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3 results on '"POLYETHYLENE OXYDE"'

1. RESEARCH ON THE BEHAVIOR OF SPINNABLE POLYMER SOLUTIONS IN A HIGH VOLTAGE ELECTROSTATIC FIELD

Author

CIOBOTARU Victor, AVRAM Dorin, and PANTILIMONESCU Florin

Subjects
electrospinning, nanofiber, jet flow rate, jet charge density, polyethylene oxyde, Manufactures, TS1-2301
Abstract

Working parameters are very important to understand the nature of electrospinning. Each of these parameters can affect the fibers morphologies and by proper control of these parameters one can fabricate electrospun fibers with desired morphologies and diameters. Jet charge density is known as one of the important parameters affecting the fiber diameter. To investigate the effect of the applied voltage on jet charge density, one must investigate its effects on the jet electric current and flow rate. There are some difficulties in measuring the jet flow rate. In this work, one method is used to calculate the electrospinning jet flow rate. For exemplification, by using a polyethylene oxide (PEO) solution in water, effects of applied voltage and feed rate on jet charge density is investigated. The jet flow rate is calculated applying different voltages, at different constant feed rates. The jet flow rate is independent of the feed rate and dependent on the applied the voltage. By defining an equation for dependence of jet flow rate on current, a relation between jet volume charge density and jet current can be defined. By measuring the electrospun fiber diameter, surface charge density of the jet can also be estimated. On increasing the voltage, the jet volume charge density decreases whereas the jet surface charge density remains unchanged.

Published
2014

2. Self-Assembling Properties of Well-Defined Poly(ethylene oxide)- b -poly(ethyl acrylate) Diblock Copolymers

Author

Cédric Gaillard, Sandie Piogé, Sagrario Pascual, Erwan Nicol, Laurent Fontaine, Institut des Molécules et Matériaux du Mans (IMMM), Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de la Recherche Agronomique (INRA), and Le Mans Université (UM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
POLYMERISATION RADICALAIRE CONTROLEE, Materials science, Polymers and Plastics, CRYO-TRANSMISSION ELECTRON MICROSCOPY, Dispersity, COPOLYMERE A BLOCS, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Micelle, AGGEGATION NUMBER, MICROSCOPIE ELECTRONIQUE A TRANSMISSION, Inorganic Chemistry, chemistry.chemical_compound, NOMBRE D'AGREGATION, Dynamic light scattering, SELF ASSEMBLY, Polymer chemistry, Materials Chemistry, Copolymer, Static light scattering, FLUORESCENCE, ComputingMilieux_MISCELLANEOUS, POLYETHYLENE OXYDE, Atom-transfer radical-polymerization, Organic Chemistry, ATOM TRANSFER RADICAL POLYMERIZATION, technology, industry, and agriculture, COPOLYMERE AMPHIPHILE, POLYETHYL ACRYLATE, DIBLOCK COPOLYMER, MICELLE, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, TRANSMISSION ELECTRON MICROSCOPY, 0104 chemical sciences, [CHIM.POLY]Chemical Sciences/Polymers, Chemical engineering, chemistry, Polymerization, STATIC LIGHT SCATTERING, Ethyl acrylate, 0210 nano-technology, DYNAMIC LIGHT SCATTERING
Abstract

International audience; Poly(ethylene oxide)-b-poly(ethyl acrylate) amphiphilic diblock copolymers were synthesized by atom transfer radical polymerization (ATRP). The controlled character of the polymerization was confirmed by kinetic studies, evolution of number-average molecular weight and polydispersity index with conversion: Various block copolymers with different PEA/PEO molar ratio were synthesized and their self-assembling properties in aqueous medium were studied by fluorescence measurements, static light scattering (SLS), and dynamic light scattering (DLS). The critical micelle concentrations (CMC) were determined by pyrene fluorescence analysis. The CMC was shown to decrease as the hydrophobic (PEA) block length increases. SLS and DLS allowed the determination of the aggregation numbers (N-agg) and hydrodynamic radii (R-h) of the core-shell micelles formed in water. Both N-agg and R-h exhibit a monotonic increase as a function of the PEA block length. TEM and cryo-TEM micrographs of the ! micelles showed spherical objects with a low polydispersity of sizes. The micelles formed in water are in a thermodynamic equilibrium and the aggregation number of the micelles was shown to vary with the temperature.

Published
2009
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3. Etude comparative des propriétés rhéologiques de mélande bentonite-PEO de différentes masses moléculaires

Author

Ebagninin, Koblan Wilfried, Benchabane, Adel, Bekkour, Karim, Association Française de Mécanique, and Service irevues, irevues

Subjects
bentonite, Polyéthylène oxyde, [PHYS.MECA]Physics [physics]/Mechanics [physics], [PHYS.MECA] Physics [physics]/Mechanics [physics], Rhéologie
Abstract

Colloque avec actes et comité de lecture. Internationale.; International audience; Le but de ce travail est d'étudier l'effet d'un polymère non ionique, utilisé généralement dans la formulation des boues de forage, sur le comportement rhéologique de suspensions de bentonite. Des mesures rhéologiques, granulométriques et zétamétriques ont été effectuées sur une suspension de bentonite, des solutions de PEO (polyéthylène oxyde de masse moléculaire de 4.106, 4.105 et 105 g/mol) et des mélanges bentonite-PEO à différentes concentrations de polymères. L'étude a révélé une forte augmentation (d'autant plus importante que la concentration et le poids moléculaire du PEO augmentent) de la viscosité, de la contrainte seuil et des propriétés viscoélastiques de la suspension argileuse. L'origine de ce changement de comportement a été discutée sur la base de l'étude zétamétrique et granulométrique. Cette dernière a mis en évidence des liaisons pont assurées par les chaînes de polymères entre les particules de bentonite.

Published
2007

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