Ernest E. Said-Galiyev

Swelling and impregnation of polystyrene using supercritical carbon dioxide

Abstract Swelling of polystyrene (PS) in supercritical carbon dioxide was studied in situ. Experiments were carried out in a high-pressure cell furnished with an optical channel. This allowed to measure the dynamics of diffusion front propagation in the polymer samples during the swelling process by the use of an optical microscope supplied with a digital video camera. The measurements of this dynamics provided information about diffusion coefficients of CO 2 molecules in PS. Diffusion coefficients and equilibrium sorption degrees of the PS samples were also calculated by the use of a gravimetric method. The data were compared with the results of in situ technique. Impregnation of PS films wish ethyl-2-cyano-3(4′-dimethylaminophenyl)acrylate as a model substance for UV-filters and electrographic materials was carried out.

Synthesis of polyimides in supercritical carbon dioxide

High-molecular-mass polyimides were synthesized in the supercritical carbon dioxide by the one-step polycyclization of diamines and tetracarboxylic dianhydrides under batch and flow regimes. The effect of various reaction parameters (including the content of water in the reaction system) on the structure, molecular mass, and yield of polymers was studied. It was shown that the solubility of monomers in supercritical CO 2 is indecisive for polymer growth. It was hypothesized that CO 2 exhibits catalytic activity when polyimides are prepared in the presence of water.

Modification of tribological properties of polyarylate by supercritical fluid impregnation of copper(II) hexafluoroacetylacetonate

Polyarylate has been used as a model polymer to study its tribological property alteration during impregnation of copper(II) hexafluoroacetylacetonate in a supercritical carbon dioxide environment followed by thermal decomposition of the copper compound in air. The initial, impregnated and thermally treated polymer samples were tested by various tribological techniques to compare their wear resistance, friction coefficient fk and surface microhardness H. SEM, EDX and ESCA have been applied to determine surface and internal domain morphology, profiles of copper complex concentration, its types and influence on the tribological properties of the samples. Dramatic surface layer modification and significant enhancement of its wear resistance (more than 400%) due to this process have been observed and discussed.

Structure of composites prepared via polypyrrole synthesis in supercritical CO2 on microporous polyethylene

The synthesis of polypyrrole in supercritical carbon dioxide in the presence of the microporous polyethylene has been studied. Formation of polymer composites based on polypyrrole and polyethylene has been demonstrated. The structure of the test samples has been investigated by vibrational spectroscopy, SAXS, and atomic force and scanning electron microscopy. It has been discovered that the oxidized structure of polypyrrole forms during the synthesis under supercritical conditions.

Corrigendum to “Synthesis of polyimides in supercritical carbon dioxide”: [J. of Supercritical Fluids 26 (2003) 147–156]

a A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Street, 28, Moscow 119991, Russia b Physics Department of Lomonosov State University, Vorobievy gory, Moscow 119992, Russia c D.I. Mendeleev University of Chemical Technology of Russia, Moscow, Russia d Centre for Interdisciplinary Studies of Molecular Interactions, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark