S. A. Vshivkov

Phase equilibrium, structure, and rheological properties of the carboxymethyl cellulose-water system

The phase transitions, structure, and rheological properties of the carboxymethyl cellulose-water system were studied via the turbidity-point method, viscometry, polarization microscopy, and the turbidityspectrum method as well as with a polarization photoelectric unit. The regions of existence of the isotropic and anisotropic phases, the gel point, and the concentration dependence of the supramolecular-particle size were determined. Magnetic-field application results in a gain in the viscosities of carboxymethyl cellulose solutions.

Effect of a magnetic field on the rheological properties of cellulose ether solutions

Application of a magnetic field is shown to be accompanied by an increase in the viscosity of hydroxyethyl cellulose and ethyl cellulose solutions and an additional assembly of macromolecules, as is evident from a gain in the radii of light-scattering particles. The concentration dependences of supramolecular-particle radius and solution viscosity in the presence of a magnetic field are described by curves with maxima.

Effect of a magnetic field on the rheological properties of the systems hydroxypropyl cellulose–ethanol and hydroxypropyl cellulose–dimethyl sulfoxide

With the use of viscometry, the cloud-point method, polarization microscopy, the turbidity-spectrum method, and a polarization photoelectric apparatus, the relaxation pattern of the rheological behaviors, phase transitions, and structures of the systems hydroxypropyl cellulose–ethanol and hydroxypropyl cellulose–dimethyl sulfoxide are studied. The regions of existence of isotropic and anisotropic phases and the concentration dependence of the sizes of supramolecular particles are determined. It is found that a magnetic field increases the viscosities of solutions. The concentration dependences of viscosity and particle size are described by curves with maxima.

Phase transitions, structures, and rheological properties of hydroxypropyl cellulose–ethylene glycol and ethyl cellulose–dimethylformamide systems in the presence and in the absence of a magnetic field

Phase transitions, structures, and rheological properties of hydroxypropyl cellulose–ethylene glycol and ethyl cellulose–dimethylformamide systems in the presence and in the absence of a magnetic field have been studied. The application of the magnetic-field results in increases in viscosity and supramolecular particle size in solutions of cellulose ethers. Concentration dependences of viscosity and particle size are described by curves with maxima.

Effect of a magnetic field on the rheological properties of iron oxide–water–glycerol system

The viscosity of magnetic fluids consisting of iron oxide nanoparticles, water, and glycerol has been studied under the conditions of a rotational flow in the presence and absence of a magnetic field. The magnetic field increases the fluid viscosity by 20–80 times. The concentration dependence of the relative viscosity on the magnetic field is described by a curve passing through a maximum. The magnetic field with the lines oriented perpendicularly to the rotor-rotation axis increases the viscosity of the fluid much more strongly than it does with the lines parallel to the rotor-rotation axis.

Relaxation Character of the Rheological Behavior of Cellulose Ether Solutions in a Magnetic Field

The relaxation character of the rheological behavior of hydroxypropyl cellulose and ethyl cellulose solutions in a magnetic field and without it was studied. Application of magnetic field leads to an increase in the viscosity of cellulose ether solutions. The mechanical and magnetic field energies stored by the solutions at flow were calculated.

Effect of a magnetic field on the rheological properties of magnetic liquids based on iron oxides

The concentration dependence of the effect a static magnetic field has on the viscosity of aqueous and water-glycerol magnetic liquids based on Fe2.8O4 iron oxide is studied. The viscosity of aqueous and water-glycerol magnetic liquids are found to grow by factors of 2.5 and 20, respectively, as the concentration of magnetic particles and the field intensity grow. The concentration dependence of the magnetic field effect passes through a maximum.

Effect of magnetic field on phase transitions in solutions and melts of flexible polymers

The effect of the magnetic field on the phase diagrams of flexible-chain polymer–solvent systems is observed for the first time. Phase transitions in systems with the crystalline-phase separation (PE–o-xylene, PE–n-hexane, PE–chloroform, PE–o-dichlorobenzene, PEG–1,4-dioxane, PEG–toluene) and the amorphous demixing (PS–methyl acetate, PVA–ethanol, PDMS–butanone) are studied. The magnetic field increases the temperatures of crystallization of PE and PEG from solutions and melts but has no effect on phase transitions in PS, PVA, and PDMS solutions. The structures of polymer entities isolated from solutions and melts are studied. Under application of the magnetic field to PEG solutions, spherulites of substantially smaller sizes than those formed outside the field appear. The magnetic field increases the degree of crystallinity of PEG, but the degree of crystallinity and size of PE spherulites remain unchanged.

Effect of magnetic field on the rheological properties of poly(ethylene glycol) and poly(dimethylsiloxane) mixtures with aerosil and iron nanoparticles

The effect of a magnetic field on the viscosity of magnetorheological poly(ethylene glycol)-aerosil-iron nanoparticle and poly(dimethylsiloxane)-aerosil-iron nanoparticle suspensions is studied. The magnetic field leads to an increase in the viscosity of the suspensions by a factor of 20–300. The concentration dependence of the effect of magnetic field on the viscosity of the systems is described by a curve with a maximum. The dependences of viscosity on shear rate upon loading and unloading do not coincide, thus indicating the relaxation character of the flow process.

Thermodynamic parameters of the interaction of cellulose ethers with low-molecular-mass liquids

The thermodynamic analysis of the interaction of methyl cellulose, cyanoethyl cellulose, cyanoethyl hydroxyethyl cellulose, and hydroxyethyl cellulose with low-molecular-mass liquids is performed via the method of static sorption. A correlation is found between the thermodynamic parameters and the chemical structures of the components.