The effect of the length of the oxyethylene chain on the conductivity of the polyurethaneurea electrolyte

Polyurethaneureas (PUU), which were synthesized from 4,4′-diphenylmethane diisocyanate (MDI), poly(ethylene glycol) (PEG), and 3,5-diaminobanzoic acid (DABA), were used as polyelectrolytes in this study. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to monitor the effect of the various kinds of PEG on the changes in morphology of PUU electrolytes corresponding to the concentration of lithium perchlorate (LiClO₄) dopants. The results of DSC and FT-IR indicate the Li⁺ ions coordinate with the soft and hard segments. Additionally, the crystallinity of the PEG soft segment and the ordered hydrogen-bonded urea carbonyl groups decreased with increasing salt concentration. Impedance spectroscopy (IS) measurements show that the PUU electrolyte with the high phase separation degree has the high ionic conductivity. The hard-segment T_g and the soft-segment T_m influence the conductivity behavior of polyelectrolytes with increasing measurement temperature.     

Influence of the properties of refractory powders on their granulation and the properties of the granules

Conclusions A study was made of the properties of aluminosilicate powders of various compositions and their influence on the densification during granulation.We established relationships between the porosity and density of the granules with various concentrations of Al₂O₃ with bulk densities and angles of natural slope. It is shown that to obtain dense and strong green articles and fired aluminosilicate granules with the minimum shrinkage, it is necessary to use bodies with a high bulk density and low internal friction, which is attained for alumina by using batches with the maximum concentration of -Al₂O₃ and grains with a pore-free structure, and for aluminosilicate refractories — an increased content of Al₂O₃ within the limits of each type of article.Translated from Ogneupory, No. 8, pp. 6–10, August, 1985.     

Composition of the solution in the hydration of cement

Tests on pure calcium hydroxide solutions have shown that solubility of calcium hydroxide decreases when alkali content increases. With addition of sulfate Ca²⁺, concentration of the solution is higher than without it. Higher Ca²⁺ concentration is not due to an oversaturation with Ca(OH)₂ but to the higher solubility of calcium sulfate. A similar result also was attained in solutions which are in contact with cement. In those cases Ca²⁺ concentration in the solution decreased to the same extent the originally dissolved sulfate was precipitated as ettringite or monosulfate and finally it reached the value corresponding to the Ca(OH)₂ equilibrium.The solutions' pH value rose with increasing alkali content. This effect, however, clearly decreased from potassium to sodium to lithium. If lithium was added to a solution already containing potassium, the pH value decreased although OH-concentration of the solution continued to increase.     

Oxidation of the sulphurised dolomite produced in the desulphurisation of the gasification gases

Dolomite reacts with H₂S to produce calcium sulphide and has been broadly investigated as a desulphurisation agent due to its low-cost and favourable properties.Because CaS reacts with water or water vapour in the environment to regenerate hydrogen sulphide and, therefore, disposal is problematic and the chemical cannot be uses as a landfill material. One of the methods used to make this material inert is oxidation to convert calcium sulphide into calcium sulphate or calcium oxide.In our study, tests were carried out using dolomite from Granada, Spain, that was previously calcined and sulphurised at high temperature with a gas similar to that produced in gasification facilities. To approximate real-scale results, a relatively large amount of substance was used for each sample (100–150 g) and the samples were used in a fixed-bed position.The influence of different conditions, such as grain size, composition of the oxidation gas, gas velocity, bed length and temperature, was them investigated. The final solid products were characterised by X-ray diffraction and chemical analysis and the CO₂, SO₂, H₂S and COS concentrations in the gases produced during oxidation were analysed by gas chromatography.The results showed that the most influential factor was grain size and that the best oxidant was O₂ mixed with nitrogen.The presence of water vapour increases the residual concentration of CaS in the end product, but increased the CaO contentThe higher the oxygen concentration and the higher the gas velocity, the lower the residual content of CaS. CO₂ used alone oxidises CaS to produce SO₂ and COS, but at very low rates. It also produces some CS₂. Water vapour used alone can also oxidise the CaS to produce H₂S and SO₂ but also at very low velocity.At higher oxidation temperature, between 700°C and 850 °C, lesser residual CaS is obtained in the oxidised product.     

Comparison of the generation of oil by the extraction and the hydropyrolysis of biomass

This paper discusses the maximisation of the yields of useful bio-oils generated from seeds and nut-shells both by extraction and by hydropyrolysis. The formation and the composition of the bio-oils are also discussed.Powdered (<0.25 mm diameter) Rapeseed, Linseed and Safflower seed and Hazel nut and Walnut shells, that is, fresh precursors of liptinite, have been characterised by their elemental analyses, infra-red and NMR spectra. Bio-oils obtained both by extraction and by slow hydropyrolysis to 520 °C at moderate pressure in the presence of ammonium dioxydithiomolybdate have been compared by the same analyses and by gas chromatography. Consistent with previous work [Hardy JA. A greener future with biodiesel. Green Chem 2001 G56-G57], extraction of the seeds with organic solvents, including Diesel oil, gave yields of up to 40% together with an uninteresting residue. However, subsequent saponification of the residues gave further yields of oil. Hydropyrolysis removed oxygen from the seeds as water and as oxides of carbon to generate bio-oil in yields of up to 75%. Whereas little oil could be extracted from the nut-shells, hydropyrolysis gave oil yields of ∼40%. Some char was also formed, suggesting that optimisation of the hydropyrolysis might give even larger yields of oil.     

Dependence of the properties of chamotte on the firing regime of the briquette

Conclusions The physicomechanical properties and phase composition of chamotte depends on the composition of the gas medium, the firing temperature, and the cooling regime. In the briquettes fired at 1500°C in an oxidizing medium with the cooling temperature lowered from 1500 to 1200°C, the apparent density increases and the porosity decreases. In the briquettes fired in a reducing medium with the cooling temperature lowered from 1500 to 1300°C, there is a reduction in the apparent density and an increase in the porosity but with a further reduction of the cooling temperature to 1200°C, these properties change in the opposite direction.The apparent density of chamotte and its concentration of mullite is increased with a reduction in the cooling rate. The apparent density of the chamotte from the Polozhsk kaolin under analogous cooling conditions increases more rapidly than that from the Novoselitsk kaolin chamotte.The temperature interval in which the cooling rate effectively increases the apparent density of the chamotte fired in an oxidizing medium is 1500–1300°C. In a reducing medium this interval is shifted 100°C toward lower temperatures.The experiments have shown that an increase in the cooling rate of the fired briquettes at temperatures below 1200°C has only a very slight effect on the apparent density and porosity of the Novoselitsk kaolin chamotte. When the chamotte has been obtained from Polozhsk kaolin, a reduction in the cooling rate at temperatures below 1200°C, and particularly in a reducing medium, has a quite perceptible effect on the increase in apparent density and reduction of porosity of the material.Translated from Ogneupory, No. 3, pp. 22–26, March, 1982.     

Effect of the microstructure of graphitic boron nitride on the kinetics of the formation of boron nitride high-pressure phases

Three types of hexagonal boron nitride (h-BN) with graphitic crystal structure having different microstructures were subjected to high pressures (HP) and high temperatures (HT), and the kinetics of the phase transitions to the sp³-hybridized phases (w-BN, c-BN) was studied using in situ synchrotron diffraction. The analysis of the phase transformation kinetics revealed the transformation paths and activation energies E_a of the transformation of h-BN to the high-pressure forms of BN for different microstructures of h-BN. Defect-poor h-BN transforms to metastable wurtzitic BN (w-BN) with E_a ≈ 0.3 eV/at. Defect-rich forms of h-BN transform directly to c-BN, but with a higher activation energy. It was observed that the turbostratic disorder in h-BN retards the phase transition as compared to h-BN containing corrugated basal planes and a low degree of turbostracity. The experimental results are discussed in view of the microstructure changes during the HP/HT treatment and compared to available theoretical phase transition models.     

On the Formation of Pentylpiperidine in the Hydrodenitrogenation of Pyridine

The hydrodenitrogenation of 2-methylpiperidine and 2-methylpyrrolidine was studied over sulfided NiMo/γ-Al₂O₃ in the presence of dialkylamines, alkylamines, and alkenes to determine why N-pentylpiperidine is formed in the hydrodenitrogenation of pyridine. N-alkylated 2-methylpiperidine and 2-methylpyrrolidine were only formed as primary products by reaction with alkylamines and not by reaction with 2-methylpiperidine and 2-methylpyrrolidine, or by reaction with an alkene. This indicates that, in the hydrodenitrogenation of pyridine, N-pentylpiperidine is formed by the reaction of the secondary intermediate pentylamine with the primary intermediate piperidine, and not by reaction of two primary piperidine intermediates or by reaction of pentene, one of the final products, with piperidine.     

Effects of the glass bead content and the surface treatment on the mechanical properties of polypropylene composites

Polypropylene composites filled with glass beads (GBs) were prepared by means of a twin‐screw extruder. The tensile properties and impact‐fracture strength of the composites were measured at room temperature to identify the effects of the GB content and surface treatment on the mechanical properties. The results show that the relative elastic modulus increased nonlinearly, whereas the tensile strength decreased with increasing GB volume fraction (?_f). The notched impact strength increased with increasing ?_f when ?_f was less than 11%, and then, it decreased; this might have been related to the GB aggregation in the case of higher concentration. The mechanical properties of the composite systems in which the GB surface was treated with silane coupling agent were better than those of the composite systems filled with the untreated GBs under the same conditions. Furthermore, the impact‐fractured surfaces were observed with a scanning electron microscope to understand the interfacial morphology between the inclusion and the matrix and to examine the toughening mechanisms. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Influence of the phosphate glass melt on the corrosion of functional particles occurring during the preparation of glass-ceramics

We report our findings on the impact of the glass composition on the corrosion of microparticles occurring during the preparation of glass-ceramics using the direct doping method. Microparticles (MPs) with the composition Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ with blue-green persistent luminescence were chosen as the changes in their spectroscopic properties can be related to the MPs’ corrosion. The MPs were added in phosphate-based glasses with different compositions. When using the same doping parameters, the glass system with the composition 90NaPO₃-10Na₂O (mol%) was found to be the least corrosive on the MPs whereas the glass system with the composition 90NaPO₃-10NaF (mol%) is the most corrosive on the MPs probably due to their different viscosity at 575?°C, the temperature at which the MPs are added in the glass melts.     

Synthesis of the stereoisomers of the female sex pheromone of the Hessian fly,Mayetiola destructor

The female-produced sex pheromone of the Hessian fly,Mayetiola destructor (Say) (Diptera: Cecidomyiidae), has been identified as (10E)-tridecen-2-yl acetate. A flexible synthetic route was developed which allowed access to the chiral and racemic forms of the pheromone, and to the 10Z stereoisomer of the pheromone. The natural compound was determined to have the 2S configuration by hydrolysis of the acetate function, derivatization of the resulting alcohol with (2S)-2-acetoxypropionyl chloride, and capillary gas Chromatographic comparison of the derivative with the corresponding derivatives prepared from the synthetic enantiomers. Trace amounts of the 10Z isomer of the pheromone have also been detected in extracts of female Hessian fly ovipositors, along with (10E)-tridecen-2-ol and 2-tridecanyl acetate. Due to the small quantities of these compounds available from ovipositor extracts, the chirality of the trace components has not yet been determined.     

Effect of the crystallinity of kaolinite precursors on the properties of mesoporous silicas

Mesoporous silicas (MesoPSs) were hydrothermally synthesized from calcined and selectively acid-leached kaolinites with a range of crystallinity, using cetyltrimethyl ammonium bromide (CTABr), to investigate the effect of the kaolinite crystallinity on the porous properties of the resulting MesoPSs. Four kaolinites were used, with Hinckley indices ranging from 0.51 to 1.20 and (001) crystallite sizes ranging from 20 to 37 nm. After calcination at 600 °C for 24 h they were selectively leached with 2.5 M H₂SO₄ at 90 °C for 2 h to prepare microporous silica (MicroPSs). The Si/Al ratios of these MicroPSs varied from 21 to 82 and their specific surface areas (S_BET) ranged from 169 to 370 m²/g, these parameters tending to increase with decreasing Hinckley index of the kaolinite. MesoPSs were synthesized by reacting the resulting MicroPSs with CTABr in NaOH solution under hydrothermal conditions. The MicroPS was mixed with CTABr, NaOH and water in the molar ratio (MicroPS):CTABr:NaOH:H₂O = 1:0.1:0.3:150. The synthesis was carried out by stirring the suspension at room temperature for 24 h, aging for 24 h, hydrothermal treatment at 110 °C for 24 h and calcination at 560 °C for 6 h to remove the surfactants. The S_BET values of the resulting MesoPSs ranged from 932 to 1240 m²/g, correlating with the S_BET values of the precursor MicroPS and the crystallinity of the kaolinite starting materials.     

Effect of the viscosity of the resin on the properties of resin — Dolomite — Magnesite refractories

Conclusions Calcined dolomite with a porosity up to 5% is not impregnated by resins of different viscosities (from 86 to 1200 sec at 40°C).Unfired products made from pastes in soft resins are characterized by a high degree of hydration and relatively low strength. Products in hard resins have better properties. The properties of the products after coking calcination are practically identical.Aging of the pastes does not substantially change the properties of unfired products. An increase in the aging time from 3 to 10 days leads to a noticeable worsening of the properties of the products after coking calcination.Since the properties of the products in resins of different viscosity after coking calcination are practically identical, in the production of resindolomite — magnesite products for converters, successful use can be made of resins of different viscosity, but with a coking number no less than 28–32%. The choice of the resin is determined by the technological flowsheet of the process for production of converter refractories: resins with low viscosity (C ₄₀ ¹⁰ up to 100 sec) by the cold process, resins with high viscosity (C ₄₀ ¹⁰ more than 1000 sec) by the hot process for preparation of the products.Translated from Ogneupory, No.4, pp. 39–45, April, 1968.     

Effect of the plant waste onto the properties of use and the microstructure of phyllosilicates based ceramics

The present study aimed at using plant waste (Musa Paradisiaca) for manufacturing clay-based ceramics in order to promote lower sintering temperature while preserving the properties of use. Two kaolinic-illitic clays (NZ1 and KO) from Central African Republic were used mixed with 1 to 10 mass% of the plant waste (MP). The clays and the waste exhibited accessory phases: quartz and iron oxides, and K₂O respectively. MP was collected, dried and sieved (<100 μm) previously to its mixture with clays. According to the sintering behavior of KO and NZ1 derived from thermodilatometry, the densification was obtained after firing at 1200°C. Results showed that open porosity decreased from 35% to 17% with increasing temperature in the range 900 to 1200°C for KO and NZ1. This porosity remained in the range 30%-40% while increasing the MP content (firing at 1000°C for 1h.). The optimized MP content was 3 and 5 mass% for KO and NZ1 clay materials respectively. The compressive strength and thermal conductivities were improved compared to clay samples without MP fired at 1200°C. Moreover a significant decrease in the sintering temperature was achieved, leading to energy saving in line with sustainability issues.     

Effect of the grain composition of the batch on the structure and properties of periclase refractories

Conclusions The structure and properties of periclase articles have been studied as a function of the quality of the powders and the grain composition of the batch. The possibility of obtaining periclase refractories with a high density (open porosity 8–12%) and heat resistance (11–16 heat cycles into water) is shown. In order to obtain strong dense articles with an enhanced heat resistance, it is recommended that dense powders with a fine-crystal structure be used; additional recrystallization during the high-temperature firing helps to strengthen the articles.The addition of 1% ZrO₂ improves the properties of the articles, which is the result of the strengthening of the diffusion processes capable of forming strong direct bonds between the periclase crystals in the aggregates and the bonding material.Deceased.Translated from Ogneupory, No. 2, pp. 52–57, February, 1979.     

Effect of the fold surface of the lamellae on the behavior of the trapped radicals in irradiated Polyamide-1010

Two types of macromolecular free radicals —CH₂CONHĊHCH₂— (a) and —CH₂Ċ=O (b) trapped in irradiated Polyamide-1010 (PA1010) and PA1010 filled with neodymium oxide (Nd₂O₃) were characterized by an ESR approach. It was found out that a was mainly trapped in the fold surface of the lamellae and b in the amorphous phase. This result suggested that trapped radicals mainly existed in the noncrystalline phases. The effect of the fold surface area of the lamellae on the behavior of the trapped radicals are discussed in this article. Whether for the specimens with similar crystallinities but different crystallite sizes or for those with the same concentration of neodymium oxide but different crystallinities, radical a exists dominantly in a specimen with a larger fold surface area of the lamellae. Under a certain circumstance, radical a can transform into radical b for a specimen with a larger fold surface area of the lamellae. It means that the fold surface area of the lamellae plays an important role in the transformation of radical a to b. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1335–1339, 1998     

On the nature of the burning rate-controlling reaction of energetic materials for the gas-phase model

For model systems with known kinetics of elementary reactions (CH₃NO₂ and HN₃), temperature ranges are established in which the rate-controlling reactions are the initial endothermic decomposition of the starting material or the subsequent secondary reactions. Heat release in reactions of NO₂, NO, and N₂O with various fuels, such as CH₂O, CO, H₂, and HCN, is modeled to establish the kinetic parameters and nature of the rate-controlling reactions in gas flames of nitro compounds. It is shown that the activation energy of the heat-release reaction due to the interaction of NO₂ with a hydrocarbon fuel (which is characteristic of the first flame of nitro compounds) is in the range of 29–33 kcal/mole, depending on the type of fuel. According to the calculations performed, the activation energy of the rate-controlling heat-releasing process due to the deoxidation of NO and N₂O (which is typical of the second flame of nitro compounds) is 43–58 kcal/mole. In the range of high pressures, where the flames merge, the kinetic parameters of heat release are determined by the reactions of the most reactive nitrogen oxide NO₂. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 3, pp. 59–71, May–June, 2007.     

The influence of the method of application of the paint on the corrosion of the substrate as assessed by ASTM and electrochemical method

Conclusions  AC together with DC and standardized procedures have considerable value in assessing the protective ability of a paint film by scientific studies of anticorrosion problems. Knowledge about the changes in permeability, conductivity and adhesion properties of coatings when exposed to aggressive environments is important, not only because it indicates how the coating may behave in practice, but also because it gives an insight into its protective properties in prevention of corrosion of the metal substrate. From the values of corrosion potential, ionic and charge transfer resistance with immersion time, the alkyd paint applied by means of four different methods showed relatively good protective properties in the order S_y>R ≅ S_n but very poor ones for B panel. On the other hand, when submitted to the salt spray cabinet test, all the steel panels coated with unscribed alkyd films have shown high resistance to the strongly aggressive medium. Likewise, the cross scribed panels show only corrosion at and close to the cross-scribing. Taking into account the overall results, the most effective application method was spraying followed by roller coating, spinning and lastly brushing. Further work needs to be done to confirm some of the assumptions made here.     

Validation of the rancimat test for the assessment of the relative stability of fish oils

The induction periods for the peroxidation of various fish oils at 55–90°C were studied by the Rancimat test. The natural logarithms of the induction periods varied linearly with respect to temperature, with a mean coefficient of −7.5×10⁻²°C⁻¹, which was significantly different from that reported for vegetable oils. The activation energy for the formation of volatile acids had a mean value of 38.9 kJ/mol and was independent of the fish oil source. Peroxide formation under Rancimat test conditions followed first-order kinetics. The same kinetics were followed under Schaal Oven test conditions (forced-air oven, 60°C). On the basis of the results obtained, the Rancimat test appears to be useful in determining the relative stabilities of fish oils without the change in peroxide decomposition kinetics that may occur at elevated temperatures.     

Effect of the composition of the initiating complex acyl halides/aluminium bromide on the cationic polymerization of isobutylene

On the basis of ¹H and ¹³C spectra obtained for solutions of complexes of acyl halides with aluminium bromide RCOX·nAlBr₃ (X = Cl, Br; n = 1, 2), it is shown that these adducts can exist in solution as donor–acceptor complexes, acyl salts, or combinations of both forms. The nature of the cationic initiating species for each case is predicted. The predictions coincide well with experimental results obtained by analysis of the isobutylene polymers prepared with these initiating complexes. Initiation by the 1:2 complexes allows polymeric molecules to be synthesized with an acyl group at one end. These polymerization processes have some of the characteristics of living polymerizations. The possibility for quantitative estimation of such systems using the criteria of ‘approach to livingness’ is demonstrated. © 2000 Society of Chemical Industry