Journal Articles

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Subject: search.filters.subject.Cellulose

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    Coconut coir pith, available in abundance especially in tropical countries, was studied as a substrate for the production of cellulase[1,4(1,3;1,4)???D?glucan 4?glucanohydrolase, EC 3.2.1.4] and ??D?glucosidase(??D?glucoside glucohydrolase, EC 3.2.1.21) in solid state fermentation. The effects of fermentation time, nutrient level, substrate particle size and inoculum size have been examined for optimal production of these enzymes by the fungal strain Aspergillus niger NCIM 1005. The highest filter paper activity (FPA) of 4.11 IU g?1, carboxyl methyl cellulose (CMCase) activity of 15·55 IU g?1 and cellobiase activity of 9·31 IU g?1 were obtained after 7 to 8 days of fermentation. Reese and Mandel's mineral solution in the substrate to mineral solution ratio of 1:10 (w/v) supported high cellulase and cellobiase activities. An inoculum size of 20–50% (v/v) based on the volume of mineral medium and substrate average particle size of 375 ?m were optimum for enzyme production. Copyright © 1994 SCI
    (Production of cellulases from coconut coir pith in solid state fermentation) Muniswaran, P.K.A.; Selvakumar, P.; Charyulu, N.C.L.N.
    1994
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    Biodegradability of PMMA blends with some cellulose derivatives
    (2006) Bhat, D.K.; Muthu, M.S.
    High polymer blends of Polymethyl methacrylate (PMMA) with cellulose acetate (CA) and Cellulose acetate phthalate (CAP) of varying blend compositions have been prepared to study their biodegradation behavior and blend miscibility. Films of PMMA-CA, and PMMA-CAP blends have been prepared by solution casting using Acetone and Dimethyl formamide(DMF) as solvents respectively. Biodegradability of these blends has been studied by four different methods namely, soil burial test, enzymatic degradation, and degradation in phosphate buffer and activated sludge degradation followed by water absorption tests to support the degradation studies. Degradation analysis was done by weight loss method. The results of all the tests showed sufficient biodegradability of these blends. Degradability increased with the increase in CA and CAP content in the blend compositions. The miscibility of PMMA-CA and PMMA-CAP blends have been studied by solution viscometric and ultrasonic methods. The results obtained reveal that PMMA forms miscible blends with either CA or CAP in the entire composition range. Miscibility of the blends may be due to the formation of hydrogen bond between the carbonyl group of PMMA and the free hydroxyl group of CA and CAP. © Springer Science+Business Media, Inc. 2006.
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    Miscibility, water uptake, ion exchange capacity, conductivity and dielectric studies of poly(methyl methacrylate) and cellulose acetate blends
    (2013) Jois, H.S.S.; Bhat, D.K.
    In the last few decades, polymer blends with good miscibility and conductivity have been the focus of study for material scientists. Here, polymer blends of Poly(methyl methacrylate) (PMMA) and Cellulose acetate (CA) of varying blend compositions have been prepared by solution casting method and their miscibility, water uptake, ion exchange capacity (IEC) proton conductivity, and dielectric properties have been studied. Dimethyl formamide (DMF) was used as solvent. Fourier transform infrared spectra (FTIR) and Differential scanning calorimetry (DSC) measurements have been used to analyze the miscibility of the blends. Up to 50/50 PMMA/CA, water uptake showed an increasing trend and for other compositions the value decreased. Ion exchange capacity and conductivity of the blends decreased with increase in PMMA content of the blends. The variations in the blend properties have been attributed to the presence of specific interactions and exchangeable groups in the blend system. The proton conductivity of the blends is in the order of 10-3 S cm-1. Impedance analysis of the blends indicated the absence of any relaxation phenomenon in the blend system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3074-3081, 2013 Copyright © 2013 Wiley Periodicals, Inc.
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    Enhanced permeation performance of cellulose acetate ultrafiltration membranes by incorporation of sulfonated poly(1,4-phenylene ether ether sulfone) and poly(styrene- Co -maleic anhydride)
    (American Chemical Society service@acs.org, 2014) Shenvi, S.; A.F., A.F.; Isloor, A.M.
    A cellulose acetate (CA)-based ultrafiltration membrane was prepared by incorporation of mechanically strong, sulfonated poly(1,4-phenylene ether ether sulfone) (SPEES) to which hydrolyzed poly(styrene-co-maleic anhydride) (PSMA) was added as a novel additive. The preparation of SPEES was investigated in detail. SPEES having a degree of sulfonation of 21%, was more suitable for the blend. The chemical constitutions of SPEES, PSMA, and the blend membranes were confirmed by attenuated total reflectance fourier transform infrared spectroscopy. The scanning electron microscopy images revealed finger-like projections in the membrane structure. The performance of the membranes was analyzed on the basis of water content, porosity, flux, and antifouling studies. A membrane comprising 30% SPEES and 2% additive showed superior performance with flux and flux recovery ratio of 228 L/(m2 h) and 91%, respectively. It was concluded that the prepared membranes showed better performance in comparison with neat CA membranes. © 2014 American Chemical Society.
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    Preparation and characterization of phosphoric acid-doped hydroxyethyl cellulose electrolyte for use in supercapacitor
    (SpringerOpen, 2015) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.
    A new borax cross-linked biodegradable solid polymer electrolyte based on hydroxyethyl cellulose and phosphoric acid (H3PO4) was prepared. Characterizations of doped and undoped SPE were done using Fourier transform infrared spectroscopic and electrochemical studies. The ionic conductivity of the films increased with increase in acid concentration and the ionic conductivity obtained at 303 K was 4.1 × 10-3 S cm-1. Furthermore, effects of acid concentration on ionic conductivity and activation energy were discussed. Dielectric studies showed long tail-like feature indicating capacitive nature. A supercapacitor was fabricated and its electrochemical characteristics were studied. The supercapacitor showed a fairly good specific capacitance of 83 F g-1 at 2 mV s-1 and galvanostatic charge-discharge studies showed the mirror-like pattern with 98 % columbic efficiency. Cyclic stability was measured up to 2000 cycles. © 2015 The Author(s).
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    Ionic conductivity and dielectric studies of acid doped cellulose acetate propionate solid electrolyte for supercapacitor
    (John Wiley and Sons Inc, 2016) Sudhakar, Y.N.; Bhat, D.; Muthu, M.
    Phosphoric acid doped cellulose acetate propionate (CAP) consisting of poly(ethylene glycol) (PEG) as plasticizer was investigated. Ionic conductivities and dielectric studies were carried at different temperature with varying concentration of H3PO4 using AC impedance method. The highest conductivity was 8.1 × 10-4 S cm-1 at 343 K and a long tail was featured in dielectric studies indicating good capacitance nature of the electrolyte. Interactions between added constituents were observed in FTIR and differential scanning calorimetry studies. Thin and compact fabricated supercapacitor demonstrated specific capacitance of 64 F g-1 using cyclic voltammetry. Furthermore, the supercapacitor properties like AC impedance and charge-discharge were studied. Stability was up to 96% at 1000th cycle. POLYM. ENG. SCI., 56:196-203, 2016. © 2015 Society of Plastics Engineers.
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    Photocatalytic degradation of phenol using Ag core-TiO2 shell (Ag@TiO2) nanoparticles under UV light irradiation
    (Springer Verlag service@springer.de, 2016) Shet, A.; Shetty K, K.V.
    Ag@TiO2 nanoparticles were synthesized by one pot synthesis method with postcalcination. These nanoparticles were tested for their photocatalytic efficacies in degradation of phenol both in free and immobilized forms under UV light irradiation through batch experiments. Ag@TiO2 nanoparticles were found to be the effective photocatalysts for degradation of phenol. The effects of factors such as pH, initial phenol concentration, and catalyst loading on phenol degradation were evaluated, and these factors were found to influence the process efficiency. The optimum values of these factors were determined to maximize the phenol degradation. The efficacy of the nanoparticles immobilized on cellulose acetate film was inferior to that of free nanoparticles in UV photocatalysis due to light penetration problem and diffusional limitations. The performance of fluidized bed photocatalytic reactor operated under batch with recycle mode was evaluated for UV photocatalysis with immobilized Ag@TiO2 nanoparticles. In the fluidized bed reactor, the percentage degradation of phenol was found to increase with the increase in catalyst loading. © 2015, Springer-Verlag Berlin Heidelberg.
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    Synthesis and characterisation of TiO2 nanofibre/cellulose acetate nanocomposite ultrafiltration membrane
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2017) Neelapala, S.D.; Nair, A.K.; JagadeeshBabu, J.
    Nanofibres of TiO2 were synthesised by hydrothermal routine. Cellulose acetate/TiO2 nanofibre composite membranes were synthesised via blending TiO2 nanofibre in cellulose acetate solutions in 1-methyl-2-pyrrolidone. In order to study the effect of addition of nanofibre, membranes with various composition were synthesised, first by keeping cellulose acetate to 1-methyl-2-pyrrolidone ratio constant and second by decreasing cellulose acetate concentration with increasing addition of TiO2 nanofibre. The membranes were characterised using scanning electron microscope and X-ray diffraction. Hydrophilicity of the membranes was evaluated in terms of contact angle measurements and water uptake study. Permeation characteristics were determined in terms of pure water flux and bovine serum albumin rejection. Antifouling property was studied in terms of flux recovery after rejection. Remarkable improvement in membrane flux and antifouling properties is achieved by the addition of TiO2 nanofibres. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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    Biocomposite composed of PVA reinforced with cellulose microfibers isolated from biofuel industrial dissipate: Jatropha Curcus L. seed shell
    (Elsevier Ltd, 2017) Manjula, M.; Srinikethan, G.; Shetty K, V.K.
    Biofuel production by Jatropha Curcas L. (JC) seeds result in large quantities of unused seed shells contributing as an extensive potential source for cellulose production. Present work consummates on isolation of cellulose microfibers (CMF) from JC seed shell by chlorination treatment and were characterized using Scanning Electron Microscope (SEM), Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and 13C NMR. Removal of hemicellulose and lignin were confirmed from FTIR results. Cellulose microfibers with diameter 0.23-1.04 ?m demonstrated considerable increase in crystallinity and thermal stability by chlorination treatment. Procured cellulose microfibers were reinforced in Poly-vinyl Alcohol (PVA) by solution casting in water to form biocomposites. Mechanical properties and thermal stability of these biocomposites increased on addition of cellulose microfiber, ensuring the potentiality of cellulose fibers as filler in biocomposites which can reinstate traditional plastics. © 2017 Published by Elsevier Ltd.
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    Biofibres from biofuel industrial byproduct—Pongamia pinnata seed hull
    (Springer Science and Business Media Deutschland GmbH, 2017) Manjula, P.; Srinikethan, G.; Shetty K, K.V.
    Background: Biodiesel production using Pongamia pinnata (P. pinnata) seeds results in large amount of unused seed hull. These seed hulls serve as a potential source for cellulose fibres which can be exploited as reinforcement in composites. Methods: These seed hulls were processed using chlorination and alkaline extraction process in order to isolate cellulose fibres. Scanning electron microscopy (SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR) analysis demonstrated the morphological changes in the fibre structure. Results: Cellulose microfibres of diameter 6–8 µm, hydrodynamic diameter of 58.4 nm and length of 535 nm were isolated. Thermal stability was enhanced by 70 °C and crystallinity index (CI) by 19.8% ensuring isolation of crystalline cellulose fibres. Conclusion: The sequential chlorination and alkaline treatment stemmed to the isolation of cellulose fibres from P. pinnata seed hull. The isolated cellulose fibres possessed enhanced morphological, thermal, and crystalline properties in comparison with P. pinnata seed hull. These cellulose microfibres may potentially find application as biofillers in biodegradable composites by augmenting their properties. © 2017, The Author(s).