recently for their use in soft electronic devices. In this work, self-standing, highly flexible, and conductive PEDOT:PSS-CNF composite films were developed using a simple vacuum-assisted filtration method. Two different composite films were successfully fabricated and then tested: 1) a single-layer composite composed of a mixture of PEDOT:PSS and CNF phases and 2) a bilayer composite composed of an upper PEDOT:PSS membrane layer and a CNF matrix sub-layer. The latter composite was constructed by electrostatic/hydrogen bonding interactions between PEDOT:PSS and CNFs coupled with sequential vacuum-assisted filtration. Our results demonstrated that the resultant bilayer composite film exhibited a competitive electrical conductivity (ca. 22.6Scm -1 ) compared to those of previously reported cellulose-based composites. Furthermore, decreases in the electrical properties were not observed in the composite films when they were bent up to 100 times at an angle of 180° and bent multiple times at an angle of 90°, clearly demonstrating their excellent mechanical flexibility. This study provides a straightforward method of fabricating highly flexible, lightweight, and conductive films, which have the potential to be used in high-performance soft electronic systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of cellulose acetate obtained from sugarcane bagasse by {sup 1}H-NMR; Caracterizacao de acetato de celulose obtido a partir do bagaco de cana-de-acucar por {sup 1}H-RMN

Energy Technology Data Exchange (ETDEWEB)

Cerqueira, Daniel A.; Rodrigues Filho, Guimes, E-mail: d.a.cerqueira@gmail.co [Universidade Federal de Uberlendia (IQ/UFU), MG (Brazil). Inst. de Quimica; Carvalho, Rui A. [Universidade de Coimbra (UC) (Portugal). Dept. de Bioquimica; Valente, Artur J.M. [Universidade de Coimbra (UC) (Portugal). Dept. de Quimica

2009-07-01

Cellulose from sugarcane bagasse was used for synthesizing cellulose acetate with different degrees of substitution, which were characterized by {sup 1}H-NMR through the relationship between the peak areas of the hydrogen atoms present at the acetate groups (-(C=O)OCH{sub 3} ) and the peaks of the hydrogen bonded to the carbon atoms of the glycosidic rings. Suppression was carried out in order to remove the peak of residual water in the materials and the peak related to impurities in cellulose triacetate. Degree of substitution values obtained through the resonance deconvolution were compared to those obtained by chemical determination through an acid-base titration. The determined degrees of substitution of the cellulose samples were 2.94 and 2.60. (author)

Fundamental Characteristics of the Newly Developed ATA™ Membrane Dialyzer.

Science.gov (United States)

Sunohara, Takashi; Masuda, Toshiaki

2017-01-01

Dialysis membranes are often made from synthetic polymers, such as polysulfone. However, membranes made from cellulose triacetate have superior biocompatibility and have been used since the 1980s. On-line hemodiafiltration treatment accompanied by massive fluid replacement is increasingly being used in Europe and Japan, but cellulose triacetate is not suitable for this treatment. Our newly developed asymmetric triacetate membrane, the ATA™ membrane, substantially improved the filtration properties and blood compatibility because of the asymmetric structure and smooth surface of this cellulose acetate membrane. Key Message: The ATA membrane maintains its high permeability even after massive filtration and shows less temporal variation in its permeation performance, lower protein adsorption, and superior biocompatibility compared with conventional membranes. © 2017 S. Karger AG, Basel.

Protein adsorption on low temperature alpha alumina films for surgical instruments

Energy Technology Data Exchange (ETDEWEB)

Cloud, A.N., E-mail: acloud@uark.ed [University of Arkansas, Fayetteville, AR 72701 (United States); Kumar, S. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia); Kavdia, M.; Abu-Safe, H.H.; Gordon, M.H. [University of Arkansas, Fayetteville, AR 72701 (United States)

2009-08-31

Bulk alumina has been shown to exhibit reduced protein adsorption, a property that can be exploited for developing alumina-coated surgical instruments and devices. Alpha alumina thin films were deposited on surgical stainless steel substrates to investigate the adsorption of a model protein (BSA, bovine serum albumin). The films were deposited at 480 {sup o}C by AC inverted cylindrical magnetron sputtering. Films were obtained at 6 kW and 50% oxygen partial pressure by volume. The presence of alpha-phase alumina has been shown by transmission electron microscopy. Results indicate that there was a 50% reduction in protein adsorption for samples with the alumina coating compared to those with no coating.

Use of CdS quantum dot-functionalized cellulose nanocrystal films for anti-counterfeiting applications

Science.gov (United States)

Chen, L.; Lai, C.; Marchewka, R.; Berry, R. M.; Tam, K. C.

2016-07-01

Structural colors and photoluminescence have been widely used for anti-counterfeiting and security applications. We report for the first time the use of CdS quantum dot (QD)-functionalized cellulose nanocrystals (CNCs) as building blocks to fabricate nanothin films via layer-by-layer (LBL) self-assembly for anti-counterfeiting applications. Both negatively- and positively-charged CNC/QD nanohybrids with a high colloidal stability and a narrow particle size distribution were prepared. The controllable LBL coating process was characterized by scanning electron microscopy and ellipsometry. The rigid structure of CNCs leads to nanoporous structured films on poly(ethylene terephthalate) (PET) substrates with high transmittance (above 70%) over the entire range of visible light and also resulted in increased hydrophilicity (contact angles of ~40 degrees). Nanothin films on PET substrates showed good flexibility and enhanced stability in both water and ethanol. The modified PET films with structural colors from thin-film interference and photoluminescence from QDs can be used in anti-counterfeiting applications.Structural colors and photoluminescence have been widely used for anti-counterfeiting and security applications. We report for the first time the use of CdS quantum dot (QD)-functionalized cellulose nanocrystals (CNCs) as building blocks to fabricate nanothin films via layer-by-layer (LBL) self-assembly for anti-counterfeiting applications. Both negatively- and positively-charged CNC/QD nanohybrids with a high colloidal stability and a narrow particle size distribution were prepared. The controllable LBL coating process was characterized by scanning electron microscopy and ellipsometry. The rigid structure of CNCs leads to nanoporous structured films on poly(ethylene terephthalate) (PET) substrates with high transmittance (above 70%) over the entire range of visible light and also resulted in increased hydrophilicity (contact angles of ~40 degrees). Nanothin films

Design and Development of Mixed Film of Pectin: Ethyl Cellulose for Colon Specific Drug Delivery of Sennosides and Triphala

Science.gov (United States)

Momin, Munira; Pundarikakshudu, K.; Nagori, S. A.

2008-01-01

The present study was aimed at developing colon specific drug delivery system for sennosides and Triphala. These drugs are reputed Ayurvedic medicines for constipation in India. The proposed device explored the application of pectin and ethyl cellulose as a mixed film for colon specific delivery. This mixed film was prepared using non-aqueous solvents like acetone and isopropyl alcohol. A 32 factorial design was adopted to optimize the formulation variables like, ratio of ethyl cellulose to pectin (X1) and coat weight (X2). The rate and extent of drug release were found to be related to the thickness and the ratio of pectin to ethyl cellulose within the film. Statistical treatments to the drug release data revealed that the X1 variable was more important than X2. Under simulated colonic conditions, drug release was more pronounced from coating formulations containing higher proportions of pectin. The surface of the device was coated with Eudragit S100 to ensure that the device was more pH dependent and trigger the drug release only at higher pH. The final product is expected to have the advantage of being biodegradable and pH dependant. This type of a film effectively releases the drug while maintaining its integrity. PMID:20046742

Metal adsorption of gamma-irradiated carboxymethyl cellulose/polyethylene oxide blend films

Science.gov (United States)

El-Naggar, Amal A.; Magida, M. M.; Ibrahim, Sayeda M.

2016-03-01

Blend films of different ratios of carboxymethyl cellulose (CMC)/polyethylene oxide (PEO) were prepared by the solution casting method. To investigate the effect of irradiation on all properties of prepared blend, it was exposed to different gamma irradiation doses (10, 20, and 30 kGy). Physical properties such as gel fraction (GF) (%) and swelling (SW) (%) were investigated. It was found that the GF (%) increases with increasing irradiation dose up to 20 kGy, while SW (%) decreases with an increase in the irradiation doses for all blend compositions. Moreover, the structural and mechanical properties of the prepared films were studied. The results of the mechanical properties obtained showed that there is an improvement in these properties with an increase in both CMC and irradiation dose up to 20 kGy. The efficiency of metal ions uptake was measured using a UV spectrophotometer. The prepared films showed good tendency to absorb and release metal ions from aqueous media. Thus, the CMC/PEO film can be used in agricultural domain.

Biodegradable plastics derived from micro-fibrillated cellulose fiber and chitosan

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, M.; Hosokawa, J.; Yoshihara, K.; Kubo, T.; Kabeya, H.; Endo, T. [Shikoku National Industrial Research Inst., Kagawa (Japan)

1995-12-25

We have been carrying out studies to develop biodegradable plastics from natural polysaccharides. We have found that a combination of micro-fibrillated cellulose fiber and chitosan produces a useful material that can be used to form biodegradable film and moldings. Cellulose-chitosan composite film demonstrate higher strength than general purpose plastic films, and wet strength peaks when chitosan content is 10-20%. The relatively small amount of chitosan needed is economically convenient because chitosan is more expensive than cellulose. This film biodegrade well in soil, completely dissolving and disappearing in two months. Biodegradability is influenced by the temperature used in thermal treatment the film, the quantity of acid groups in the cellulose, and other factors. These characteristics will be used to control decomposition. Since cellulose-chitosan-plastics are not thermoplastics, we have been working on joint research with companies to produce films, nonwoven fabrics and foams. We discuss here the properties and application of these composite moldings. 4 refs., 3 figs., 3 tabs.

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.

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

Science.gov (United States)

Qi, Xian-Ming; Liu, Shi-Yun; Chu, Fang-Bing; Pang, Shuai; Liang, Yan-Ru; Guan, Ying; Peng, Feng; Sun, Run-Cang

2015-01-01

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. PMID:28787804

Tunnelling conductive hybrid films of gold nanoparticles and cellulose and their applications as electrochemical electrodes

International Nuclear Information System (INIS)

Liu, Zhiming; Wang, Xuefeng; Wu, Wenjian; Li, Mei

2015-01-01

Conductive hybrid films of metal nanoparticles and polymers have practical applications in the fields of sensing, microelectronics and catalysis, etc. Herein, we present the electrochemical availability of tunnelling conductive hybrid films of gold nanoparticles (GNPs) and cellulose. The hybrid films were provided with stable tunnelling conductive properties with 12 nm GNPs of 12.7% (in weight). For the first time, the conductive hybrid films were used as substrates of electrochemical electrodes to load calmodulin (CaM) proteins for sensing of calcium cations. The electrodes of hybrid films with 20 nm GNPs of 46.7% (in weight) exhibited stable electrochemical properties, and showed significant responses to calcium cations with concentrations as low as 10 −9 M after being loaded with CaM proteins. (paper)

{sup 1}H-NMR characterization of cellulose acetate obtained from sugarcane bagasse; Caracterizacao de acetato de celulose obtido a partir do bagaco de cana-de-acucar por {sup 1}H-RMN

Energy Technology Data Exchange (ETDEWEB)

Cerqueira, Daniel A., E-mail: daniel.cerqueira@ufba.b [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Ciencias Ambientais e Desenvolvimento Sustentavel; Rodrigues Filho, Guimes [Universidade Federal de Uberlandia (UFU), MG (Brazil). Inst. de Quimica; Carvalho, Rui de A. [Universidade de Coimbra (Portugal). Dept. de Bioquimica; Valente, Artur J.M. [Universidade de Coimbra (Portugal). Dept. de Quimica

2010-07-01

Cellulose from sugarcane bagasse was used for synthesizing cellulose acetate with different degrees of substitution, which were characterized by {sup 1}H-NMR through the relationship between the peak areas of the hydrogen atoms of the acetate groups (-(C=O)OCH{sub 3}) and the peaks of the hydrogen bonded to the carbon atoms of the glycosidic rings. Suppression of some signals was carried out in order to remove the residual water resonance in the materials and those related to impurities in cellulose triacetate as well. A deconvolution method for the computation of the degree of substitution of acetylation is proposed. The degrees of substitution for the cellulose samples were 2.94 and 2.60, in good agreement with those obtained by chemical determination through an acid-base titration. (author)

Influence of drying restraint on physical and mechanical properties of nanofibrillated cellulose films

Science.gov (United States)

Carlos Baez; John Considine; Robert Rowlands

2014-01-01

Nanofibrillated cellulose (NFC) is a renewable and biodegradable fibril that possesses high strength and stiffness resulting from high level hydrogen bonding. Films made from NFC shrink and distort as they transition from a wet state (20 wt% solids) to a state of moisture equilibrium (90 wt% solids at 50 % RH, 23 °C). Material distortions are driven by development of...

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

Science.gov (United States)

Soni, Bhawna; Hassan, El Barbary; Schilling, M Wes; Mahmoud, Barakat

2016-10-20

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 mechanical and barrier properties. This was accomplished by incorporating TEMPO-oxidized cellulose nanofibers (2,2,6,6-tetramethylpiperidine-1-oxyl radical) into a chitosan matrix. An aqueous suspension of chitosan (100-75wt%), sorbitol (25wt%) and TEMPO-oxidized cellulose nanofibers (TEMPO-CNFs, 0-25wt%) were cast in an oven at 40°C for 2-4days. Films were preconditioned at 25°C and 50% RH for characterization. The surface morphology of the films was revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal properties and crystal structure of the films were evaluated by thermogravimetric analysis (TGA-DTG) and X-ray diffraction (XRD). Incorporation of TEMPO-CNFs enhanced the mechanical strength of the films due to the high aspect ratio (3-20nm width, and 10-100nm length) of TEMPO-CNFs and strong interactions with the chitosan matrix. Oxygen and water vapor transmission rates for films that are prepared with chitosan and TEMPO-CNFs (15-25wt%) were significantly reduced. Furthermore, these bionanocomposite films had good thermal stability. Use of TEMPO-CNFs in this method makes it possible to produce bionanocomposite films that are flexible, transparent, and thus have potential in food packaging applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antimicrobial effectiveness of oregano and sage essential oils incorporated into whey protein films or cellulose-based filter paper.

Science.gov (United States)

Royo, Maite; Fernández-Pan, Idoya; Maté, Juan I

2010-07-01

In this study the antimicrobial effectiveness of oregano and sage essential oils (EOs) incorporated into two different matrices, whey protein isolate (WPI) and cellulose-based filter paper, was analysed. Antimicrobial properties of WPI-based films containing oregano and sage EOs were tested against Listeria innocua, Staphylococcus aureus and Salmonella enteritidis. Oregano EO showed antimicrobial activity against all three micro-organisms. The highest inhibition zones were against L. innocua. However, sage EO did not show antimicrobial activity against any of the micro-organisms. Antimicrobial activity was confirmed for both EOs using cellulose-based filter paper as supporting matrix, although it was significantly more intense for oregano EO. Inhibition surfaces were significantly greater when compared with those of the WPI films. This finding is likely due to the higher porosity and diffusivity of the active compounds in the filter paper. The interactions between the EOs and the films have a critical effect on the diffusivity of the active compounds and therefore on the final antimicrobial activity. As a result, to obtain active edible films, it is necessary to find the equilibrium point between the nature and concentration of the active compounds in the EO and the formulation of the film.

Cellulose-glycerol-polyvinyl alcohol composite films for food packaging: Evaluation of water adsorption, mechanical properties, light-barrier properties and transparency.

Science.gov (United States)

Cazón, Patricia; Vázquez, Manuel; Velazquez, Gonzalo

2018-09-01

Nowadays consumers are aware of environmental problems. As an alternative to petrochemical polymers for food packaging, researchers have been focused on biopolymeric materials as raw material. The aim of this study was to evaluate mechanical properties (toughness, burst strength and distance to burst), water adsorption, light-barrier properties and transparency of composite films based on cellulose, glycerol and polyvinyl alcohol. Scanning electron microscopy, spectral analysis (FT-IR and UV-VIS-NIR) and differential scanning calorimetry were performed to explain the morphology, structural and thermal properties of the films. Results showed that polyvinyl alcohol enhances the toughness of films up to 44.30 MJ/m 3 . However, toughness decreases when glycerol concentration is increased (from 23.41 to 10.55 MJ/m 3 ). Water adsorption increased with increasing polyvinyl alcohol concentration up to 222%. Polyvinyl alcohol increased the film thickness. The films showed higher burst strength (up to 12014 g) than other biodegradable films. The films obtained have optimal values of transparency like those values of synthetic polymers. Glycerol produced a UV protective effect in the films, an important effect for food packaging to prevent lipid oxidative deterioration. Results showed that it is feasible to obtain cellulose-glycerol-polyvinyl alcohol composite films with improved properties. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

High field nuclear magnetic resonance application to polysaccharide chemistry

International Nuclear Information System (INIS)

Vincendon, Marc

1972-01-01

Nuclear magnetic resonance has been applied to polysaccharide chemistry using time averaging technique and high fields (100 and 250 MHz). The three methyl signals of methyl cellulose and cellulose triacetate are separated, and the C-6 substituent has been identified. Biosynthesis of bacterial cellulose has been performed using deuterium labelled D-glucose and Acetobacter xylinum. Per-acetylated derivative of bacterial cellulose has been studied by NMR; this study permitted us to determine the quantity of deuterium on each position of the anhydro-glucose unit in the polymer. NMR has also been used to see the anomeric end chain of cellulose and amylose derivatives and to show the fixation of bromine and t-butyl group on the free anomeric end chain of cellulose triacetate. (author) [fr

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

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...... solvent-cast films. The optical, mechanical, and oxygen-barrier properties of these films were determined. A reduction in the quantity and appearance of large fiber fragments and fiber aggregates in the films as a function of increasing homogenization was illustrated with optical microscopy, atomic force...... microscopy, and scanning electron microscopy. Film opacity decreased with increasing homogenization, and the use of three additional homogenization steps after initial gel production resulted in highly transparent films. The oxygen permeability of the films was not significantly influenced by the degree...

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.

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.

Adsorption of Xyloglucan onto Cellulose Surfaces of Different Morphologies: An Entropy-Driven Process.

Science.gov (United States)

Benselfelt, Tobias; Cranston, Emily D; Ondaral, Sedat; Johansson, Erik; Brumer, Harry; Rutland, Mark W; Wågberg, Lars

2016-09-12

The temperature-dependence of xyloglucan (XG) adsorption onto smooth cellulose model films regenerated from N-methylmorpholine N-oxide (NMMO) was investigated using surface plasmon resonance spectroscopy, and it was found that the adsorbed amount increased with increasing temperature. This implies that the adsorption of XG to NMMO-regenerated cellulose is endothermic and supports the hypothesis that the adsorption of XG onto cellulose is an entropy-driven process. We suggest that XG adsorption is mainly driven by the release of water molecules from the highly hydrated cellulose surfaces and from the XG molecules, rather than through hydrogen bonding and van der Waals forces as previously suggested. To test this hypothesis, the adsorption of XG onto cellulose was studied using cellulose films with different morphologies prepared from cellulose nanocrystals (CNC), semicrystalline NMMO-regenerated cellulose, and amorphous cellulose regenerated from lithium chloride/dimethylacetamide. The total amount of high molecular weight xyloglucan (XGHMW) adsorbed was studied by quartz crystal microbalance and reflectometry measurements, and it was found that the adsorption was greatest on the amorphous cellulose followed by the CNC and NMMO-regenerated cellulose films. There was a significant correlation between the cellulose dry film thickness and the adsorbed XG amount, indicating that XG penetrated into the films. There was also a correlation between the swelling of the films and the adsorbed amounts and conformation of XG, which further strengthened the conclusion that the water content and the subsequent release of the water upon adsorption are important components of the adsorption process.

Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

International Nuclear Information System (INIS)

Josefsson, Gabriella; Gamstedt, E. Kristofer; Ahvenainen, Patrik; Mushi, Ngesa Ezekiel

2015-01-01

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

Surface crystallographic structures of cellulose nanofiber films and overlayers of pentacene

Science.gov (United States)

Nakayama, Yasuo; Mori, Toshiaki; Tsuruta, Ryohei; Yamanaka, Soichiro; Yoshida, Koki; Imai, Kento; Koganezawa, Tomoyuki; Hosokai, Takuya

2018-03-01

Cellulose nanofibers or nanocellulose is a promising recently developed biomass and biodegradable material used for various applications. In order to utilize this material as a substrate in organic electronic devices, thorough understanding of the crystallographic structures of the surfaces of the nanocellulose composites and of their interfaces with organic semiconductor molecules is essential. In this work, surface crystallographic structures of nanocellulose films (NCFs) and overlayers of pentacene were investigated by two-dimensional grazing-incidence X-ray diffraction. The NCFs are found to crystallize on solid surfaces with the crystal lattice preserving the same structure of the known bulk phase, whereas distortion of interchain packing toward the surface normal direction is suggested. The pentacene overlayers on the NCFs are found to form the thin-film phase with an in-plane mean crystallite size of over 10 nm.

Investigation of ATR-FTIR spectroscopy as an alternative to the Water Leach Free Acidity test for cellulose acetate-based film

DEFF Research Database (Denmark)

Johansen, Karin Bonde; Shashoua, Yvonne

2005-01-01

Cellulose acetate film loses acetate groups on ageing which results in the formation of damaging acetic acid. Water-Leach Free Acidity Test (WLFAT) is the definitive technique to quantify acidity, but requires 1g film and 26 hours. ATR-FTIR spectroscopy is a non-destructive, rapid technique which...

Characteristics of unique HBr-hydrolyzed cellulose nanocrystals from freshwater green algae (Cladophora rupestris) and its reinforcement in starch-based film.

Science.gov (United States)

Sucaldito, Melvir R; Camacho, Drexel H

2017-08-01

Cellulose nanocrystals (CNCs) are promising materials that are readily extracted from plants and other cellulose-containing organisms. In this study, CNCs were isolated from freshwater green algae (Cladophora rupestris) thriving in a volcanic lake, using hydrobromic acid (HBr) hydrolysis. Morphological and structural studies revealed highly crystalline CNCs (94.0% crystallinity index) with preferred orientation to [100] lattice plane as shown by XRD measurements and have an average diameter of 20.0 (±4.4)nm as shown by TEM. Thermal studies showed increased temperature for thermal decomposition of CNCs (381.6°C), which is a result of HBr hydrolysis for CNCs isolation. The isolated CNCs were reinforced into starch based biocomposites via solution casting and evaporation method. Mechanical strength was improved as high as 78% upon addition of 1% cellulose nanocrystals in the films. The produced films are promising materials for their high mechanical strength, biodegradability and availability of raw materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transparent cellulose/polyhedral oligomeric silsesquioxane nanocomposites with enhanced UV-shielding properties.

Science.gov (United States)

Feng, Ye; Zhang, Jinming; He, Jiasong; Zhang, Jun

2016-08-20

The solubility of eight types of polyhedral oligomeric silsesquioxane (POSS) derivatives in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) and the dispersion of POSS in cellulose matrix were examined. Only a special POSS containing both aminophenyl and nitrophenyl groups (POSS-AN, NH2:NO2=2:6) was selected to prepare nanocomposites, because of its good solubility in AmimCl and high stability during the preparation process. POSS-AN nanoparticles were uniformly dispersed in a cellulose matrix with a size of 30-40nm, and so the resultant cellulose/POSS-AN nanocomposite films were transparent. The mechanical properties of the films achieved a maximum tensile strength of 190MPa after addition of 2wt% POSS-AN. Interestingly, all of the cellulose/POSS-AN films exhibited high UV-absorbing capability. For the 15wt% cellulose/POSS-AN film, the transmittance of UVA (315-400nm) and UVB (280-315nm) was only 9.1% and nearly 0, respectively. The UV aging and shielding experiments showed that the transparent cellulose/POSS-AN nanocomposite films possessed anti-UV aging and UV shielding properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reinforcement of poly (vinyl alcohol films with alpha-chitin nanowhiskers

Directory of Open Access Journals (Sweden)

Hugo Lisboa

2018-03-01

Full Text Available Abstract Composites Films were produced using Poly (Vinyl Alcohol as the soft material and reinforced with Chitin Nanowhiskers(NWCH as the rigid material. The present work studies the reinforcing mechanisms of NWCH in PVA films, made through a solvent casting technique and characterized for their calorimetric, swelling and mechanical properties. DSC tests revealed a sharp increase of 45 °C in glass transition temperatures with only 1.5% NWCH, while melting temperature had a small increases suggesting an anti-plasticizing effect. Swelling tests revealed decreasing hygoscopy when NWCH volume fraction increases. Estimates for elastic tensile modulus using a model that predicts the formation of a percolating network were not consistent with the experimental data of tensile tests suggesting that contrary to the reinforcement with cellulose nanowhiskers the percolating network is not primarily responsible for the reinforcement of the films. By adjusting the Halpin-Tsai equations, modified by Nielsen it was found that the mechanical properties were mainly influenced by the packing of the NWCH.

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.

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.

Novel carboxymethyl cellulose-polyvinyl alcohol blend films stabilized by Pickering emulsion incorporation method.

Science.gov (United States)

Fasihi, Hadi; Fazilati, Mohammad; Hashemi, Mahdi; Noshirvani, Nooshin

2017-07-01

The aim of this study was to investigate the possibility of increasing the antimicrobial and antioxidant properties of biodegradable active films stabilized via Pickering emulsions. The blend films were prepared from carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA), emulsified with oleic acid (OL) and incorporated with rosemary essential oil (REO). Formation of Pickering emulsion was confirmed by scanning electron microscopy (SEM), optical microscopy, mean droplet size and emulsion stability. Morphological, optical, physical, mechanical, thermal, antifungal and antioxidant properties of the films incorporated with different concentrations of REO (0.5, 1.5 and 3%) were determined. The results showed an increase in UV absorbance and elongation at break but, a decrease in tensile strength and thermal stability of the films. Interestingly, films containing REO exhibited considerable antioxidant and antimicrobial properties. In vitro microbial tests exhibited 100% fungal inhibition against Penicillium digitatum in the films containing 3% REO. In addition, no fungal growth were observed after 60days of storage at 25°C in bread slices were stored with active films incorporated with 3% REO, could attributed to the slow and regular release of REO caused by Pickering emulsions. The results of this study suggest that Pickering emulsion is a very promising method, which significantly affects antioxidant and antimicrobial activities of the films. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antibacterial hydroxypropyl methyl cellulose edible films containing nanoemulsions of Thymus daenensis essential oil for food packaging.

Science.gov (United States)

Moghimi, Roya; Aliahmadi, Atousa; Rafati, Hasan

2017-11-01

Edible films containing essential oils (EO) as natural antibacterial agents are promising systems for food preservation. In this work, nanoemulsions of Thymus daenensis EO (wild; F1 and cultivated; F2) were loaded in hydroxyl propyl methyl cellulose (HPMC) films and the effect of different parameters (polymer, plasticizer, and EO concentration) on the film properties were analyzed and optimized. Prepared HPMC films were characterized in terms of EO loading, morphology, mechanical properties, and the antibacterial activity. The results of SEM showed uniform incorporation of nanoemulsions into the edible film. Investigation of the mechanical properties of two edible films revealed a plasticizing effect of T. daenensis EO on the films. Also, edible films had noticeable antimicrobial activity against selected microorganisms, i.e. 47.0±2.5mm and 22.6±0.5mm zone of inhibition against S. aureus for films containing F1 and F2, respectively. Incorporation of nanoemulsions into the HPMC films can be used for active food preservation. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Significant Enhancement of Thermal Conductivity in Nanofibrillated Cellulose Films with Low Mass Fraction of Nanodiamond.

Science.gov (United States)

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

2017-11-22

High thermal conductive nanofibrillated cellulose (NFC) hybrid films based on nanodiamond (ND) were fabricated by a facile vacuum filtration technique. In this issue, the thermal conductivity (TC) on the in-plane direction of the NFC/ND hybrid film had a significant enhancement of 775.2% at a comparatively low ND content (0.5 wt %). The NFC not only helps ND to disperse in the aqueous medium stably but also plays a positive role in the formation of the hierarchical structure. ND could form a thermal conductive pathway in the hierarchical structures under the intermolecular hydrogen bonds. Moreover, the hybrid films composed of zero-dimensional ND and one-dimensional NFC exhibit remarkable mechanical properties and optical transparency. The NFC/ND hybrid films possessing superior TC, mechanical properties, and optical transparency can open applications for portable electronic equipment as a lateral heat spreader.

Applications of alpha particles detectors made of nitrocellulose film

International Nuclear Information System (INIS)

Segovia, N.; Salinas, B.; Pineda, H.

1978-01-01

We describe the experiments realized in order to probe the response of the alpha particles detectors manufactured in our laboratory and their suitability to some important applications. The detection system is a nitrocellulose film which register the transit of the charged particles. The traces left by the particles during their transit are manifested through a controlled chemical attack and counted after that with a microscope. This monitor system was utilized in the following applications: 1) uranium prospection 2) alpha autoradiography 4) determination of air pollution by alpha emitters. The results which were obtained are satisfactory and in spite that in these first applications only qualitative measurements were made the method could be used for quantitative determinations when we will have a better knowledge of the effect of factors which are not under our control. (author)

Fabrication of Al2O3 Nano-Structure Functional Film on a Cellulose Insulation Polymer Surface and Its Space Charge Suppression Effect

Directory of Open Access Journals (Sweden)

Jian Hao

2017-10-01

Full Text Available Cellulose insulation polymer (paper/pressboard has been widely used in high voltage direct current (HVDC transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard surface using reactive radio frequency (RF magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS, X-ray photoelectron spectroscopy (XPS, and X-ray diffraction (XRD. The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al2O3 film with amorphous phase was successfully fabricated onto the fibre surface. The cellulose insulation pressboard surface sputtered by Al2O3 film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<103 Hz region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al2O3 film for 90 min, the pressboard sputtered with Al2O3 film for 60 min had a better space charge suppression effect. Ultra-small Al2O3 particles (<10 nm grew on the surface of the larger nanoparticles. The nano-structured Al2O3 film sputtered on the fibre surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function surface against space charge injection/accumulation in HVDC equipment.

A comparative study of gelatin and starch-based nano-composite films modified by nano-cellulose and chitosan for food packaging applications.

Science.gov (United States)

Noorbakhsh-Soltani, S M; Zerafat, M M; Sabbaghi, S

2018-06-01

Environmental concerns have led to extensive research for replacing polymer-based food packaging with bio-nano-composites. In this study, incorporation of nano-cellulose into gelatin and starch matrices is investigated for this purpose. Chitosan is used to improve mechanical, anti-fungal and waterproof properties. Experiments are designed and analyzed using response surface methodology. Nano-Cellulose is synthesized via acid hydrolysis and incorporated in base matrices through wet processing. Also, tensile strength test, food preservation, transparency in visible and UV and water contact angle are performed on the nano-composite films. DSC/TGA and air permeability tests are also performed on the optimal films. The results show that increasing nano-cellulose composition to 10% leads to increase the tensile strength at break to 8121 MN/m 2 and decrease the elongation at break. Also, increasing chitosan composition from 5% to 30% can enhance food preservation up to 15 days. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Key product development based on cyclo olefin polymer for LCD-TV

Science.gov (United States)

Konishi, Yuichiro; Kobayashi, Masahi; Arakawa, Kouhei

2006-09-01

Cyclo Olefin Polymer (COP), which was developed by Zeon Corporation, is well known and used as an optical plastic in optical markets, having unique properties such as high light transmission, low water absorption, low birefringence etc. Optes Inc, who is ZEON CORPORATION's affiliate optical parts manufacturer, has succeeded in the development of high performance optical base films. These are used for retardation and polarizing films in LCD's (Liquid Crystal Displays), made from Cyclo Olefin Polymer with own film extrusion technologies. The Optical base film developed by Optes Inc has superior properties compared with those of existing products such as polycarbonate (PC), polyethylene terephthalate (PET) and Triacetate Cellulose (TAC) base in terms of low birefringence, high optical isotropy and high dimensional stability under high humidity and temperature conditions.

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.

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

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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. Copyright © 2016. Published by Elsevier B.V.

Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

Energy Technology Data Exchange (ETDEWEB)

Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

2009-10-15

Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

International Nuclear Information System (INIS)

Wong, T.P.W.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

2009-01-01

Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

Strong and Optically Transparent Films Prepared Using Cellulosic Solid Residue Recovered from Cellulose Nanocrystals Production Waste Stream

Science.gov (United States)

Qianqian Wang; J.Y. Zhu; John M. Considine

2013-01-01

We used a new cellulosic material, cellulosic solid residue (CSR), to produce cellulose nanofibrils (CNF) for potential high value applications. Cellulose nanofibrils (CNF) were produced from CSR recovered from the hydrolysates (waste stream) of acid hydrolysis of a bleached Eucalyptus kraft pulp (BEP) to produce nanocrystals (CNC). Acid hydrolysis greatly facilitated...

Facile green synthesis of silver nanodendrite/cellulose acetate thin film electrodes for flexible supercapacitors.

Science.gov (United States)

Devarayan, Kesavan; Park, Jiyoung; Kim, Hak-Yong; Kim, Byoung-Suhk

2017-05-01

In this study, we present a highly efficient and economical solution called as 'in situ hydrogenation' for preparation of highly conductive thin film electrode based on silver nanodendrites. The silver nanodendrite (AgND)/cellulose acetate (CA) thin film electrodes exhibited sheet resistance ranging from 0.32ohm/sq to 122.1ohm/sq which could be controlled by changing the concentration of both silver and polymer. In addition, these electrodes exhibited outstanding toughness during the bending test. Further, these thin film electrodes have great potential for scale-up with an average weight of 3mg/cm 2 and can be also combined with active nanomaterials such as multiwalled carbon nanotubes (MWCNTs) to fabricate AgND/CA/MWCNTs thin film for high-performance flexible supercapacitor electrode. The AgND/CA/MWCNTs electrodes exhibited a maximum specific capacitance of 237F/g at a current density of 0.3A/g. After 1000 cycles, the AgND/MWCNT/CA exhibited a decrease of 16.0% of specific capacitance. Copyright © 2017 Elsevier Ltd. All rights reserved.

The anomalous low temperature resistivity of thermally evaporated alpha-Mn thin film

Energy Technology Data Exchange (ETDEWEB)

Ampong, F.K., E-mail: kampxx@yahoo.co [Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana); Boakye, F.; Nkum, R.K. [Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana)

2010-08-15

Electrical resistivity measurements have been carried out on thermally evaporated alpha-Mn thin film between 300 and 1.4 K using the van der Pauw four probe technique. The film was grown on a glass substrate held at a temperature of 373 K, in an ambient pressure of 5x10{sup -6} Torr. The results show a resistance minimum, a notable characteristic of alpha-Mn but at a (rather high) temperature of 194+-1 K. Below the resistivity maximum which corresponds to 70 K, the resistivity drops by only 0.02 muOMEGAm indicating a rather short range magnetic ordering. The low temperature results show a tendency towards saturation of the resistivity as the temperature approaches zero suggesting a Kondo scattering.

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.

Development of polylactic acid nanocomposite films reinforced with cellulose nanocrystals derived from coffee silverskin.

Science.gov (United States)

Sung, Soo Hyun; Chang, Yoonjee; Han, Jaejoon

2017-08-01

Bio-nanocomposite films based on polylactic acid (PLA) matrix reinforced with cellulose nanocrystals (CNCs) were developed using a twin-screw extruder. The CNCs were extracted from coffee silverskin (CS), which is a by-product of the coffee roasting process. They were extracted by alkali treatment followed by sulfuric acid hydrolysis. They were used as reinforcing agents to obtain PLA/CNC nanocomposites by addition at different concentrations (1%, 3%, and 5% CNCs). Morphological, tensile, and barrier properties of the bio-nanocomposites were analyzed. The tensile strength and Young's modulus increased with both 1% and 3% CNCs. The water vapor permeability decreased gradually with increasing addition of CNCs up to 3% and good oxygen barrier properties were found for all nanocomposites. These results suggest that CNCs from CS can improve the physical properties of PLA-based biopolymer film. The developed PLA/CNC bio-nanocomposite films can potentially be used for biopolymer materials with enhanced barrier and mechanical properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physical and Mechanical Properties of Cellulose Nanofibril Films from Bleached Eucalyptus Pulp by Endoglucanase Treatment and Microfluidization

Science.gov (United States)

Wangxia Wang; Ronald C. Sabo; Michael D. Mozuch; Phil Kersten; J. Y. Zhu; Yongcan Jin

2015-01-01

A GH5 hyperthermostable endoglucanase (Ph-GH5) from the archaeon Pyrococcus horikoshii and a commercial endoglucanase (FR) were used to treat bleached eucalyptus pulp (BEP) fibers to produce cellulose nanofibrils (CNF) and subsequently to CNF films. TEM imaging indicated that Ph-GH5 produced longer and more entangled CNF than FR with the same number...

Superhydrophobic cellulose-based bionanocomposite films from Pickering emulsions

Science.gov (United States)

Bayer, Ilker S.; Steele, Adam; Martorana, Philip J.; Loth, Eric; Miller, Lance

2009-04-01

Inherently superhydrophobic and flexible cellulose-based bionanocomposites were fabricated from solid stabilized (Pickering) emulsions. Emulsions were formed by dispersing cyclosiloxanes in water stabilized by layered silicate particles and were subsequently modified by blending into a zinc oxide nanofluid. The polymer matrix was a blend of cellulose nitrate and fluoroacrylic polymer (Zonyl 8740) precompatibilized in solution. Coatings were spray cast onto aluminum substrates from polymer blends dispersed in modified Pickering emulsions. No postsurface treatment was required to induce superhydrophobicity. Effect of antiseptic additives on bionanocomposite superhydrophobicity is also discussed. Replacing cellulose nitrate with commercial liquid bandage solutions produced identical superhydrophobic coatings.

Design and construction of a device for elaborate films of Vyns or Cellulose with control thickness

International Nuclear Information System (INIS)

Patlan C, F.

1998-01-01

This work is a part of the studies about the elaboration of reference radioactive sources, which are done in the National Institute of Nuclear Research in Mexico. Specially concerns with the elaboration of α-β radioactive sources. The importance of this work is because their applications increase day by day. Medicine, engineering, agriculture and even the arts cannot escape to the influence and impact of the nuclear sciences. But, what are the radioactive sources?, what is a holder of a radioactive source?, why we elaborate holders with special materials?, which is the best technique to elaborate them?. These topics are commented in this work. The material is as follows: the introduction and objective are described in chapter one. The second chapter deals with concepts about atomic and molecular structures, general description of nuclear radiation and their characteristics, comments about radioactive law decay, interaction of the alpha particles with the matter and a short description about surface barrier detectors. The different methods for elaborate a radioactive source holders are described in the chapter three. This same chapter speaks the topic about the elaboration of vyns or cellulose films and a device is proposed for make them; are some methods described how to take measure of their thickness. Chapter four shows the results, analysis and the respective conclusions. (Author)

Biodegradation behaviors of cellulose nanocrystals -PVA nanocomposites

Directory of Open Access Journals (Sweden)

Mahdi Rohani

2014-11-01

Full Text Available In this research, biodegradation behaviors of cellulose nanocrystals-poly vinyl alcohol nanocomposites were investigated. Nanocomposite films with different filler loading levels (3, 6, 9 and 12% by wt were developed by solvent casting method. The effect of cellulose nanocrystals on the biodegradation behaviors of nanocomposite films was studied. Water absorption and water solubility tests were performed by immersing specimens into distilled water. The characteristic parameter of diffusion coefficient and maximum moisture content were determined from the obtained water absorption curves. The water absorption behavior of the nanocomposites was found to follow a Fickian behavior. The maximum water absorption and diffusion coefficients were decreased by increasing the cellulose nanocrystals contents, however the water solubility decrease. The biodegradability of the films was investigated by immersing specimens into cellulase enzymatic solution as well as by burial in soil. The results showed that adding cellulose nanocrystals increase the weight loss of specimens in enzymatic solution but decrease it in soil media. The limited biodegradability of specimens in soil media attributed to development of strong interactions with solid substrates that inhibit the accessibility of functional groups. Specimens with the low degree of hydrolysis underwent extensive biodegradation in both enzymatic and soil media, whilst specimens with the high degree of hydrolysis showed recalcitrance to biodegradation under those conditions.

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.

Surface-type humidity sensor based on cellulose-PEPC for telemetry systems

International Nuclear Information System (INIS)

Karimov, Kh. S.; Saleem, M.; Qasuria, T. A.; Farooq, M.

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. (semiconductor integrated circuits)

Critical rate of energy loss for registration of charged particles in cellulose nitrate

International Nuclear Information System (INIS)

Knoefel, T.M.J.; Sachett, I.A.

1979-09-01

Cellulose nitrate films LR-115 type II (Kodak-Pathe) have been exposed, at right angles, to alpha-particle beams in the energy range 2.5 - 5.5 MeV. From measurements of both through etched track density, a critical rate of energy lo ss for track registration of (0.85 +- 0.05) MeV cm 2 /mg has been derived, which corresponds to a critical alpha-particle energy of (4.6 +- 0.4) MeV. These results are compatible with those obtained by other authors whenever similar etching conditions are used. The concepts of threshold rate of energy loss and a threshold energy for etched-track formation are introduced, and their values are obtained from the experiment as being (0.80 +- 0.05) MeV cm 2 /mg and (5.1 +- 0.4) Mev, respectively. In addition, the present work provides a suitable set of useful, reference data for further applications of such plastic nuclear track detector in problems concerned with the detection of low-energy alpha particles. (Author) [pt

Fabrication Flexible and Luminescent Nanofibrillated Cellulose Films with Modified SrAl2O4: Eu, Dy Phosphors via Nanoscale Silica and Aminosilane

Directory of Open Access Journals (Sweden)

Longfei Zhang

2018-05-01

Full Text Available Flexible 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO-oxidized nanofibrillated cellulose (ONFC films with long afterglow luminescence containing modified SrAl2O4: Eu2+, Dy3+ (SAOED phosphors were fabricated by a template method. Tetraethyl orthosilicate (TEOS and (3-aminopropyl trimethoxy-silane (APTMS were employed cooperatively to improve the water resistance and compatibility of the SAOED particles in the ONFC suspension. The structure and morphology after modification evidenced the formation of a superior SiO2 layer and coarse amino-compounds on the surface of the phosphors. Homogeneous dispersions containing ONFC and the modified phosphors were prepared and the interface of composite films containing the amino-modified particles showed a more closely packed structure and had less voids at the interface between the cellulose and luminescent particles than that of silica-modified phosphors. The emission spectra for luminescent films showed a slight blue shift (3.2 nm at around 512 nm. Such flexible films with good luminescence, thermal resistance, and mechanical properties can find applications in fields like luminous flexible equipment, night indication, and portable logo or labels.

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)

Addition of silica nanoparticles to tailor the mechanical properties of nanofibrillated cellulose thin films.

Science.gov (United States)

Eita, Mohamed; Arwin, Hans; Granberg, Hjalmar; Wågberg, Lars

2011-11-15

Over the last decade, the use of nanocellulose in advanced technological applications has been promoted both due the excellent properties of this material in combination with its renewability. In this study, multilayered thin films composed of nanofibrillated cellulose (NFC), polyvinyl amine (PVAm) and silica nanoparticles were fabricated on polydimethylsiloxane (PDMS) using a layer-by-layer adsorption technique. The multilayer build-up was followed in situ by quartz crystal microbalance with dissipation, which indicated that the PVAm-SiO(2)-PVAm-NFC system adsorbs twice as much wet mass material compared to the PVAm-NFC system for the same number of bilayers. This is accompanied with a higher viscoelasticity for the PVAm-SiO(2)-PVAm-NFC system. Ellipsometry indicated a dry-state thickness of 2.2 and 3.4 nm per bilayer for the PVAm-NFC system and the PVAm-SiO(2)-PVAm-NFC system, respectively. Atomic force microscopy height images indicate that in both systems, a porous network structure is achieved. Young's modulus of these thin films was determined by the Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) technique. The Young's modulus of the PVAm/NFC films was doubled, from 1 to 2 GPa, upon incorporation of silica nanoparticles in the films. The introduction of the silica nanoparticles lowered the refractive index of the films, most probably due to an increased porosity of the films. Copyright © 2011 Elsevier Inc. All rights reserved.

Printed optically transparent graphene cellulose electrodes

Science.gov (United States)

Sinar, Dogan; Knopf, George K.; Nikumb, Suwas; Andrushchenko, Anatoly

2016-02-01

Optically transparent electrodes are a key component in variety of products including bioelectronics, touch screens, flexible displays, low emissivity windows, and photovoltaic cells. Although highly conductive indium tin oxide (ITO) films are often used in these electrode applications, the raw material is very expensive and the electrodes often fracture when mechanically stressed. An alternative low-cost material for inkjet printing transparent electrodes on glass and flexible polymer substrates is described in this paper. The water based ink is created by using a hydrophilic cellulose derivative, carboxymethyl cellulose (CMC), to help suspend the naturally hydrophobic graphene (G) sheets in a solvent composed of 70% DI water and 30% 2-butoxyethanol. The CMC chain has hydrophobic and hydrophilic functional sites which allow adsorption on G sheets and, therefore, permit the graphene to be stabilized in water by electrostatic and steric forces. Once deposited on the functionalized substrate the electrical conductivity of the printed films can be "tuned" by decomposing the cellulose stabilizer using thermal reduction. The entire electrode can be thermally reduced in an oven or portions of the electrode thermally modified using a laser annealing process. The thermal process can reduce the sheet resistance of G-CMC films to < 100 Ω/sq. Experimental studies show that the optical transmittance and sheet resistance of the G-CMC conductive electrode is a dependent on the film thickness (ie. superimposed printed layers). The printed electrodes have also been doped with AuCl3 to increase electrical conductivity without significantly increasing film thickness and, thereby, maintain high optical transparency.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development and characterization of bacterial cellulose reinforced biocomposite films based on protein from buckwheat distiller's dried grains.

Science.gov (United States)

Wang, Xuejiao; Ullah, Niamat; Sun, Xuchun; Guo, Yan; Chen, Lin; Li, Zhixi; Feng, Xianchao

2017-03-01

Biocomposite films were manufactured by combining protein extracted from buckwheat distiller's dried grains with bacterial cellulose (BC). The film microstructures showed that BC is compatible with protein matrix and endows the film with high rigidity. Differential scanning calorimetry (DSC) showed that BC can promote thermal stability of the composite films. BC promoted the transition from a Newtonian to a non-Newtonian fluid and the shear thinning behavior of protein-BC solution. Fourier Transform Infrared (FTIR) spectroscopy showed the main functional groups' absorption peaks shifted to lower wavenumbers. Results of both FTIR and viscosity analysis proved the formation of intermolecular interactions through hydrogen bonds. These bonds affected film characteristics such as moisture content (MC), water solubility (WS), and water vapor permeability (WVP), which decreased with addition of BC. The WVP (6.68±0.78-5.95±0.54×10 -10 gm/Pasm 2 ) of the films were lower than other protein films. Tensile strength (TS) values of films containing 1.8% and 2.0% BC (14.98±0.97 and 15.03±2.04MPa) were significantly higher than that of pure protein films (4.26±0.66MPa). Combination of proteins extracted from a waste product and BC led to composite films with low water vapor permeability and excellent mechanical properties. Copyright © 2016 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

Mahadeva, Suresha K; Kim, Jaehwan

2011-01-01

A highly flexible nanocomposite was developed by coating a regenerated cellulose film with a thin layer of tin oxide (SnO 2 ) 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 SnO 2 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-SnO 2 hybrid nanocomposite can be used for biodegradable and disposable chemical, humidity and biosensors.

Paper actuators made with cellulose and hybrid materials.

Science.gov (United States)

Kim, Jaehwan; Yun, Sungryul; Mahadeva, Suresha K; Yun, Kiju; Yang, Sang Yeol; Maniruzzaman, Mohammad

2010-01-01

Recently, cellulose has been re-discovered as a smart material that can be used as sensor and actuator materials, which is termed electro-active paper (EAPap). This paper reports recent advances in paper actuators made with cellulose and hybrid materials such as multi-walled carbon nanotubes, conducting polymers and ionic liquids. Two distinct actuator principles in EAPap actuators are demonstrated: piezoelectric effect and ion migration effect in cellulose. Piezoelectricity of cellulose EAPap is quite comparable with other piezoelectric polymers. But, it is biodegradable, biocompatible, mechanically strong and thermally stable. To enhance ion migration effect in the cellulose, polypyrrole conducting polymer and ionic liquids were nanocoated on the cellulose film. This hybrid cellulose EAPap nanocomposite exhibits durable bending actuation in an ambient humidity and temperature condition. Fabrication, characteristics and performance of the cellulose EAPap and its hybrid EAPap materials are illustrated. Also, its possibility for remotely microwave-driven paper actuator is demonstrated.

Cellulose acetate-based SiO2/TiO2 hybrid microsphere composite aerogel films for water-in-oil emulsion separation

Science.gov (United States)

Yang, Xue; Ma, Jianjun; Ling, Jing; Li, Na; Wang, Di; Yue, Fan; Xu, Shimei

2018-03-01

The cellulose acetate (CA)/SiO2-TiO2 hybrid microsphere composite aerogel films were successfully fabricated via water vapor-induced phase inversion of CA solution and simultaneous hydrolysis/condensation of 3-aminopropyltrimethoxysilane (APTMS) and tetrabutyl titanate (TBT) at room temperature. Micro-nano hierarchical structure was constructed on the surface of the film. The film could separate nano-sized surfactant-stabilized water-in-oil emulsions only under gravity. The flux of the film for the emulsion separation was up to 667 L m-2 h-1, while the separation efficiency was up to 99.99 wt%. Meanwhile, the film exhibited excellent stability during multiple cycles. Moreover, the film performed excellent photo-degradation performance under UV light due to the photocatalytic ability of TiO2. Facile preparation, good separation and potential biodegradation maked the CA/SiO2-TiO2 hybrid microsphere composite aerogel films a candidate in oil/water separation application.

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.

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.

Effect of polyethelene oxide on the thermal degradation of cellulose biofilm – Low cost material for soft tissue repair in dentistry

Science.gov (United States)

Tyler, Rakim; Schiraldi, David; Roperto, Renato; Faddoul, Fady; Teich, Sorin

2017-01-01

Background Bio cellulose is a byproduct of sweet tea fermentation known as kombusha. During the biosynthesis by bacteria cellulose chains are polymerized by enzyme from activated glucose. The single chains are then extruded through the bacterial cell wall. Interestingly, a potential of the Kombucha’s byproduct bio cellulose (BC) as biomaterial had come into focus only in the past few decades. The unique physical and mechanical properties such as high purity, an ultrafine and highly crystalline network structure, a superior mechanical strength, flexibility, pronounced permeability to gases and liquids, and an excellent compatibility with living tissue that reinforced by biodegradability, biocompatibility, large swelling ratios. Material and Methods The bio-cellulose film specimens were provided by the R.P Dressel dental materials laboratory, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, US. The films were harvested, washed with water and dried at room temperature overnight. 1wt% of PEG-2000 and 10wt% of NaOH were added into ultrapure water to prepare PEG/NaOH solution. Then bio-cellulose film was added to the mixture and swell for 3 h at room temperature. All bio-cellulose film specimens were all used in the TA Instruments Q500 Thermogravmetric Analyzer to investigate weight percent lost and degradation. The TGA was under ambient air conditions at a heating rate of 10ºC/min. Results and Conclusions PEG control exhibited one transition with the peak at 380ºC. Cellulose and cellulose/ PEG films showed 3 major transitions. Interestingly, the cellulose/PEG film showed slightly elevated temperatures when compared to the corresponding transitions for cellulose control. The thermal gravimetric analysis (TGA) degradation curves were analyzed. Cellulose control film exhibited two zero order transitions, that indicate the independence of the rate of degradation from the amount on the initial substance. The

Plasticized Biodegradable Poly(lactic acid) Based Composites Containing Cellulose in Micro- and Nanosize

OpenAIRE

Halász, Katalin; Csóka, Levente

2013-01-01

The aim of this work was to study the characteristics of thermal processed poly(lactic acid) composites. Poly(ethylene glycol) (PEG400), microcrystalline cellulose (MCC), and ultrasound-treated microcrystalline cellulose (USMCC) were used in 1, 3, and 5 weight percents to modify the attributes of PLA matrix. The composite films were produced by twin screw extrusion followed by film extrusion. The manufactured PLA-based films were characterized by tensile testing, differential scanning calorim...

Caracterização de membranas assimétricas de acetato de celulose produzidas a partir do aproveitamento do resíduo da palha de milho para uso em ultrafiltração

Directory of Open Access Journals (Sweden)

Elaine Angélica Mundim Ribeiro

2014-06-01

Full Text Available Cellulose acetates (CA with different degrees of acetylation were synthesized from cellulose extracted from corn stover. Membranes were prepared for the ultrafiltration process with pure polymers and blend form of CA utilizing a dioxane/acetone system. The membranes were characterized according to their transport properties. The blend form materials presented the best results for application in ultrafiltration experiments. M-TAC/DAC (corn stover triacetate and diacetate and M-TAC/DAC-Rho (corn stover triacetate and Rhodia diacetate presented rejection to egg albumin protein of 87.39% and 80.50%, respectively. Thus, MWCO of 45 kDa was determined for these materials.

Spongy film of cellulosic polysaccharide as a dressing for aphthous stomatitis treatment in rabbits.

Science.gov (United States)

Fernandes Teixeira, Fernanda Mossumez; Figueiredo Pereira, Márcia de; Gomes Ferreira, Nara Lins; Miranda, Guilherme Marcelino de; Andrade Aguiar, José Lamartine de

2014-04-01

To develop an experimental model of acute inflammation, like aphthous ulcers, in oral cavity of rabbits, and also, to evaluate the results of the application of a polysaccharide spongy film of molasses from sugar cane as assist treatment in the healing process. Twenty adult rabbits weighting between 2.5 kg and 3.9 kg were divided into two groups: experimental and control infected ulcers were induced on the jugal mucosa by surgical excision. They were treated at the experimental group by curettage and dressing with spongy film of cellulosic polysaccharide film, whereas saline solution was used in the control group. Temporal evolution of the healing area, histopathology and bacteriological analysis were used to evaluate the healing process on the 3rd (D3), 7th (D7) and 11th days (D11). The healing time and bacteriological study showed no statistical differences on the group means. Analyzing the histopathology of the experimental group we verified epithelial hyperplasia from D3 to D11, instead in the control group there was a greater clutter of the epithelial cells from the D3 to D11. The experimental model used caused aphthous ulcers and the polysaccharide sponge film can be used as an aid in the symptomatic treatment and healing of the ulcerative lesions of the oral mucosa.

Preparation and characterization of novel wound dressing based on silver nanoparticle-impregnated bacterial cellulose and bacterial cellulose-aloe vera

International Nuclear Information System (INIS)

Ventigan, Sarla V.; Santiago, Karen S.; Balitaan, Jolleen Natalie I.

2015-01-01

Ideal wound dressings stimulate wound healing, control unpleasant odors, and provide antimicrobial action in wounds. However, most traditional wound dressings such as gauze and biological dressings exhibit exudate leaking which increases the risk of infection and delayed wound healing of tissues. This study aims to develop and characterize a bio-composite of bacterial cellulose and aloe vera having the ideal features of a wound dressing from Acetobacter xylinum-activated culture medium supplemented with various aloe vera concentrations from )-50% (v/v) and the film which exhibits the most uniform results is used for the incorporation of silver nanoparticle as an antibacterial agent. The biopolymer composites of bacterial cellulose and aloe vera were developed by adding 0-50% aloe vera (v/v) in the A. xylinum-activated coconut water medium during biosynthesis in static cultivation for 10 days. The films obtained after drying the membranes were named as bacterial cellulose-aloe vera (BC-A) films. The moisture content of films reached 99% which indicates that the films may be suitable for providing a moist environment to facilitate wound healing fast. With the addition of aloe vera up to 30% (v/v) during BC synthesis, it resulted in a significant improvement in the water absorption capacity of the films showing a WAC ration of 36.46 (r.s.d.= 12.17%, n=3) compared to the unmodified film having a ratio of 9.03 (r.s.d.= 13.95%, n=3). However, the addition of aloe vera at a concentration greater than 30% (v/v) resulted in a decrease in pellicle formation which can be observed from the very weak properties of the films. The BC-A (30%) displayed significantly improved in comparison to the unmodified BC film. Also, it is capable of absorbing high amount of water than its weight and can act as a potential wound dressing which reduces irritation and inflammation. (author)

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

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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.

Improvement in Functional Properties of Soy Protein Isolate-Based Film by Cellulose Nanocrystal–Graphene Artificial Nacre Nanocomposite

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Kuang Li

2017-07-01

Full Text Available A facile, inexpensive, and green approach for the production of stable graphene dispersion was proposed in this study. We fabricated soy protein isolate (SPI-based nanocomposite films with the combination of 2D negative charged graphene and 1D positive charged polyethyleneimine (PEI-modified cellulose nanocrystals (CNC via a layer-by-layer assembly method. The morphologies and surface charges of graphene sheets and CNC segments were characterized by atomic force microscopy and Zeta potential measurements. The hydrogen bonds and multiple interface interactions between the filler and SPI matrix were analyzed by Attenuated Total Reflectance–Fourier Transform Infrared spectra and X-ray diffraction patterns. Scanning electron microscopy demonstrated the cross-linked and laminated structures in the fracture surface of the films. In comparison with the unmodified SPI film, the tensile strength and surface contact angles of the SPI/graphene/PEI-CNC film were significantly improved, by 99.73% and 37.13% respectively. The UV–visible light barrier ability, water resistance, and thermal stability were also obviously enhanced. With these improved functional properties, this novel bio-nanocomposite film showed considerable potential for application for food packaging materials.

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

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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.

Detector for imaging and dosimetry of laser-driven epithermal neutrons by alpha conversion

Science.gov (United States)

Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Wilson, L. A.; Ansell, S.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Notley, M.; Raspino, D.; Rusby, D. R.; Borghesi, M.; Rhodes, N. J.; McKenna, P.; Neely, D.; Brenner, C. M.; Kar, S.

2016-10-01

An epithermal neutron imager based on detecting alpha particles created via boron neutron capture mechanism is discussed. The diagnostic mainly consists of a mm thick Boron Nitride (BN) sheet (as an alpha converter) in contact with a non-borated cellulose nitride film (LR115 type-II) detector. While the BN absorbs the neutrons in the thermal and epithermal ranges, the fast neutrons register insignificantly on the detector due to their low neutron capture and recoil cross-sections. The use of solid-state nuclear track detectors (SSNTD), unlike image plates, micro-channel plates and scintillators, provide safeguard from the x-rays, gamma-rays and electrons. The diagnostic was tested on a proof-of-principle basis, in front of a laser driven source of moderated neutrons, which suggests the potential of using this diagnostic (BN+SSNTD) for dosimetry and imaging applications.

Bio-active nanocomposite films based on nanocrystalline cellulose reinforced styrylquinoxalin-grafted-chitosan: Antibacterial and mechanical properties.

Science.gov (United States)

Fardioui, Meriem; Meftah Kadmiri, Issam; Qaiss, Abou El Kacem; Bouhfid, Rachid

2018-07-15

In this study, active nanocomposite films based on cellulose nanocrystalline (NCC) reinforced styrylquinoxalin-grafted-chitosan are prepared by solvent-casting process. The structures of the two styrylquinoxaline derivatives were confirmed by FT-IR, 1 H, 13 C NMR spectral data and the study of the antibacterial activity against Escherichia coli (EC), Staphylococcus aureus (SA), Bacillus subtilis (BS) and Pseudomonas Aeruginosa (PA) exhibits that they have a good antibacterial activity against (PA). On their side, the styrylquinoxalin-g-chitosan films are able to inhibit the growth of (PA) through their contact area without being damaged by the antibacterial test conditions. The addition of 5wt% of NCCs as nano-reinforcements revealed no change at the level of antibacterial activity but led to an important improvement of the mechanical properties (more than 60% and 90% improvement in Young's modulus and tensile strength, respectively) of the modified-chitosan films. Thereby, the present nanocomposite films are prepared by a simple way and featured by good mechanical and antibacterial properties which enhance the possibility to use them as bio-based products for biomedical and food packaging. Copyright © 2018 Elsevier B.V. All rights reserved.

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

OpenAIRE

Issa, A.A.; 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...

Development of nano-sized {alpha}-Al{sub 2}O{sub 3}:C films for application in digital radiology

Energy Technology Data Exchange (ETDEWEB)

Silva, Edna C., E-mail: edca@cdtn.b [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Nuclear; Fontainha, Crissia C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Dept. de Propedeutica Complemetar; Oliveira, Vitor H.; Ferraz, Wilmar B.; Faria, Luiz O. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

Ceramic materials are widely used as sensors for ionizing radiation. In nuclear applications, the alpha-alumina doped with carbon ({alpha}-Al{sub 2}O{sub 3}:C) is the most widely ceramic used because of its excellent optically stimulated luminescence (OSL) and thermoluminescent (TL) properties applied to detection of ionizing radiation. Another application of OSL and TL materials are in Digital Radiography, with ceramic/polymeric film composites. Recently, Computed Radiography (CR) devices based on OSL materials are replacing the old conventional film radiography. In this study we investigate the thermoluminescence of nano-sized {alpha}-Al{sub 2}O{sub 3} samples doped with different percentages of carbon, sintered in reducing atmospheres at temperatures ranging from 1300 to 1750 deg C. The results indicate that the nano-sized {alpha}-Al{sub 2}O{sub 3}:C materials have a luminescent response that could be due to both OSL and RPL properties, but without application to radiation dosimetry. Moreover, the results indicate that micro-sized {alpha}-Al{sub 2}O{sub 3}:C, doped with 0.5% carbon, and nano-sized ones doped with 2% of carbon, present thermoluminescent signal around 30 to 100 times the TL output signal of commercial TLD-100, the most used TL dosimeter in the world. The results indicate that these ceramic nano-particles have great potential for use in Digital Radiography based on thermoluminescent film imaging, being able to provide image resolutions much higher than the micro-sized {alpha}-Al{sub 2}O{sub 3}:C, in view of their improved resolution provided by nano-particulates. (author)

Biopolymer Electrolyte Based on Derivatives of Cellulose from Kenaf Bast Fiber

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Mohd Saiful Asmal Rani

2014-09-01

Full Text Available A cellulose derivative, carboxymethyl cellulose (CMC, was synthesized by the reaction of cellulose from kenaf bast fiber with monochloroacetic acid. A series of biopolymer electrolytes comprised of the synthesized CMC and ammonium acetate (CH3COONH4 were prepared by the solution-casting technique. The biopolymer-based electrolyte films were characterized by Fourier Transform Infrared spectroscopy to investigate the formation of the CMC–CH3COONH4 complexes. Electrochemical impedance spectroscopy was conducted to obtain their ionic conductivities. The highest conductivity at ambient temperature of 5.77 × 10−4 S cm−1 was obtained for the electrolyte film containing 20 wt% of CH3COONH4. The biopolymer electrolyte film also exhibited electrochemical stability up to 2.5 V. These results indicated that the biopolymer electrolyte has great potential for applications to electrochemical devices, such as proton batteries and solar cells.

UV-curable polyurethane coatings derived from cellulose

International Nuclear Information System (INIS)

Patel, M. M.; Patel, K. I.; Patel, H. B.; Parmar, J. S.

2009-01-01

At the present time coating industry is devoting much research in the direction of low volatile organic compounds to make eco-friendly coating material. In this study, such materials are developed from cellulose derived from bagasse, a sugar industry waste. Cellulose is converted to cellulose glyco glycoside by acid hydrolysis of cellulose under heterogeneous condition. Cellulose glyco glycoside is treated with polyethylene glycol having different molecular weights to give glyco glycosides which in turn are reacted with various diisocyanates to obtain polyurethane having free NCO groups. These materials are then reacted with hydroxyethylmethacrylate to give polyurethane acrylates. The acrylates are characterized for specific gravity, viscosity, colour and molecular weight as well as by fourier transform infrared spectroscopy. The UV-curable coating composition was prepared by blending PU-acrylate, reactive diluents and photoinitiator. Coating compositions were cured under UV-light and characterized for adhesion, flexibility, impact resistance, solvent resistance and for dynamic mechanical analysis as well as by thermal gravimetric analysis for thermal stability. The cured films give thickness of 23-24 microns and cure time required is less than 1.5-2.0 min. There is no liberation of any volatiles during curing and films have good adhesion to mild steel substrate. The cured coatings give excellent dynamic, mechanical and chemical properties. The scratch resistance was found to be satisfactory. The application was made in unpigmented form but it is found that various pigments can be used to give coloured UV-curable coatings.

Polyaniline- and poly(ethylenedioxythiophene)-cellulose nanocomposite electrodes for supercapacitors

OpenAIRE

Liew, Soon Yee; Thielemans, Wim; Walsh, Darren A.

2014-01-01

The formation and characterisation of films of polyaniline (PANI) and poly(ethylenedioxythiophene) (PEDOT) containing cellulose nanocrystals (CNXLs) from cotton are described. PANI/CNXL films were electrodeposited from a solution containing CNXLs, HCl and aniline, while PEDOT/CNXL films were electrodeposited from a solution containing CNXLs, lithium perchlorate and ethylenedioxythiophene. In each case, incorporation of CNXLs into the electrodepositing polymer film led to the formation of a po...

Cellulose-Based Nanomaterials for Energy Applications.

Science.gov (United States)

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

2017-11-01

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.

Comparative studies on dyeing rate migration and wash fastness ...

African Journals Online (AJOL)

Migration and diffusion properties of synthesized azo dyes from 2-aminothiazole derivatives applied on commercial grade undyed cellulose acetate (CA) and cellulose triacetate (CTA) were investigated using dyeing conditions of 2% on weight of fabric (owf), 50:1 liquor ratio and subjected to ISO3 and ISO4 standard wash ...

Chemical cross-linked polyvinyl alcohol/cellulose nanocrystal composite films with high structural stability by spraying Fenton reagent as initiator.

Science.gov (United States)

Song, Meili; Yu, Houyong; Gu, Jiping; Ye, Shounuan; Zhou, Yuwei

2018-07-01

Cross-linked polyvinyl alcohol (PVA) composite films with high structural stability were prepared by free radical copolymerization between cellulose nanocrystal (CNC) and maleic anhydride (MAH) modified PVA through spraying Fenton free radical as initiator. The influence of chemical cross-linked and physical network structure on mechanical, thermal and water absorption properties of the composite films were investigated. Compared to PVA and PVA/CNC composite film, significant improvements in the mechanical, thermal and water uptake properties of the cross-linked composite film were found. The tensile strength of the cross-linked composite film was enhanced from 23.1MPa (neat PVA film) and 32.6MPa (PVA/CNC-10%) to 42.5MPa, and the maximum thermal degradation temperature was increased from 266.8°C and 281.2°C to 366.7°C (cross-linked composite film). Besides, the water absorption was reduced from 385.9% and 220.6% to 175.7% for cross-linked composite film. It indicates that compared with physical network structure in PVA/CNC composite film, the multiple cross-linked networks showed excellent thermal stability, resistance of water swelling and structural stability at the same CNC loading level. Thus, the PVA/CNC composite film with the multiple cross-linked network shows greater property reinforcements. Copyright © 2018 Elsevier B.V. All rights reserved.

The Effects of Montmorillonite and Cellulose Nanocrystals on Physical Properties of Carboxymethyl Cellulose/Polyvinyl Alcohol Blend Films

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Leila Abolghasemi Fakhri

2013-01-01

Full Text Available Cellulose nanocrystal  CNC is a type of nanomaterial which is produced by  partial hydrolysis of cellulose and elimination of its amorphous regions. CNC has several advantages such as biodegradability and safety toward human health. In this study, CNC was produced from cotton linters and methods such as transmission electron microscopy and atomic force microscopy were used for confrmation of nanoscale  size production of cellulose crystals. Carboxymethyl cellulose  CMC/polyvinyl alcohol  PVA-nanoclay  MMT and CMC-PVA-CNC flms, containing 3-10% (wt/wt CMC nanofllers, were prepared by casting method and their physical properties were compared in order to approve the use of CNC instead of MMT for its contribution in improving the physical properties of carboxymethyl cellulose-based  flms.  The  X-ray  diffraction  results  indicated  the  formation  of  an exfoliated nanostructure at all nanoparticle concentrations. The results showed that there was no signifcant difference (p < 0.5 between the moisture absorption properties of flms containing the two types of nanofller. The flms containing nanoclay showed higher mechanical strength compared to those containing CNC. The ultimate tensile strengths of the flms containing 10% nanoclay and CNC were higher than the control flm (69.72% and 47.05%, respectively.

Plasticized Biodegradable Poly(lactic acid Based Composites Containing Cellulose in Micro- and Nanosize

Directory of Open Access Journals (Sweden)

Katalin Halász

2013-01-01

Full Text Available The aim of this work was to study the characteristics of thermal processed poly(lactic acid composites. Poly(ethylene glycol (PEG400, microcrystalline cellulose (MCC, and ultrasound-treated microcrystalline cellulose (USMCC were used in 1, 3, and 5 weight percents to modify the attributes of PLA matrix. The composite films were produced by twin screw extrusion followed by film extrusion. The manufactured PLA-based films were characterized by tensile testing, differential scanning calorimetry (DSC, scanning electron microscopy (SEM, wide angle X-ray diffraction (WAXD, and degradation test.

Using carboxylated cellulose nanofibers to enhance mechanical and barrier properties of collagen fiber film by electrostatic interaction.

Science.gov (United States)

Wang, Wenhang; Zhang, Xiuling; Li, Cong; Du, Guanhua; Zhang, Hongjie; Ni, Yonghao

2018-06-01

Collagen-based films including casings with a promising application in meat industry are still needed to improve its inferior performance. In the present study, the reinforcement of carboxylated cellulose nanofibers (CNF) for collagen film, based on inter-/intra- molecular electrostatic interaction between cationic acid-swollen collagen fiber and anionic carboxylated CNF, was investigated. Adding CNF decreased the zeta-potential but increased particle size of collagen fiber suspension, with little effect on pH. Furthermore, CNF addition led to a higher tensile strength but a lower elongation, and the water vapor and oxygen barrier properties were improved remarkably. Because the CNF content was 50 g kg -1 or lower, the films had a homogeneous interwoven network, and CNF homogeneously embedded into collagen fiber matrix according to the scanning electron microscopy and atomic force microscopy analysis. Additionally, CNF addition increased film thickness and opacity, as well as swelling rate. The incorporation of CNF endows collagen fiber films good mechanical and barrier properties over a proper concentration range (≤ 50 g kg -1 collagen fiber), which is closely associated with electrostatic reaction of collagen fiber and CNF and, subsequently, the form of the homogenous, compatible spatial network, indicating a potential applications of CNF in collagenous protein films, such as edible casings. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Application of Nanofibrillated Cellulose on BOPP/LDPE Film as Oxygen Barrier and Antimicrobial Coating Based on Cold Plasma Treatment

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Peng Lu

2018-05-01

Full Text Available The application of nanofibrillated cellulose (NC films in packaging industry has been hindered by its lack of heat-sealing ability. Incorporation of NC films with the biaxially oriented polypropylene/low density polyethylene (BOPP/LDPE laminates can take advantage of each material and endow the films with novel functions for food packaging applications. In this study, a coating that consists of NC and nisin was applied onto a cold plasma treated BOPP/LDPE film to fabricate a novel active packaging with an improved oxygen barrier performance and an added antimicrobial effect. The results showed that cold plasma treatment improved the surface hydrophilicity of BOPP/LDPE films for better attachment of the coatings. NC coatings significantly enhanced oxygen barrier property of the BOPP/LDPE film, with an oxygen transmission rate as low as 24.02 cc/m2·day as compared to that of the non-coated one (67.03 cc/m2·day. The addition of nisin in the coating at a concentration of 5 mg/g caused no significant change in barrier properties but imparted the film excellent antimicrobial properties, with a growth inhibition of L. monocytogenes by 94%. All films exhibit satisfying mechanical properties and transparency, and this new film has the potential to be used as antimicrobial and oxygen barrier packaging.

Layer-by-layer assembled hydrophobic coatings for cellulose nanofibril films and textiles, made of polylysine and natural wax particles.

Science.gov (United States)

Forsman, Nina; Lozhechnikova, Alina; Khakalo, Alexey; Johansson, Leena-Sisko; Vartiainen, Jari; Österberg, Monika

2017-10-01

Herein we present a simple method to render cellulosic materials highly hydrophobic while retaining their breathability and moisture buffering properties, thus allowing for their use as functional textiles. The surfaces are coated via layer-by-layer deposition of two natural components, cationic poly-l-lysine and anionic carnauba wax particles. The combination of multiscale roughness, open film structure, and low surface energy of wax colloids, resulted in long-lasting superhydrophobicity on cotton surface already after two bilayers. Atomic force microscopy, interference microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy were used to decouple structural effects from changes in surface energy. Furthermore, the effect of thermal annealing on the coating was evaluated. The potential of this simple and green approach to enhance the use of natural cellulosic materials is discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Thermal effects on the bulk luminous transmittance and track recording characteristics of dyed cellulose nitrate detectors

International Nuclear Information System (INIS)

Chakarvarti, S.K.; Lal, N.; Nagpaul, K.K.

1980-01-01

Simple heat treatment of polymers produces various typical morphological and chemical changes which consequently alter their physical and track registration properties. Bulk colour fading and alpha-track annealing effects have been studied in Kodak Pathe red-dyed cellulose nitrate film LR-115, type II and another Kodak product CA80-15, lightly rose-tinted cellulose nitrate, as a result of thermal annealing (room temperature to 155 0 C for times of 30 min to 16 h). The degree of colour fading has been measured in terms of percentage transmission of ordinary white light as sensed by a cadmium sulphide photoconductive cell, imitating the response of the human eye. It is found that at a given temperature, the transmittance rises first and acquires near-saturation after a certain annealing time. In the measurements reported here, it is seen that near-saturation transmittance is approximately proportional to the square root of the product of annealing time and temperature. The possibility of using these colour fading and transmittance measurements as an index of latent track fading is described. (orig.)

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.

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.

Cellulose nanocrystals from acacia bark-Influence of solvent extraction.

Science.gov (United States)

Taflick, Ticiane; Schwendler, Luana A; Rosa, Simone M L; Bica, Clara I D; Nachtigall, Sônia M B

2017-08-01

The isolation of cellulose nanocrystals from different lignocellulosic materials has shown increased interest in academic and technological research. These materials have excellent mechanical properties and can be used as nanofillers for polymer composites as well as transparent films for various applications. In this work, cellulose isolation was performed following an environmental friendly procedure without chlorine. Cellulose nanocrystals were isolated from the exhausted acacia bark (after the industrial process of extracting tannin) with the objective of evaluating the effect of the solvent extraction steps on the characteristics of cellulose and cellulose nanocrystals. It was also assessed the effect of acid hydrolysis time on the thermal stability, morphology and size of the nanocrystals, through TGA, TEM and light scattering analyses. It was concluded that the extraction step with solvents was important in the isolation of cellulose, but irrelevant in the isolation of cellulose nanocrystals. Light scattering experiments indicated that 30min of hydrolysis was long enough for the isolation of cellulose nanocrystals. Copyright © 2017 Elsevier B.V. All rights reserved.

POLYPYRROLE COATED CELLULOSIC SUBSTRATE MODIFIED BY COPPER OXIDE AS ELECTRODE FOR NITRATE ELECTROREDUCTION

OpenAIRE

A. HAMAM; D. OUKIL; A. DIB; H. HAMMACHE; L. MAKHLOUFI; B. SAIDANI

2015-01-01

The aim of this work is to synthesize polypyrrole (PPy) films on nonconducting cellulosic substrate and modified by copper oxide particles for use in the nitrate electroreduction process. Firstly, the chemical polymerization of polypyrrole onto cellulosic substrate is conducted by using FeCl3 as an oxidant and pyrrole as monomer. The thickness and topography of the different PPy films obtained were estimated using a profilometer apparatus. The electrochemical reactivity of the obtained electr...

Preparation and Characterization of Potentially Antimicrobial Polymer Films Containing Starch Nano- and Microparticles

Directory of Open Access Journals (Sweden)

Paulius Pavelas DANILOVAS

2014-09-01

Full Text Available The forming conditions of biodegradable polymer films containing iodine-modified starch particles as well as the properties of the obtained films were investigated. Cationic cross-linked starch microparticles and cationic starch nanoparticles were dispersed in cellulose acetate and hydroxyethyl cellulose solution, respectively, and composite films were spin-casted. The obtained films were characterized and their mechanical properties were assessed. The cellulose acetate solution has been found to be an appropriate matrix for the dispersion of dry modified starch microparticles, but not in the case of nanoparticles. Starch nanoparticles were obtained in an aqueous medium, and the mechanical properties of the formed cellulose acetate films are significantly reduced by water present in the casting solution. It has been estimated that a fairly high amount of nanoparticles (18 wt% can be immobilized into films of water-soluble hydroxyethyl cellulose without markedly affecting the mechanical properties of the films. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.5426

Holocene climate variability revealed by oxygen isotope analysis of Sphagnum cellulose from Walton Moss, northern England

Science.gov (United States)

Daley, T. J.; Barber, K. E.; Street-Perrott, F. A.; Loader, N. J.; Marshall, J. D.; Crowley, S. F.; Fisher, E. H.

2010-07-01

Stable isotope analyses of Sphagnum alpha-cellulose, precipitation and bog water from three sites across northwestern Europe (Raheenmore, Ireland, Walton Moss, northern England and Dosenmoor, northern Germany) over a total period of 26 months were used to investigate the nature of the climatic signal recorded by Sphagnum moss. The δ18O values of modern alpha-cellulose tracked precipitation more closely than bog water, with a mean isotopic fractionation factor αcellulose-precipitation of 1.0274 ± 0.001 (1 σ) (≈27‰). Sub-samples of isolated Sphagnum alpha-cellulose were subsequently analysed from core WLM22, Walton Moss, northern England yielding a Sphagnum-specific isotope record spanning the last 4300 years. The palaeo-record, calibrated using the modern data, provides evidence for large amplitude variations in the estimated oxygen isotope composition of precipitation during the mid- to late Holocene. Estimates of palaeotemperature change derived from statistical relationships between modern surface air temperatures and δ18O precipitation values for the British Isles give unrealistically large variation in comparison to proxies from other archives. We conclude that use of such relationships to calibrate mid-latitude palaeo-data must be undertaken with caution. The δ18O record from Sphagnum cellulose was highly correlated with a palaeoecologically-derived index of bog surface wetness (BSW), suggesting a common climatic driver.

Effect of combining cellulose nanocrystals and graphene nanoplatelets on the properties of poly(lactic acid based films

Directory of Open Access Journals (Sweden)

S. Montes

2018-06-01

Full Text Available In the present work, cellulose nanocrystals (CNC and graphene nanoplatelets (GR were combined in two different ratios and incorporated into polylactic acid (PLA by melt blending technique, at a total loading level of 1 wt%. The obtained PLA-CNC/GR nanocomposites were further processed by hot pressing for manufacturing films. For comparison purposes, PLA-CNC, PLA-GR and PLA-T (PLA blended with the organic surfactant Triton X-100 compositions were also prepared following the same procedure. The produced materials were characterized by several techniques, including Field-Emission Scanning Electron Microscopy (FE-SEM. The mechanical properties assessment showed an increase of 8 and 11% in the Young’s modulus and tensile strength respectively for PLA- CNC/GR (ratio 50/50 film compared to PLA-T. The thermal properties were also positively influenced by the incorporation of both nanofillers. Similarly, the gas barrier properties were improved by 23% in Oxygen Transmission Rate (OTR for films containing simultaneously CNC and GR. Finally, the antifungal properties were evaluated against Aspergillus Niger finding a superior antifungal activity in the CNC/GR hybrid films. The incorporation of CNC and GR in PLA showed a favourable impact in the overall properties of the obtained materials with only 1 wt% of nanofiller content. These results suggest that CNC/GR hybrid nanocomposites have a considerable potential in agricultural films or in food packaging trays applications.

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.

Preparation of thin {alpha}-particle sources using poly-pyrrole films functionalized by a chelating agent; Preparation de sources minces d'emetteurs alpha a l'aide de films de polypyrrole fonctionnalises par un ligand chelatant

Energy Technology Data Exchange (ETDEWEB)

Mariet, C. [CEA Saclay, INSTN, Institut National des Sciences et Techniques Nucleaires, 91 - Gif-sur-Yvette (France); Universite Pierre et Marie Curie, 75 - Paris (France)

2000-07-01

This work takes place in the scope of analysis of the {alpha}-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the {alpha}-ray characteristics require the analyst to implement a sequence of chemical steps in which the more restricting is the actinides concentration in a uniform and thin layer en allowing an accurately measure of alpha activity. On this account, we studied a new technique for radioactive sources preparation based on tow steps: preparation of a thin film as source support; incorporation of radioactive elements by a chelating extraction mechanism. The thin films were obtained through electro-polymerization of pyrrole monomer functionalized by an chelating ligand able to extract actinides from concentrated acidic solutions. Polymerization conditions of this monomer were perfected, then obtained films were characterized from a physico-chemical point of view. We point out their extracting properties were comparable to (retention capacity, distribution coefficient) to those of usual ion-exchange resins. The underscore of uranyl and americium nitrate complexes formed in the thin layer allowed to calculate the extraction constants in case acid extraction is negligible. Thanks to this results, the values of the coefficients distribution D{sub U} and D{sub Am} could be provided for all nitric solutions in which acid extraction is negligible. Optimal actinides retention conditions in the polymer were defined and used to settle a protocol for plutonium analysis in environmental samples. (author)

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reusable photocatalytic titanium dioxide-cellulose nanofiber films

Science.gov (United States)

Alexandra Snyder; Zhenyu Bo; Robert Moon; Jean-Christophe Rochet; Lia. Stanciu

2013-01-01

Titanium dioxide (TiO2) is a well-studied photocatalyst that is known to break down organic molecules upon ultraviolet (UV) irradiation. Cellulose nanofibers (CNFs) act as an attractive matrix material for the suspension of photocatalytic particles due to their desirable mechanical and optical properties. In this work, TiO2...

Cellulose Electro-Active Paper: From Discovery to Technology Applications

Science.gov (United States)

Abas, Zafar; Kim, Heung Soo; Kim, Jaehwan; Kim, Joo-Hyung

2014-09-01

Cellulose electro-active paper (EAPap) is an attractive material of electro-active polymers (EAPs) family due to its smart characteristics. EAPap is thin cellulose film coated with metal electrodes on both sides. Its large displacement output, low actuation voltage and low power consumption can be used for biomimetic sensors/actuators and electromechanical system. Because cellulose EAPap is ultra-lightweight, easy to manufacture, inexpensive, biocompatible, and biodegradable, it has been employed for many applications such as bending actuator, vibration sensor, artificial muscle, flexible speaker, and can be advantageous in areas such as micro-insect robots, micro-flying objects, microelectromechanical systems, biosensors, and flexible displays.

Study of influence of catechins on bystander responses in alpha-particle radiobiological experiments using thin PADC films

Energy Technology Data Exchange (ETDEWEB)

Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

2009-10-15

In this study, Chinese hamster ovary (CHO) cells were cultured in custom-made petri dishes with thin PADC films as substrates. Alpha particles with energies of 5 MeV were then irradiated from the bottom of PADC films. The DNA strand breaks in the bystander cells induced by irradiation were quantified with the use of terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay. To study the influence of catechins on the bystander responses, catechins were added into the medium before alpha-particle irradiation of the cells. Fewer DNA strand breaks in the bystander cells were observed. As catechins are ROS (reactive oxygen species)-scavengers, the studied bystander cells might have been protected from radiation through scavenging of ROS by catechins.

Study of influence of catechins on bystander responses in alpha-particle radiobiological experiments using thin PADC films

International Nuclear Information System (INIS)

Law, Y.L.; Yu, K.N.

2009-01-01

In this study, Chinese hamster ovary (CHO) cells were cultured in custom-made petri dishes with thin PADC films as substrates. Alpha particles with energies of 5 MeV were then irradiated from the bottom of PADC films. The DNA strand breaks in the bystander cells induced by irradiation were quantified with the use of terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay. To study the influence of catechins on the bystander responses, catechins were added into the medium before alpha-particle irradiation of the cells. Fewer DNA strand breaks in the bystander cells were observed. As catechins are ROS (reactive oxygen species)-scavengers, the studied bystander cells might have been protected from radiation through scavenging of ROS by catechins.

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

Carboxymethyl Cellulose From Kenaf Reinforced Composite Polymer Electrolytes Based 49 % Poly (Methyl Methacrylate)-Grafted Natural Rubber

International Nuclear Information System (INIS)

Serawati Jafirin; Ishak Ahmad; Azizan Ahmad; Ishak Ahmad; Azizan Ahmad

2014-01-01

Composite polymer electrolytes based 49 % poly(methyl methacrylate)-grafted natural rubber (MG49) incorporating lithium triflate (LiCF 3 SO 3 ) were prepared. The study mainly focuses on the ionic conductivity performances and mechanical properties. Prior to that, carboxymethyl cellulose was synthesized from kenaf fiber. The films were characterized by electrochemical impedance (EIS) spectroscopy, linear sweep voltammetry (LSV), universal testing machine and scanning electron microscopy (SEM). The conductivity was found to increase with carboxymethyl cellulose loading. The highest conductivity value achieved was 6.5 x 10 -6 Scm -1 upon addition of 6 wt % carboxymethyl cellulose. LSV graph shows the stability of this film was extended to 2.7 V at room temperature. The composition with 6 wt % carboxymethyl cellulose composition showed the highest tensile strength value of 7.9 MPa and 273 MPa of Young's modulus. The morphology of the electrolytes showed a smooth surface of films after addition of salt and filler indicating amorphous phase in electrolytes system. Excellent mechanical properties and good ionic conductivity are obtained, enlightening that the film is suitable for future applications as thin solid polymer electrolytes in lithium batteries. (author)

Investigation into nanocellulosics versus acacia reinforced acrylic films

Science.gov (United States)

Yunqiao Pu; Jianguo Zhang; Thomas Elder; Yulin Deng; Paul Gatenholm; Arthur J. Ragauskas

2007-01-01

Three closely related cellulosic acrylic latex films were prepared employing acacia pulp fibers, cellulose whiskers and nonocellulose balls and their respective strength properties were determined. Cellulose whisker reinforced composites had enhanced strength properties compared to the acacia pulp and nanoball composites. AFM analysis indicated that the cellulose...

Physicochemical properties of soy protein isolate/carboxymethyl cellulose blend films crosslinked by Maillard reactions: Color, transparency and heat-sealing ability

International Nuclear Information System (INIS)

Su Junfeng; Yuan Xiaoyan; Huang Zhen; Wang Xinyu; Lu Xuzhen; Zhang Lidan; Wang Shengbao

2012-01-01

Soy protein isolate (SPI) films have many potential applications in the biomaterial field as surgical dressings for burns, films for reduction of wound inflammation, and facial masks. The appearance and the sealing ability are important physicochemical properties that greatly influence consumer acceptance of such protein-based films. The aim of the present work was to investigate the chemical structure and the physical properties associated with color, transparency and heat-sealing ability for SPI/carboxymethyl cellulose (CMC) blend films prepared by solution casting, with weight proportions 90/10, 80/20, 70/30 and 60/40. Fourier transform infra-red (FTIR) and solid-state 13 C nuclear magnetic resonance (NMR) spectra confirmed that Maillard reactions occurred between SPI and CMC. The Hunter color value (L, a, b) and transparency of films were affected by varying the proportions of SPI and CMC. With increasing degree of crosslinking of SPI and CMC, the yellow color of the films was diluted and transparency was improved. Peel strength and tensile strength measurements showed that the Maillard reactions had the main effect of enhancing the heat-sealing ability above the melting temperature. These results indicated that the structure and properties of SPI-based films could be modified and improved by blending with CMC. - Highlights: ► Maillard reactions occurred in SPI/CMC films. ► The color and transparency of SPI/CMC films were affected by Maillard reactions. ► Maillard reactions enhanced the heat-sealing ability of SPI/CMC films.

Composite polymer electrolytes based on MG49 and carboxymethyl cellulose from kenaf

International Nuclear Information System (INIS)

Jafirin, Serawati; Ahmad, Ishak; Ahmad, Azizan

2013-01-01

The development of 49% poly(methyl methacrylate)-grafted natural rubber (MG49) and carboxymethyl cellulose as a composite polymer electrolyte film incorporating LiCF 3 SO 3 were explored. Carboxymethyl cellulose was synthesized from kenaf bast fibres via carboxymethylation process by alkali catalyzed reaction of cellulose with sodium chloroacetate. Reflection fourier transform infrared (ATR-FTIR) spectroscopy showed the presence of carboxyl peak after modification of cellulose with sodium chloroacetate. X-ray diffraction (XRD) analysis revealed that the crystallinity of cellulose was decrease after synthesis. High performance composite polymer electrolytes were prepared with various composition of carboxymethyl cellulose (2–10 wt%) via solution-casting method. The conductivity was increased with carboxymethyl cellulose loading. The highest conductivity value achieved was 3.3 × 10 −7 Scm −1 upon addition of 6% wt carboxymethyl cellulose. 6% wt carboxymethyl cellulose composition showed the highest tensile strength value of 7.9 MPa and 273 MPa of modulus value which demonstrated high mechanical performance with accepatable level of ionic conductivity

Composite polymer electrolytes based on MG49 and carboxymethyl cellulose from kenaf

Science.gov (United States)

Jafirin, Serawati; Ahmad, Ishak; Ahmad, Azizan

2013-11-01

The development of 49% poly(methyl methacrylate)-grafted natural rubber (MG49) and carboxymethyl cellulose as a composite polymer electrolyte film incorporating LiCF3SO3 were explored. Carboxymethyl cellulose was synthesized from kenaf bast fibres via carboxymethylation process by alkali catalyzed reaction of cellulose with sodium chloroacetate. Reflection fourier transform infrared (ATR-FTIR) spectroscopy showed the presence of carboxyl peak after modification of cellulose with sodium chloroacetate. X-ray diffraction (XRD) analysis revealed that the crystallinity of cellulose was decrease after synthesis. High performance composite polymer electrolytes were prepared with various composition of carboxymethyl cellulose (2-10 wt%) via solution-casting method. The conductivity was increased with carboxymethyl cellulose loading. The highest conductivity value achieved was 3.3 × 10-7 Scm-1 upon addition of 6% wt carboxymethyl cellulose. 6% wt carboxymethyl cellulose composition showed the highest tensile strength value of 7.9 MPa and 273 MPa of modulus value which demonstrated high mechanical performance with accepatable level of ionic conductivity.

Discovery of an 'internal heating effect' during electrochemical etching of polymeric dosimeters: a study of polymer characteristics

International Nuclear Information System (INIS)

Sohrabi, M.

1986-01-01

This paper investigates the importance of the internal heating effect by studying the role of different polymer physical and chemical characteristics (composition, effective foil size, thickness and electrical properties), on the rate of heating or temperature rise responses for cellulose tri-acetate (CTA), cellulose acetate (CA), allyl diglycol carbonate (CR-39), cellulose nitrate (CN), cellulose acetate butyrate (CAB), polyester (PES), polycarbonate (PC) and polyethylene (PE). Efforts have been made to justify the observed effects by different mechanisms such as dielectric loss, electro-osmosis, dielectrophoresis, and electrostriction. (author)

Cellulose Electro-Active Paper: From Discovery to Technology Applications

Directory of Open Access Journals (Sweden)

Zafar eAbas

2014-09-01

Full Text Available Cellulose electro-active paper (EAPap is an attractive material of electro-active polymers (EAPs family due to its smart characteristics. EAPap is thin cellulose film coated with metal electrodes on both sides. Its large displacement output, low actuation voltage and low power consumption can be used for biomimetic sensors/actuators and electromechanical system. Because cellulose EAPap is ultra-lightweight, easy to manufacture, inexpensive, biocompatible, and biodegradable, it has been employed for many applications such as bending actuator, vibration sensor, artificial muscle, flexible speaker, and can be advantageous in areas such as micro-insect robots, micro-flying objects, microelectromechanical systems, biosensors, and flexible displays.

Effect of growth conditions on the photovoltaic efficiency of poly(terthiophene) based photoelectrochemical cells

International Nuclear Information System (INIS)

Tsekouras, George; Too, Chee O.; Wallace, Gordon G.

2005-01-01

Conditions associated with the electrochemical growth of poly(terthiophene) (PTTh) were shown to have a considerable effect on photovoltaic (PV) performance indicators, namely, short-circuit-current (I sc ), open-circuit-voltage (V oc ), fill-factor (FF) and power-conversion-efficiency (PCE). The solvent and electrochemical technique used during growth were found to have an effect on PV performance. Increasing the upper potential limit associated with growth by cyclic voltammetry (CV) was found to decrease PV efficiency. The use of higher temperatures during growth was found to improve PV performance. Conditions associated with the electrochemical growth of PTTh were found to affect PV performance because of resultant changes to the polymer morphology. Such changes were characterised using scanning electron microscopy (SEM). In general, PTTh morphologies that exhibited increased porosity gave better PV performance by increasing the contact area between the PTTh and the liquid electrolyte. Combining the optimum conditions for the electrochemical growth of PTTh yielded a photoelectrochemical cell (PEC) showing I sc = 888 μA cm -2 , V oc 152 mV, FF = 37.3% and PCE = 0.101% under halogen light (solar simulated) intensity of 500 W m -2

Experimental and Theoretical Studies on Alkaline Degradation of Cellulose and its Impact on the Sorption of Radionuclides

Energy Technology Data Exchange (ETDEWEB)

Loon, L.R. van; Glaus, M A

1998-08-01

For more than ten years, cellulose degradation has been regarded as an important process which can adversely effect the sorption of radionuclides on cement in a radioactive waste repository. However, so far, it was not possible to quantify this effect. This study reports new experimental data on alkaline degradation of cellulose, together with a re-evaluation of old literature data. For the first time now, it becomes possible to quantitatively estimate the potential role of cellulose degradation in performance assessment studies. In the first part of this study, a literature overview of other studies on alkaline degradation of cellulose is given, together with a general discussion on the effect of organic ligands on the sorption of radionuclides. Further, an overview of the important mechanisms of alkaline degradation of cellulose and some kinetic aspects of the main reactions taking place is presented. The relevance of the processes for performance assessment is explained in detail. The discussion forms the starting-point for a detailed experimental program for evaluating the role of alkaline degradation of cellulose in performance assessment. In the second part, experimental studies on alkaline degradation are presented. Different cellulosic materials were degraded in an artificial cement pore water, representing the first stage of cement degradation. The most important degradation products ({alpha}- and {beta}-isosaccharinic acid) were characterised and the results compared with other studies. Kinetic parameters for the main reactions were measured and discussed. A good agreement was found between the measured values and values extrapolated from the literature. The solubility of the sparingly soluble Ca-salt of {alpha}-isosaccharinic acid (ISA) was studied as well as the interaction of ISA with cement. Sorption of ISA on cement can keep the ISA concentration in the pore water of a repository at a low level. The effect of pure ISA and degradation products on the

Effect of cellulose nanocrystals (CNC) addition and citric acid as co-plasticizer on physical properties of sago starch biocomposite

Science.gov (United States)

Nasution, Halimatuddahliana; Afandy, Yayang; Al-fath, M. Thoriq

2018-04-01

Cellulose has potential applications in new high-performance materials with low environmental impact. Rattan biomass is a fiber waste from processing industry of rattan which contains 37,6% cellulose. The high cellulose contents of rattan biomass make it a source of cellulose nanocrystals as a filler in biocomposite. Isolation of alpha cellulose from biomass rattan was prepared by using three stages: delignification, alkalization, and bleaching. It was delignificated with 3,5% HNO3 and NaNO2, precipitated with 17,5% NaOH, bleaching process with 10% H2O2. Nanocrystals obtained through the hydrolysis of alpha cellulose using 45% H2SO4 and followed by mechanical processes of ultrasonication, centrifugation, and filtration with a dialysis membrane. Sago starch biocomposites were prepared using a solution casting method, which includes 1-4 wt % cellulose nanocrystals rattan biomass as fillers, 10-40 wt% citric acid as co-plasticizer and 30 wt% glycerol as plasticizer. The results of TEM and FTIR characteristic of cellulose nanocrystals show spherical like shape FTIR and chemical composition analysis demonstrated that lignin and hemicellulose structures were successfully removed. Biocomposite characteristic consists of density and water absorption. The results showed the highest density values were 0,266 gram/cm3 obtained at an additional of 3% cellulose nanocrystals rattan biomass and 30% citric acid. The lowest water absorption was 7,893% obtained at an additional of 4% cellulose nanocrystals rattan biomass and 10% citric acid.

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.

Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films

International Nuclear Information System (INIS)

Ng, C.K.M.; Chong, E.Y.W.; Roy, V.A.L.; Cheung, K.M.C.; Yeung, K.W.K.; Yu, K.N.

2012-01-01

We proposed a simple method to fabricate micropillar substrates. Polyallyldiglycol carbonate (PADC) films were irradiated by alpha particles and then chemically etched to form a cast with micron-scale spherical pores. A polydimethylsiloxane (PDMS) replica of this PADC film gave a micropillar substrate with micron-scale spherical pillars. HeLa cells cultured on such a micropillar substrate had significantly larger percentage of cells entering S-phase, attached cell numbers and cell spreading areas. - Highlights: ► We proposed a simple method to fabricate micropillar substrates. ► Polyallyldiglycol carbonate films were irradiated and etched to form casts. ► Polydimethylsiloxane replica then formed the micropillar substrates. ► Attachment and proliferation of HeLa cells were enhanced on these substrates.

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.

Composite polymer electrolytes based on MG49 and carboxymethyl cellulose from kenaf

Energy Technology Data Exchange (ETDEWEB)

Jafirin, Serawati; Ahmad, Ishak; Ahmad, Azizan [Polymer Research Centre (PORCE), School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor Darul Ehsan (Malaysia)

2013-11-27

The development of 49% poly(methyl methacrylate)-grafted natural rubber (MG49) and carboxymethyl cellulose as a composite polymer electrolyte film incorporating LiCF{sub 3}SO{sub 3} were explored. Carboxymethyl cellulose was synthesized from kenaf bast fibres via carboxymethylation process by alkali catalyzed reaction of cellulose with sodium chloroacetate. Reflection fourier transform infrared (ATR-FTIR) spectroscopy showed the presence of carboxyl peak after modification of cellulose with sodium chloroacetate. X-ray diffraction (XRD) analysis revealed that the crystallinity of cellulose was decrease after synthesis. High performance composite polymer electrolytes were prepared with various composition of carboxymethyl cellulose (2–10 wt%) via solution-casting method. The conductivity was increased with carboxymethyl cellulose loading. The highest conductivity value achieved was 3.3 × 10{sup −7} Scm{sup −1} upon addition of 6% wt carboxymethyl cellulose. 6% wt carboxymethyl cellulose composition showed the highest tensile strength value of 7.9 MPa and 273 MPa of modulus value which demonstrated high mechanical performance with accepatable level of ionic conductivity.

Radiation-induced grafting from binary mixture of monomers onto cellulose acetate film and the characterization of the graft copolymer

International Nuclear Information System (INIS)

Bhattacharyya, S.N.; Maldas, D.

1984-01-01

Binary mixtures of styrene and acrylamide in methanol-water were grafted onto cellulose acetate films by taking recourse to preirradiation grafting technique. The extent of total grafting was determined from the measured weight increase. The percent acrylamide residue in the graft copolymer was calculated from the observed nitrogen content but the polystyrene residue in the grafted sample was determined by IR spectral studies. When the specific permeability of water vapour through the grafted films is measured, it is observed that the specific permeability increases with the increase of grafting of acrylamide in all humidities, but in case of styrene which is a nonpolar molecule the permeability is found to show a reversed order. In the case of mixed graft the permeability pattern pertains to that when both styrene and acrylamide have their effective roles to play. (author)

Some Limitations in the Use of Plastic and Dyed Plastic Dosimeters

DEFF Research Database (Denmark)

Miller, Arne; Bjergbakke, Erling; McLaughlin, W. L.

1975-01-01

Several practical plastic and dyed plastic dosimeters were examined under irradiation conditions similar to those used for radiation processing of materials. Cellulose triacetate, polymethyl methacrylate, polyvinyl chloride, dyed polymethyl methacrylate, dyed Cellophane and dyed Nylon were given...

Design, optimization and characterization of coenzyme Q10- and D-panthenyl triacetate-loaded liposomes

Directory of Open Access Journals (Sweden)

Çelik B

2017-07-01

Full Text Available Burak Çelik,1 Ali Asram Sağıroğlu,1 Samet Özdemir2 1Department of Pharmaceutical Technology, Faculty of Pharmacy, Bezmialem Vakif University, 2Department of Pharmaceutical Technology, Faculty of Pharmacy, Yeditepe University, Istanbul, Turkey Abstract: Coenzyme Q10 (CoQ10 is a lipid-soluble molecule found naturally in many eukaryotic cells and is essential for electron transport chain and energy generation in mitochondria. D-Panthenyl triacetate (PTA is an oil-soluble derivative of D-panthenol, which is essential for coenzyme A synthesis in the epithelium. Liposomal formulations that encapsulate both ingredients were prepared and optimized by applying response surface methodology for increased stability and skin penetration. The optimum formulation comprised 4.17 mg CoQ10, 4.22 mg PTA and 13.95 mg cholesterol per 100 mg of soy phosphatidylcholine. The encapsulation efficiency of the optimized formulation for CoQ10 and PTA was found to be 90.89%±3.61% and 87.84%±4.61%, respectively. Narrow size distribution was achieved with an average size of 161.6±3.6 nm, while a spherical and uniform shape was confirmed via scanning electron microscopy and transmission electron microscopy images. Cumulative release of 90.93% for PTA and 24.41% for CoQ10 was achieved after 24 hours of in vitro release study in sink conditions. Physical stability tests indicated that the optimized liposomes were suitable for storage at 4°C for at least 60 days. The results suggest that the optimized liposomal formulation would be a promising delivery system for both ingredients in various topical applications. Keywords: coenzyme Q10, D-panthenyl triacetate, liposomes, response surface methodology, stability

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.

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.

Evaluating the effect of different draw solutes in a baffled osmotic membrane bioreactor-microfiltration using optical coherence tomography with real wastewate

KAUST Repository

Pathak, Nirenkumar; Fortunato, Luca; Li, Sheng; Chekli, Laura; Phuntsho, Sherub; Ghaffour, NorEddine; Leiknes, TorOve; Shon, Ho Kyong

2018-01-01

(OCT) technique was employed. On-line monitoring of biofilm growth on a flat sheet cellulose triacetate forward osmosis (CTA-FO) membrane was conducted for 21 days. Further, the process performance was evaluated in terms of water flux, organic

Thermally Stable Cellulose Nanocrystals toward High-Performance 2D and 3D Nanostructures.

Science.gov (United States)

Jia, Chao; Bian, Huiyang; Gao, Tingting; Jiang, Feng; Kierzewski, Iain Michael; Wang, Yilin; Yao, Yonggang; Chen, Liheng; Shao, Ziqiang; Zhu, J Y; Hu, Liangbing

2017-08-30

Cellulose nanomaterials have attracted much attention in a broad range of fields such as flexible electronics, tissue engineering, and 3D printing for their excellent mechanical strength and intriguing optical properties. Economic, sustainable, and eco-friendly production of cellulose nanomaterials with high thermal stability, however, remains a tremendous challenge. Here versatile cellulose nanocrystals (DM-OA-CNCs) are prepared through fully recyclable oxalic acid (OA) hydrolysis along with disk-milling (DM) pretreatment of bleached kraft eucalyptus pulp. Compared with the commonly used cellulose nanocrystals from sulfuric acid hydrolysis, DM-OA-CNCs show several advantages including large aspect ratio, carboxylated surface, and excellent thermal stability along with high yield. We also successfully demonstrate the fabrication of high-performance films and 3D-printed patterns using DM-OA-CNCs. The high-performance films with high transparency, ultralow haze, and excellent thermal stability have the great potential for applications in flexible electronic devices. The 3D-printed patterns with porous structures can be potentially applied in the field of tissue engineering as scaffolds.

Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films

Energy Technology Data Exchange (ETDEWEB)

Ng, C.K.M. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chong, E.Y.W. [Department of Orthopaedics and Traumatology, University of Hong Kong (Hong Kong); Roy, V.A.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Cheung, K.M.C.; Yeung, K.W.K. [Department of Orthopaedics and Traumatology, University of Hong Kong (Hong Kong); Yu, K.N., E-mail: appetery@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

2012-07-15

We proposed a simple method to fabricate micropillar substrates. Polyallyldiglycol carbonate (PADC) films were irradiated by alpha particles and then chemically etched to form a cast with micron-scale spherical pores. A polydimethylsiloxane (PDMS) replica of this PADC film gave a micropillar substrate with micron-scale spherical pillars. HeLa cells cultured on such a micropillar substrate had significantly larger percentage of cells entering S-phase, attached cell numbers and cell spreading areas. - Highlights: Black-Right-Pointing-Pointer We proposed a simple method to fabricate micropillar substrates. Black-Right-Pointing-Pointer Polyallyldiglycol carbonate films were irradiated and etched to form casts. Black-Right-Pointing-Pointer Polydimethylsiloxane replica then formed the micropillar substrates. Black-Right-Pointing-Pointer Attachment and proliferation of HeLa cells were enhanced on these substrates.

2, 3-Dihydrazone cellulose: Prospective material for tissue engineering scaffolds

International Nuclear Information System (INIS)

Verma, Vipin; Verma, Poonam; Ray, Pratima; Ray, Alok R.

2008-01-01

Cellulose was oxidized by sodium metaperiodate to give rise to 2, 3-dialdehyde cellulose with 92% oxidation ratio, which was further reacted with hydrazine to form 2, 3-dihydrazone cellulose for the incorporation of NH 2 groups. Two forms of matrix, i.e. films and sponges were fabricated. The materials were characterized by FTIR spectroscopy. Scanning electron microscopy revealed its porous architecture with an average pore size of 150 μm. Swelling studies were carried out in phosphate buffer saline (PBS) at physiological pH 7.4. The contact angle of the 2, 3-dihydrazone cellulose surface was determined for assessing its hydrophilicity which came out to be 23 deg. ± 2 deg. NIH3T3 mice fibroblast cells were used for determining the cytocompatibility of the surfaces. The morphology of the cells was observed through optical inverted microscopy. The results show that 2, 3-dihydrazone cellulose can be used as scaffold material in tissue engineering

Characterization of ethyl cellulose polymer.

Science.gov (United States)

Mahnaj, Tazin; Ahmed, Salah U; Plakogiannis, Fotios M

2013-01-01

Ethyl cellulose (EC) polymer was characterized for its property before considering the interactions with the plasicizer. Ethocel Std.10 FP Premium from Dow chemical company USA was tested for its solubility, morphology and thermal properties. Seven percentage of EC solution in ethanol was found to be the right viscosity used to prepare the film. The EC polymer and EC film without any plasticizers showed almost identical thermal behavior, but in X-ray diffraction showed different arrangements of crystallites and amorphous region. Dynamic mechanical analysis of film showed that without a plasticizer, EC film was not flexible and had very low elongation with high applied force. The aim of the work was to avoid using the commercially available EC dispersions Surelease® and Aquacoat®; both already have additives on it. Instead, Ethocel EC polymer (powder) was characterized in our laboratory in order to find out the properties of polymer before considering the interactions of the polymer with various plasticizers.

Cellulose Degradation at Alkaline Conditions: Long-Term Experiments at Elevated Temperatures

Energy Technology Data Exchange (ETDEWEB)

Glaus, M.A.; Van Loon, L.R

2004-04-01

hydrolysis at the temperatures tested here. It may be hypothesised that the alkaline hydrolysis has even not been observed in the experiments. However, if this is true, cellulose degradation proceeded via another unknown type of reaction. Mass balances for carbon show that the large majority of reaction products found in solution can be explained by formation of isosaccharinic acids and other low-molecular weight carboxylic acids. With respect to long-term predictions for cellulose degradation at room temperature it can be concluded that the kinetic parameters for alkaline hydrolysis as proposed in the work of PAVASARS (Linkoping Studies in Arts and Science, 196, Linkoping University, Sweden, 1999) are too large and that complete cellulose degradation at these temperatures occurs only within time scales larger than hundreds of years. However, it is not possible from the experimental evidences, to corroborate the validity of a linear extrapolation (Arrhenius equation) of the reaction rates measured at temperatures between 140 and 190{sup o}C to room temperature, from which it was previously concluded that complete cellulose degradation would take time spans of the order of millions of years. An interesting observation in the present experiments is the chemical instability of aisosaccharinic acid at 90{sup o}C, which has been hypothetically interpreted as a fragmentation induced by the sorption of {alpha}-isosaccharinic acid on Ca(OH){sub 2}. Carbon mass balances show that {alpha}-isosaccharinic acid is thereby transformed to other lowmolecular weight carboxylic acids. Such a reaction would be an interesting long-term perspective for performance assessment of the disposal of cellulose-containing radioactive waste, in that it may reduce the concentration of organic compounds strongly complexing radionuclides. (author)

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.

{alpha} Fe{sub 2}O{sub 3} films grown by the spin-on sol-gel deposition method

Energy Technology Data Exchange (ETDEWEB)

Avila G, A.; Carbajal F, G. [Seccion de Electronica del Estado Solido, Departamento de Ingenieria Electrica, CINVESTAV del l.P.N., Av. I.P.N. No. 2508, Apartado Postal 14-740, Mexico 07360, D.F (Mexico); Tiburcio S, A. [Division Posg, lnstituto Tecnologico de Toluca-SEP, P.O. Box 890, 50000 Toluca, Edo. Mex. (Mexico); Barrera C, E. [Departamento de IPH, Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-lztapalapa, Apartado Postal 55-5340, Mexico, D.F. (Mexico); Andrade I, E. [Instituto de Fsica, Universidad Nacional Autononca de Mexico, Apartado Postal 20-364, Mexico 01000, D. F (Mexico)

2003-07-01

{alpha}-Fe{sub 2}O{sub 3} polycrystalline films with grains larger than 31 nm were grown by the spin-on sol-gel deposition method. The particular sol used was prepared starting from two distinct precursor reagents. Both precursors leaded to similar films. Order within the films was altered by adding tin to the samples. Transmittance measurements confirmed that the hematite phase is obtained by annealing the samples above 400 C and yielded an optical gap of about 2.2 eV, but additional transitions at 2.7 eV were also observed. From RBS measurements it was found that tin inclusion decreases iron content as expected, but also increases oxygen concentration within the films. This last observation was associated to the disorder rise when introducing tin atoms. (Author)

Microwave flexible transistors on cellulose nanofibrillated fiber substrates

Science.gov (United States)

Jung-Hun Seo; Tzu-Hsuan Chang; Jaeseong Lee; Ronald Sabo; Weidong Zhou; Zhiyong Cai; Shaoqin Gong; Zhenqiang Ma

2015-01-01

In this paper, we demonstrate microwave flexible thin-film transistors (TFTs) on biodegradable substrates towards potential green portable devices. The combination of cellulose nanofibrillated fiber (CNF) substrate, which is a biobased and biodegradable platform, with transferrable single crystalline Si nanomembrane (Si NM), enables the realization of truly...

Thermal neutron detection by means of an organic solid-state track detector

International Nuclear Information System (INIS)

Doerschel, B.; Streubel, G.

1979-01-01

Thermal neutrons can be detected by means of organic solid-state track detectors if they are combined with radiators in which charged secondary particles are produced in neutron interaction processes. The secondary particles can produce etchable tracks in the detector material. For thermal neutron fluence determination from the track densities, the thermal neutron sensitivity was calculated for cellulose triacetate detectors with LiF radiators, taking into account energy and angular distribution of the alpha particles produced in the LiF radiator. This value is in good agreement with the sensitivity measured during irradiation in different neutron fields if corrections are considered the production of etchable or visuable tracks. Measuring range and measuring accuracy meet the requirements of thermal neutron detection in personnel dosimetry. Possibilities of extending the measuring range are discussed. (author)

Synthesis and characterization of composite based on cellulose acetate and hydroxyapatite application to the absorption of harmful substances.

Science.gov (United States)

Azzaoui, Khalil; Lamhamdi, Abdelatif; Mejdoubi, El Miloud; Berrabah, Mohammed; Hammouti, Belkheir; Elidrissi, Abderrahman; Fouda, Moustafa M G; Al-Deyab, Salem S

2014-10-13

The aim of this work is to develop composite materials with hydroxyapatite (HAp) mineral and organic matrix such as cellulosic polymers. We use cellulose acetate with different percentages, and then inorganic-organic films were fabricated by evaporation of solvent. The composite films were characterized using emission scanning electron microscopy (FEG-SEM), thermo-gravimetric analysis (TGA) and Fourier transform infra-red (FT-IR) spectra. Test results show that these films are uniform and have good ductility. A strong interaction existed between HAp and cellulosic polymers, and the method allows the production of very fine particles size of about 92 nm. We have developed a new chromatographic method for the quantification of bisphenol A (BPA) in samples of baby food. The result of this study demonstrates how to use this type of composite materials to remove pollutants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermally Induced Alpha-Helix to Beta-Sheet Transition in Regenerated Silk Fibers and Films

Energy Technology Data Exchange (ETDEWEB)

Drummy,L.; Phillips, D.; Stone, M.; Farmer, B.; Naik, R.

2005-01-01

The structure of thin films cast from regenerated solutions of Bombyx mori cocoon silk in hexafluoroisopropyl alcohol (HFIP) was studied by synchrotron X-ray diffraction during heating. A solid-state conformational transition from an alpha-helical structure to the well-known beta-sheet silk II structure occurred at a temperature of approximately 140 degrees C. The transition appeared to be homogeneous, as both phases do not coexist within the resolution of the current study. Modulated differential scanning calorimetry (DSC) of the films showed an endothermic melting peak followed by an exothermic crystallization peak, both occurring near 140 degrees C. Oriented fibers were also produced that displayed this helical molecular conformation. Subsequent heating above the structural transition temperature produced oriented beta-sheet fibers very similar in structure to B. mori cocoon fibers. Heat treatment of silk films at temperatures well below their degradation temperature offers a controllable route to materials with well-defined structures and mechanical behavior.

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.

Increases thermal stability and cellulose-binding capacity of Cryptococcus sp. S-2 lipase by fusion of cellulose binding domain derived from Trichoderma reesei

Energy Technology Data Exchange (ETDEWEB)

Thongekkaew, Jantaporn, E-mail: jantaporn_25@yahoo.com [Department of Biological Science, Faculty of Science, Ubon-Ratchathani University, Warinchumrab, Ubon-Ratchathani 34190 (Thailand); Ikeda, Hiroko; Iefuji, Haruyuki [Application Research Division, National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashi-Hiroshima 739-0046 (Japan)

2012-03-30

Highlights: Black-Right-Pointing-Pointer The CSLP and fusion enzyme were successfully expressed in the Pichia pastoris. Black-Right-Pointing-Pointer The fusion enzyme was stable at 80 Degree-Sign C for 120-min. Black-Right-Pointing-Pointer The fusion enzyme was responsible for cellulose-binding capacity. Black-Right-Pointing-Pointer The fusion enzyme has an attractive applicant for enzyme immobilization. -- Abstract: To improve the thermal stability and cellulose-binding capacity of Cryptococcus sp. S-2 lipase (CSLP), the cellulose-binding domain originates from Trichoderma reesei cellobiohydrolase I was engineered into C-terminal region of the CSLP (CSLP-CBD). The CSLP and CSLP-CBD were successfully expressed in the Pichia pastoris using the strong methanol inducible alcohol oxidase 1 (AOX1) promoter and the secretion signal sequence from Saccharomyces cerevisiae ({alpha} factor). The recombinant CSLP and CSLP-CBD were secreted into culture medium and estimated by SDS-PAGE to be 22 and 27 kDa, respectively. The fusion enzyme was stable at 80 Degree-Sign C and retained more than 80% of its activity after 120-min incubation at this temperature. Our results also found that the fusion of fungal exoglucanase cellulose-binding domain to CSLP is responsible for cellulose-binding capacity. This attribute should make it an attractive applicant for enzyme immobilization.

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.

Polypyrrole Coated Cellulosic Substrate Modified by Copper Oxide as Electrode for Nitrate Electroreduction

Science.gov (United States)

Hamam, A.; Oukil, D.; Dib, A.; Hammache, H.; Makhloufi, L.; Saidani, B.

2015-08-01

The aim of this work is to synthesize polypyrrole (PPy) films on nonconducting cellulosic substrate and modified by copper oxide particles for use in the nitrate electroreduction process. Firstly, the chemical polymerization of polypyrrole onto cellulosic substrate is conducted by using FeCl3 as an oxidant and pyrrole as monomer. The thickness and topography of the different PPy films obtained were estimated using a profilometer apparatus. The electrochemical reactivity of the obtained electrodes was tested by voltamperometry technique and electrochemical impedance spectroscopy. Secondly, the modification of the PPy film surface by incorporation of copper oxide particles is conducted by applying a galvanostatic procedure from a CuCl2 solution. The SEM, EDX and XRD analysis showed the presence of CuO particles in the polymer films with dimensions less than 50 nm. From cyclic voltamperometry experiments, the composite activity for the nitrate electroreduction reaction was evaluated and the peak of nitrate reduction is found to vary linearly with initial nitrate concentration.

Alpha particles detection in nitrocellulose

International Nuclear Information System (INIS)

Romero C, M.

1976-01-01

The method for the manufacturing of the detection films follows these steps: preparation of the mass which includes nitrocellulose in the form of cotton as raw material ethyl acetate, cellosolve acetate, isopropyl and butyl alcohols as solvents and dioctyl phtalate as plasticiser; dilution of the paste; pouring of the diluted mass; and drying of the detection films. The results obtained experimentally are: The determination of the development times of the different thicknesses of the manufactured films. Response linearity of the detectors, variation of the number of tracks according to the distance of the source to the detector. Sizes of the diameter of the tracks depending of the distance detector-alpha emmission source. As a conclusion we can say the the nitrocellulose detectors are specific for alpha radiation; the more effective thicknesses in uranium prospecting works were those of 60 microns, since for the laboratory works the thicknesses of 30 to 40 microns were the ideal; the development technique of the detection films is simple and cheap and can be realized even in another place than the laboratory; this way of the manufacturing of nitrocellulose detection film sensitive to alpha nuclear radiation is open to future research. (author)

Construction of proton exchange membranes under ultrasonic irradiation based on novel fluorine functionalizing sulfonated polybenzimidazole/cellulose/silica bionanocomposite.

Science.gov (United States)

Esmaielzadeh, Sheida; Ahmadizadegan, Hashem

2018-03-01

Novel sulfonated polybenzimidazole (s-PBI)/cellulose/silica bionanocomposite membranes were prepared from fluorine-containing s-PBI copolymer with a cellulose/silica precursor and a bonding agent. The introduction of the bonding agent results in the reinforcing interfacial interaction between s-PBI chains and the cellulose/silica nanoparticles. Commercially available silica nanoparticles were modified with biodegradable nanocellolose through ultrasonic irradiation technique. Transmission electron microscopy (TEM) analyses showed that the cellulose/silica composites were well dispersed in the s-PBI matrix on a nanometer scale. The mechanical properties and the methanol barrier ability of the s-PBI films were improved by the addition of cellulose/silica. The modulus of the s-PBI/10 wt% cellulose/silica nanocomposite membranes had a 45% increase compared to the pure s-PBI films, and the methanol permeability decreased by 62% with respect to the pure s-PBI membranes. The conductivities of the s-PBI/cellulose/silica nanocomposites were slightly lower than the pure s-PBI. The antibacterial activity of (s-PBI)/cellulose/silica was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria, ie, Escherichia coli, E. coli O157:H7 and Pseudomonas aeruginosa by the disc diffusion method using Mueller Hinton agar at different sizes of cellulose/silica. All of the synthesized (s-PBI)/cellulose/silica were found to have high antibacterial activity. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Effects of alpha particles on zebrafish embryos

International Nuclear Information System (INIS)

Yum, E.H.W.; Choi, V.W.Y.; Yu, K.N.; Li, V.W.T.; Cheng, S.H.

2008-01-01

Full text: Ionizing radiation such as X-ray and alpha particles can damage cellular macromolecules, which can lead to DNA single- and double-strand breaks. In the present work, we studied the effects of alpha particles on dechorionated zebrafish embryos. Thin polyallyldiglycol carbonate (PADC) films with a thickness of 16 μm were prepared from commercially available PADC films (with thickness of 100 μm) by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 1.25 hours post fertilization (hpf) with various absorbed dose. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was performed on the embryos at different time stages after irradiation. Marked apoptosis was detected only in embryos at earlier time stages. The results showed that DNA double-strand break during zebrafish embryogenesis can be induced by alpha-particle irradiation, which suggests that zebrafish is a potential model for assessing the effects of alpha-particle radiation

Intensive beam dosimetry of accelerated electrons of low energy

International Nuclear Information System (INIS)

Oproiu, C.

1984-01-01

Dosimetric control of electron beams ranging between 0.3 MeV and 10 MeV is treated using proper dosimetric methods relying on calorimetry, Tricke chemical solution, dosimetric film of cellulose triacetate. Proper methods are pointed out for measurements in inhomogeneous fields, bringing into evidence the results obtained in deep dose distributions and on the surface of irradiated material. A measuring method of dose distribution in depth by means of an assembly with calorimetric elements, as well as a practical method to pointing out dose distribution and equidose curves along the depth of irradiated electric cable depth are presented. In order to find out the main sizes of accelerated electron beam one uses proper devices relying on Faraday cylinder, total absorption calorimeter, ionization chambers. (author)

Control of polythiophene film microstructure and charge carrier dynamics through crystallization temperature

KAUST Repository

Marsh, Hilary S.; Reid, Obadiah G.; Barnes, George; Heeney, Martin; Stingelin, Natalie; Rumbles, Garry

2014-01-01

The microstructure of neat conjugated polymers is crucial in determining the ultimate morphology and photovoltaic performance of polymer/fullerene blends, yet until recently, little work has focused on controlling the former. Here, we demonstrate that both the long-range order along the (100)-direction and the lamellar crystal thickness along the (001)-direction in neat poly(3-hexylthiophene) (P3HT) and poly[(3,3″-didecyl[2,2′:5′, 2″-terthiophene]-5,5″-diyl)] (PTTT-10) thin films can be manipulated by varying crystallization temperature. Changes in crystalline domain size impact the yield and dynamics of photogenerated charge carriers. Time-resolved microwave conductivity measurements show that neat polymer films composed of larger crystalline domains have longer photoconductance lifetimes and charge carrier yield decreases with increasing crystallite size for P3HT. Our results suggest that the classical polymer science description of temperature-dependent crystallization of polymers from solution can be used to understand thin-film formation in neat conjugated polymers, and hence, should be considered when discussing the structural evolution of organic bulk heterojunctions. © 2014 Wiley Periodicals, Inc.

Control of polythiophene film microstructure and charge carrier dynamics through crystallization temperature

KAUST Repository

Marsh, Hilary S.

2014-03-22

The microstructure of neat conjugated polymers is crucial in determining the ultimate morphology and photovoltaic performance of polymer/fullerene blends, yet until recently, little work has focused on controlling the former. Here, we demonstrate that both the long-range order along the (100)-direction and the lamellar crystal thickness along the (001)-direction in neat poly(3-hexylthiophene) (P3HT) and poly[(3,3″-didecyl[2,2′:5′, 2″-terthiophene]-5,5″-diyl)] (PTTT-10) thin films can be manipulated by varying crystallization temperature. Changes in crystalline domain size impact the yield and dynamics of photogenerated charge carriers. Time-resolved microwave conductivity measurements show that neat polymer films composed of larger crystalline domains have longer photoconductance lifetimes and charge carrier yield decreases with increasing crystallite size for P3HT. Our results suggest that the classical polymer science description of temperature-dependent crystallization of polymers from solution can be used to understand thin-film formation in neat conjugated polymers, and hence, should be considered when discussing the structural evolution of organic bulk heterojunctions. © 2014 Wiley Periodicals, Inc.

Synthesis and Characterization of Methyl Cellulose/Keratin Hydrolysate Composite Membranes

Directory of Open Access Journals (Sweden)

Bernd M. Liebeck

2017-03-01

Full Text Available It is known that aqueous keratin hydrolysate solutions can be produced from feathers using superheated water as solvent. This method is optimized in this study by varying the time and temperature of the heat treatment in order to obtain a high solute content in the solution. With the dissolved polypeptides, films are produced using methyl cellulose as supporting material. Thereby, novel composite membranes are produced from bio-waste. It is expected that these materials exhibit both protein and polysaccharide properties. The influence of the embedded keratin hydrolysates on the methyl cellulose structure is investigated using Fourier transform infrared spectroscopy (FTIR and wide angle X-ray diffraction (WAXD. Adsorption peaks of both components are present in the spectra of the membranes, while the X-ray analysis shows that the polypeptides are incorporated into the semi-crystalline methyl cellulose structure. This behavior significantly influences the mechanical properties of the composite films as is shown by tensile tests. Since further processing steps, e.g., crosslinking, may involve a heat treatment, thermogravimetric analysis (TGA is applied to obtain information on the thermal stability of the composite materials.

Natural cellulose ionogels for soft artificial muscles.

Science.gov (United States)

Nevstrueva, Daria; Murashko, Kirill; Vunder, Veiko; Aabloo, Alvo; Pihlajamäki, Arto; Mänttäri, Mika; Pyrhönen, Juha; Koiranen, Tuomas; Torop, Janno

2018-01-01

Rapid development of soft micromanipulation techniques for human friendly electronics has raised the demand for the devices to be able to carry out mechanical work on a micro- and macroscale. The natural cellulose-based ionogels (CEL-iGEL) hold a great potential for soft artificial muscle application, due to its flexibility, low driving voltage and biocompatibility. The CEL-iGEL composites undergo reversible bending already at ±500mV step-voltage values. A fast response to the voltage applied and high ionic conductivity of membranous actuator is achieved by a complete dissolution of cellulose in 1-ethyl-3-methylimidazolium acetate [EMIm][OAc]. The CEL-iGEL supported cellulose actuator films were cast out of cellulose-[EMIm][OAc] solution via phase inversion in H 2 O. The facile preparation method ensured uniform morphology along the layers and stand for the high ionic-liquid loading in a porous cellulose scaffold. During the electromechanical characterization, the CEL-iGEL actuators showed exponential dependence to the voltage applied with the max strain difference values reaching up to 0.6% at 2 V. Electrochemical analysis confirmed the good stability of CEL-iGEL actuators and determined the safe working voltage value to be below 2.5V. To predict and estimate the deformation for various step input voltages, a mathematical model was proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

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

KAUST Repository

Achoundong, Carine S. K.; Bhuwania, Nitesh; Burgess, Steven K.; Karvan, Oguz; Johnson, Justin R.; Koros, William J.

2013-01-01

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.

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.

Development of diamond thin film-based alpha particle detectors for online assay of plutonium content in corrosive liquid medium

International Nuclear Information System (INIS)

Nuwad, J.; Jain, Dheeraj; Manoj, N.; Sudarsan, V.; Panja, S.; Dhami, P.S.

2014-01-01

In the present work, diamond thin films were prepared using microwave plasma chemical vapor deposition (MPCVD) method and characterized using XRD, OES, SEM, Raman spectroscopy and I-V techniques. These films were subjected to annealing and chemical cleaning for further improving the film quality. Surface metallization was obtained by gold deposition using PVD. These films were configured in semiconductor-insulator-metal heterostructure and mounted in SS shells. Gold coated growth surface (detector's active area) was sealed by chemical resistant sealing. Suitable bias was applied between the front and back electrical contacts to enable charge collection generated upon alpha particle interaction with diamond. The photograph of developed detector in the lab is shown

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.

Effects of modified cellulose nanocrystals on the barrier and migration properties of PLA nano-biocomposites.

Science.gov (United States)

Fortunati, E; Peltzer, M; Armentano, I; Torre, L; Jiménez, A; Kenny, J M

2012-10-01

The aim of this paper is to report the impact of the addition of cellulose nanocrystals on the barrier properties and on the migration behaviour of poly(lactic acid), PLA, based nano-biocomposites prepared by the solvent casting method. Their microstructure, crystallinity, barrier and overall migration properties were investigated. Pristine (CNC) and surfactant-modified cellulose nanocrystals (s-CNC) were used, and the effect of the cellulose modification and content in the nano-biocomposites was investigated. The presence of surfactant on the nanocrystal surface favours the dispersion of CNC in the PLA matrix. Electron microscopy analysis shows the good dispersion of s-CNC in the nanoscale with well-defined single crystals indicating that the surfactant allowed a better interaction between the cellulose structures and the PLA matrix. Reductions of 34% in water permeability were obtained for the cast films containing 1 wt.% of s-CNC while good oxygen barrier properties were detected for nano-biocomposites with both 1 wt.% and 5 wt.% of modified and un-modified cellulose nanocrystals, underlining the improvement provided by cellulose on the PLA films. Moreover, the migration level of the studied nano-biocomposites was below the overall migration limits required by the current normative for food packaging materials in both non-polar and polar simulants. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhancement of Egyptian soft white cheese shelf life using a novel chitosan/carboxymethyl cellulose/zinc oxide bionanocomposite film.

Science.gov (United States)

Youssef, Ahmed M; El-Sayed, Samah M; El-Sayed, Hoda S; Salama, Heba H; Dufresne, Alain

2016-10-20

A novel bionanocomposites packaging material prepared using chitosan (CH), carboxymethyl cellulose (CMC), and zinc oxide nanoparticles (ZnO-NPs), namely CH/CMC/ZnO bionanocomposites, was prepared by casting method. The CH/CMC/ZnO bionanocomposites were investigated using FT-IR, TEM, SEM, XRD, and TGA. The acquired bionanocomposites exhibited improved mechanical and thermal properties compare with the biocomposites (CH/CMC) blend. The soft white cheese were manufactured, packaged within the prepared bionanocomposites films and stored at 7°C for 30days. The influence of packaging material on packaged cheese (rheological properties, colour measurements, moisture, pH and titratable acidity) were assessed. Furthermore, the effect of packaging material on the total bacterial counts, mold & yeast and coliform in cheese was evaluated. The prepared bionanocomposites displayed good antibacterial activity against gram positive (Staphylococcus aureus), gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria and fungi (Candidia albicans). Moreover, the packaging films assisted in increasing the shelf life of white soft cheese. Therefore, it can be used in food packaging applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

DFT Study of Electronic and Optical Properties of Small Oligothiophenes Based on Terthiophene End-capped by Several Donor Groups

Directory of Open Access Journals (Sweden)

El Alamy Aziz

2017-07-01

Full Text Available Eight small molecules based on terthiophene end-capped by several donor groups have been carried out using density functional theory (DFT and time-dependent (TDDFT methods in neutral and doped states. The theoretical ground-state geometry, electronic structure and optical properties of the studied molecules were obtained by the DFT and TD-DFT methods at the B3LYP level with 6-31G(d basis set. Theoretical knowledge of the highest occupied molecular orbital (HOMO, the lowest unoccupied molecular orbital (LUMO energy levels the gap energy (Eg and the open-circuit voltage (Voc of the studied compounds are calculated and discussed. The effects of the donor group substituents on the geometries and optoelectronic properties of these materials are discussed to investigate the relationship between molecular structure and optoelectronic properties. The results of this work suggest some of these materials as a good candidate for organic solar cells. DOI: http://dx.doi.org/10.17807/orbital.v9i3.995

Polymer Inclusion Membrane Containing a Tripodal Diglycolamide Ligand: Actinide Ion Uptake and Transport Studies

NARCIS (Netherlands)

Mahanty, B.; Mohapatra, P.K.; Raut, D.R.; Das, D.K.; Behere, P.G.; Afzal, M.; Verboom, Willem

2016-01-01

A cellulose triacetate (CTA)-based polymer inclusion membrane (PIM) containing a C-pivot tripodal diglycolamide (T-DGA) as the carrier extractant and 2-nitrophenyl octyl ether (NPOE) as the plasticizer shows potential for the uptake of actinides from acidic feed solutions. The uptake of actinides

Curaua and eucalyptus nanofibers films by continuous casting: Mechanical and thermal properties.

Science.gov (United States)

Claro, Pedro Ivo Cunha; Corrêa, Ana Carolina; de Campos, Adriana; Rodrigues, Vanessa Bolzan; Luchesi, Bruno Ribeiro; Silva, Luiz Eduardo; Mattoso, Luiz Henrique Capparelli; Marconcini, José Manoel

2018-02-01

A wide variety of new green materials such as curaua leaf fibers (CLFs) has potential applications in nanotechnology. This study aims to investigate the thermomechanical properties and morphological structure of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) films obtained by continuous casting. The CNCs were obtained by acid hydrolysis and CNFs by mechanical shearing from bleached CLFs and eucalyptus pulp. The morphology after continuous casting resulted in oriented nanofibers, and as a consequence there was mechanical anisotropy. CNCs films showed the greatest values of tensile strength (36±4MPa) and the more effective fibrillation provided better mechanical strength of eucalyptus CNFs films than curaua CNFs films. Sulfur groups and mechanical shear degradation affected the stability of CNCs and CNFs films, respectively. Thus, the type of nanostructure, the way they interact to each other, the cellulose source and the process interfere significantly on the properties of the films. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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...... the drug-polymer solutions onto filter paper substrates. The quality of the electrodes and the release profile of Pr+ and Ld+ were investigated with \\r\

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

International Nuclear Information System (INIS)

Villarruel, S.; Giannuzzi, L.; Rivero, S.; Pinotti, A.

2015-01-01

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 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

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.

Cellulose acetate nanocomposite with nanocellulose obtained from bagasse of sugarcane

International Nuclear Information System (INIS)

Santos, Frirllei Cardozo dos

2016-01-01

This study presents a methodology for the extraction of nanocellulose of sugarcane bagasse for use in nanocomposites with cellulose acetate (CA). The bagasse sugarcane was treated with sodium hydroxide (NaOH) and sodium hypochlorite (NaClO) to remove lignin, hemicellulose, pectin and impurities. For removal of the amorphous region of cellulose microfibrils obtained from alkali treatments were submitted to acid hydrolysis with sulfuric acid under different temperature conditions. The nanocellulose obtained through acid hydrolysis heated at 45 ° C was used for the formulation of nanocomposites by smaller dimensions presented. The films were formulated at different concentrations (1, 2, 4 and 6 wt%) by the casting technique at room temperature. Each alkaline treatment was accompanied by spectrophotometry by infrared and fluorescence analysis to confirm the removal of the amorphous fraction, micrographs carried out by Scanning Electron Microscope (SEM) to display the fiber defibration. The efficiency of acid hydrolysis was confirmed by micrographs obtained by transmission electron microscope (TEM). The crystallinity index (CI) of the nanocrystals was determined by X-ray Diffraction (XRD). The surface of the obtained films were characterized by SEM and AFM microscopy of. The results showed that the sugarcane bagasse is an excellent source for nanocellulose extraction, the amorphous fraction of the fiber can be removed with the suggested alkaline treatments, and hydrolysis with H_2SO_4 was efficient both in the removal of amorphous cellulose as in reducing cellulose nanoscale with a length around 250 nm and a diameter of about 10 nm. The use of heated nanocellulose obtained through hydrolysis was selected after analysis of XRD, it was confirmed that this material had higher when compared to IC hydrolysis at room temperature. The nanocomposites showed high rigidity and brittleness with high crystallinity when compared to the pure polymer film was observed by AFM and SEM

Opinion of the Scientific Committee on Consumer Safety (SCCS) - Opinion on the fragrance ingredients Tagetes minuta and Tagetes patula extracts and essential oils (phototoxicity only) in cosmetic products

NARCIS (Netherlands)

Coenraads, Pieter-Jan

Conclusion of the opinion: The SCCS considers a maximum level of 0.01% Tagetes minuta and Tagetes patula extracts and essential oils in leave-on products (except sunscreen cosmetic products) as safe, provided that the alpha terthienyl (terthiophene) content of the Tagetes extracts and oils does not

Physical properties of sago starch biocomposite filled with Nanocrystalline Cellulose (NCC) from rattan biomass: the effect of filler loading and co-plasticizer addition

Science.gov (United States)

Nasution, H.; Harahap, H.; Fath, M. T. Al; Afandy, Y.

2018-02-01

Rattan biomass is an abundant bioresources from processing industry of rattan which contains 37.6% cellulose. The high cellulose contents of rattan biomass make it a source of nanocrystalline cellulose as a filler in biocomposites. Isolation of alpha cellulose from rattan biomass was being prepared by using three stages: delignification, alkalization, and bleaching. It was delignificated with 3.5% HNO3 and NaNO2, precipitated with 17.5% NaOH, bleaching process with 10% H2O2. Nanocrystal obtained through the hydrolysis of alpha cellulose using 45% H2SO4 and followed by mechanical steps of ultrasonication, centrifugation, and filtration with a dialysis membrane. Biocomposite was being prepared by using a solution casting method, which includes 1-4 wt% nanocrystalline cellulose from rattan biomass as fillers, 10-40 wt% acetic acid as co-plasticizer and 30 wt% glycerol as plasticizer. The biocomposite characteristic consists of density, water absorption, and water vapors transmission rate. The results showed the highest density values was 0.266 gram/cm3 obtained at an additional of 3 wt% nanocrystalline cellulose from rattan biomass and 30 wt% acetic acid. The lowest water absorption was 9.37% at an additional of 3 wt% nanocrystalline cellulose from rattan biomass and 10 wt% acetic acid. It was observed by the addition of nanocrystalline cellulose might also decrease the rate of water vapor transmission that compared to the non-filler biocomposite.

Use of alpha-particle excited x-rays to measure the thickness of thin films containing low-Z elements

International Nuclear Information System (INIS)

Hanser, F.A.; Sellers, B.; Ziegler, C.A.

1976-01-01

The thickness of thin surface films containing low Z elements can be determined by measuring the K X-ray yields from alpha particle excitation. The samples are irradiated in a helium atmosphere by a 5 mCi polonium-210 source, and the low energy X-rays detected by a flow counter with a thin-stretched polypropylene window. The flow counter output is pulse height sorted by a single channel analyzer (SCA) and counted to give the X-ray yield. Best results have been obtained with Z = 6 to 9 (C, N, O, and F), but usable yields are obtained even for Z = 13 or 14 (Al and Si). The low energy of the X-rays (0.28 to 1.74 keV) limits the method to films of several hundred nm thickness or less and to situations where the substrate does not produce interfering X-rays. It is possible to determine the film thickness with 50 percent accuracy by direct calculation using the measured alpha-particle spectrum and known or calculated K X-ray excitation cross sections. By calibration with known standards the accuracy can be increased substantially. The system has thus far been applied to SiO 2 on Si, Al 2 O 3 on Al, and CH 2 on Al

Electrode effects of a cellulose-based electro-active paper energy harvester

International Nuclear Information System (INIS)

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

2014-01-01

The possibility of cellulose-based electro-active paper (EAPap) as a vibrational energy transducer was investigated in this paper. Thin cellulose EAPap film specimens were prepared by the regenerating process. Three different metal electrodes of gold, silver and aluminum were deposited on a 50 × 50 mm 2 cellulose film using a thermal evaporator. An aluminum cantilever beam was used as a vibrational bender and EAPap was attached close to the root of the cantilever beam. The voltage output of the EAPap was measured under harmonic base excitation of the cantilever beam. The EAPap with aluminum electrode provided the largest open circuit voltage output compared to those with gold or silver electrodes. The output voltages of the EAPap increased linearly with increase of the area of the electrodes. The output voltages also increased with increasing input acceleration but became saturated at a certain magnitude. From the experimental results, we conclude that EAPap with metal electrodes can be used as a flexible energy harvesting transducer by external mechanical stress, and the output voltage is related to the electrode material due to its work function. (paper)

Preparation And Properties Of Bionanocomposite Films Reinforced With Nanocellulose Isolated From Moroccan Alfa Fibres

Directory of Open Access Journals (Sweden)

Youssef Benyoussif

2015-09-01

Full Text Available Nanocellulose (NC were extracted from the Moroccan Alfa plant (Stipa tenacissima L. and characterised. These Alfa cellulosic nanoparticles were used as reinforcing phase to prepare bionanocomposite films using carboxymethyl cellulose as matrix. These films were obtained by the casting/evaporation method. The crystallinity of NC was analysed by X-ray diffraction, the dimension of NC by atomic force microscopy, molecular interactions due to incorporation of NC in carboxymethyl cellulose (CMC matrix were supported by Fourier transforms infrared (FTIR spectroscopy. The properties of the ensuing bionanocomposite films were investigated using tensile tests, water vapour permeability (WVP study and thermogravimetric analysis. With the progress of purification treatment of cellulose, the crystallinity is improved compared to the untreated fibres; this can be explained by the disappearance of the amorphous areas in cellulose chain of the plant. Consequently, the tensile modulus and tensile strength of CMC film increased by 60 and 47%, respectively, in the bionanocomposite films with 10 wt% of NC, and decrease by 8.6% for WVP with the same content of NC. The NC obtained from the Moroccan Alfa fibres can be used as a reinforcing agent for the preparation of bionanocomposites, and they have a high potential for the development of completely biodegradable food packaging materials.

Development of an avidin sensor based on the poly(methoxy amino-β-styryl terthiophene)-coated glassy carbon electrode

KAUST Repository

Mehenni, Hakim

2012-03-01

In this study, a simple and direct biosensor was proposed, which was based on biotin immobilized onto a conducting polymer-coated electrode, for the determination of avidin, a highly stable glycoprotein found in egg whites. Biotin was immobilized onto the electrode by covalent coupling to the primary amine group on poly-3′-(2-methoxy-5-amino-β-styryl)-(2,2′: 5′,2″-terthiophene) (PMAST), and the biotin-avidin interaction was monitored by square-wave voltammetry. Incubation of the PMAST/biotin-modified coated electrode with avidin in a phosphate-buffered saline solution caused a significant change to its square-wave voltammogram, which was explained by the binding of avidin by biotin, and resulted in restricted ion transfer to and from the conducting polymer. This change was then utilized to determine avidin. Importantly, we found a linear relationship for the avidin sensor in the range of 4 × 10 -14 to 3 × 10 -4 mol/L, and the detection limit was determined to be approximately 10 -14 mol/L. © 2012 Published by NRC Research Press.

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.

The elution of erbium from a cation exchanger bed by means of the N-hydroxyethyl-ethylene-diamine triacetic acid

International Nuclear Information System (INIS)

Amer Amezaga, S.

1963-01-01

A physicochemical study of the phenomena resulting when erbium is eluted from a cation-exchanger bed at a steady by means of the N-hydroxyethyl-ethylene-diamine-triacetic acid (HEDTA) is made. Two different retaining beds are used, a hydrogen bed, in which no ammonium passes through, and a zinc bed, which leaks ammonium ion. Good agreement between experimental and calculated values by using the equations deduced for the concentrations of the main species has been achieved, with errors around 1-2% in most of the experiments. (Author) 69 refs

Measurement of outdoor radioactivities of radon and thoron by the passive radon-thoron monitor of cup type with cellulose nitrate film

International Nuclear Information System (INIS)

Ogawa, Y.; Kimura, Y.; Iida, T.; Yamasaki, K.; Tsujimoto, T.

1993-01-01

In order to get information as to effective dose of radon and thoron for the public, we investigated the dosimetry of the average outdoor concentrations of radon and thoron by the cup type radon/thoron monitor using cellulose nitrate film. To overcome the disadvantages of cup monitors which are the relatively low sensitivity and the relatively high detection limit, the present dosimetry is based on the usage of several pairs of cup monitors and the statistical treatments (significant test). Because the detection limit could be lowered using the present dosimetry, we could measure the outdoor concentration levels more precisely. (1 tab.)

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

An isozyme of acid alpha-glucosidase with reduced catalytic activity for glycogen.

OpenAIRE

Beratis, N G; LaBadie, G U; Hirschhorn, K

1980-01-01

Both the common and a variant isozyme of acid alpha-glucosidase have been purified from a heterozygous placenta with CM-Sephadex, ammonium sulfate precipitation, dialysis, Amicon filtration, affinity chromatography by Sephadex G-100, and DEAE-cellulose chromatography. Three and two activity peaks, from the common and variant isozymes, respectively, were obtained by DEAE-cellulose chromatography using a linear NaCl gradient. The three peaks of activity of the common isozyme were eluted with 0....

Radioimmunoassay of alpha-fetoprotein, with special reference to iodination and purification techniques

International Nuclear Information System (INIS)

Schiller, H.S.; Kulchinski, L.; Luthy, D.A.

1978-01-01

We report a relatively simple and convenient method for iodinating human alpha-fetoprotein and for purifying the 125 I-labeled material. The label is incorporated into human alpha-fetoprotein enzymatically by use of lactoperoxidase. Before each assay the labeled material is purified over two successive short columns: Sephacryl S-200 Superfine and cellulose. This procedure removes both free iodine and damaged fetoprotein. With the purified material we developed a sensitive and reliable radioimmunoassay for alpha-fetoprotein in serum and amniotic fluid

Diketopyrrolopyrrole-Based Conjugated Polymer Entailing Triethylene Glycols as Side Chains with High Thin-Film Charge Mobility without Post-Treatments

Energy Technology Data Exchange (ETDEWEB)

Yang, Si-Fen [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; University of Chinese Academy of Sciences, Beijing 100049 P. R. China; Liu, Zi-Tong [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Cai, Zheng-Xu [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Dyson, Matthew J. [Department of Materials and Centre for Plastic Electronics, Imperial College London, London SW72AZ UK; Stingelin, Natalie [Department of Materials and Centre for Plastic Electronics, Imperial College London, London SW72AZ UK; Chen, Wei [Materials Science Division, Argonne National Laboratory, 9700 Cass Avenue Lemont IL 60439 USA; Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue Chicago IL 60637 USA; Ju, Hua-Jun [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Zhang, Guan-Xin [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Zhang, De-Qing [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; University of Chinese Academy of Sciences, Beijing 100049 P. R. China

2017-04-18

Side chain engineering of conjugated donor-acceptor polymers is a new way to manipulate their optoelectronic properties. Two new diketopyrrolopyrrole (DPP)-terthiophene-based conjugated polymers PDPP3T-1 and PDPP3T-2, with both hydrophilic triethylene glycol (TEG) and hydrophobic alkyl chains, are reported. It is demonstrated that the incorporation of TEG chains has a significant effect on the interchain packing and thin-film morphology with noticeable effect on charge transport. Polymer chains of PDPP3T-1 in which TEG chains are uniformly distributed can self-assemble spontaneously into a more ordered thin film. As a result, the thin film of PDPP3T-1 exhibits high saturated hole mobility up to 2.6 cm(2) V-1 s(-1) without any post-treatment. This is superior to those of PDPP3T with just alkyl chains and PDPP3T-2. Moreover, the respective field effect transistors made of PDPP3T-1 can be utilized for sensing ethanol vapor with high sensitivity (down to 100 ppb) and good selectivity.

Chapter 2.3 Cellulose Nanofibril Composite Substrates for Flexible Electronics

Science.gov (United States)

Ronald Sabo; Jung-Hun Seo; Zhenqiang Ma

2013-01-01

Flexible electronics have a large number of potential applications, including malleable displays and wearable computers. Current research into high-speed, flexible electronic substrates uses plastics for the flexible substrate, but these plastics typically have drawbacks, such as high thermal expansion coefficients. Transparent films made from cellulose...

Synthesis and characterization of graphene/cellulose nanocomposite

Science.gov (United States)

Kafy, Abdullahil; Yadav, Mithilesh; Kumar, Kishor; Kumar, Kishore; Mun, Seongcheol; Gao, Xiaoyuan; Kim, Jaehwan

2014-04-01

Cellulose is one of attractive natural polysaccharides in nature due to its good chemical stability, mechanical strength, biocompatibility, hydrophilic, and biodegradation properties [1-2]. The main disadvantages of biopolymer films like cellulose are their poor mechanical properties. Modification of polymers with inorganic materials is a new way to improve polymer properties such as mechanical strength [3-4]. Presently, the use of graphene/graphene oxide (GO) in materials research has attracted tremendous attention in the past 40 years in various fields including biomedicine, information technology and nanotechnology[5-7]. Graphene, a single sheet of graphite, has an ideal 2D structure with a monolayer of carbon atoms packed into a honeycomb crystal plane. Using both experimental and theoretical scientific research, researchers including Geim, Rao and Stankovich [8-10] have described the attractiveness of graphene in the materials research field. Due to its sp2 hybrid carbon network as well as extraordinary mechanical, electronic, and thermal properties, graphene has opened new pathways for developing a wide range of novel functional materials. Perfect graphene does not exist naturally, but bulk and solution processable functionalized graphene materials including graphene oxide (GO) can now be prepared [11-13].The large surface area of GO has a number of functional groups, such as -OH, -COOH, -O- , and C=O, which make GO hydrophilic and readily dispersible in water as well as some organic solvents[14] , thereby providing a convenient access to fabrication of graphene-based materials by solution casting. According to several reports [15-17], GO can be dispersed throughout a selected polymer matrix to make GO-based nanocomposites with excellent mechanical and thermal properties. Since GO is prepared from low-cost graphite, it has an outstanding price advantage over CNTs, which has encouraged studies of GO/synthetic polymer composites [18-20]. In some reported papers

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.

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

Study of substrate topographical effects on epithelial cell behavior using etched alpha-particle tracks on PADC films

International Nuclear Information System (INIS)

Ng, C.K.M.; Poon, W.L.; Li, W.Y.; Cheung, T.; Cheng, S.H.; Yu, K.N.

2008-01-01

Micrometer-size pits on the surface of a polymer (polyallyldiglycol carbonate or PADC) substrate created by alpha-particle irradiation and subsequent chemical etching were used to study the topographical effects alone on cell behavior. Vinculin, the cell adhesion and membrane protrusion protein, was used as an indicator of cytoskeletonal reorganization on the substrate and localization of vinculin was used to demonstrate the presence of focal adhesions. In our experiments, vinculin expressed in epithelial HeLa cells cultured on PADC films with track-etch pits, but not in cells cultured on the raw or chemically etched blank films. In other words, vinculin expression was induced by the topography of track-etch pits, while etching of the substrate alone (without alpha-particle irradiation) did not cause up-regulation of vinculin protein expression. HeLa cells cultured on PADC films with track-etch pits also showed changes in cell proliferation, cell area and cell circularity, and were largely contained by the pits. In other words, the cell membrane edges tended to be in contact with the pits. By comparing the correlation between the positions of HeLa cells and the pits, and that between the positions of cells and computer-simulated pits, the tendency for membrane edges of HeLa cells to be in contact with the pits was recognized. This could be explained by inhibition of membrane protrusion at the pits. In conclusion, substrate track-etch pits were an important determinant of epithelial cell behaviors

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.

Cellulose synthase complex organization and cellulose microfibril structure.

Science.gov (United States)

Turner, Simon; Kumar, Manoj

2018-02-13

Cellulose consists of linear chains of β-1,4-linked glucose units, which are synthesized by the cellulose synthase complex (CSC). In plants, these chains associate in an ordered manner to form the cellulose microfibrils. Both the CSC and the local environment in which the individual chains coalesce to form the cellulose microfibril determine the structure and the unique physical properties of the microfibril. There are several recent reviews that cover many aspects of cellulose biosynthesis, which include trafficking of the complex to the plasma membrane and the relationship between the movement of the CSC and the underlying cortical microtubules (Bringmann et al. 2012 Trends Plant Sci. 17 , 666-674 (doi:10.1016/j.tplants.2012.06.003); Kumar & Turner 2015 Phytochemistry 112 , 91-99 (doi:10.1016/j.phytochem.2014.07.009); Schneider et al. 2016 Curr. Opin. Plant Biol. 34 , 9-16 (doi:10.1016/j.pbi.2016.07.007)). In this review, we will focus on recent advances in cellulose biosynthesis in plants, with an emphasis on our current understanding of the structure of individual catalytic subunits together with the local membrane environment where cellulose synthesis occurs. We will attempt to relate this information to our current knowledge of the structure of the cellulose microfibril and propose a model in which variations in the structure of the CSC have important implications for the structure of the cellulose microfibril produced.This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'. © 2017 The Author(s).

Enhanced plastic deformations of nanofibrillated cellulose film by adsorbed moisture and protein-mediated interactions.

Science.gov (United States)

Malho, Jani-Markus; Ouellet-Plamondon, Claudiane; Rüggeberg, Markus; Laaksonen, Päivi; Ikkala, Olli; Burgert, Ingo; Linder, Markus B

2015-01-12

Biological composites are typically based on an adhesive matrix that interlocks rigid reinforcing elements in fiber composite or brick-and-mortar assemblies. In nature, the adhesive matrix is often made up of proteins, which are also interesting model systems, as they are unique among polymers in that we know how to engineer their structures with atomic detail and to select protein elements for specific interactions with other components. Here we studied how fusion proteins that consist of cellulose binding proteins linked to proteins that show a natural tendency to form multimer complexes act as an adhesive matrix in combination with nanofibrillated cellulose. We found that the fusion proteins are retained with the cellulose and that the proteins mainly affect the plastic yield behavior of the cellulose material as a function of water content. Interestingly, the proteins increased the moisture absorption of the composite, but the well-known plastifying effect of water was clearly decreased. The work helps to understand the functional basis of nanocellulose composites as materials and aims toward building model systems for molecular biomimetic materials.

Incorporation of Sunflower Oil and d-alpha-tocopherol Effect on Mechanical Properties and Permeability of Corn Starch Composite Edible Film

Directory of Open Access Journals (Sweden)

Pramono Putro Utomo

2015-06-01

Full Text Available Corn starch-based films are inherently brittle and lack the necessary mechanical integrity for conventional packaging. However, the incorporation of additives can potentially improve the mechanical properties and processability of starch films. In this work sunflower oil (SO and vitamin E (d-alpha-tocopherol at three levels each (0.05%, 0.1% and 0.15% (w/vtotal and (0.18%, 0.36% and 0.54% (w/vtotal were incorporated into corn starch films using a solution casting method to improve the mechanical and water vapour transmission rate (WVTR properties. The addition of SO and vitamin E increased elongation at break of starch-based film while decreased tensile strength and WVTR of starch-based film. The best edible film obtained on addition of sunflower oil concentration of 0.15% and 0.54%, vitamin E with a value of 0.121 mm thickness, tensile strength of 65.38 kg/cm2, elongation at break 14.17% and WVTR 1144 g/m2 24 hours.

21 CFR 173.357 - Materials used as fixing agents in the immobilization of enzyme preparations.

Science.gov (United States)

2010-04-01

... glucose isomerase enzyme preparations for use in the manufacture of high fructose corn syrup, in... manufacture of high fructose corn syrup, in accordance with § 184.1372 of this chapter. Cellulose triacetate... enzyme preparations for use in the manufacture of high fructose corn syrup, in accordance with § 184.1372...

Cellulose nanocrystals from Actinidia deliciosa pruning residues combined with carvacrol in PVA_CH films with antioxidant/antimicrobial properties for packaging applications.

Science.gov (United States)

Luzi, Francesca; Fortunati, Elena; Giovanale, Geremia; Mazzaglia, Angelo; Torre, Luigi; Balestra, Giorgio Mariano

2017-11-01

Kiwi Actinidia deliciosa pruning residues were here used for the first time as precursors for the extraction of high performing cellulose nanocrystals (CNC) by applying a bleaching treatment followed by an acidic hydrolysis. The resultant cellulosic nanostructures, obtained by an optimize extraction procedure (0.7% wt/v two times of sodium chlorite NaClO 2 ) followed by an hydrolysis step, were then used as reinforcements phases in poly(vinyl alcohol) (PVA) blended with natural chitosan (CH) based films and also combined, for the first time, with carvacrol used here as active agent. Morphological and optical characteristics, mechanical response, thermal and migration properties, moisture content and antioxidant and antimicrobial assays were conducted. The morphological, optical and colorimetric results underlined that no particular alterations were induced on the transparency and color of PVA and PVA_CH blend by the presence of CNC and carvacrol, while they were able to modulate the mechanical responses, to induce antioxidant activities maintaining the migration levels below the permitted limits and suggesting the possible application in industrial sectors. Finally, inhibitions on bacterial development were detected for multifunctional systems, suggesting their protective function against microorganisms contamination. Copyright © 2017 Elsevier B.V. All rights reserved.

The preparation, characterization and actuation behavior of polyaniline and cellulose blended electro-active paper

International Nuclear Information System (INIS)

John, Amalraj; Mahadeva, Suresha K; Kim, Jaehwan

2010-01-01

This paper reports polyaniline and cellulose blended electro-active paper (EAPap) that can produce large bending displacement at ambient humidity conditions with long lifetime durability. A novel solution processable polyaniline-p-toluene sulfonate (PANI–PTSA) salt was prepared by an inverted emulsion polymerization technique using benzoyl peroxide and p-toluene sulfonic acid. Cellulose solution prepared by dissolving cotton with lithium chloride/N, N-dimethylacetamide was mixed with the PANI emaraldine salt solution and a cellulose–PANI blended film was obtained. The obtained cellulose–PANI film was characterized by ultraviolet–visible (UV–visible), x-ray diffraction, scanning electron microscopy and tensile test methods. A cellulose–PANI EAPap actuator was made by depositing very thin gold electrodes on both sides of the cellulose–PANI film. When the actuator performance of the cellulose–PANI EAPap was evaluated in terms of bending displacement with respect to the actuation frequencies, voltages and relative humidity levels, a large bending displacement was shown at ambient humidity conditions with long lifetime durability

Active packaging using regenerated cellulose and hydroxypropyl amylopectin for fresh food products

Science.gov (United States)

As an alternate to non-sustainable plastic packaging, polymer blends were engineered using regenerated cellulose and a hydroxypropyl functionalized starch derivative. Initially, films were cast out of solution to determine optimum blend composition, and then components were reactively extruded to in...

Towards the development of a direct electrochemical biodetector of avidin based on the poly(chloro amino β-styryl terthiophene)-coated glassy carbon electrode

KAUST Repository

Mehenni, Hakim

2012-03-30

In this study, a simple and direct biodetector was proposed, which was based on biotin immobilized onto a conducting polymer-coated electrode, for the detection of avidin, a highly stable glycoprotein found in egg-whites. Biotin was immobilized onto the electrode by covalent coupling to the primary amine group on the poly 3′-(3-chloro-4-amino-β-styryl)-(2,2′: 5′,2″-terthiophene) (PCAST), and the biotinavidin interaction was monitored by cyclic voltammetry. Incubation of the PCAST/biotin-modified-coated electrode with avidin in a phosphate buffered saline solution caused a significant change to its cyclic voltammogram, which was explained by the binding of avidin by biotin, and resulted in restricted ion transfer to and from the conducting polymer. This change was then utilized to detect avidin at 4 × 10 -6molL -1. © 2012 CSIRO.

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...

Cellulose is not just cellulose

DEFF Research Database (Denmark)

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

2012-01-01

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...... 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...

Uranium exploration in Pakistan using alpha sensitive plastic films (ASPF)

Energy Technology Data Exchange (ETDEWEB)

Qureshi, A.A.; Khan, H.A. (Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan). Health Physics Div.); Samad Beg, M.A.; Ahmed, Fazal (Atomic Energy Minerals Centre, Lahore (Pakistan))

1988-01-01

The Alpha Sensitive Plastic Film (ASPF) technique has been successfully developed in Pakistan. Studies concerning optimisation of tube size, exposure time, position of detector in tube, etching conditions, type of detector, etc. have been done in the laboratory. Some studies like effects of depth, size and grade of ore body and water table were carried out in the field. The application of this technique was fairly successful in sandstone areas. Based on this technique, subsurface uranium occurrences were established in D.G. Khan and Isa Khel. The ASPF-results were confirmed by subsequent drilling and other methods. The technique has been found to be workable and inexpensive. It has been found to supplement the conventional exploration methods, and if applied as a part of normal exploration programme may reduce overall project cost substantially. This paper briefly describes the methodology, parameters, applications and results of the ASPF technique in the field of uranium prospecting and exploration in Pakistan. (author).

Characterisation of bacterial cellulose partly acetylated by dimethylacetamide/lithium chloride

International Nuclear Information System (INIS)

Lima, G. de Marco; Sierakowski, M.-R.; Faria-Tischer, P.C.S.; Tischer, C.A.

2011-01-01

Cellulose is a water-insoluble polysaccharide used at an industrial scale for the manufacture of paper and films or in the dust form, natural, hydrolysed or derivatised. The cellulose produced by G. hansenii (former A. xylinum) has a structure identical to that of plants, but is free of lignin and hemicellulose, with several unique physical-chemical properties. The main barrier to the use of cellulose is its insolubility in water and most organic solvents, but soluble derivatives can be obtained with the use of ionic solvents. Bacterial cellulose, produced in a static, 4% glucose medium, was dissolved in hot DMAc/LiCl (120, 150 or 170 deg. C). The solution was analysed by 13 C NMR, and the effect of the dissolution on the crystalline state was shown by X-ray crystallography. The crystalline structure was lost upon dissolution, becoming amorphous; this was also observed for Avicel plant cellulose. The soluble cellulose was partly acetylated in acetic anhydride with acetic anhydride-cellulose ratios of 1:50, 1:6 and 1:12 (w/v). The resulting cellulose acetates were examined by infrared spectroscopy, and the best result was 43% (w/v). The degree of acetylation was determined via 1 H NMR spectroscopy by comparing the area of the glucose ring at 2.60-5.20 ppm and that of the methyl proton of the acetate group at 1.80-2.20 ppm. The 13 C NMR spectra showed acetylation at C6 >> C2 > C3 at 60-80 ppm, with C1 signals at ∼ 100-104 ppm. The derivatisation of bacterial cellulose in DMAc/LiCl/acetic anhydride (1:4:50, v/v/v) gave rise to 87% substitution. The process of dissolution of the bacterial cellulose is essential for the analysis of the insoluble polymer in water, facilitating analysis and characterisation of these composites by 13 C NMR spectroscopy, size exclusion chromatography and light scattering techniques.

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.

Mechanical Properties of Poly(lactic acid Sheet Reinforced with Microfibrillated Cellulose from Corn Cobs

Directory of Open Access Journals (Sweden)

Deejam Prapatsorn

2015-01-01

Full Text Available In this study, cellulose was extracted from corn cobs by successive hot NaOH solution and followed by H2O2 bleaching. XRD pattern show characteristic peak of Cellulose I. Microfibrillated cellulose (MFC was successfully prepared by dissolving the extracted cellulose in NaOH/urea solution, shearing in a homogenizer and finally by freezing and thawing. To improve strength of MFC, MFC was physically crosslinked using PVA by freezing and thawing. The crosslinked MFC/PVA was added to poly(lactic acid (PLA to improve its mechanical properties. The non-crosslinked MFC/PVA was also prepared by only stirring the solution without freezing and thawing. MFC/PVA reinforced PLA films with various ratios of PLA and MFC/PVA at100:0, 99:1, 97:3 and 95:5were prepared through a solution casting method. Tensile strength and elongation at breakof PLA films increased with the addition of physically crosslinked MFC/PVA at 1%wt, whereas, the addition of non-crosslinked MFC/PVA decreased elongation at break. Crosslinking of MFC/PVA can improve tensile strength of PLA.It can render better tensile strength than that of non-crosslinked MFC/PVA. However, when MFC/PVA contents increase, tensile strength of PLA fims reinforced with non-crosslinked and crosslinked MFC/PVA decreased. Morphology of fracture surfaces reveals good dispersion and adhesion between 1% crosslinked MFC/PVA and PLA matrix.

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

Bio-hybridization of nanobactericides with cellulose films for effective treatment against members of ESKAPE multi-drug-resistant pathogens

Science.gov (United States)

Baker, Syed; Volova, Tatiana; Prudnikova, Svetlana V.; Shumilova, Anna A.; Perianova, Olga V.; Zharkov, Sergey M.; Kuzmin, Andrey; Olga, Kondratenka; Bogdan, Kiryukhin; Shidlovskiy, Ivan P.; Potkina, Zoya K.; Khohlova, Olga Y.; Lobova, Tatiana I.

2018-03-01

The rapid expansion of drug-resistant pathogens has created huge global impact and development of novel antimicrobial leads is one of the top priority studies in the current scenario. The present study aims to develop bio-hybridized nanocellulose films which comprise of phytogenic silver nanobactericides. The nanobactericides were synthesized by treating 1 mM silver nitrate with aqueous extract of Chamerion angustifolium which reduced the metal salt to produce polydispersed nanobactericides which were tested against the members of ESKAPE drug-resistant communities. The synthesized silver nanobactericides were subjected to characterization with UV-visible spectra which displayed maximum absorbance at 408 nm. The bio-molecular interaction of phyto-constituents to mediate synthesis and stabilization of nanobactericides was studied with Fourier-transform infrared spectroscopy (FTIR) which depicted functional groups associated with nanobactericides. The crystalline nature was studied with X-ray diffraction (XRD) which showed Bragg's intensities at 2θ angle which denoted (111), (200), (220), and (311) planes. The morphological characteristics of silver nanobactericides were defined with transmission electron Microscopy (TEM) image which displayed polydispersity of silver nanobactericides with size ranging from 2 to 40 nm. The synthesized nanobactericides showed a significant activity against MRSA strain with 21 mm zone of inhibition. The minimal inhibitory concentration of silver nanobactericides to inhibit the growth of test pathogens was also determined which ranged between 0.625 and 1.25 μg/ml. The silver nanobactericides were bio-hybridized onto nanocellulose films produced by Komagataeibacter xylinus B-12068 culture strain. The films were dried to determine the mechanical properties which showed increased in Young's modulus and tensile strength in comparison with control bacterial cellulose films. Overall, the results obtained in the present investigation are

Fluorescence spectra of bithiophene and terthiophene single crystals and of their isolated molecules in cyclodextrin

International Nuclear Information System (INIS)

Gombojav, Bold; Namsrai, Nasanbat; Yoshinari, Takehisa; Nagasaka, Shin-ichiro; Itoh, Hiroki; Koyama, Kiyohito

2004-01-01

In order to examine the effect of subsumption space of β- and γ-cyclodextrin (CyD) on the photophysics of oligothiophenes, 2, 2'-bithiophene (BT) and 2, 2': 5', 2''-terthiophene (TT), the fluorescence spectra were compared with those of the single crystals (SC) at 15, 77 K and room temperature (RT). Both the numbers of BT included in β- and γ-CyD are twin (BT 2 ). The numbers of TT included in β- and γ-CyD are unit (TT 1 ) and twin (TT 2 ), respectively. Electronic excitation of BT encapsulated in β- and γ-CyD gives similar fluorescence spectra, showing bathochromic shift compared with that of BT single crystal, (BT) SC . The observation that the fluorescence spectra of encapsulated BT 2 are similar to the spectra of its THF solution suggests the configuration of BT 2 in β- and γ-CyD should be face-to-face configuration (BT 2 ) parrallel . On the contrary, TT in β- and in γ-CyD afford quite different fluorescence spectra. Encapsulated TT in β-CyD exhibits the hypsochromic shift of fluorescence maxima compared to that of TT single crystal, (TT) SC . While the bathochromically shifted fluorescence spectra of TT 2 in γ-CyD is also ascribed to the face-to-face configuration (TT 2 ) parallel as in the case of BT 2 in γ-CyD. Fluorescence spectra show the excited ground state complex of BT 2 and TT 2 in γ-CyD

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.

Etude de la fixation d'atomes de brome dans les traces latentes d'ions

Science.gov (United States)

Vareille, J. C.; Moliton, J. P.; Decossas, J. L.; Teyssier, J. L.; Delaunay, B.

1981-09-01

We show that the branching of bromide atoms is possible on chemically active sites produced by Kr 8+, Cl 6+ and He 2+ ion irradiation on cellulose triacetate. The number of fixed atoms increases with ion fluence and atomic number. These results are in good agreement with those concerning radical yield around the ions' path.

Microencapsulation of Thai rice grass (O. Sativa cv. Khao Dawk Mali 105) extract incorporated to form bioactive carboxymethyl cellulose edible film.

Science.gov (United States)

Rodsamran, Pattrathip; Sothornvit, Rungsinee

2018-03-01

Microencapsulation was investigated to enhance the stability of Thai rice grass extract. Microencapsulated powder (MP) was formed using total solid of extract solution and maltodextrin ratios of 1:4 (MP 1:4) and 1:9 (MP 1:9). The absence of an endothermic peak for both MPs confirmed all extract solutions were coated with maltodextrin. MP 1:9 had a lower total phenolic content (TPC) but was higher in antioxidant capacity than MP 1:4. Moreover, the TPC of the MPs slightly decreased (70.02-93.04%) during storage at 10, 30 and 70°C for 30d. Comparatively, the TPC of the extract solution significantly decreased from 100% down to 20.8%, 11.2% and 8.6% at 10, 30 and 70°C, respectively. Therefore, MP 1:9 incorporated with blended carboxymethyl cellulose film increased the water barrier and the TPC. This film can serve as a bioactive biodegradable packaging material to reduce plastic packaging in the food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sustainable and Low Viscous 1-Allyl-3-methylimidazolium Acetate + PEG Solvent for Cellulose Processing

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Airong Xu

2017-02-01

Full Text Available Developing sustainable, low viscous and efficient solvents are always advantageous to the processing/fabricating of cellulose materials in practical applications. To this end, in this work novel solvents were developed; ([Amim][CH3COO]/PEG by dissolving polyethylene glycol 200 (PEG-200 in 1-allyl-3-methylimidazolium acetate ([Amim][CH3COO]. The solubilities of cellulose in [Amim][CH3COO]/PEG solvents were determined as a function of temperature, and the possible dissolution mechanism of cellulose in [Amim][CH3COO]/PEG solvent was investigated. The novel solvent exhibits outstanding advantages for good dissolution capacity of cellulose, such as low viscosity, negligible vapor pressure, and recycling capability. The [CH3COO]− anion and the [Amim]+ cation of [Amim][CH3COO] in [Amim][CH3COO]/PEG-10 are the driving force for cellulose dissolution verified by the 13C NMR spectra. In addition, the regenerated cellulose films from [Amim][CH3COO]/PEG solvent were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR, and thermogravimetric analysis (TGA to estimate their morphologies and structures.

Properties of cellulose derivatives produced from radiation-Modified cellulose pulps

International Nuclear Information System (INIS)

Iller, Edward; Stupinska, Halina; Starostka, Pawel

2007-01-01

The aim of project was elaboration of radiation methods for properties modification of cellulose pulps using for derivatives production. The selected cellulose pulps were exposed to an electron beam with energy 10 MeV in a linear accelerator. After irradiation pulps underwent the structural and physico-chemical investigations. The laboratory test for manufacturing carboxymethylocellulose (CMC), cellulose carbamate (CC) and cellulose acetate (CA) with cellulose pulps irradiated dose 10 and 15 kGy have been performed. Irradiation of the pulp influenced its depolimerisation degree and resulted in the drop of viscosity of CMC. However, the expected level of cellulose activation expressed as a rise of the substitution degree or increase of the active substance content in the CMC sodium salt was not observed. In the case of cellulose esters (CC, CA) formation, the action of ionising radiation on cellulose pulps with the dose 10 and 15 kGy enables obtaiment of the average values of polimerisation degree as required for CC soluble in aqueous sodium hydroxide solution. The properties of derivatives prepared by means of radiation and classic methods were compared

Synthesis and characterization of cellulose derivatives obtained from bacterial cellulose

International Nuclear Information System (INIS)

Oliveira, Rafael L. de; Barud, Hernane; Ribeiro, Sidney J.L.; Messaddeq, Younes

2011-01-01

The chemical modification of cellulose leads to production of derivatives with different properties from those observed for the original cellulose, for example, increased solubility in more traditional solvents. In this work we synthesized four derivatives of cellulose: microcrystalline cellulose, cellulose acetate, methylcellulose and carboxymethylcellulose using bacterial cellulose as a source. These were characterized in terms of chemical and structural changes by examining the degree of substitution (DS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy - NMR 13 C. The molecular weight and degree of polymerization were evaluated by viscometry. The characterization of the morphology of materials and thermal properties were performed with the techniques of X-ray diffraction, electron microscopy images, differential scanning calorimetry (DSC) and thermogravimetric analysis. (author)

High-performance green flexible electronics based on biodegradable cellulose nanofibril paper.

Science.gov (United States)

Jung, Yei Hwan; Chang, Tzu-Hsuan; Zhang, Huilong; Yao, Chunhua; Zheng, Qifeng; Yang, Vina W; Mi, Hongyi; Kim, Munho; Cho, Sang June; Park, Dong-Wook; Jiang, Hao; Lee, Juhwan; Qiu, Yijie; Zhou, Weidong; Cai, Zhiyong; Gong, Shaoqin; Ma, Zhenqiang

2015-05-26

Today's consumer electronics, such as cell phones, tablets and other portable electronic devices, are typically made of non-renewable, non-biodegradable, and sometimes potentially toxic (for example, gallium arsenide) materials. These consumer electronics are frequently upgraded or discarded, leading to serious environmental contamination. Thus, electronic systems consisting of renewable and biodegradable materials and minimal amount of potentially toxic materials are desirable. Here we report high-performance flexible microwave and digital electronics that consume the smallest amount of potentially toxic materials on biobased, biodegradable and flexible cellulose nanofibril papers. Furthermore, we demonstrate gallium arsenide microwave devices, the consumer wireless workhorse, in a transferrable thin-film form. Successful fabrication of key electrical components on the flexible cellulose nanofibril paper with comparable performance to their rigid counterparts and clear demonstration of fungal biodegradation of the cellulose-nanofibril-based electronics suggest that it is feasible to fabricate high-performance flexible electronics using ecofriendly materials.

Investigation of branching of bromine in latent ion traces

International Nuclear Information System (INIS)

Vareille, J.C.; Moliton, J.P.; Decossas, J.L.; Teyssier, J.L.; Delaunay, B.

1981-01-01

We show that the branching of bromide atoms is possible on chemically active sites produced by Kr 8+ , Cl 6+ and He 2+ ion irradiation on cellulose triacetate. The number of fixed atoms increases with ion fluence and atomic number. These results are in good agreement with those concerning radical yield around the ions' path. (orig.)

A new procedure for coupling antibody to paper discs for radioimmunoassay: application to the determination of alpha-fetoprotein

International Nuclear Information System (INIS)

Sasaki, T.; Tsukada, Y.; Hirai, H.

1983-01-01

Horse anti-alpha-fetoprotein was coupled to CM-cellulose discs by a modified carbodiimide reaction. The resulting coupled CM-discs were used in solid-phase radioimmunoassay of human alpha-fetoprotein. The sensitivity of these discs and conventional BrCN activated filter paper discs coupled anti-alpha-fetoprotein was approximately the same. A fair correlation between the alpha-fetoprotein levels determined by both methods was observed. The coupling procedure with carbodiimide is simple and the use of hazardous BrCN is eliminated. (Auth.)

INFLUENCE OF CELLULOSE POLYMERIZATION DEGREE AND CRYSTALLINITY ON KINETICS OF CELLULOSE DEGRADATION

OpenAIRE

Edita Jasiukaitytė-Grojzdek,; Matjaž Kunaver,; Ida Poljanšek

2012-01-01

Cellulose was treated in ethylene glycol with p-toluene sulfonic acid monohydrate as a catalyst at different temperatures. At the highest treatment temperature (150 °C) liquefaction of wood pulp cellulose was achieved and was dependant on cellulose polymerization degree (DP). Furthermore, the rate of amorphous cellulose weight loss was found to increase with cellulose degree of polymerization, while the rate of crystalline cellulose weight loss was reciprocal to the size of the crystallites. ...

Cellulose-Hemicellulose Interactions at Elevated Temperatures Increase Cellulose Recalcitrance to Biological Conversion

Energy Technology Data Exchange (ETDEWEB)

Mittal, Ashutosh [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Himmel, Michael E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kumar, Rajeev [University of California, Riverside; Oak Ridge National Laboratory; ; Smith, Micholas Dean [Oak Ridge National Laboratory; University of Tennessee; Petridis, Loukas [Oak Ridge National Laboratory; University of Tennessee; Ong, Rebecca G. [Michigan Technological University; Cai, Charles M. [University of California, Riverside; Oak Ridge National Laboratory; Balan, Venkatesh [University of Houston; Dale, Bruce E. [Michigan State University; Ragauskas, Arthur J. [Oak Ridge National Laboratory; University of Tennessee; Smith, Jeremy C. [Oak Ridge National Laboratory; University of Tennessee; Wyman, Charles E. [University of California, Riverside; Oak Ridge National Laboratory

2018-01-23

It has been previously shown that cellulose-lignin droplets' strong interactions, resulting from lignin coalescence and redisposition on cellulose surface during thermochemical pretreatments, increase cellulose recalcitrance to biological conversion, especially at commercially viable low enzyme loadings. However, information on the impact of cellulose-hemicellulose interactions on cellulose recalcitrance following relevant pretreatment conditions are scarce. Here, to investigate the effects of plausible hemicellulose precipitation and re-association with cellulose on cellulose conversion, different pretreatments were applied to pure Avicel(R) PH101 cellulose alone and Avicel mixed with model hemicellulose compounds followed by enzymatic hydrolysis of resulting solids at both low and high enzyme loadings. Solids produced by pretreatment of Avicel mixed with hemicelluloses (AMH) were found to contain about 2 to 14.6% of exogenous, precipitated hemicelluloses and showed a remarkably much lower digestibility (up to 60%) than their respective controls. However, the exogenous hemicellulosic residues that associated with Avicel following high temperature pretreatments resulted in greater losses in cellulose conversion than those formed at low temperatures, suggesting that temperature plays a strong role in the strength of cellulose-hemicellulose association. Molecular dynamics simulations of hemicellulosic xylan and cellulose were found to further support this temperature effect as the xylan-cellulose interactions were found to substantially increase at elevated temperatures. Furthermore, exogenous, precipitated hemicelluloses in pretreated AMH solids resulted in a larger drop in cellulose conversion than the delignified lignocellulosic biomass containing comparably much higher natural hemicellulose amounts. Increased cellulase loadings or supplementation of cellulase with xylanases enhanced cellulose conversion for most pretreated AMH solids; however, this approach

Experimental setup for studying the effects of alpha particles on zebrafish embryos

International Nuclear Information System (INIS)

Yum, E.H.W.; Ng, C.K.M.; Lin, A.C.C.; Cheng, S.H.; Yu, K.N.

2007-01-01

In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 μm were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human

Experimental setup for studying the effects of alpha particles on zebrafish embryos

Energy Technology Data Exchange (ETDEWEB)

Yum, E.H.W.; Ng, C.K.M. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Lin, A.C.C.; Cheng, S.H. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China)], E-mail: peter.yu@cityu.edu.hk

2007-11-15

In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 {mu}m were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human.

Anticodeine aptamer immobilized on a Whatman cellulose paper for thin-film microextraction of codeine from urine followed by electrospray ionization ion mobility spectrometry.

Science.gov (United States)

Hashemian, Zahra; Khayamian, Taghi; Saraji, Mohammad

2015-02-01

A combination of thin-film microextaction based on an aptamer immobilized on modified Whatman cellulose paper followed by electrospray ionization ion mobility spectrometry has been developed for the analysis of codeine in urine samples. The immobilization is based on the covalent linking of an amino-modified anticodeine aptamer to aldehyde groups of the oxidized cellulose paper. The covalent bonds were examined by infrared spectroscopy and elemental analysis. The effect of the extraction parameters, including the elution conditions (solvent type and volume), extraction time, and extraction temperature, on the extraction efficiency were investigated. Under the optimized conditions, the linear dynamic range was found to be 10-300 ng/mL with a detection limit of 3.4 ng/mL for codeine in urine. The relative standard deviation was 6.8% for three replicate measurements of codeine at 100 ng/mL in urine. Furthermore, the samples were analyzed with a standard method for the analysis of codeine using high-performance liquid chromatography with ultraviolet detection. The comparison of the results validates the accuracy of the proposed method as an alternative method for the analysis of codeine in urine samples.

Preparation and properties of thin films used in activity determinations with a 4 {pi} counter; Preparation et proprietes des films minces utilises dans les determinations d'activite au compteur 4 {pi}

Energy Technology Data Exchange (ETDEWEB)

Jannez, M; Le Gallic, Y; Thenard, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

Comparative study of various methods of preparing thin films, for use as source holders in the 4 {pi} counter, and of measuring their thickness. Comparative study of various properties: mechanical resistance; heat resistance; ageing; resistance of rhodopas, polystyrene, formvar and cellulose acetate films to the action of various chemical agents. (author) [French] Etude comparee de divers procedes de preparation de films minces, destines a etre utilises comme supports de sources dans le compteur 4 {pi} et de la mesure de leur epaisseur. Etude comparee de diverses proprietes: resistance mecanique; resistance a la chaleur; vieillissement; resistance a l'action de divers agents chimiques de films de rhodopas, polystyrene, formvar et acetate de cellulose. (auteur)

FILMES BIODEGRADÁVEIS DE AMIDO DE MANDIOCA, PULULANA E CELULOSE BACTERIANA

Directory of Open Access Journals (Sweden)

Ana Claudia Sueiro

Full Text Available The largest consumption of plastics in the world is referred to the synthetic polymers, which are not biodegradable and have a non-renewable source, generating a large environmental impact, especially in urban centers. As a result, in the last two decades several polymers obtained from renewable sources (biopolymers have been studied as potential raw materials for the production of new biodegradable materials with different applications. The objectives of this study were to produce biodegradable films based on cassava starch, pullulan and bacterial cellulose, and also to characterize these films according to their microstructure, barrier, thermal and mechanical properties. The addition of bacterial cellulose and pullulan to the starch films resulted in films with more homogeneous surfaces, and also decreased solubility and water vapor permeability, and increased elongation and thermal stability.

Response of CVD diamond detectors to alpha radiation

Energy Technology Data Exchange (ETDEWEB)

Souw, E.-K. [Brookhaven National Lab., Upton, NY (United States); Meilunas, R.J. [Northrop-Grumman Corporation, Bethpage, NY 11714-3582 (United States)

1997-11-21

This article describes some results from an experiment with CVD diamond films used as {alpha} particle detectors. It demonstrates that bulk polarization can be effectively stopped within a reasonable time interval. This will enable detector calibration and quantitative measurement. A possible mechanism for the observed polarization quenching is discussed. It involves two types of carrier traps and a tentative band-gap model derived from the results of photoconductive current measurements. The experiment was set up mainly to investigate {alpha} detection properties of polycrystalline diamond films grown by the technique of microwave plasma enhanced chemical vapor deposition. For comparison, two commercially purchased diamond wafers were also investigated, i.e., one grown by the DC arc jet method, and the other, a type-IIa natural diamond wafer (not preselected). The best response to {alpha} particles was obtained using diamond thin-films grown by the microwave PECVD method, followed by the type-IIa natural diamond, and finally, the CVD diamond grown by the DC arc jet technique. (orig.). 43 refs.

Cellulose whisker/epoxy resin nanocomposites.

Science.gov (United States)

Tang, Liming; Weder, Christoph

2010-04-01

New nanocomposites composed of cellulose nanofibers or "whiskers" and an epoxy resin were prepared. Cellulose whiskers with aspect ratios of approximately 10 and approximately 84 were isolated from cotton and sea animals called tunicates, respectively. Suspensions of these whiskers in dimethylformamide were combined with an oligomeric difunctional diglycidyl ether of bisphenol A with an epoxide equivalent weight of 185-192 and a diethyl toluenediamine-based curing agent. Thin films were produced by casting these mixtures and subsequent curing. The whisker content was systematically varied between 4 and 24% v/v. Electron microscopy studies suggest that the whiskers are evenly dispersed within the epoxy matrix. Dynamic mechanical thermoanalysis revealed that the glass transition temperature (T(g)) of the materials was not significantly influenced by the incorporation of the cellulose filler. Between room temperature and 150 degrees C, i.e., below T(g), the tensile storage moduli (E') of the nanocomposites increased modestly, for example from 1.6 GPa for the neat polymer to 4.9 and 3.6 GPa for nanocomposites comprising 16% v/v tunicate or cotton whiskers. The relative reinforcement was more significant at 185 degrees C (i.e., above T(g)), where E' was increased from approximately 16 MPa (neat polymer) to approximately 1.6 GPa (tunicate) or approximately 215 MPa (cotton). The mechanical properties of the new materials are well-described by the percolation model and are the result of the formation of a percolating whisker network in which stress transfer is facilitated by strong interactions between the whiskers.

Nanocellulose-Zeolite Composite Films for Odor Elimination.

Science.gov (United States)

Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

2015-07-08

Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 μm thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

Novel cellulose-based halochromic test strips for naked-eye detection of alkaline vapors and analytes.

Science.gov (United States)

Abou-Yousef, Hussein; Khattab, Tawfik A; Youssef, Yehia A; Al-Balakocy, Naser; Kamel, Samir

2017-08-01

A simple, portable and highly sensitive naked-eye test strip is successfully prepared for optical detection of gaseous and aqueous alkaline analytes. Novel pH-sensory tricyanofuran-hydrazone (TCFH) disperse colorant containing a hydrazone recognition functional moiety is successfully synthesized via azo-coupling reaction between active methyl-containing tricyanofuran (TCF) heterocycle and diazonium salt of 4-aminobenzaldehyde followed by Knoevenagel condensation with malononitrile. UV-vis absorption spectra display solvatochromism and reversible color changes of the TCFH solution in dimethyl sulfoxide in response to pH variations. We investigate the preparation of hydrophobic cellulose/polyethylene terephthalate composites characterized by their high affinity for disperse dyes. Composite films made from CA, Cell/CA, PET/CA, and Cell/PET-CA are produced via solvent-casting procedure using 10-30% modified cellulose or modified polyethylene terephthalate. The mechanical properties and morphologies of these composite films are investigated. The prepared pH-sensory hydrazone-based disperse dye is then applied to dye the produced cellulose-based composite films employing the high temperature pressure dyeing procedure. The produced halochromic PET-CA-TCFH test strip provide an instant visible signal from orange to purple upon exposure to alkaline conditions as proved by the coloration measurements. The sensor strip exhibits high sensitivity and quick detection toward ammonia in both of aqueous and vapor phases by naked-eye observations at room temperature and atmospheric pressure. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical reactivity of {alpha}-isosaccharinic acid in heterogeneous alkaline systems

Energy Technology Data Exchange (ETDEWEB)

Glaus, M. A.; Loon, L. R. Van

2009-05-15

Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, {alpha}- isosaccharinic acid ({alpha}-ISA) is the strongest complexant. The prediction of the equilibrium concentration of {alpha}-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of {alpha}-ISA in heterogeneous alkaline model systems containing either Ca(OH){sub 2} or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of {alpha}-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, at either 25 {sup o}C or 90 {sup o}C, and under anaerobic atmospheres obtained by various methods. It was found that {alpha}-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than {alpha}-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was {approx} 50 % of the amount of {alpha}-ISA reacted. Sorption of {alpha}-ISA to Ca(OH){sub 2} contributed only to a minor extent to the loss of {alpha}-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of {alpha}-ISA. Under aerobic conditions {alpha}-ISA was

Preparation and properties of thin films used in activity determinations with a 4 {pi} counter; Preparation et proprietes des films minces utilises dans les determinations d'activite au compteur 4 {pi}

Energy Technology Data Exchange (ETDEWEB)

Jannez, M.; Le Gallic, Y.; Thenard, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

Comparative study of various methods of preparing thin films, for use as source holders in the 4 {pi} counter, and of measuring their thickness. Comparative study of various properties: mechanical resistance; heat resistance; ageing; resistance of rhodopas, polystyrene, formvar and cellulose acetate films to the action of various chemical agents. (author) [French] Etude comparee de divers procedes de preparation de films minces, destines a etre utilises comme supports de sources dans le compteur 4 {pi} et de la mesure de leur epaisseur. Etude comparee de diverses proprietes: resistance mecanique; resistance a la chaleur; vieillissement; resistance a l'action de divers agents chimiques de films de rhodopas, polystyrene, formvar et acetate de cellulose. (auteur)

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...

Radiation modification of cellulose pulps. Preparation of cellulose derivatives

International Nuclear Information System (INIS)

Iller, E.; Zimek, Z.; Stupinska, H.; Mikolajczyk, W; Starostka, P.

2005-01-01

One of the most common methods of cellulose pulp modification (activation) applied in the production process of cellulose derivatives is the treatment of the pulp with NaOH solutions leading to the formation of alkalicellulose. The product then undergoes a prolonged process of maturation by its storage under specific conditions. The goal of the process is lowering of the molecular weight of cellulose down to the level resulting from various technological requirements. The process is time-consuming and costly; besides, it requires usage of large-capacity technological vessels and produces considerable amounts of liquid waste. Therefore, many attempts have been made to limit or altogether eliminate the highly disadvantageous stage of cellulose treatment with lye. One of the alternatives proposed so far is the radiation treatment of the cellulose pulp. In the pulp exposed to an electron beam, the bonds between molecules of D-antihydroglucopiranoses loosen and the local crystalline lattice becomes destroyed. This facilitates the access of chemical reagents to the inner structure of the cellulose and, in consequence, eliminates the need for the prolonged maturation of alkalicellulose, thus reducing the consumption of chemicals by the whole process. Research aimed at the application of radiation treatment of cellulose pulp for the production of cellulose derivatives has been conducted by a number of scientific institutions including the Institute of Nuclear Chemistry and Technology, Institute of Biopolymers and Chemical Fibres, and Pulp and Paper Research Institute. For the investigations and assessment of the molecular, hypermolecular, morphologic properties and the chemical reactivity, cellulose pulps used for chemical processing, namely Alicell, Borregaard and Ketchikan, as well as paper pulps made from pine and birch wood were selected. The selected cellulose pulps were exposed to an electron beam with an energy of 10 MeV generated in a linear electron accelerator

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

KAUST Repository

Ong, Rui Chin; Chung, Neal Tai-Shung; de Wit, Jos S.; Helmer, Bradley J.

2015-01-01

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

Mild and modular surface modification of cellulose via hetero Diels-Alder (HDA) cycloaddition.

Science.gov (United States)

Goldmann, Anja S; Tischer, Thomas; Barner, Leonie; Bruns, Michael; Barner-Kowollik, Christopher

2011-04-11

A combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and hetero Diels-Alder (HDA) cycloaddition was used to effect, under mild (T ≈ 20 °C), fast, and modular conditions, the grafting of poly(isobornyl acrylate) (M(n) = 9800 g mol(-1), PDI = 1.19) onto a solid cellulose substrate. The active hydroxyl groups expressed on the cellulose fibers were converted to tosylate leaving groups, which were subsequently substituted by a highly reactive cyclopentadienyl functionality (Cp). By employing the reactive Cp-functionality as a diene, thiocarbonyl thio-capped poly(isobornyl acrylate) synthesized via RAFT polymerization (mediated by benzyl pyridine-2-yldithioformiate (BPDF)) was attached to the surface under ambient conditions by an HDA cycloaddition (reaction time: 15 h). The surface-modified cellulose samples were analyzed in-depth by X-ray photoelectron spectroscopy, scanning electron microscopy, elemental analysis, Fourier transform infrared (FT-IR) spectroscopy as well as Fourier transform infrared microscopy employing a focal plane array detector for imaging purposes. The analytical results provide strong evidence that the reaction of suitable dienophiles with Cp-functional cellulose proceeds under mild reaction conditions (T ≈ 20 °C) in an efficient fashion. In particular, the visualization of individual modified cellulose fibers via high-resolution FT-IR microscopy corroborates the homogeneous distribution of the polymer film on the cellulose fibers.

Radon detection in soils by solid state nuclear track detectors

International Nuclear Information System (INIS)

Moraes, M.A.P.V. de; Khouri, M.T.F.C.

1986-01-01

The solid state nuclear track detectors technique was developed to be used in radon detection, by alpha particles tracks, and its application in uranium prospecting on the ground. The sensitive films to alpha particles used are the cellulose nitrate films LR 115 and CA 8015. Several simulations experiments and field measurements were carried out to verify the method possibilities. Maps of some anomalies in Caetite City (Bahia, Brazil) were made with the densities of tracks obtained. The results were compared with scintillation counter measurements. (Author) [pt

Bacterial cellulose membrane as flexible substrate for organic light emitting devices

International Nuclear Information System (INIS)

Legnani, C.; Vilani, C.; Calil, V.L.; Barud, H.S.; Quirino, W.G.; Achete, C.A.; Ribeiro, S.J.L.; Cremona, M.

2008-01-01

Bacterial cellulose (BC) membranes produced by gram-negative, acetic acid bacteria (Gluconacetobacter xylinus), were used as flexible substrates for the fabrication of Organic Light Emitting Diodes (OLED). In order to achieve the necessary conductive properties indium tin oxide (ITO) thin films were deposited onto the membrane at room temperature using radio frequency (r.f.) magnetron sputtering with an r.f. power of 30 W, at pressure of 8 mPa in Ar atmosphere without any subsequent thermal treatment. Visible light transmittance of about 40% was observed. Resistivity, mobility and carrier concentration of deposited ITO films were 4.90 x 10 -4 Ohm cm, 8.08 cm 2 /V-s and - 1.5 x 10 21 cm -3 , respectively, comparable with commercial ITO substrates. In order to demonstrate the feasibility of devices based on BC membranes three OLEDs with different substrates were produced: a reference one with commercial ITO on glass, a second one with a SiO 2 thin film interlayer between the BC membrane and the ITO layer and a third one just with ITO deposited directly on the BC membrane. The observed OLED luminance ratio was: 1; 0.5; 0.25 respectively, with 2400 cd/m 2 as the value for the reference OLED. These preliminary results show clearly that the functionalized biopolymer, biodegradable, biocompatible bacterial cellulose membranes can be successfully used as substrate in flexible organic optoelectronic devices

16 CFR 1611.33 - Test procedures for textile fabrics and film.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Test procedures for textile fabrics and film... REGULATIONS STANDARD FOR THE FLAMMABILITY OF VINYL PLASTIC FILM Rules and Regulations § 1611.33 Test procedures for textile fabrics and film. (a)(1) All textile fabrics (except those with a nitro-cellulose...

Self-Standing Nanocellulose Janus-Type Films with Aldehyde and Carboxyl Functionalities.

Science.gov (United States)

Nypelö, Tiina; Amer, Hassan; Konnerth, Johannes; Potthast, Antje; Rosenau, Thomas

2018-03-12

Nanocellulose-based self-standing films are becoming a substrate for flexible electronics, diagnostics, and sensors. Strength and surface chemistry are vital variables for these film-based endeavors, the former is one of the assets of nanocellulose. To contribute to the latter, nanocellulose films are tuned with a side-specific functionalization, having an aldehyde and a carboxyl side. The functionalities were obtained combining premodification of the film components by periodate oxidation with ozone post-treatment. Periodate oxidation of cellulose nanocrystals results in film components that interact through intra- and intermolecular hemiacetals and lead to films with an elastic modulus of 11 GPa. The ozone treatment of one film side induces conversion of the aldehyde into carboxyl functionalities. The ozone treatment on individual crystals was largely destructive. Remarkably, such degradation is not observed for the self-standing film, and the film strength at break is preserved. Preserving a physically intact film despite ozone treatment is a credit to using the dry film structure held together by interparticle covalent linkages. Additionally, gas-phase post-treatment avoids disintegration that could result from immersion into solvents. The crystalline cellulose "Janus" film is suggested as an interfacial component in biomaterial engineering, separation technology, or in layered composite materials for tunable affinity between the layers.

In-situ Long-range Alpha Particles and X-ray Detection for Thin-film Pd Cathodes During Electrolysis in Li_2SO_4/H_2O

Science.gov (United States)

Lipson, A. G.; Roussetski, A. S.; Castano, C. H.; S-O, Kim; Miley, G. H.

2002-03-01

Measurements of long-range alpha and soft X-ray emissions have been performed using cyclotron calibrated CR-39 plastic track and LiF/Al_2O_3:C-Thermo-Luminescent (TLD) detectors. Application of CR-39 and TLD detectors to the surface of the thin Pd film-cathodes sputtered on the insulator substrate (glass, Al_2O_3, PMMA) allows detection of both alpha and soft X-ray emissions simultaneously with excess heat measurements during electrolysis using 1 Molar Li_2SO_4/H_20 electrolyte. The alpha particles in the range of 8.0 d> 6.0 μm) were detected upon the electrolysis. Those alpha-tracks are quite unique, never having been observed during CR-39 exposure with trans-uranium alpha -sources (Am^241, Pu^239). The TLD measurement shows generation of the low intensity 5.0-10.0 keV X-ray quanta (Φx < 5.0 s -1*cm-2) accompanying the alpha emission.

Characterization of composite biofilms of wheat gluten and cellulose acetate phthalate

Directory of Open Access Journals (Sweden)

F. M. Fakhouri

2004-06-01

Full Text Available The objective of this research was to develop and characterize composite biofilms produced using wheat gluten and cellulose acetate phthalate. Biofilms act as barriers to moisture and oxygen diffusion through the film. The films were prepared with different thicknesses and component concentrations and were analyzed for water vapor and oxygen permeabilities, water and acid solubilities and mechanical properties. Results showed that the mixture improved film characteristics more than each of the individual components alone. The 1:1 mixture had properties of better permeability to water and oxygen. The composite films were completely soluble in water and acid, with the exception of the film with the highest gluten concentration, which was 50% soluble in water and acid. An increase in gluten concentration in the composite films resulted in a decrease in tensile strength. There was no significant difference in elongation at break between the composite films. No difference in thickness was detected either. Results showed that the mixture improved the characteristics more than of the individual components alone.

Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

Directory of Open Access Journals (Sweden)

Hudson Alves Silvério

2014-12-01

Full Text Available In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH30 on the mechanical, thermal, and barrier properties of methylcellulose (MC nanocomposites were evaluated. MC/WSH30 nanocomposite films with different filler levels (2, 4, 6, 8, and 10% were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH30, formation of a continuous network of WSH30 linked by hydrogen interactions and a close association between filler and matrix.

Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Silverio, Hudson Alves; Flauzino Neto, Wilson Pires; Silva, Ingrid Souza Vieira da; Rosa, Joyce Rover; Pasquini, Daniel, E-mail: pasquini@iqufu.ufu.br, E-mail: danielpasquini2005@yahoo.com.br [Universidade de Uberlandia (USU), MG (Brazil). Instituto de Quimica; Assuncao, Rosana Maria Nascimento de [Universidade de Uberlandia (USU), Ituiutaba, MG (brazil). Fac. de Ciencias Integradas do Pontal; Barud, Hernane da Silva; Ribeiro, Sidney Jose Lima [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica

2014-11-15

In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH{sub 30}) on the mechanical, thermal, and barrier properties of methylcellulose (MC) nanocomposites were evaluated. MC/WSH{sub 30} nanocomposite films with different filler levels (2, 4, 6, 8, and 10%) were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH{sub 30}, formation of a continuous network of WSH{sub 30} linked by hydrogen interactions and a close association between filler and matrix. (author)

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

16 CFR 1610.33 - Test procedures for textile fabrics and film.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Test procedures for textile fabrics and film... for textile fabrics and film. (a)(1) All textile fabrics (except those with a nitro-cellulose fiber... under the procedures outlined in part 1611, Standard for the Flammability of Vinyl Plastic Film, and if...

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.

Uniform irradiation system using beam scanning method for cyclotron

International Nuclear Information System (INIS)

Agematsu, Takashi; Okumura, Susumu; Arakawa, Kazuo

1994-03-01

JAERI AVF-cyclotron is equipped with an ion beam scanner for large area irradiation. The two-dimensional fluence distribution of ion beam obtained using cellulose triacetate film dosimeter was not uniform. This is resulted from the distortion of excitation current for electromagnet of the scanner. So, the beam scanning condition, i.e., the relation between the ion species, the beam profile and the scanning width, was extremely limited to make a good uniformity. We have developed a beam scanning simulator to get fluence distributions by calculation and then compared the simulated distributions with the measured ones. It was revealed that the both of them are in good agreement and the beam scanning condition to get good uniformity was led by using this simulator. On the basis of these results, the power supply of scanner was improved. A good uniformity of beam distribution was available. (author)

Pigment-cellulose nanofibril composite and its application as a separator-substrate in printed supercapacitors

Science.gov (United States)

Torvinen, Katariina; Lehtimäki, Suvi; Keränen, Janne T.; Sievänen, Jenni; Vartiainen, Jari; Hellén, Erkki; Lupo, Donald; Tuukkanen, Sampo

2015-11-01

Pigment-cellulose nanofibril (PCN) composites were manufactured in a pilot line and used as a separator-substrate in printed graphene and carbon nanotube supercapacitors. The composites consisted typically of 80% pigment and 20% cellulose nanofibrils (CNF). This composition makes them a cost-effective alternative as a substrate for printed electronics at high temperatures that only very special plastic films can nowadays stand. The properties of these substrates can be varied within a relatively large range by the selection of raw materials and their relative proportions. A semi-industrial scale pilot line was successfully used to produce smooth, flexible, and nanoporous composites, and their performance was tested in a double functional separator-substrate element in supercapacitors. The nanostructural carbon films printed on the composite worked simultaneously as high surface area active electrodes and current collectors. Low-cost supercapacitors made from environmentally friendly materials have significant potential for use in flexible, wearable, and disposable low-end products. [Figure not available: see fulltext.

Intrinsic efficiency of LR-115 in alpha particles detection: simulations and experiments

International Nuclear Information System (INIS)

Aharmim, B.; Sabir, A.; Marah, H.

2002-01-01

A numerical simulation is developed to characterize the response of the cellulose nitrate detector ''LR-115 type II'' to alpha particles of different incidence angles and energies. It permits to know whether an alpha particle at a given energy and direction is able to produce a visible etched track or not. For this purpose, a V t -variable track etch rate model is used. We have considered that the track etch rate is a function of the ionization rate and the defect created by delta rays along the alpha particle trajectory. Validation of the model is presented in the form of comparisons between theoretically computed values of the sensitive energy range and the track diameters and experimentally determined ones

Electrochemical and dissolution studies on coated film and magnetite pellet in PDCA and NTA based formulations

International Nuclear Information System (INIS)

Srinivasan, M.P.; Sumathi, S.; Rangarajan, S.; Narasimhan, S.V.

2000-01-01

In water cooled nuclear reactors magnetite often exists as both mobile particulate protective film on the inner surface of the PHT system. To determine the mechanism and kinetics of dissolution from a film coated on carbon steel (CS) and magnetite pellet electrochemical measurements were carried out in 2,6-pyridine dicarboxylic acid (PDCA) and nitrilo-triacetic acid (NTA) based formulations containing ascorbic acid (AA) and citric acid (CA) at 28 degC and 60 degC. The solution redox potential arises based on the release of relative amounts of Fe 2+ and Fe 3+ . Complexation, adsorption and reduction affect the concentration of these species in solutions. On coated specimen, the pore size and rate of formation via auto reduction contribute to the observed potential. In PDCA based formulation higher percentage of magnetite dissolution with lower base metal corrosion was observed as compared to that in NTA based formulation. The base metal aided dissolution due to the pores and microcracks in the film (Auto reduction) was observed for coated film. The dominant role of surface adsorption characteristics of PDCA, AA and CA were evident in magnetite pellet dissolution studies. (author)

Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

Directory of Open Access Journals (Sweden)

Chukwuemeka P. Azubuike