Physicochemical properties of chitosan from different raw material sources

A microelemental, thermal, and IR spectroscopic analysis of samples of chitosan separated from fresh-and salt-water crustaceans was performed. The viscometric and optical properties of the solutions made from them — freshly prepared and during storage — were investigated. It was found that the physicochemical characteristics of crayfish shell chitosan almost do not differ from the indexes for the industrial polymer prepared from a traditional source of raw material — crab shells. This allows considering crayfish shells as an alternative raw material resource for obtaining chitosan. __________ Translated from Khimicheskie Volokna, No. 1, pp. 33–36, January–February, 2008.     

Surfactant-enhanced steam drives for heavy oil recovery

A steam/noncondensible gas foam formulation was developed to reduce steam mobility in the steam drive process as applied to heavy oil reservoirs with little or no dip such as the Kern River field. The steam/noncondensible gas foam process is intended to reduce or minimize the gravity layover problem in such reservoirs. Laboratory experimentation started with foam studies in the absence of both porous media and crude oil at a substeam temperature. Conditions existing in the application under actual field use were then added in a step-by-step manner, i.e., inclusion of porous media, existence of an oil saturation, and the addition of steam foam components to injected steam. Added salt was necessary for mobility reduction. Mode of noncondensible gas injection (constant mass vs constant volume) was not important. Adsorption of surfactant was shown to be quite low at steam temperature. The concentrations of steam foam components — Siponate DS-10, salt and nitrogen — recommended for the Kern River pilot resulted in a steam mobility 0.18 of that obtained with steam alone.     

Rheological properties of spinning solutions for cellulose acetate ultrafiltration membranes

Addition of ethyl alcohol in the amount of 5 to 25 wt. % significantly reduces the viscosity of secondary cellulose acetate (SCA)—acetone—water spinning solutions. The effective viscosity of the spinning solutions decreases significantly when the shear stress changes. SCA membranes made from solutions with lower viscosity have higher permeability both for water and for cheese whey. The data obtained can be used to vary the performance properties of ultrafiltration membranes within wide limits. __________ Translated from Khimicheskie Volokna, No. 1, pp. 15–17, January–February, 2007.     

Determination of the composition of condensate after physicochemical treatment in production of capron fibre

The possibility of separate determination of the content of condensate components — caprolactam and oiling agent — based on absorption in the UV region of the spectrum was demonstrated. The caprolactam content can be determined in both aqueous solutions and in chloroform extracts. The oiling agent content can be determined after extraction from the condensate with chloroform followed by spectrophotometric determination. __________ Translated from Khimicheskie Volokna, No. 4, pp. 61–66, July–August, 2007.     

Regulation of the structure of fibres from polymer solutions

The properties of fibres “wet” spun from solutions of polymers can be altered within wide limits by using information on the rheological properties of the spinning solutions, the phase equilibrium diagrams of polymer—solvent—precipitator systems, and information on the glass transition and crystallization in the system. The homogeneity of the structure and properties of the fibre increase in the order of spinning methods: diffusion, thermotropic, mechanotropic. __________ Translated from Khimicheskie Volokna, No. 4, Pp. 10–17, July–August, 2006.     

Electrophoretic mobility studies of colloidal particles in aqueous solutions of various phosphates

Electrophoretic mobilities of carbon black, titanium dioxide, ferric oxide and bentonite particles have been systematically measured in solutions of a series of sodium polyphosphates and metaphosphates. The mobilities of those particles carrying negative charge in phosphate solutions are relatively high as compared with those in solutions of various electrolytes other than phosphates. This would be indicative of strong adsorption of phosphate ions onto the surface of the particle. In polyphosphate (Na_n+2P_nO_3n+1) solutions the mobility increases with increasing n in the region of n≤3 and then becomes constant at n>3, while in metaphosphate (Na_nP_nO_3n) solutions the mobility is nearly constant independent of n except the case with n of 3. The electrophoretic behavior of the particles is highly dependent on the pH of the solutions—the higher the pH of the solution, the greater the mobility of the particle. However, the mobilities in phosphate solutions are in general much higher than those expected from the pH of the solutions. The electrophoretic data in solutions of acid and neutral phosphates have also been included.     

Optical properties of process solutions of secondary cellulose acetate in acetone

Addition of alcohol to SCA—acetone spinning solutions for manufacture of ultrafiltration membranes causes disaggregation of microgel particles and results in more homogeneous solutions. Decreasing the concentration of the spinning solution also causes disaggregation of microgel particles. Membranes made of 5% SCA—acetone solutions swell more rapidly than membranes from 7 and 10% solutions and have higher throughput of water and cheese whey for the same alcohol content. __________ Translated from Khimicheskie Volokna, No. 1, pp. 11–13, January–February, 2006.     

State of lithium cation in a solution of polyurethane in deviethylformamide

The viscosity characteristics of solutions of PU in DMF containing different amounts of lithium chloride and perchlorate wer investigated. The dependence of the relative viscosity of the ternary systems LiX—PU—DMF on the type and content of the lithium salt was established. A hypothesis was advanced concerning the coordination of lithium cations with polyurethane functional groups. __________ Translated from Khimicheskie Volokna, No. 6, pp. 5–6, November–December, 2006.     

Anodic oxidation of organic pollutants on a Ti/SnO<Subscript>2</Subscript>–Sb<Subscript>2</Subscript>O<Subscript>4</Subscript> anode

A Ti/SnO₂–Sb₂O₄ electrode was prepared by alternate Sn and Sb electrodepositions using the thermo-electrochemical method. The chemical, electrochemical, and structural characterization of the electrode was performed and it was tested in the anodic oxidation of several pollutants, phenol, ibuprofen, acid orange 7 (AO7), and diclofenac, all in aqueous 0.035 M Na₂SO₄ solutions at current densities of 10 and 20 mA cm⁻². After the 24 h assay, removal of chemical oxygen demand, total organic carbon (TOC) and absorbance were very high, especially at the higher current density. TOC removals presented the lowest value. However, after 24 h at 20 mA cm⁻², TOC removals were: phenol—94%; ibuprofen—83%; AO7—88%; and diclofenac—73%. Combustion efficiency and instantaneous and mineralization current efficiencies were also determined.     

Destruction processes in coagulation structures in vibration of coarse thixotropic corundum — Mullite — Alumina and corundum — Zircon — Alumina mixtures

Results obtained in studying the destruction processes in coagulation structures in vibration of castable thixotropic corundum — mullite — alumina and corundum — zircon — alumina mixtures containing fine alumina are presented as a function of various manufacturing parameters. General regularities and destruction mechanisms in these mixtures are established. The results are used to devise manufacturing techniques for vibrocast corundum and mullite — corundum — zircon refractories. Translated from Ogneupory, No. 8, pp. 12 – 17, August, 1994.     

Molecular mobility in the superstrong para-aramid fibre—water system

The state of the components in the para-aramid fibre—water system was investigated by NMR and sorption methods. The correlation of the parameters of the sorption isotherm and NMR spectra was demonstrated. In the fibres investigated, water molecules sorbed by the Rusar sample had the lowest mobility and water molecules sorbed by the Technora sample had the highest mobility. The low values of T_2k of Rusar fibre suggest strong bonding of the sorbate with the sorbent, which indirectly confirms the low crystallinity and high chain orientation in this fibre. Translated from Khimicheskie Volokna, No. 3, p. 29–30, May–June, 2008.     

Esterification of viscose fibres with orthophosphoric acid and study of their physicochemical and mechanical properties

Esterification of viscose fibres with aqueous solutions of orthophosphoric acid and urea at different ratios of components was investigated. It was shown that in phosphorylation of cellulose with these solutions, one-substituted cellulose phosphates are formed and a side process of formation of cellulose carbamates takes place together with accumulation of phosphate groups. A decrease was found in the mechanical strength of the phosphorylated cellulose preparations and the degree was a function of the concentration of orthophosphoric acid and urea as the phosphorylating solution. Phosphorus-containing viscose fibres (up to 0.5 mmole/g of phosphate groups) obtained in solutions of orthophosphoric acid and urea with a 0.25–0.63 and 3.33–4.17 M concentration have the most satisfactory mechanical properties and stability in phosphate buffer with pH 7.5. __________ Translated from Khimicheskie Volokna, No. 1, pp. 26–30, January—February, 2007.     

Basalt plastics — new materials for road construction

The effectiveness of using basalt fibres and substandard basalt wool — large-tonnage waste from chemical plants and nuclear generating stations — as a reinforcing component in road construction was demonstrated. Incorporation of basalt fibre or wool in asphalt concrete in an amount of up to 0.4 wt. % increased the strength characteristics of the asphalt concrete by 10–30%. The presence of a physicochemical reaction in the basalt fibre—polymer-asphalt binder system, which increased the strength characteristics, heat resistance, and lifetime of the polymer—asphalt—concrete, was demonstrated. IR spectroscopy showed ordering of the structure of the PAB due to formation of organosilicate compounds that strengthened the structure of the polymer asphalt concrete. Translated from Khimicheskie Volokna, No. 6, pp. 11–14, November–December, 2009.     

Efficiency of use of bottoms from regeneration of lactam water for production of magnetoplastics

The efficiency of using bottoms from regeneration of lactam water as a polymeric thermoplastic binder for creating magnetoplastics was demonstrated. A formula for magnetoplastics with magnetic characteristics corresponding to a foreign analog — the magnetoplastic from the German firm Neofer — was developed. The magnetoplastics are chemically stable in conditions of exposure to aggressive media — machine oil and gasoline. Translated from Khimicheskie Volokna, No. 1, pp. 53–55, January–February, 1998.     

Corrosion protection of Mg alloys by cathodic electrodeposition coating pretreated with silane

The corrosion resistance characteristics of three coatings on magnesium alloy AZ31—conventional paint with phosphate film, cathodic electrodeposition coating (E-coating), and E-coating pretreated with silane (Mg/silane/E-coating)—have been studied by means of electrochemical impedance spectroscopy (EIS) in a 3.5 wt% NaCl neutral aqueous solution and salt spray test using ASTM B117. Silane film was obtained by dipping AZ31 specimens in diluted hydroalcoholic silanic solutions and successively curing. It was found that the corrosion resistance of the Mg alloy with E-coating was superior to conventional paint and could be further enhanced with silane pretreatment as an interfacial film. The results of water volume fraction (Φ_saturation) and diffusion coefficient (D) also indicated that the Mg/silane/E-coating possessed excellent compactness and corrosion resistance. A model of the corrosion mechanism for Mg/silane/E-coating has been presented through EIS analysis.     

The fruit and kernel oil of the plumy coconut(Arecastrum Romanzoffianum)

Summary The nuts and oil fromArecastrum Romanzoffianum have been examined. Full-grown dried nuts from a mature tree average 23 per cent of fibrous husk, 69 per cent of shell and 8 per cent of oily kernel. The dried kernel contains about 52 per cent of oil of a non-drying character, and somewhat similar to palm kernel oil in physical properties. The chemical and physical characteristics of the kernel oil are: Sp. G. 25°/25°—0.9194; Refrac. Index N_D 20° C.—1.4580; Free Fatty Acids (as oleic)—0.19 per cent; Saponification Value—239.5; Iodine No. (Hanus) 28.4; Unsaponifiable Matter—0.41 per cent; Pol. Value—0.85; Acetyl Value—3.5; Hehner Value—88.4; Thiocyanogen No.—24.5; R-M. Value—0.72. Agricultural Chemical Research Division Contribution No. 44.     

Fluorochalcogenide glasses

A new variety of chalcogenide vitreous materials—fluorochalcogenide glasses—have been synthesized by the introduction of sodium, thallium, lead, manganese, and bismuth fluorides into the Ga₂S-GeS₂ system. These glasses are characterized by high glass transition temperatures (560–670 K), an optical transmittance up to 75% in the visible (from 0.48 μm) and IR (to 7.5 μm) spectral ranges, chemical durability in reactive acid media, low crystallization ability, and the stability of physicochemical and optical properties. Depending on the introduced fluoride, the glasses can be dielectrics, semiconductors, or ionic semiconductors. The spectral investigation of fluorochalcogenide glasses by using the X-ray emission, Raman, NMR, and EPR spectroscopy reveals the complex features of their structure. The metal cations form bonds with sulfur in different structural positions. The glass network providing the mobility of sodium ions is formed in sodium fluoride-containing glasses. The formation of groupings of the [≡Ga ← F-Ge≡] type is the main structural feature of fluorochalcogenide glasses.     

Fluorochalcogenide glasses

A new variety of chalcogenide vitreous materials—fluorochalcogenide glasses—have been synthesized by the introduction of sodium, thallium, lead, manganese, and bismuth fluorides into the Ga₂S-GeS₂ system. These glasses are characterized by high glass transition temperatures (560–670 K), an optical transmittance up to 75% in the visible (from 0.48 μm) and IR (to 7.5 μm) spectral ranges, chemical durability in reactive acid media, low crystallization ability, and the stability of physicochemical and optical properties. Depending on the introduced fluoride, the glasses can be dielectrics, semiconductors, or ionic semiconductors. The spectral investigation of fluorochalcogenide glasses by using the X-ray emission, Raman, NMR, and EPR spectroscopy reveals the complex features of their structure. The metal cations form bonds with sulfur in different structural positions. The glass network providing the mobility of sodium ions is formed in sodium fluoride-containing glasses. The formation of groupings of the [≡Ga ← F-Ge≡] type is the main structural feature of fluorochalcogenide glasses.     

Electrochemical properties of aluminium anodes for Al/air batteries with aqueous sodium chloride electrolyte

In order to develop the new anode materials for Al/air batteries, electrochemical properties of pure aluminium (99.999 %), technical grade aluminium (99.8 %) and the alloys with indium and tin, i.e. Al—0.1 % In, Al—0.2 % Sn and Al—0.1 % In—0.2 % Sn have been investigated in 2 mol dm⁻³ NaCl solution. The aluminium materials were polarized anodically in the range 20–100 mA cm⁻² for a 30 min period. During the anodic polarization variation in potential was recorded as a function of time and the simultaneous hydrogen evolution was measured. The rate of hydrogen evolution reaction was found to increase with increasing anodic polarization which is characteristic of the negative difference effect. The additional information concerning the corrosion behaviour of the tested materials was provided by light microscope imaging. The results show that the examined technical grade aluminium alloys could serve as suitable anodes for Al/air batteries containing sodium chloride electrolyte; with Al–In exhibiting the most remarkable characteristics. The addition of In as alloying component to aluminium reduces electrode polarization, decreases hydrogen evolution rate and increases the anode efficiency.     

Biological behavior of some soap-based detergents

The biodegradability of tallow soap, three soap-based detergent formulations and their component lime soap dispersing agents—sodium methyl α-sulfotallowate, sulfated N-(2-hydroxypropyl) tallowamide, and sodium N-methyl N-(2-sulfoethyl) tallowamide—was determined under aerobic and microaerophilic conditions. Both sewage and river water microorganisms were used as the sources of inoculum. The course of biodegradation was followed by loss of carbon and methylene blue active substance, and by increase in turbidity and surface tension. Carbon analysis for soap in solutions containing Ca⁺⁺ and Mg⁺⁺, which would precipitate soap, was performed by an improved technique using the disodium salt of ethylenediamine tetraacetic acid. Invariably a decrease in carbon content was accompanied by an increase in turbidity and surface tension. Also, loss in methylene blue active substance was concurrent with an increase in turbidity and surface tension of the degrading solutions of the detergent. Soap cannot be determined as methylene blue active substance because of the low pH of the test. Soap and the built soap formulations degraded under aerobic and microaerophilic conditions. Preliminary toxicity data upon mammals and fish indicated that the soap-based detergents are as safe as conventional commercial detergents. ARS, USDA.