New sorption materials based on polysiloxane xerogels with incorporated calix[4]arene: Synthesis and structure

Polysiloxane xerogels with incorporated (without covalent binding) 25,26,27,28-tetrahydroxycalix[4]arene molecules are prepared by hydrolytic polycondensation. The elemental analysis indicates the presence of incorporated macrocyclic molecules, as well as solvent molecules used in synthesis, in the composition of materials synthesized. These conclusions agree with the data of thermal analysis, IR spectroscopy, and ¹³C CP/MAS NMR. The adsorbents synthesized are characterized by the developed porous structure and are capable of extracting cesium ions from acidic aqueous media. It is found that the maximal amount of calix[4]arene molecules participating in cesium sorption is 40%.     

Synthesis of polysiloxane xerogels with fluorine-containing groups in the surface layer and their sorption properties

Hydrolysis and polycondensation reactions of tetraethoxysilane (TEOS) with 3,3,3-trifluoropropyl-trimethoxysilane (TFMS) or 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFES) were used to synthesize xerogels functionalized with fluorine-containing groups. According to transmission electron microscopy, the skeletons of synthesized polysiloxane xerogels have globular structures and consist of agglomerates of particles with fluorinated groups on their surfaces. FTIR spectroscopy showed that primary xerogel particles possess spatial polysiloxane networks, with fluorinated groups along with silanol groups and water in the surface layer. According to thermal analyses, the water content was 3–8 wt.%, and it decreased with increasing length of the fluorinated chain. Thermal destruction of the surface layer starts above 300 °C. The sorbents that were obtained were predominantly mesoporous materials with well-developed porous structures (S_BET = 400–960 m² g⁻¹, V_s = 0.66–0.93 cm³ g⁻¹). The influence of the TEOS/functional silane ratio and the natures of the functional groups on the structural and adsorptive properties were shown. The samples synthesized are organophilic. The affinity for n-hexane increases with increasing length of the fluorine-containing chain (PFES) and the content of fluorinated groups in the surface layer. The hybrid organic–inorganic materials that were obtained can be used for adsorption of hydrocarbons, including oil, from water.     

1-芳氨基丙基杂氮硅三环的合成及生物活性

有机硅化合物;1-芳氨基丙基杂氮硅三环的合成及生物活性     

Interpenetrating polymer networks based on polyurethane and polysiloxane

A series of interpenetrating polymer networks (IPNs), based on a polyurethane (PU) and polydimethylsiloxane, has been synthesized and characterized by means of DSC, TEM, TGA, 1H-NMR and IR spectroscopies, and other techniques. The homo-networks have been characterized by swelling in n-hexane and chloroform. The IPNs are obtained by combination of a PU based of the castor oil and 2,4-toluene diisocyanate (TDI) with different amounts of polydimethylsiloxane-α,ω-diol (PDMS). These materials have interesting individual physical properties, but some IPNs exhibited superior properties than either of the separate networks. For interesting results, it was used as compatibilizer the polydimethylsiloxane graft polyalkylene oxide. All the IPNs exhibited phase separation and maximum extent at the point of phase inversion.     

水溶性的反式-二苯二乙烯基苯型非线性光学材料的合成

由3，4，5-三羟基苯甲酸甲酯经烷基化、还原、氧化和高度立体选择性的 Wadsworth-Emmons反应，合成了两个带六条烷氧基长链的水溶性的反式-二苯二乙 烯基苯(1a)和(1b)，经~1H NMR、MS及元素分析确证其结构。     

Synthesis of hemocompatible materials based on branched polyvinyl alcohol

The possibility of modification of polyvinyl alcohol with epichlorohydrin was examined with the aim of preparing hemocompatible materials exhibiting high mechanical density at limited swellability. The conditions of modification and preparation of branched polyvinyl alcohol and of hemocompatible hydrogel systems with improved operation properties were determined.     

New materials for sorption of hydrogen

The influence of temperature, duration of thermal treatment, and oxidation modes of the aluminum base on processes in which intermetallic compounds LiLaAl are formed by the method of electrochemical cathodic intercalation was studied. The optimal modes of formation of LiLaAl_ox compounds exhibiting high sorption capacity for hydrogen were determined.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9, 2004, pp. 1516–1519.Original Russian Text Copyright © 2004 by Olshanskaya, Sobgaida, Popova.     

Water vapor sorption by chitin-containing materials

Water vapor sorption by natural polysaccharides, namely, chitin-glucan complexes extracted from native biomass of higher fungi, chitin of bees, Arthropoda chitin, and cotton cellulose, is studied. A model of the sorption is proposed. It is shown that the analytical expression derived for sorption isotherms in terms of this model satisfactorily describes the process for different chitin-containing materials in a wide range of humidity. The main parameters of absorption isotherms are determined for examined samples. The analysis of the experimental data indicates that chitin-glucan complexes obtained from fungi demonstrate higher sorption ability, as compared with the reference sample of cotton cellulose and chitin of animal origin.     

Rhenium sorption by fibrous chitosan-carbon materials

We studied equilibrium and kinetic characteristics of rhenium sorption by Busofit-based fibrous carbon materials (FCMs) treated electrochemically with recovery potentials varying from −900 to +600 mV from aqueous solutions in the presence of natural biopolymer chitosan. Materials obtained in the anodic potential region and at the open-circuit potential have the best capacity characteristics. The highest rhenium capacity is observed for the material prepared at the recovery potential +600 mV. The relevant sorption isotherm is described by the Langmuir equation with the constant 73.0 ± 8.1 mL/mg; the half-conversion time is 3 min. Original Russian Text ? A.V. Plevaka, I.D. Troshkina, L.A. Zemskova, A.V. Voit, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 7, pp. 1229–1232.     

Synthesis and photocatalytic properties of materials based on bismuth silicates

The influence of the preparation technique of bismuth silicate-based catalysts on their formation, phase composition, absorption characteristics, and photocatalytic properties is investigated. Samples the with initial ratio of Bi: Si = 2: 1 are prepared via the hydrothermal method with varied temperature conditions in the hydrothermal aging and calcination stages. The synthesized catalysts demonstrate photocatalytic activity in the decomposition of the methanol equilibrium vapor and visible light-induced decolorization of a methylene blue (MB) aqueous solution.     

Synthesis of novel polydiazocine for electroactive materials based on diazocine

In this study, we successfully designed and synthesized a novel class of ladder‐type polymer polydi‐benzoyl[b,f][1,5]diazocine ( PBDA‐a ) and polydimethoxybenzoyl[b,f][1,5]diazocines ( PBDA‐b ) for novel electrochemical actuators via one‐pot polymerization. The structure of polymers was characterized using ¹³C NMR, FTIR and MALDI‐TOF. Both of the polydiazocines exhibited high thermal stability and excellent solubility in common solvent. Molecular conformation studies using the density functional theory method revealed that the conformational structure of PBDA‐a preferred to display zigzag conformation while PBDA‐b display helix conformation. The mechanism of the polydiazocine synthesis is assumed to condensation polymerization proceeding by an unprecedented cyclization of the isocyanate with the neighboring acyl group, followed by the dimerization to form diazocine ring. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4694–4701     

Integrated processing of anthracite into sorption materials

The possibility of using anthracite to produce activated carbon in the form of microporous and mesoporous anthracite, a cation exchanger, and composite sorption materials was analyzed and the porometric properties of a variety of sorption materials based on anthracite from the Donets coal basin were studied. A flowsheet for integrated processing of anthracite to give a set of four products was composed.     

The sorption properties of chitosan-carbon fibrous materials

The kinetics and equilibrium of sorption of copper(II) ions on natural biopolymer chitosan, activated carbon fiber, and composite materials prepared by electrochemical modification of activated carbon fibers with chitosan were studied. The influence of the conditions of modification of the microporous carbon matrix on the sorption properties of composite materials with respect to copper(II) was investigated. It was shown that changes in modification conditions could be used to control the sorption properties of chitosan-carbon materials. The mechanisms of copper(II) ion absorption by the sorption materials studied were considered.     

Synthesis of copolymer electrolytes based on polysiloxane and their high temperature durability analysis for solvent-free dye-sensitized solar cells

The present work develops a new type of solvent-free copolymer electrolyte based on polysiloxane for dye-sensitized solar cells (DSSCs). The electrolyte is characterized by conductivity measurements, hydrogen-1 nuclear magnetic resonance spectroscopy, rheology, and DSSC performance. Repeated units of the ethylene oxide on methylhydrosiloxane show plasticizing effects and enhanced durability of the DSSCs. DSSC employing the polysiloxane electrolytes show no energy conversion efficiency decay after 16 days test at room temperature and yields a conversion efficiency of 1.5% during long-term stability measurement at 90 °C under white light irradiation of 100 mW cm⁻². The new solvent-free polysiloxane copolymer electrolyte can be good candidate for next generation DSSC.     

The preparation of immobilized polysiloxane coated on packings materials for high-pressure gas chromatography

Summary In high pressure gas chromatography efficient columns can be packed by the slurry packing technique. However, polysiloxane stationary phases like OV 101 and OV 3 dissolve in the packing liquids. In order to make them suitable for slurry packing these stationary phases have to be made insoluble. This immobilization is achieved by bonding the stationary phases to the surface by means of a high temperature treatment. Successive layers are applied by recoating and are immobilized by a cross-link reaction. A range of loading percentages from 4 upto 20 by weight could be prepared in this way. On the evaluated columns compounds like butanol and dioxane elute as rather symmetrical peaks with the correct values for the retention index, indicating the absence of adsorption effects. Efficiency is good and bleeding rate is low. The columns could be successfully used in the analysis of turpentines.     

Synthesis and properties of polysiloxane side chain cholesteric elastomers

The synthesis of new side chain cholesteric liquid crystalline elastomers containing the flexible non-mesomorphic crosslinking agent M-1 and the cholesteric monomer M-2 by a one-step hydrosilylation reaction is described. The chemical structures of the obtained monomers and network polymers were confirmed by ¹H NMR and FTIR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. The glass transition temperatures and isotropic temperatures of the mesomorphic elastomers decreased as the concentration of crosslinking units increased; in the mesomorphic region the liquid crystalline elastomers showed elasticity, reversible phase transitions and Grandjean texture. The flexible crosslinking agent did not disturb the cholesteric structure; moreover, it was beneficial for adjusting the helix of the cholesteric liquid crystalline polymers, and cholesteric elastomers P-6, P-7, show reversible selective reflection of visible light.     

Synthesis and surface properties of polyurethane modified by polysiloxane

A series of polyurethanes modified by polysiloxane (Si-PU) were synthesized based on 2,4-toluene diisocyanate (TDI), dihydroxybutyl-terminated polydimethylsiloxane (DHPDMS), polytetramethylene glycol (PTMG) and 1,4-butanediol (BDO). Fourier transform infrared spectroscopy analysis showed that DHPDMS had been incorporated into the polyurethane chains. With the increase of DHPDMS content, the water contact angle increased while the surface tension decreased. As the DHPDMS content increases above 5%, both the contact angle and the surface tension tend to approach a constant. The contact angle increases with increasing temperature, and it tends to approach a constant when the temperature is higher than 50°C. The result indicates that Si-PU exhibits good surface and mechanical properties when the DHPDMS content is 5%. __________ Translated from Polymer Materials Science and Engineering, 2007, 23(3): 47–50 [译自: 高分子科学与工程]     

Synthesis and surface structural characteristics of new polysiloxane xerogel

Pyridylethylaminopropylpolysiloxane xerogel (PEAPPSX) was synthesized by sol-gel technology. The composition of the substance was determined via elemental analysis and 1H NMR spectroscopy. The surface structural characteristics of the xerogel were determined by electron microscopy and low-temperature nitrogen sorption; thermal analysis was also performed. It was established that the content of functional groups in PEAPPSX was 2.43 mmol/g, and that xerogel is a mesoporous substance with a developed surface (121.71 m²/g).     

Synthesis of new materials based on polythiophenes substituted with mesogen groups

A new family of conjugated polymers formed by 3-alkyloximethylthiophenes substituted with a biphenyl group was synthesised by a route involving first the coupling of a functionalised alkyl chain, from 8 to 12 carbon atoms, to 3-methanolthiophene, and then the attachment of the mesogen group. The monomer was characterised by conventional techniques, and thermal studies were also achieved. The polymerisation of these units was carried out via oxidative polymerisation with FeCl₃. The resultant polymers were characterised by FT-IR, elemental microanalysis and XPS. Subsequently, these materials were doped with I₂ and characterised by the above techniques and conductivity measurements, which indicated that these materials are in the semiconductor range. The polymerisation of these monomers was also carried out via electrochemical methods, and it was found that, together with the oxidation of the thiophene ring, the oxidation of the biphenyl group is also produced, for which an over-oxidised material is obtained, as demonstrated by XPS analysis and theoretical calculations.