Formation and Phase Behavior of Winsor Type III <Emphasis Type="Italic">Jatropha curcas</Emphasis>-Based Microemulsion Systems

The formation and phase behavior of Jatropha curcas-based microemulsion systems, which could potentially be used in enhanced oil recovery applications, has been investigated. Winsor type III microemulsions were obtained by adding n-octane to Winsor type I microemulsion systems prepared using various concentrations of alkyl polyglucoside (APG). To optimize the formulation of type III microemulsion systems, five different types of co-surfactants, i.e. normal butyl alcohol (NBA), isobutyl alcohol, isopropyl alcohol, fatty acid alcohol C8 (FAC8) and fatty acid alcohol C8/C10 (FAC8/C10) were used. The microemulsion phase behavior was determined along with particle size distributions by dynamic light scattering measurements. Results show that the optimum Winston type III system can be achieved by mixing 3 wt% of NBA, 1 wt% APG and 3 wt% NaCl. At the optimum formulation, the IFT reached a minimum value (0.016 mN/m) and formed very small emulsion droplets with a narrow particle size distribution.     

Utilization of aluminum sludge and aluminum slag (dross) for the manufacture of calcium aluminate cement

Four calcium aluminate cement mixes were manufactured from aluminum sludge as a source of calcium oxide and Al₂O₃ and aluminum slag (dross) as a source of aluminum oxide with some additions of pure alumina. The mixes were composed of 35–50% aluminum sludge, 37.50–48.75% aluminum slag (dross) and 12.50–16.25% aluminum oxide. The mixed were processed then sintered at different firing temperatures up to 1500 °C or 1550 °C. The mineralogical compositions of the fired mixes investigated using X-ray diffraction indicated that the fired mixes composed of variable contents of calcium aluminate (CA), calciumdialuminate (CA₂), calciumhexaaluminate (CA₆) in addition to some content of magnesium aluminate spinel (MA). Sintering parameters (bulk density, apparent porosity and linear change) and mechanical properties (cold crushing strength) of the fired briquettes were tested at different firing temperature. Refractoriness of the cement samples manufactured at the optimum firing temperature was detected. Cementing properties (water of consistency, setting time and compressive strength as a function of curing time up to 28 days of hydration) of pasted prepared from the manufactured cement mixes at the selected optimum firing temperatures (1400 °C or 1500 °C) were also tested. Cement mixes manufactured from 45 to 50% aluminum sludge, 37.50–41.25% aluminum slag (dross) with 12.50–13.75% alumina were selected as the optimum mixes for manufacturing calcium aluminate cement since they satisfy the requirements of the international standard specifications regarding cementing and refractory properties as a result of their content of CA (the main hydraulic phase in calcium aluminate cement) and CA₂(the less hydraulic but more refractory phase). Although the recognized high refractoriness of CA₆, its formation affect badly the cementing properties of the other non-optimum mixes.     

Facile synthesis of novel optically active poly(amide‐imide)s containing N,N′‐(pyromellitoyl)‐bis‐l‐phenylalanine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation

Pyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) (1) was reacted with L‐phenylalanine (2) in a mixture of acetic acid and pyridine (3 : 2) at room temperature, then was refluxed at 90–100°C and N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid (3) was obtained in quantitative yield. The imide‐acid (3) was converted to N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid chloride (4) by reaction with thionyl chloride. Rapid and highly efficient synthesis of poly(amide‐imide)s (6a–f) was achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid chloride (4) with six different derivatives of 5,5‐disubstituted hydantoin compounds (5a–f) in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly, compared with the conventional melt polycondensation and solution polycondensation, and was almost completed within 10 min, giving a series of poly(amide‐imide)s with inherent viscosities about 0.28–0.44 dL/g. The resulting poly(amide‐imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity (η_inh), solubility test and specific rotation. Thermal properties of the poly(amide‐imide)s were investigated using thermal gravimetric analysis (TGA). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 516–524, 2004     

Synthesis and properties of new thermally stable poly(amide-imide)s containing flexible ether moieties

Six new poly(amide-imide)s (PAIs) 8a-f were synthesized from the direct polycondensation reaction of 1,1-bis[4-(trimellitimido)phenoxy]methane 6 with various aromatic diamine 7a–f. The polymerization reactions produced a series of thermally stable and organosoluble PAIs with high yield and good inherent viscosity. The resulted polymers were fully characterized by means of FTIR and ¹H-NMR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Also thermal properties of the PAIs 8a–f were investigated using thermal gravimetric analysis (TGA) and derivative of thermaogravimetric (DTG) analysis. dicarboxylic acid 6 was synthesized from the reaction of 1,1-bis[4-aminophenoxy]methane 4 with trimellitic anhydride 5 in a solution of glacial acetic acid/pyridine (Py) at refluxing temperature.     

Preparation of tailor‐made polystyrene nanocomposite with mixed clay‐anchored and free chains via atom transfer radical polymerization

Tailor‐made polystyrene nanocomposite with mixed free and clay‐attached polystyrene chains was synthesized using atom transfer radical polymerization. Vinylbenzyl trimethylammonium chloride having a double bond, which could be incorporated into polystyrene chains by a grafting through process, was used as a nanoclay modifier. Conversion and molecular weight evaluation was carried out using gas chromatography and gel permeation chromatography, respectively. The thermogravimetric analysis results confirmed the elevated thermal stability of the nanocomposites in comparison with the neat polystyrene sample. Additionally, the T_g increases by clay loading was confirmed by differential scanning calorimetry (DSC). The difference in the degradation temperature of C? Br bond in attached and free polystyrene chains was well revealed in DSC thermograms. Finally, a lower clay loading resulted in an exfoliated structure as proved by X‐ray diffraction and transmission electron microscopy results. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Application of GA-Optimized ANNs to Predict the Water Content,CO2 and H2S Absorption Capacity of Diethanolamine (DEA) in Khangiran Gas Sweetening Plant

Theoretical Foundations of Chemical Engineering - In this work, with the aim of accurate prediction of water content, H2S and CO2 absorption capacity of diethanolamine (DEA) solvent in Khangiran...     

Preparation and characterization of doped manganese dioxides

Doped manganese dioxide samples, containing cations of different valency, were prepared. The doped and undoped samples contained small amounts of physically held and chemically bound water. The X-ray diffraction patterns of the doped samples were very similar to the pattern of the undoped sample and they all belong to the-modification mixed with-MnO₂ and-Mn₂O₃. The specific surface area of the samples measured by nitrogen adsorption and calculated by the _s-method was in the range 2–5 m²g^–1, indicating a lower porosity and a lower reactivity compared to the-forms. From measurements of pore radii the pores were classified as lying in the mesopore/macropore range (8–35 nm). A decrease in the mean pore radius was observed for the doped samples except for that doped with Li⁺ ions.     

Sterols of scallop. III. Characterization of some C-24 epimeric sterols by high resolution (220 MHz) nuclear magnetic resonance spectroscopy

Alkyl sterols epimeric at C-24 isolated from the Atlantic scallop,Placopecten magellanicus, were analyzed by high resolution (220 MHz) nuclear magnetic resonance spectrometry, and their spectra compared with authentic samples. This technique was used to assign absolute stereochemistry in epimeric mixtures of 24 R and S 24-methylcholest-5-en-3β-ol, (22E)-24-methylcholesta-5,22-dien-3β-ol and 24-ethylcholest-5-en-3β-ol. It also allowed a semiquantitative estimate of the R/S isomers present in the mixture. M.S.R.L. Contribution Number 242.     

Kinetic study of styrene atom transfer radical polymerization from hydroxyl groups of graphene nanoplatelets: Heterogeneities in chains and graft densities

Confinement effect of graphene nanoplatelets on the kinetics of styrene atom transfer radical polymerization was studied by a “grafting from” reaction. Graphene oxide was modified by different amounts of (3‐aminopropyl) triethoxysilane and then alpha‐bromoisobutyryl bromide from the hydroxyl groups. Polymerization of styrene in the presence of modified graphene and free initiator, ethyl alpha‐bromoisobutyrate, was accomplished at 110°C. Then, effect of various graft densities and different graphene loadings on the heterogeneous graft and free polystyrene chains characteristics and also kinetics of polymerization was studied by gas and gel permeation chromatographies. Efficiency of grafting reactions along with the graft contents was studied by X‐ray photoelectron spectroscopy, elemental analysis, and thermogravimetric analysis. Confinement effects of graphene on the relaxation behavior of polystyrene chains and also morphology of the graphenes were studied by differential scanning calorimetry and transmission electron microscopy, respectively. POLYM. ENG. SCI., 55:1720–1732, 2015. © 2014 Society of Plastics Engineers