Effect of the Molecular Structure on the Adsorption Properties of Cationic Surfactants at the Air–Water Interface

The surface activity and thermodynamic properties of adsorption at the air–water interface of two series of cationic surfactants based on isourea: the O-dodecyl-N,N′-diisopropylisourea hydrochloride, hydrobromide, and hydroiodide and the O-tridecafluorooctyl-N,N′-diisopropylisourea hydrochloride and hydrobromide were studied. The effect of structural parameters as the nature of the halide counter ion and the nature of the non-polar chain on the surface activity and thermodynamic properties of adsorption were investigated. The surface parameters, the maximum surface excess concentration (Γ _max), the minimum area per molecule (A _min) at the aqueous solution-air interface, effectiveness of surface tension reduction (π_CMC), and efficiency of surface tension reduction (pC ₂₀) were estimated. The standard Gibbs free energy of adsorption, (ΔG°_ads) change has been calculated at different temperatures.     

Synthesis and Properties of Lipoamino Acid–Fatty Acid Mixtures: Influence of the Amphiphilic Structure

The acylation of amino acids by acid chlorides with from 8 to 12 carbon atoms in alkaline aqueous medium following Schotten–Baumann reaction results in sodium salts of a N ^α-acylamino acid and fatty acid mixture. The latter are present in a proportion from 40 to 60%. These compositions represent mixtures of amphiphilic anionic surfactants. Together they contribute to the properties of the formulation. Measurements of the surface-active properties of these formulations, such as critical micelle concentration (CMC), surface tension at the CMC (ST), foaming capacity (FC) and foaming stability (FS), show that surfactant mixtures with the longest chain have the most desirable properties. They are comparable to commercial petroleum-based surfactants. Thus, the CMC, ST and CM values of the formulation obtained starting from leucine and dodecanoyl chloride (310 mg/l, 30.1 mN/m and 200%, respectively) are similar to, and even better than, sodium dodecylsulfate (290 mg/l, 39.1 mN/m and 230%, respectively).     

Passage of the Roughening Temperature Influence on the Crystalline Structure and Morphology of a Nano Metal–Organic Material

The reactions between 2-mercaptobenzothiazole (HMBT) and AgNO₃ in ultrasonic bath with low and high concentrations of initial reagents provided yellow precipitates of [Ag₆(MBT)₆] (1), which can be considered as 1L and 1H, respectively. Powder XRD patterns of them showed that they have crystalline structure and SEM images of 1L and 1H approved that microblocks and nanosheets of 1 were formed, respectively. Similar studies after mechanical and thermo-mechanical treatment of 1L and 1H indicated that compound 1 with nanoparticle and agglomerated nanoparticle morphologies were obtained. As a result of heat and energy created from the friction process and also external heat source a roughening transition was occurred and the crystalline samples of 1L and 1H, loses their facets. This can be understood by considering compound 1 surface above the roughening temperature as a liquid surface.     

Influence of the Reduction of Graphene Oxide with Hydroiodic Acid on the Structure and Photoactivity of CdS–rGO Hybrids

The temperature used in the chemical reduction of graphene oxide (GO) with hydroiodic acid has a significant influence on the removal of surface oxygenated functional groups, on the residual iodine species and on the rupture, stacking and graphitization of the graphene sheets in the reduced graphene oxides. The modification in the characteristics of the reduced graphene oxides induces changes in the surface area, the exposition of reduced graphene oxide entities and in the concentration of small CdS nanocrystals with strong confinement effect on the CdS-reduced graphene oxide hybrids. The hybridization of the reduced graphene oxide with CdS modifies in different way their photocatalytic behavior for hydrogen production from aqueous solutions of Na₂S and Na₂SO₃ under simulated sunlight irradiation. Only the hybrid formed between the CdS and the reduced graphene oxide treated at higher temperature showed improved hydrogen production rate respect to the bare CdS reference associated with the better conductivity of the reduced graphene oxide and with the increase in the concentration of small CdS nanocrystals sith strong confinement effect observed in the hybrid.     

Effect of Carbon Nanotubes on the Structure,Internal Loss Storage,and Damping–Absorption Properties of CNT/PZT/RTV

Composites with damping–absorption performance and storage-loss behavior based on carbon nanotubes as a modifier and zinc titanate/room temperature vulcanized silicone rubbers as a matrix were fabricated by a reactive solution mixing process, wet ball milling, and the three-roller milling method. The microstructures, chemical structures, and morphologies of the composites were characterized by scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The thermal stabilities were investigated by thermogravimetric analysis. The effect of carbon nanotubes on the comprehensive performance of the carbon nanotube/zinc titanate/room temperature vulcanized silicon rubber composites was investigated. It was found that doping with carbon nanotubes can improve the comprehensive performance of the zinc titanate/room temperature vulcanized silicon rubber complex matrix. The best comprehensive properties were d₃₃?=?72 pC/N, storage modulus?=?4,100?MPa, loss modulus?=?400?MPa, damping coefficient?=?0.23, and absorption coefficients?=?0.4–0.6 for 4?wt% carbon nanotube/zinc titanate/room temperature vulcanized silicon rubber. In addition, the lattice parameters of zinc titanate were found to be highly dependent on the carbon nanotube content, and the absorption and damping performance of the composites were dependent on the frequency and temperature.     

The Influence of Copper–Copper Interaction on the Structure and Applications of a Metal–Organic Framework Based on Cyanide and 3-Chloropyridine

The structure of the new metal–organic framework, [(CuCN)₂·(3-Clpy)], 1, was characterized by IR, UV–visible, TGA and X-ray single crystal analysis. The structure of 1 consists of CuCN building blocks, which are connected by CN group to form two different chains; one puckered chain with TP-3 geometry around Cu(1) and a linear Cu(2)(CN)₂ chain. The two kinds of chains are bonded by cuprophilic interactions creating a 3D-network. The network structure of 1 is further close-backed by π–π stacking and hydrogen bonds. The electronic absorption and emission spectra as well as the thermodynamic parameters from TGA of the MOF 1 are discussed. MOF 1 was used as an effective heterogeneous catalyst for the oxidative discoloration of methylene blue dye by dilute solution of hydrogen peroxide as the oxidant. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the in vitro antitumor activity of MOF 1 on human breast cancer cell line, MCF7.     

Effect of α-Radioiysis on TRUEX-NPH Solvent

Abstract

An unexpectedly high degradation of the TRUEX (TRansUranic Extraction) solvent occurred during the treatment of waste solutions from the New Brunswick Laboratory. The waste solutions treated contained approximately 1 g/L of Pu-239 and 20 mg/L of Am-241. Earlier studies of α-radiolysis using carbon tetrachloride rather than normal paraffinic hydrocarbons (NPH) as a diluent indicated greater resistance to radiation damage than observed. For this study, the TRUEX-NPH solvent was loaded with Am-241 in nitric acid, irradiated with doses up to 3.5 Mrad, and monitored for decline in extraction capability as a function of absorbed dose. Results of this study are being used to improve the Generic TRUEX Model, a thermodynamic model that permits flow-sheet design for solvent extraction processing.     

Effect of Microsilica Addition on the Properties of Mullite-Corundum Ceramic

1IntroductionCorundum-mullite materials have been recognizedand adopted as important refractories because of theirexcellent properties,such as high refractoriness,highresistance to creep,good mechanical and chemical sta-bility at high temperatures,high th…     

Effect of a Shale Oil–Based Additive on the Properties of Biodiesel Fuel

Multifunctional diesel fuel additives SOMAN and SO-2E were obtained on the basis of kukersite shale oil fractions. Possibilities for the practical application of the additives in diesel engines under actual service conditions were considered. It was shown that the use of the additives decreases fuel consumption and improves the performance characteristics of the engine, including reduction in the amount of exhaust gases.     

Effect of Zr–Al Co-Doping on Structure and Photocatalytic Performance of ZnO Photocatalyst

利用水热处理结合焙烧的方法分别制备了Zr、Al掺杂及Zr–Al共掺的ZnO光催化剂。研究了制备的光催化剂样品的相结构和光谱性能;以紫外光（λ=254nm）为光源,酸性橙Ⅱ为降解对象,进行光催化活性测试;考察了Zr、Al掺杂对ZnO光催化剂反应活性的影响。研究表明,制备的产物均为六方晶系纤锌矿结构的ZnO;Zr、Al掺杂及Zr–Al共掺的ZnO样品的光催化活性相对于纯ZnO均有较大程度的提高,而且Zr–Al共掺的ZnO的光催化性能明显优于单一掺杂的。Zr–Al共掺可以明显改善ZnO表面状态,使ZnO具有更丰富的表面羟基,同时可以抑制光生电子–空穴对的复合,从而有利于光催化活性和稳定性的提高。     

Influence of Matrix Polarity on the Properties of Ethylene Vinyl Acetate–Carbon Nanofiller Nanocomposites

A series of ethylene vinyl acetate (EVA) nanocomposites using four kinds of EVA with 40, 50, 60, and 70 wt% vinyl acetate (VA) contents and three different carbon-based nanofillers—expanded graphite (EG), multi-walled carbon nanotube (MWCNT), and carbon nanofiber (CNF) have been prepared via solution blending. The influence of the matrix polarity and the nature of nanofillers on the morphology and properties of EVA nanocomposites have been investigated. It is observed that the sample with lowest vinyl acetate content exhibits highest mechanical properties. However, the enhancement in mechanical properties with the incorporation of various nanofillers is the highest for EVA with high VA content. This trend has been followed in both dynamic mechanical properties and thermal conductivity of the nanocomposites. EVA copolymer undergoes a transition from partial to complete amorphousness between 40 and 50 wt% VA content, and this changes the dispersion of the nanofillers. The high VA-containing polymers show more affinity toward fillers due to the large free volume available and allow easy dispersion of nanofillers in the amorphous rubbery phase, as confirmed from the morphological studies. The thermal stability of the nanocomposites is also influenced by the type of nanofiller.     

Three-Dimensional Structure of Barium–Cupric Nitrilotriacetate and One-Dimensional Structure of Cobalt–Cupric Nitrilotriacetate: Template Effect of Cations on the Formation of Coordination Polymers

Three mixed-metal nitrilotriacetates [Ba(H₂O)₃Co(nta)Cl]_n (1), [Ba(H₂O)₃Ni(nta)Cl]_n (2), and [Ba(H₂O)₃Cu(nta)Cl]_n (3) (H₃nta = nitrilotriacetic acid) were prepared by the reaction of M²⁺ ions (M = Co, Ni, and Cu), K₃nta, and Ba²⁺ ions in water. The reaction of complexes 1 and 2 with CuSO₄·5H₂O afforded [Co(H₂O)₆]_n[Cu₂(nta)₂]_n·2nH₂O (4) and [Ni(H₂O)₆]_n[Cu₂(nta)₂]_n·2nH₂O (5), respectively. The reaction mechanism was elucidated. The crystal structure analyses indicate that the Ba²⁺ ions formed one-dimensional (1D) zigzag chains in complex 3, and the chains were connected by Cu(nta)^? anions to form a three-dimensional network. On the other hand, in complexes 4 and 5, the Cu(nta)^? anions formed 1D zigzag chains, and the [Co(H₂O)₆]²⁺ (or [Ni(H₂O)₆]²⁺) cations existed as isolated units.     

Effect of Direct Dyes on the Physical and Mechanical Properties of α-Keratin Fibers

Fibre Chemistry - The effect of direct dyes on the physical and mechanical properties of human hair (a-keratin fibers) in the native state and subjected to bleaching with Estel haute couture...     

Influence of TiO2-Modification on the Mechanical and Thermal Properties of Sugarcane Bagasse–EVA Composites

The effect of nano-particles of TiO₂ on the mechanical and thermal properties of sugarcane bagasse (SCB)–ethylene co-vinyl acetate (EVA) composite was investigated. Composite materials were prepared using a melt-mix intercalation method on a rheomex mixer coupled with a single screw extruder. differential scanning calorimeter (DSC), thermogravimetric (TG) analyser and an Instron, were used to probe the thermal and mechanical properties of the samples. Composites with TiO₂ were compared with those without TiO₂ but with the same content of sugarcane bagasse (SCB). After the addition of TiO₂, the tensile strength increased by 10%, from 11.26 MPa for neat EVA, which correlated with the enthalpy of fusion, however, the tensile strength decreased by 18% at higher SCB loading. Elongation at break decreased from 463 to 0% as the filler (SCB) was increased which was inversely proportional to the modulus. The composite showed an improved thermal stability with the addition of TiO₂.     

Influence of Ultra-Fine B4C and Nano-SiO2 on the Properties of Alumina-Graphite Refractories

The role of nano-SiO2 and ultra-fine boron carbide on the properties of alumina-graphite materials was investigated.The study showed that the ultra-fine boron carbide added modified the microstructure of residual carbon and promoted the chemical bond between residual carbon from phenolic resin and flake graphite.The carbon white could strengthen the residual carbon from phenolic resin.These two additives improved the mechanical properties of AG refractories at both room temperature and high temperature,and thermal shock resistance was improved noticeably.When the two additives were doped together,carbon white could retard the evaporation of B2O3.Thermal shock resistance was guaranteed with a smaller amount of ultrafine born carbide.     

Evaluation of the Effect of Nanosilica on Thermal and Mechanical Properties of Metal–Metal and Metal–Glass Canola-Based Polyurethane/Nanosilica Adhesives

Nanocomposites with different concentration of nanofiller were prepared by adding nanosilica to the canola-based polyurethane matrix via in situ polymerization. The effect of nanosilica on the mechanical properties of adhesives was evaluated by tensile tests. Adhesive characteristics on metal–metal and metal–glass bondings were also evaluated by lap shear strength tests. Incorporation of nanosilica into the canola-based polyurethane enhanced both tensile and lap shear strength of synthesized adhesives. Also the effect of nanoparticles on glass transition temperature and thermal stability was investigated by differential scanning calorimetry and thermogravimetric analysis, respectively. The increase of nanosilica content in the polyurethane adhesives, thermal property of the nanocomposites improved.     

The Effect of Yttrium Oxide on the Microstructure and Properties of Ceramics Based on Lanthanum Hexaaluminate Synthesized by the Sol–Gel Method

The effect of a sintering aid, yttrium oxide, on the properties of ceramic materials based on lanthanum hexaaluminate synthesized by a sol–gel method is studied. The synthesis of a sol of ternary oxide composition conducted via hydrolysis of a mixed salt solution leads to the formation of particles with a nucleus – shell-type structure. The synthesis of lanthanum hexaaluminate with the participation of these particles proceeds at 1000 – 1100°C, and the sintering of ceramic at 1400 – 1500°C. Ceramic based on yttrium-containing lanthanum hexaaluminate exhibits improved strength properties.     

Influence of a Zwitterionic Surfactant on the Surface Properties of Electroless Ni–P Coating on Mild Steel

3-(N,N-Dimethyl myristyl-ammonio) propane sulfonate zwitterionic surfactant (C14-SB) which possessed both positive and negative charges was evaluated in the electroless Ni–P coating process. It was observed that the deposition rate, morphology and microhardness of the deposits were enhanced by the addition of C14-SB surfactant. The excess attractive forces from the negative head of C14-SB were strong enough to draw metallic nickel particles towards the substrate. Ni particles attempting to deposit on the electrolyte container were eliminated by the repulsive force from the positive head of the surfactant monomers. Thus, the deposition rate of the coating process was improved. The surfactant at its critical micelle concentration (CMC) doubles the deposition rate when compared to the substrate without surfactant. In addition, the microhardness of the deposit at the surfactant CMC increased by 62 %. The corrosion rate of the substrate without surfactant was 7.15 mpy, while it was 3.97 mpy for the substrate deposited with C14-SB zwitterionic surfactant at the CMC.     

Effect of Sintering Additive on the Properties of Sialon-SiC by Gelcasting

Sintering additivesto gelcasting Sialon‘SiC were decided by the optimizing experiments , The resuhs show that Sialon-SiC can be sintered under 1450℃ and sintering temperature dcreases by 100℃，when 2%～3% TiO2 or Guangxi clay is used as sintering additive.     

Effect of Ultrasound on the Structural and Textural Properties of Al–Fe Pillared Clays in a Concentrated Medium

A modification of bentonite with the Al–Fe mixed system in a concentrated medium was performed, assisting the intercalation with ultrasound. The solid pillaring agent and clay powder were placed in a dialysis membrane in contact with a minimum amount of water, and ultrasound was used to promote species exchange. Al–Fe pillared clays (2, 5 and 10 mol% Fe) were characterized by XRF, CEC, XRD, H₂-TPR and N₂ adsorption at 77 K, revealing changes in the structural and textural properties of the modified clays in the presence of ultrasound during the intercalation. The catalytic properties of pillared clays were evaluated by using the catalytic wet peroxide oxidation of phenol in a diluted aqueous medium, showing an activity comparable to that of a solid modified through the conventional method.