Polymer Science Series B

Published by MAIK Nauka/Interperiodica
Online ISSN: 1555-6123
Print ISSN: 1560-0904
Publications
The free-radical copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with N-phenyl- and N-p-carboxyphenylmaleimide is studied in bulk and in organic solvents. It is shown that copolymerization proceeds to form copolymers with a high tendency toward alternation of monomer units. The kinetic laws of the reaction are investigated, and the relative activities of the monomers are determined. It is found that 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride is involved in copolymerization with N-substituted maleimides to give rise to pyrrolidinium structures. This work was supported by the Russian Foundation for Basic Research (project no. 09-03-00220) and the by the Presidium of the Russian Academy of Sciences through the program Development of Methods of Synthesis of Chemical Substances and the Creation of Novel Materials.
 
A change in the X-ray patterns of unoriented poly(ɛ-caproamide) films cast from poly(ɛ-caproamide) solutions in formic acid in the presence of 1,1,5-trihydroperfluoropentanol has been examined. It has been shown that the polyfluorinated alcohol increases the proportion of polymer molecules in the planar trans conformation owing to their transition from the gauche conformation constituting the amorphous phase and facilitates formation of hydrogen-bonded layers of macromolecules oriented perpendicular to the film plane.
 
It is shown that chlorine-containing polymeric products may be produced on the basis of the syndiotactic 1,2-polybutadiene by incorporating chlorine atoms into macromolecules via double carbon-carbon bonds. The functionalization of the polydiene with halogen atoms markedly changes the viscosity of solutions, flowability of the melt, and thermal stability of polymeric products. Chlorine derivatives of the syndiotactic 1,2-polybutadiene may be used as high-molecular-mass modifiers improving rheological properties of polymeric compounds in poly(vinyl chloride)-based polymeric composites.
 
The kinetics of radical polymerization of 1-vinyl-3-amino-1,2,4-triazole was studied. The results show that the presence of the amino group as a substituent on the heterocycle decreases the polymerization activity of the triazole-containing monomer. It was found that water has an accelerating effect on the 1-vinyl-3-amino-1,2,4-triazole polymerization process. The substitution of the amino group on the triazole cycle enhances the hydrophilic properties of the polymer relative to those of unsubstituted polyvinyltriazole and opens up possibilities for its further modification.
 
Methods of preparing diverse metallosupramolecular polymers containing 2,2′-bipyridine and 2,2′:6′,2″-terpyridine moieties in main chains and their properties have been considered and analyzed. It has been shown that these polymers offer new possibilities for the design of materials possessing valuable specific characteristics.
 
Degree of acylation of chitosan in the samples prepared at different component ratios in the reaction mixtures and diff ferent synthesis temperatures
Data of fractional analysis in the aqueous media for the BHMPAAmodified chitosan samples
Main thermophysical characteristics of the mixed composite samples and of the pure BHMPA
New polymer salts and N-acetylated chitosan derivatives are prepared in an extruder by the method of solid-phase synthesis via the interaction of chitosan and 2,2-bis(hydroxymethyl)propionic acid. The effect of the initial component ratio and temperature on the yield and structure of the target products is studied. Joint deformation of solid components at room temperature is found to cause the quantitative formation of salt bonds between carboxylic groups of the acid and amino groups of chitosan. At elevated temperatures of synthesis, the corresponding acetylated derivatives with a degree of substitution of amino groups varying from 0.16 to 0.43 are prepared. The relaxation and phase transitions in the polymer salts and acetylated chitosan derivatives and their sorptional activity are studied. The films prepared from aqueous solutions of the new salt modification of chitosan are characterized by a homogeneous structure and improved mechanical characteristics relative to those of the films based on chitosan acetates. An additional thermal treatment of the products of the solid-phase synthesis leads to the formation of crosslinked and water-swollen materials that can be used for the development of novel polymeric chitosan-based membranes and sorbents.
 
The main kinetic and thermodynamic parameters of the pseudoliving radical polymerization of styrene mediated by 4-linoleamido-2,2,6,6-tetramethyl-1-piperidinyloxy have been studied. It has been shown that the introduction of the said substituent into nitroxide leads to a marked reduction in the rate constant of reinitiation that is compensated for by the simultaneous reduction in the rate constant of reversible termination. As a result, the rate of pseudoliving polymerization, the rate of molecular mass growth, and the polydispersity of the polymer appear to be practically the same for processes mediated by both unsubstituted and substituted nitroxides.
 
The main achievements in the synthesis of aromatic condensation monomers and polymers containing quinoxal-2,3-diyl groups are surveyed. Two general approaches to incorporation of such groups into macromolecules are considered: (i) the synthesis of polymers with α-diketone groups (polybenzyls) followed by their polymer-analogous transformations under the influence of o-phenylenediamine and its derivatives and (ii) the synthesis of target polymers of various classes from monomers containing quinoxal-2,3-diyl groups. Particular attention is focused on the properties of the polymers of interest.
 
Series of high molecular weight, readily soluble copolymers were synthesized by Suzuki palladium catalyzed coupling reaction from 9,9-dioctylfluorene and 2,3-dimethylnaphthopyrazine. The absorption, electrochemical and photoluminescence properties of the copolymers were studied. The external electrolu-minescence efficiencies in the devices of configuration indium-tin oxide/polyethylenedioxythiophene-polystyrene sulfonic acid/poly(fluorene-naphthopyrazine)/barium/aluminium varied with the copolymers composition, and the electroluminescence emission peaks of the copolymers were red-shifted from 530 nm to 584 nm as 2,3-dimethylnaphthopyrazine mole contents increasing from 0.5% to 30%. The best device performance was observed for devices fabricated with the copolymer of 2,3-dimethylnathphpyrazine 5% mole contents, showed maximum external quantum efficiency of 1.38% and electroluminescence peaks at around 537 nm.
 
The effect of trimethylaluminum in commercial methylaluminoxane on the molecular-mass characteristics of polyethylene formed with the phenoxyimine titanium catalyst bis[N-(3,5-di-tert-butylsalicylidene)-2,3,5,6-tetrafluoroanilinato]titanium(IV) dichloride activated by methylaluminoxane of varying purity is studied. It is shown that, all other conditions being equal, an increase in the content of trimethylaluminum in the reaction solution leads to an appreciable decrease in the molecular mass of the polymer. With an increase in the time of polymerization, the molecular mass tends to increase, while overall polydispersity indexes M w/M n remain substantially less than 2. The causes of the above effects are discussed.
 
Copolymerization of MVP (M 1 ) with VC (M 2 ) ([AIBN] = 0.5 wt %, 60°C, 0.5 h)
The radical copolymerization of vinyl chloride with 2-methyl-5-vinylpyridine and 1-vinyl-4,5,6,7-tetrahydroindole is accompanied by dehydrochlorination. In the vinyl chloride-2-methyl-5-vinylpyridine system, the evolved hydrogen chloride interacts with a pyridine hydrogen atom to give charged units of a heterocycle. In the vinyl chloride-1-vinyl-4,5,6,7-tetrahydroindole system, the hydrogen chloride being formed initiates the cationic dimerization of a nitrogen-containing monomer. The synthesized copolymers based on vinyl chloride surpass the commercial poly(vinyl chloride) in terms of thermal stability and solubility in organic solvents.
 
The free-radical copolymerization of N,N-diallyl-N,N-dimethylammonium chloride with vinyl acetate in DMSO, methanol, and a methanol-water (70: 30, mol %) mixture proceeds to yield statistical copolymers. The nature of solvents significantly affects the reactivity ratios of the comonomers. N,N-Diallyl-N,N-dimethylammonium chloride shows a higher reactivity than vinyl acetate. The kinetic features of the processes have been investigated, and the structure and properties of the copolymers have been studied.
 
A decrease in the molecular mass of chitosan as a result of polymer degradation during storage of its acetic acid solutions has been simulated by means of mixing of chitosan fractions with different molecular masses. It has been shown that a decline in the polymer molecular mass is responsible for a reduction in the dynamic viscosity of chitosan solutions in acetic acid during their storage.
 
The boundary curves of ( 1 , 2 ) HPC-1-ethanol, ( 3 , 4 ) HPC-3-ethanol, and ( 5-7 ) HPC-2-acetic acid systems measured under ( 1 , 3 , 5 , 6 ) dynamic and ( 2 , 4 , 7 ) static conditions. γ = ( 1 , 6 ) 12, ( 3 ) 8, and ( 5 ) 60 s-1 .
Micrograph of the HPC-1 solution in ethanol after deformation. Magnification × 60; c = 45.0% and γ = 12 s-1. The palaroids are crossed.
The effect of concentration on |∆ T | for ( 1 ) HPC-1-ethanol and ( 2 ) HPC-3-ethanol systems.
The phase transitions and phase state of hydroxypropylcellulose mixtures with ethanol and acetic acid under static conditions and in the shear field have been studied by the turbidity-point method and polarization microscopy with the use of a polarization-photoelectric setup and a modified plastoviscometer. The deformation of solutions leads to a decrease in the temperature of mesomorphic phase formation and to a change in the type of liquid crystals from cholesteric to nematic.
 
The colloidal properties of monoesters of aromatic dicarboxylic acids and the heterophase polymerization of styrene in their presence have been studied. It has been shown that particles are formed from micro-droplets of the monomer. A high stability of polymer suspensions during the synthesis has been found to be provided by a strong interfacial adsorption layer formed on the surface of particles from the polymer being synthesized and a surfactant.
 
A peptide separation model based on the technique of liquid chromatography of macromolecules at the critical condition was proposed. In terms of this model, the array of experimental data on the separation of peptides is considered. The main phenomenological parameters of the model—effective adsorption energies of amino acid residues—were determined, thus allowing the influence of character of their alternation in the chain on retention times to be predicted. The model is applicable to investigation into the feasibility of separation in different chromatographic modes of not only peptides with the same amino acid composition and different sequences of units in the chain but also peptides containing amino acid isomers and mirror sequences with different terminal groups.
 
Potentialities of the bifunctional cell of the sensor type, in which acoustoelectric (based on surface-acoustic waves) and optical (in the visible spectral region) measurements of ammonia chemosorption by thin films of a PDMS-based functional polymer may be simultaneously performed, have been demonstrated. It has been found that the gas diffusion coefficient associated with chemosorption and calculated from optical measurements (2.65 × 10−11 cm2/s) differs from that obtained from acoustoelectric studies (4.16 × 10−12 cm2/s). The diffusion coefficient determined from the acoustoelectric data presumably characterizes the propagation of structural relaxation of polymer chains from chemosorption sites into the polymer bulk.
 
The conformational properties of macromolecules of chitosan and its copolymers with acrylamide in a mixed solvent 0.33 M CH3COOH + 0.3 M NaCl have been investigated by means of translation diffusion and viscometry. The copolymer macromolecules in a solvent suppressing polyelectrolyte effects possess a higher intracoil density (ρav = 0.010 g/cm3) than the chitosan macromolecules (ρav = 0.006 g/cm3), even though the hydrodynamic radius R h of chitosan is smaller by a factor of ∼1.5.
 
The specific features of radical copolymerization of N,N-diethylacrylamide with acrylamide and the processes of diffusion of N,N-diethylacrylamide into the matrix of N,N-diethylacrylamide-acrylamide copolymers of various compositions were studied. The Huggins thermodynamic interaction parameters in the test copolymer-N,N-diethylacrylamide systems were determined and their dependence on the copolymer composition was obtained. It was shown that the type of this relation is determined by the effect of specific sorption of N,N-diethylacrylamide. An approach that makes it possible to take into account the effect of the specific binding of the blend components and to estimate their “true” local concentrations within the polymer coil was proposed.
 
The effect of the nature of a solvent on the kinetic parameters of the process and the intrinsic viscosities of copolymers formed by the homogeneous free-radical copolymerization of the sodium salt of 2-acrylamido-2-methylpropane sulfonic acid and the sodium salt of acrylic acid initiated by potassium persulfate in water, water-methanol mixtures (92: 8, 84: 16, 75: 25, 50: 50), and water-isopropanol (50: 50) mixtures at pH 9 and 60°C is studied. The initial rate of copolymerization increases with increases in the concentrations of the comonomers and initiator, the content of 2-acrylamido-2-methylpropane sulfonic acid in the initial monomer mixture, and the content of water in a water-methanol mixture and in the sequence of solvents water-methanol < water-isopropanol. The intrinsic viscosity and yield of the copolymer grow when the content of 2-acrylamido-2-methylpropane sulfonic acid in the initial monomer mixture and water in water-methanol mixtures are increased and when isopropanol is replaced with methanol. The reactivity ratios of the monomers in water-methanol (50: 50) and water-isopropanol (50: 50) mixtures are determined.
 
The X-ray diffraction study of 2,2′-(1,2-phenylene-bis(oxy)diethanol and 2,2′-(1,4-phenylenebis(oxy)diethanol dimethacrylates and 2,2′-(1,4-phenylenebis(oxy)diethanol diacrylate (Tm = 40–42, 68–70, and 62–64°C, respectively) indicates that oligomer molecules are packed in crystals as stacks in which methacrylate fragments of adjacent molecules are parallel to each other. The minimum distances between the centers of C=C double bonds of adjacent methacrylate fragments in crystals of di(meth)acrylates are 4.373, 4.215, and 3.996 respectively. The conversion dependences of the reduced rates of photopolymerization of melted oligomers (9,10-phenanthrenequinone as a photoinitiator) pass through maxima at conversions of 40, 11, and 2%, while the ultimate conversions are 85, 33, and 73%, respectively. The addition of ionic liquids based on phosphonium and imidazolium cations to dimethacrylates of 2,2′-(1,2 phenylenebis(oxy)diethanol and triethylene glycol increases the maximum reduced rate of photopolymerization.
 
Sols of zero-valence copper are prepared via the chemical reduction of Cu(II) ions by hydrazine borane in aqueous solutions of high-molecular-mass poly(acrylic acid), which forms stable complexes with copper ions at 20°C in a wide pH range. The study of the composition of coordination centers, the ligand surrounding of metal ions, and the character of distribution of copper ions over poly(acrylic acid) coils in a wide range of solution compositions and pH values shows that the size of copper nanoparticles in the sols can be controlled by varying the ratio between ligand groups (carboxylate anions in poly(acrylic acid)) and copper ions in the reaction system during the synthesis of sols. This effect can be accomplished either by variation in the initial composition of solution or change in pH (the degree of ionization of the initial poly(acrylic acid) in the presence of copper ions).
 
It is shown that nonstoichiometric interpolymer complexes composed of high-molecular-mass poly( acrylic acid) and PEG of various molecular masses are more efficient stabilizers of copper sols than each component of the complex taken separately. This conclusion is based on comparison of dimensions of copper nanoparticles in sols formed via reduction of copper(II) ions in solutions of poly (acrylic acid), PEG, and their blends and on the enhanced stability of sols protected by the interpolymer complex against aggregation and oxidation of metal particles. Much shorter PEG chains than those necessary for formation of corresponding interpolymer complexes in the absence of nanoparticles can be involved in formation of tertiary complexes including copper nanoparticles, poly(acrylic acid), and PEG. On the basis of the experimental data, it is inferred that the mutual enhancement of the complexing behavior of components occurs in tertiary complexes containing copper nanoparticles and both polymers.
 
Degree of conversion plotted against time (absorbed dose) for the radiationninduced emulsion polymerization of AN. Polymerization conditions are given in the text.  
Cumulative molecularrmass distributions for PAN samples with different degrees of conversion: Ψ = (1) 13, (2) 25, (3) 36, (4) 50, (5) 68, (6) 76, and (7) 93%.  
Changes in the parameters of cumulative and interval molecularrmass distributions with conversion and molecularr mass characteristics of the components of the Gaussians of interval molecularrmass distributions
A combination of statistic and kinetic methods of analysis is used to collect quantitative data on the kinetics of elementary reactions of growth and termination of kinetic chains in each phase of a heterophase system as well as on interfacial mass exchange at the quasistationary stage of radiation-induced emulsion polymerization of acrylonitrile. It is found that, in the system, a steady-state concentration of polymer—monomer particles is attained, and these particles are able to increase their dimensions with an increase in monomer conversion. Activation of particles and chain termination on particles are due to the entrapment of macroradicals from water. As a result of a gradual increase in the dimensions of polymer-monomer particles and a decrease in the monomer concentration in the aqueous phase, the adsorption layer of acrylonitrile becomes so thin that, at the final stage, monomolecular layers lose integrity and the conditions of quasi-stationarity are violated.
 
The complex formation constants for styrene (donor)-acrylonitrile (acceptor) and styrene-maleic anhydride (acceptor) systems are found to be 0.19 ± 0.01 and 0.28 ± 0.01 l/mol (1H NMR, CCl4, 298 K); the same values are characteristic for three-component systems of these monomers. The calculated ΔH 0 values (the AM1 method) for styrene-acrylonitrile (C1) and styrene-maleic anhydride (C2) complexes comprise −1.24 and −2.30 kJ/mol. Changes in charges on double bonds of complex-bonded molecules are in the range from 0.001 to 0.006 au. These values are typical of π-π complexes. By analyzing the composition and rate of bulk copolymerization (333 K, 0.03 mol/l AIBN), we have shown that two complexes are involved in chain propagation: r 1 = \( k_{2C_1 } /k_{2C_2 } \) = 0.26 ± 0.015 and r 2 = \( k_{3C_2 } /k_{3C_1 } \) = 4.17 ± 0.143.
 
The free-radical copolymerization of N-vinylpyrrolidone with N,N-diallyl-N′-acetylhydrazine and N,N-diallyl-N′-butanoylhydrazine has been investigated in bulk and solution. The copolymerization yields random copolymers enriched with N-vinylpyrrolidone units. The kinetic study of the reaction has revealed that the rate of copolymerization decreases with a rise in the fraction of an allyl monomer in the initial monomer mixture. Both double bonds of diallylacylhydrazines are involved in the copolymerization to give rise to five-membered pyrrolidine rings.
 
Branched copolymers are synthesized via the crosslinking free-radical copolymerization of N-vinyl-2-pyrrolidone and dimethacrylates of various st ructures that is conducted in the presence of the chain-transfer agent 1-decanethiol. The kinetics of this process and the composition of the products are studied by IR spectroscopy, and the content of pendant C=C bonds is estimated. Correlations between the content of dimethacrylate monomer units in the copolymer and the rate of discoloration of a photochromic probe (6-nitrospiropyran) incorporated into the product are established.
 
The free-radical alternating cyclocopolymerization of maleic anhydride and divinyl ether is studied at 60–80°C in the presence of benzyl dithiobenzoate and dibenzyl trithiocarbonate as reversible addition-fragmentation chain-transfer agents. It is shown that the structure of the repeating unit of the cyclocopolymer prepared in the presence of a reversible addition-fragmentation chain-transfer agent coincides with the structure of the repeating unit of the copolymer synthesized under the conditions of conventional free-radical cyclocopolymerization. When the cyclocopolymer is used as a reversible addition-fragmentation chaintransfer agent, a successive increase in the molecular mass of the copolymer with conversion and formation of the block copolymer in the polymerization of styrene are unambiguous evidence that the copolymerization proceeds according to the pseudoliving radical mechanism.
 
The kinetic features of the homopolycondensation of furfuryl alcohol in an aqueous medium in the presence of acids of different strengths have been studied. The second order of the reaction with respect to the monomer has been established. A kinetic scheme of the polycondensation reaction has been proposed, and the activation parameters of the process have been calculated.
 
In this article, the graft copolymerization of 4-vinyl pyridine onto poly(vinyl alcohol) via the potassium diperiodatocuprate(III)-poly(vinyl alcohol) redox system as an initiator was investigated in an alkaline medium. The graft copolymer was characterized with Fourier-transform infrared spectra analysis. A mechanism is proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of monomer to poly(vinyl alcohol), pH, and reaction temperature and time, are investigated, and the grafting conditions are optimized. Graft copolymers with high grafting efficiency are obtained, thus indicating that potassium diperiodatocuprate(III)-PVA redox system is an efficient initiator for this graft copolymerization.
 
Composites based on aligned carbon nanotubes and polyaniline are prepared via the electrochemical polycondensation of aniline in a sulf uric acid solution. The structure of the composites and the character of interaction of polyaniline and the surface of carbon nanotubes are studied by scanning and transmission electron microscopy, X-ray diffraction, and IR and X-ra y photoelectron spectroscopy. It is shown that in the composites, electron density is transferred from the carbon nanotube to the polyaniline film. The occurrence of polyaniline on the surface of nanotubes increases the mean current in cyclic voltammograms of the composite material and leads to a marked increase in the calculated specific capacity of electrodes formed on its basis.
 
The polymerization of butadiene catalyzed by the preformed Co(2-ethylhexanoate)2-Et3Al2Cl3-isoprene (a molar ratio of 1: 20: 20) catalytic system in toluene, cyclohexane, and hexane has been studied. In toluene, the catalyst demonstrates high activity and stereospecificity and yields a high-molecular-mass polymer. In cyclohexane and hexane, the catalyst has a high activity but affords polymers with lower contents of 1,4-cis-units and reduced intrinsic viscosities. The addition of EtAlCl2 and/or a decrease in the polymerization temperature make it possible to obtain polybutadiene containing more than 96% 1,4-cis-units and an acceptable intrinsic viscosity (2.0–2.8 dl/g) in the nonaromatic solvents as well.
 
Conditions and results of PAAP synthesis
The organoelement polymer bases poly(methylaminophosphazene) and pol(ethylaminophosphazene) have been synthesized by the solid-phase aminolysis of linear ultrahigh-molecular-weight poly(dichlorophosphazene) and characterized. The related cationic polyelectrolytes have been prepared in aqueous solutions in the presence of HCl. As exemplified by the interaction with sodium polystyrenesulfonate and sodium polyphosphate, the polymers form interpolyelectrolyte complexes with anionic polyelectrolytes.
 
Polypyrrole was prepared by chemical oxidation with ammonium persulfate as the oxidant, phosphotungstic acid as the dopant, and its molecular structure was characterized by FTIR spectrum, X-ray diffraction and EDX. A composite coating by using polypyrrole as functional component was prepared on the low alloy steel surface, and its anticorrosion properties were investigated by the open circuit potential and EIS. The results indicated that the coating contained dopant displayed an excellent anticorrosion property for the low alloy steel.
 
The reaction between allyl compounds and fullerene C60 has been investigated via dilatometry under the conditions of free-radical polymerization. It has been shown that the rate of a variation in the volume of the reaction mixture plotted versus the concentration of fullerene C60 is described by a curve with a minimum. It has been established that, in the presence of fullerene and the allyl monomer, the polymerization of methyl methacrylate proceeds without any induction period. It has been concluded that allyl radicals interact with fullerene C60.
 
2,6-Bis-(2,5-dioxo-tetrahydro-N-(4-carboxyphenyl)pyrrol-3-yl)-pyrrolo[3,4-f]isoindole-1,3,5,7-teraone, a chiral diacid, was prepared from pyromellitic anhydride and L-aspartic acid in a three steps reaction pathway. The polycondensation reactions of the monomer with aromatic diamines were carried out in direct condensation reaction conditions. The synthesized poly(amide-imide)s had inherent viscosities in the range of 0.30–0.80 dl/g. Identification of all of the products were performed by conventional analytical techniques such as TLC, IR and 1H NMR/13C MR spectroscopy. Thermoanalytical techniques (TGA/DSC) showed useful levels of thermal stability, associated with relatively high glass transition temperatures and carbonized residues in excess of 40% at 600°C for the synthesized polymers. Amorphous morphology was obtained based on XRD patterns and DSC traces. The polymers were soluble in a variety of polar organic solvents and afforded transparent and relatively flexible to brittle films by solution casting.
 
Characteristics of the compounds under study with the general formula
Characteristics of the PNAs with the general formula
Characteristics of PBIs with the general formula
New poly(benzimidazoles) containing piperazine rings have been prepared via the reductive polyheterocyclization of poly(o-nitroamides) synthesized through the interaction of the new monomer N, N′-di(3-amino-4-nitrophenyl)piperazine with dichlorides of aromatic dicarboxylic acids. The relationship between the characteristics of poly(o-nitroamides) and poly(benzimidazoles) and their chemical structure has been studied.
 
N-acylated chitosan modified by maleic anhydride was prepared by the method of the solid-state synthesis (Bridgman anvils, semipilot extruder). In contrast to the synthesis under homogeneous conditions, solid-state acylation is accompanied by the reaction of imidization of the formed amic acid as well as by reaction through double bonds, thus leading to the formation of derivatives of succinic anhydride. By simultaneous or subsequent interaction of chitosan modified with maleic anhydride with a PE matrix, either modified or not modified with maleic anhydride, new chitosan-polyethylene composite materials are prepared, and these composites are characterized by the combined valuable medicinal and biochemical properties of chitosan and high mechanical characteristics of the polyolefin component. The above composites are of obvious interest as amphiphilic sorbents, which are highly resistant to the action of aggressive media, as well as antimicrobial and biodegradable PE-based materials.
 
Competition between poly(1,2-dimethyl-5-vinylpyridinium methyl sulfate) polycationic macromolecules and micelles of amphiphilic polymers containing hydrophilic and hydrophobic blocks (polyethylene glycol-600 monolaurate and poly-N-vinylpyrrolidone monostearate) for copper nanoparticles was studied by means of electrophoresis and electron microscopy techniques. It was shown that, irrespective of the formation method, almost all copper nanoparticles were bonded to the polycation in polycation-polyethylene glycol-600 monolaurate mixed solutions but were distributed between the polymers in polycation-poly-N-vinylpyrrolidone monostearate mixtures. It was concluded that the stability of the complex of copper nanoparticles with the polycation is higher than that with polyethylene glycol-600 monolaurate and is comparable with that of the copper particle-poly-N-vinylpyrrolidone monostearate complex.
 
Tercopolymers of methyl methacrylate with methacrylic acid and dimethylphenyl (methyldiphenyl)silyl methacrylates are synthesized and investigated as components of chemically amplified resistive formulations with sulfonium and iodonium salts as photoacid generators for UV lithography in the 254-nm range. The surface behavior and the kinetics of dissolution of resistive films in an aqueous solution of tetraethylammonium hydroxide in relation to the concentration of onium salts and the temperatures of postapply and postexposure bakes are studied. The introduction of sulfonium salt into the resistive formulation brings about an increase in the solubility of unexposed films, thereby erasing the difference in dissolution rates of exposed and unexposed areas of a resist and preventing image formation. The iodonium salt plays the role of an inhibitor for dissolution of unexposed films of both copolymers, which makes it possible to obtain a high-contrast positive image in resists.
 
ICPPOES instrumental conditions
XXray diffraction patterns for Fe 2 O 3 (a) and leached IIP (b).
Effect pH on extraction efficiency of iron ions.
Effect of adsorption time on extraction efficiency of iron ions.
Effect of desorption time on extraction efficiency of iron ions.
This work reports the preparation of molecularly imprinted polymer particles for selective extraction and determination of iron ions from aqueous media. The polymer particles were synthesized from Fe(NO3)3, morin, 4-vinylpyridine, ethyleneglycoldimethacrylate, and 2,2′-azobisisobutyronitrile and characterized by IR and DSC both prior to and after removing the Fe-morin complex by leaching with HCl. The effect of different parameters, such as pH, adsorption and desorption time, type and minimum amount of eluent for removing the complex from polymer was evaluated and optimized. The proposed method is characterized by the detection limit of 3.1 µg l−1 anddynamic linear range of 25 to 200 µg l−1, with the relative standard deviation less than 8.8%. The method was applied to the recovery and determination of iron ions in a few real samples.
 
The method for producing chitosan coatings on solid surfaces with anchoring layers of poly(glycidyl methacrylate) and maleic anhydride copolymers has been proposed. It is shown that, owing to a high reactivity of epoxy and anhydride groups, the efficiency of immobilization and the stability of the coatings are considerably higher than those prepared by the conventional method of chitosan grafting onto the surface modified by poly(acrylic acid). The properties of chitosan coatings are examined via atomic force microscopy, X-ray photoelectron spectroscopy, ellipsometry, and electrokinetic measurements. Depending on the anchoring layer used, the total thickness of the coatings is 6–16 nm with an rms roughness less than 1.2 nm, while the isoelectric points of the surfaces modified with chitosan are located in the pH range 5–6.
 
Cyclic voltammorams of growth of PANI on GC electrode in 1.7M H 2 SO 4 with 0.1M ANI at scan rate of 25 mV/s. 
Solubility of homoo and copolymers of aniline (ANI) and diphenylamine (DPA) prepared via interfacial method 
Cyclic voltammograms of growth of copolymer films on a GC electrode in 1.7M H 2 SO 4 at a scan rate of 25 mV/s. Feed ratio of [ANI] : [DPA] = 8 : 1; total concentration of ANI and DPA is equal to 100 mM. 
Cyclic voltammograms of growth of copolymer films on a GC electrode in 1.7M H 2 SO 4 at a scan rate of 25 mV/s. Feed ratio of [ANI] : [DPA] = 12 : 1; total concentration of ANI and DPA is equal to 100 mM. 
Conductive poly(diphenylamine-co-aniline) was prepared by electrochemical and chemical oxidative polymerization. Using the electrochemical method, homo- and copolymer thin films with different feed ratio of aniline and diphenylamine were synthesized under cyclic voltammetric conditions in aqueous sulfuric acid on the surface of the working Glassy carbon electrode. The copolymer formation, their electrochemical behavior and the structure were examined. The analogous homo- and copolymers were prepared via a chemical oxidative polymerization by the interfacial method (chloroform and an aqueous solution) in 1M H2SO4 or 1M CH3SO3H in the presence of ammonium persulfate as an oxidant. SEM and conductivity measurements were applied for the characterization of the obtained copolymers.
 
A thick film of aniline-formaldehyde copolymer and PMMA is synthesized via dispersion of aniline-formaldehyde copolymer powder as filler particles in PMMA with two different concentrations. Variation of the complex elastic modulus and mechanical loss factor (tanδ) with temperature is studied. It is observed that the complex elastic modulus decreases with temperature owing to thermal expansion of films. On the other hand, tanδ increases up to a characteristic temperature beyond which it shows a decreasing trend toward melting. Transition temperature T g of sample S1 (pure PMMA) is found to be 80°C. In sample S2 (1 wt % aniline formaldehyde copolymer), the peak of tanδ at a lower temperature (66°C) corresponds to glass transition temperature T g of the PMMA matrix, while the peak of tanδ at a higher temperature (107.8°C) corresponds to T g of a polymer chain restricted by filler particles of aniline-formaldehyde copolymer. A further increase (10 wt % aniline-formaldehyde copolymer) in the concentration of filler particles of aniline-formaldehyde copolymer results in a more compact structure and a shift of T g to a higher temperature, 122.2°C. This shift in the glass transition temperature of thick films of aniline-formaldehyde copolymer and PMMA is dependent upon the concentration of filler particles in the sample.
 
Approaches for the development of anisotropic electroconducting composite materials based on polyaniline and Na-montmorillonite prepared by the me thods of boundary and intercalation polymerization of aniline and mechanical blending are proposed. Parallel plane compression of solid and plasticized dispersions is shown to lead to the development of primarily planar ordering of anisometric clay particles with sorbed or intercalated polymer; as a result, nanocomposites with anisotropic electrical conductivity are formed. In the prepared polymer-silicate films, the parameter of anisotropy in electrical conductivity achieves 6 × 103.
 
Methods of synthesis, the structure, properties, and application areas of nucleus-fluorinated aromatic polyethers are considered. The main attention is given to polymers for which chain propagation occurs via formation of an ether bond, and the fluorinated monomers suitable for the synthesis of these polymers are indicated. Approaches to the incorporation of sulfonic acid, phosphoric acid, aldehyde, and maleimide groups and other reactive moieties into fluorinated aromatic polyethers are analyzed.
 
Isotherms of water vapor sorption by fibers of aromatic polyamides of several types have been obtained in a wide range of relative pressures (p/p s from 0 to 0.8–0.9). It has been shown that different values of moisture sorption determined from sorption isotherms correlate with molecular and structural characteristics, such as the thermodynamic rigidity of macromolecules, the integral specific surface area with respect to an inactive sorbate (krypton), the average off-orientation angle, and the phase state of the structure. It has been speculated that a difference in the moisture sorption of the test fibers is primarily related to their phase structure, particularly, to the prevalence of either a mesophase or crystalline order.
 
Hyperbranched poly(aryl ether ketones) with M n = (8–10) × 103 and terminal fluorine atoms have been synthesized through the polycondensation of 3,3′,5,5′-tetramethyl-4,4′-dihydroxydiphenyl(A2) and 1,3,5-tris[4-(4-fluorobenzoyl)phenoxy]benzene (B3) taken at a molar ratio of (0.720–0.675): 1. The replacement of the terminal fluorine atoms by residues of m-N,N-dimethylaminophenol yields polymers demonstrating green-blue fluorescence both in solution and in the solid state. Fluorescence quenching is observed at concentrations of the said polymers in solutions above 3 g/l.
 
Top-cited authors
Alexey V. Volkov
  • Institute of Petrochemical Synthesis
Vladimir V. Volkov
  • Institute of Petrochemical Synthesis
Marina Pigaleva
  • Lomonosov Moscow State University
Marat O. Gallyamov
  • Lomonosov Moscow State University
Aziz M. Muzafarov
  • Russian Academy of Sciences