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Sedush N.G.,RAS Research Center Kurchatov Institute | Strelkov Y.Y.,RAS Research Center Kurchatov Institute | Chvalun S.N.,RAS Enikolopov Institute of Synthetic Polymer Materials
Polymer Science - Series B | Year: 2014

The kinetics of polymerization of D,L-lactide and glycolide are studied via differential scanning calorimetry at different temperatures and concentrations of the catalyst tin octanoate. For the polymerization of D,L-lactide and glycolide, the enthalpies are determined to be -17 ± 1.5 and 16.5 ± 1.5 kJ/mol, respectively. The time to attain reaction equilibration decreases from 300 to 100 min with an increase in temperature from 200 to 220 °C. The time of reaction at 200 °C decreases from 280 to 100 min as the concentration of the catalyst is increased from 500 to 830 ppm. When the polymerization of glycolide is conducted at temperatures below 200 °C, the reaction is accompanied by crystallization of polyglycolide and an increase in the total enthalpy of the process. © 2014 Pleiades Publishing, Ltd. Source

Zezin A.A.,RAS Enikolopov Institute of Synthetic Polymer Materials
Polymer Science - Series C | Year: 2016

This review is concerned with the synthesis of hybrid materials in solutions, suspensions, and gels of polyelectrolytes with emphasis being placed on the role of interaction between functional groups of macromolecules and ions/surfaces of metals in the control over the processes of nucleation and growth of nanoparticles. The use of several macromolecules carrying nonionogenic groups for the effective control over the sizes and shapes of nanoparticles is exemplified. As the main method for the synthesis of metal nanostructures in colloidal systems, a method based on the reduction of metal ions is discussed. Mechanisms and conditions determining the assembly of metal–polymer nanocomposites of various architectures in polyelectrolyte matrixes and organized polymer systems are considered. © 2016, Pleiades Publishing, Ltd. Source

Zezin A.B.,Moscow State University | Rogacheva V.B.,Moscow State University | Feldman V.I.,Moscow State University | Afanasiev P.,University Claude Bernard Lyon 1 | Zezin A.A.,RAS Enikolopov Institute of Synthetic Polymer Materials
Advances in Colloid and Interface Science | Year: 2010

Nanocomposite polymer materials containing metal or metal oxide particles attract growing interest due to their specific unique combination of physical and electric behavior. Stoichometric triple interpolyelectrolytemetal complexes (TIMC) are insoluble in water and in aqueous organic media and may include high content of metal ions; concentration of ions is easy to vary in such polymeric systems. Reduction of metal ions is a common method for obtaining nanoparticles. Interpolyelectrolyte complexes reveal high permeability for polar low-molecular substances and salts. Such swelling behavior is important for the reduction of metal ions included in these solids. The properties of triple interpolyelectrolyte-metal complexes and preparation of nanocomposites from these materials using various methods of metal ion reduction are discussed in this work. © 2010 Elsevier B.V. All rights reserved. Source

Elkina I.B.,RAS Topchiev Institute of Petrochemical Synthesis | Gilman A.B.,RAS Enikolopov Institute of Synthetic Polymer Materials | Ugrozov V.V.,All Russian Institute of Finance and Economic | Volkov V.V.,RAS Topchiev Institute of Petrochemical Synthesis
Industrial and Engineering Chemistry Research | Year: 2013

Membrane distillation was suggested for the regeneration of volatile inorganic acids (hydrochloric and nitric acids) from the metal pickling solutions using hydrophobic porous and nonporous asymmetric membranes. The investigations were performed with a flat-sheet commercial microfiltration membrane based on tetrafluoroethylene/vinylidenefluoride copolymer MFF-2 and with a plasma-modified commercial asymmetric gas separation membrane based on poly(vinyltrimethyl silane) (PVTMS). The influence of acid concentration (varying over a wide concentration range from 0.01 to 7.0 N) and the feed temperature (Th = 313-333 K) on the transmembrane flux and selectivity was studied. It was shown that the concentrating of volatile inorganic acids in the feed using a porous MFF-2 membrane is effective up to 1.0 N concentration. Plasma-modified PVTMS membrane was used for the separation of feed solutions with higher acid content up to 7.0 N. It was established that the plasma treatment essentially increases the hydrophilic properties of PVTMS membrane surface. © 2013 American Chemical Society. Source

Bazhenov S.L.,RAS Enikolopov Institute of Synthetic Polymer Materials | Kechek'Yan A.S.,RAS Enikolopov Institute of Synthetic Polymer Materials
Polymer Science - Series A | Year: 2013

The heating of polyethylene terephthalate, polyamide-66, and polyamide-6 during tensile drawing at room temperature was studied theoretically and experimentally. At a low draw rate, the necking temperature was close to the temperature of the surrounding air. An increase in the rate results in the transition to the adiabatic conditions of drawing. A necking temperature of 140 C was experimentally recorded in polyethylene terephthalate at a draw rate of 1000 mm/min and during the approach to the adiabatic conditions of drawing. A formula describing the dependence of the necking temperature on the draw rate was derived. The resulting value agreed fairly well with the theoretical estimation of the temperature. The drawing (strain) ratio in the neck and the draw stress are the crucial parameters determining the temperature. The rate of the transition to the adiabatic conditions of drawing was determined. The temperatures of adiabatic heating for various polymers were calculated. The increases in the temperatures of polycarbonate and low- and high-density polyethylene are relatively low. The increases in temperature can be regarded as moderate for polypropylene and polyvinyl chloride, while they attain the highest values in polyamide-6 and polyethylene terephthalate owing to the high draw ratios in the neck and the high draw-stress values. © 2013 Pleiades Publishing, Ltd. Source

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