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Catarina M M Duarte - One of the best experts on this subject based on the ideXlab platform.

  • preparation of ethyl Cellulose Methyl Cellulose blends by supercritical antisolvent precipitation
    International Journal of Pharmaceutics, 2006
    Co-Authors: Ana Rita C Duarte, M.d. Gordillo, Margarida M Cardoso, Ana Luísa Simplício, Catarina M M Duarte
    Abstract:

    Abstract The supercritical antisolvent (SAS) technique was used to prepare ethyl Cellulose/Methyl Cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl Cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as Methyl Cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 μm were obtained. The effect of CO 2 and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and diMethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 °C and 80 bar.

  • Preparation of ethyl Cellulose/Methyl Cellulose blends by supercritical antisolvent precipitation.
    International Journal of Pharmaceutics, 2006
    Co-Authors: Ana Rita C Duarte, M.d. Gordillo, Margarida M Cardoso, Ana Luísa Simplício, Catarina M M Duarte
    Abstract:

    Abstract The supercritical antisolvent (SAS) technique was used to prepare ethyl Cellulose/Methyl Cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl Cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as Methyl Cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 μm were obtained. The effect of CO 2 and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and diMethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 °C and 80 bar.

  • Preparation of ethyl Cellulose/Methyl Cellulose blends by supercritical antisolvent precipitation.
    International journal of pharmaceutics, 2006
    Co-Authors: Ana Rita C Duarte, M.d. Gordillo, Margarida M Cardoso, Ana Luísa Simplício, Catarina M M Duarte
    Abstract:

    The supercritical antisolvent (SAS) technique was used to prepare ethyl Cellulose/Methyl Cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl Cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as Methyl Cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 microm were obtained. The effect of CO(2) and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and diMethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 degrees C and 80 bar.

A K Arof - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of Methyl Cellulose-NH_4NO_3-PEG electrolyte and application in fuel cells
    Journal of Solid State Electrochemistry, 2010
    Co-Authors: N E A Shuhaimi, S R Majid, N. A. Alias, M. Z. Kufian, A K Arof
    Abstract:

    We report the viability of Methyl Cellulose (MC) as a membrane in a polymer electrolyte membrane fuel cell (PEMFC). Methyl Cellulose serves as the polymer host, ammonium nitrate (NH_4NO_3) as the doping salt and poly(ethylene glycol) (PEG) as plasticizer. Conductivity measurement was carried out using electrochemical impedance spectroscopy. The room temperature conductivity of pure MC film is $$ \left( {{3}.0{8}\pm 0.{63}} \right) \times {1}{0^{ - {11}}}{\hbox{S}}\,{\hbox{c}}{{\hbox{m}}^{ - {1}}} $$ . The conductivity increased to $$ \left( {{2}.{1}0\pm 0.{37}} \right) \times {1}{0^{ - {6}}}{\hbox{S}}\,{\hbox{c}}{{\hbox{m}}^{ - {1}}} $$ on addition of 25 wt.% NH_4NO_3. By adding 15 wt.% of PEG 200 to the highest conducting sample in the MC-NH_4NO_3 system, the conductivity was further raised by two orders of magnitude to $$ \left( {{1}.{14}\pm 0.{37}} \right) \times {1}{0^{ - {4}}}{\hbox{S}}\,{\hbox{c}}{{\hbox{m}}^{ - {1}}} $$ . The highest conducting sample containing 15 wt.% PEG was used as membrane in PEMFC and was operated at room and elevated temperatures. From voltage-current density characteristics, the short circuit current density was 31.52 mA cm^−2 at room temperature (25 °C).

  • transport studies of nh4no3 doped Methyl Cellulose electrolyte
    Synthetic Metals, 2010
    Co-Authors: N E A Shuhaimi, S R Majid, A K Arof
    Abstract:

    Abstract This work reports on the transport properties of NH 4 NO 3 doped Methyl Cellulose (MC) polymer electrolyte. The polymer electrolyte films were prepared by the technique of solvent casting. The highest room temperature conductivity of MC doped with 25 wt.% NH 4 NO 3 is 2.10 ± 0.37 × 10 −6  S cm −1 . Conductivity–temperature relationship obeys the Vogel–Tamman–Fulcher (VTF) rule from which the glass transition temperature, T g was evaluated. The mobility, μ and number density of charge carrier, n were calculated using the Rice and Roth model.

Ana Rita C Duarte - One of the best experts on this subject based on the ideXlab platform.

  • preparation of ethyl Cellulose Methyl Cellulose blends by supercritical antisolvent precipitation
    International Journal of Pharmaceutics, 2006
    Co-Authors: Ana Rita C Duarte, M.d. Gordillo, Margarida M Cardoso, Ana Luísa Simplício, Catarina M M Duarte
    Abstract:

    Abstract The supercritical antisolvent (SAS) technique was used to prepare ethyl Cellulose/Methyl Cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl Cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as Methyl Cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 μm were obtained. The effect of CO 2 and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and diMethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 °C and 80 bar.

  • Preparation of ethyl Cellulose/Methyl Cellulose blends by supercritical antisolvent precipitation.
    International Journal of Pharmaceutics, 2006
    Co-Authors: Ana Rita C Duarte, M.d. Gordillo, Margarida M Cardoso, Ana Luísa Simplício, Catarina M M Duarte
    Abstract:

    Abstract The supercritical antisolvent (SAS) technique was used to prepare ethyl Cellulose/Methyl Cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl Cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as Methyl Cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 μm were obtained. The effect of CO 2 and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and diMethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 °C and 80 bar.

  • Preparation of ethyl Cellulose/Methyl Cellulose blends by supercritical antisolvent precipitation.
    International journal of pharmaceutics, 2006
    Co-Authors: Ana Rita C Duarte, M.d. Gordillo, Margarida M Cardoso, Ana Luísa Simplício, Catarina M M Duarte
    Abstract:

    The supercritical antisolvent (SAS) technique was used to prepare ethyl Cellulose/Methyl Cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl Cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as Methyl Cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 microm were obtained. The effect of CO(2) and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and diMethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 degrees C and 80 bar.

Ajay Misra - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of worm like silver nanoparticles in Methyl Cellulose polymeric matrix and its catalytic activity
    Carbohydrate Polymers, 2012
    Co-Authors: Dipak Kumar Bhui, Ajay Misra
    Abstract:

    Abstract A facile one step method for the synthesis of wormlike silver nanoparticles has been carried out in Methyl Cellulose matrix. Synthesis is based on the reduction of AgNO3 by sodium borohydride (NaBH4) in aqueous Methyl Cellulose (MC). Synthesized nanoparticles are mostly mono disperse in size and their aggregation is controlled by varying the concentration of AgNO3. Silver nanoparticles are analyzed using transmission electron microscope (TEM), UV–vis spectroscopy and X-ray diffraction (XRD) technique. It has been found that the concentration of AgNO3 has a significant effect on the morphology of Ag nanostructures. Worm like nanostructures showed excellent catalytic activity in the borohydride reduction of p-nitrophenol compared to spherical shaped nanoparticles.

  • Synthesis and characterization of gold nanoparticles adsorbed in Methyl Cellulose micro fibrils
    Journal of Molecular Liquids, 2010
    Co-Authors: Gobinda Prasad Sahoo, Dipak Kumar Bhui, Priyanka Sarkar, Sadhan Samanta, Santanu Pyne, Ajay Misra
    Abstract:

    article i nfo SPR HRTEM EDAX XPS Methyl Cellulose (MC) capped gold nanoparticles are successfully prepared through a simple route. Synthesis is based on the reduction of aqueous HAuCl4.4H2O by hydrogen gas at 85 °C and Methyl Cellulose has been used as encapsulating agent. Gold nanoparticle so-prepared are characterized by UV-Vis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high resolution transmission electron microscopy (HR- TEM). Methyl Cellulose encapsulated gold hydrosol shows broad surface plasmon resonance (SPR) band with maxima at 537 nm along with a broad tail at 635 nm. In accordance with the SPR band, HRTEM micrograph shows two broad distributions of particles, most of them are small and spherical and nearly 25% particles are bigger with uneven shapes.

A. M. Bochek - One of the best experts on this subject based on the ideXlab platform.

  • Orientational order and dimensions of associates in moderately concentrated aqueous solutions of cyanoethyl Methyl Cellulose
    Polymer science. Series A Chemistry physics, 2020
    Co-Authors: N. A. Kalinina, L. I. Kutsenko, E. B. Karetnikova, A. M. Bochek, I. G. Silinskaya, Alexander P. Filippov, L. M. Kalyuzhnaya
    Abstract:

    Specific features of the supramolecular organization of moderately concentrated Methyl Cellulose and cyanoethyl Methyl Cellulose solutions in the pre-gel region are quantitatively described by the method of static scattering of polarized light using the Debye-Bueche-Stein theory. The parameters characterizing the fluctuational heterogeneity and statistical dimensions of associates, as well as the dimensions of oriented regions and the ordering of the system, depend on the amount of highly polar hydrophobic cyanoethyl groups introduced into the Methyl Cellulose macrochains. As this amount increases, the solutions display a tendency for increasing fluctuational heterogeneity and decreasing correlation dimensions of the associates. These structural features are due to a superposition of two processes that take place in the system: the molecular mass of the polymer decreases because of its degradation during esterification and the polymer-solvent thermodynamic affinity deteriorates because of the increasing hydrophobicity of mixed-ester macromolecules. The supramolecular orientational order and hydrophobic association processes in cyanoethyl Methyl Cellulose solutions are compared to the structural organization of moderately concentrated aqueous solutions of propyl Methyl Cellulose.

  • Characteristics of composite films based on Methyl Cellulose and poly(N-vinylformamide) prepared from solutions in water and diMethyl sulfoxide
    Polymer Science Series A, 2011
    Co-Authors: A. M. Bochek, E. F. Panarin, Vladimir E. Yudin, Iosif V. Gofman, N. M. Zabivalova, Sh. Nishiyama, I. I. Gavrilova, N. A. Nesterova, G. M. Poltoratskii, V. E. Smirnova
    Abstract:

    The stress-strain characteristics of composite films based on Methyl Cellulose and poly(vinylformamide) prepared from solutions of polymer blends in water and diMethyl sulfoxide are studied. The temperature of relaxation transitions in the mixed films and the concentration interval where the polymers are compatible are defined via the thermomechanical method and dynamic mechanical analysis. The effect of the nature of a solvent on the mechanism of crystallization of Methyl Cellulose, the stress—strain characteristics of the composite films, and the compatibility between the polymers is investigated.

  • Structure and characteristics of film composites based on Methyl Cellulose, poviargol, and montmorillonite
    Polymer Science Series A, 2011
    Co-Authors: I. P. Dobrovol’skaya, A. M. Bochek, Vladimir E. Yudin, N. F. Drozdova, V. E. Smirnova, Iosif V. Gofman, E. N. Popova, N. M. Zabivalova, I. V. Plugar, E. F. Panarin
    Abstract:

    The structure of film composites based on Methyl Cellulose and fillers, such as montmorillonite and silver nanoparticles stabilized by poly(vinylpyrrolidone) (Poviargol), is studied by X-ray diffraction. In the composite, montmorillonite nanoparticles exist in the exfoliated state; when the content of the nanoparticles is below 7 wt %, the crystallinity of Methyl Cellulose increases. Owing to the presence of the filler and structural ordering of the matrix, elastic characteristics improve and the degradation temperature of the composites increases. The X-ray structural data show that the Ag particles in the Methyl Cellulose-Poviargol composite are 30 nm in size. The introduction of up to 20 wt % Poviargol assists the crystallization of Methyl Cellulose. The strength and strain characteristics of the film composites based on Methyl Cellulose and Poviargol make it possible to use these composites in medicine and agriculture.

  • Properties of blends of Methyl Cellulose and carboxyMethyl Cellulose with different degrees of ionization in solutions and solids
    Russian Journal of Applied Chemistry, 2008
    Co-Authors: A. M. Bochek, I. L. Shevchuk, L. M. Kalyuzhnaya
    Abstract:

    The rheological properties of dilute and moderately concentrated aqueous solutions of Methyl Cellulose with carboxyMethyl Cellulose having different degrees of ionization, were examined. The solvent vapor sorption method was applied to examine the compatibility of the polymers in the solid state and elucidate how the amount of nonionized carboxy groups in carboxyMethyl Cellulose affects its compatibility with Methyl Cellulose.

  • Properties of the Methyl Cellulose-polyvinylpyrrolidone binary system in solution and in the solid state
    Russian Journal of Applied Chemistry, 2007
    Co-Authors: L. I. Kutsenko, E. B. Karetnikova, A. M. Bochek, Iosif V. Gofman, Yu. G. Santuryan, E. F. Panarin
    Abstract:

    Rheological properties of dilute and moderately concentrated aqueous solutions of Methyl Cellulose-polyvinylpyrrolidone blends, as well as the conditions of gelation in them, were studied. Films were obtained from solutions of the polymer blends, and their physicomechanical properties were examined. The range of the compositions corresponding to thermodynamic compatibility of Methyl Cellulose with polyvinylpyrrolidone was identified by the solvent vapor sorption method and by thermomechanical examinations of the films.