A novel terthienyl based polymer electrochrome with peripheral BODIPY

Design, synthesis and electropolymerization of a new hybrid material based on terthienyl system bearing BODIPY appendage are reported. This electrochemically polymerized unique combination readily gives an electrochromic polymer with a narrow optical band gap (1.71 eV). The electrochrome exhibits purple color when neutralized and sky blue color when oxidized in a monomer-free electrolyte solution containing 0.1 M tetrabutylammonium tetrafluoroborate dissolved in acetonitrile. Spectroscopic and electrochemical features of the electroactive polymer electrochrome indicate that it is a promising candidate for electrochromic device and display applications.     

Pressureless sintering of β-SiAlON ceramic compositions using fluorine and oxide additive system

SiAlONs are silicon aluminium oxynitride ceramic materials with a range of technically important applications, from cutting tools to specialised refractories and the properties of SiAlONs can be tailored for specific purposes. In this study, different β-SiAlON compositions were prepared using fluoride (MgF₂ as fluorine source plus Y₂O₃) and oxide (MgO plus Y₂O₃). These compositions were pressureless sintered under nitrogen atmosphere in the range of 1450–1750 °C for 0.5–2.5 h for comparison of densification behaviour and mechanical properties. Densities of samples were measured and analyses of result products were carried out using SEM and XRD. The F-doped sintered β-SiAlON ceramics showed better densities and less pore micrographs especially at lower temperatures compared with the fluorine free samples. Full densifications were achieved for β-SiAlON ceramics with fluoride addition at 1700 °C for 60 min. Consequently, fluorine addition to additive system has a good effect on mechanical properties and densification behaviour.     

Synthesis and characterization of polyphenols derived from 4-fluorobenzaldeyde: The effect of electron-donating group on some physical properties

In this study, we proposed to investigate how the effect of electron-donating methyl ( CH₃) group at p-position of amin ( NH₂) group in aminophenol (AP) compound affected thermal stability, optical, electrochemical properties, and conductivity measurement. For this reason, we choice 2-AP and 2-amino-4-methylphenol compounds and synthesized phenolic monomers by condensation reactions 4-fluorobenzaldehyde with aromatic amino phenols. Then, these monomers were converted to their polyphenol derivatives by oxidative polycondensation reactions in an aqueous alkaline medium. Structural characterizations were carried out by FTIR, NMR, and size exclusion chromatography. Cyclic voltammetry was used to determine the electrochemical oxidation-reduction characteristics. Optical properties were investigated by UV–vis and fluorescence analyses. Solid state electrical conductivities were measured on polymer films by four-point probe technique using an electrometer. Thermal data of monomer/polymer and polymers were obtained by TG-DTA and DSC techniques, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

EXTRACTION OF NITRIC AND PHOSPHORIC ACIDS WITH TRIBUTYL PHOSPHATE

The extraction of nitric acid and phosphoric acid by tributyl phosphate (TBP), from solutions containing acid mixture and in the presence of nitrate salts, has been studied. The effect of the temperature on acid extraction has been also investigated. It is found that TBP extracts nitric acid preferentially to phosphoric acid, especially in the presence of nitrate salts. The coextraction of nitric acid suppresses the extraction of phosphoric acid. These results were interpreted in terms of common ion effect and variation of the activity coefficients variation in both phases. The simultaneous effects of the salts and acids on the extraction of both acids is also studied

Some tests were carried out, using process solution, to evaluate the extraction of acids. Both batch experiments and continuous tests (using mixer settler) were performed. Some flowsheets were tested in order to improve the extractivity and the selectivity of phosphoric acid. The results show the limitation of TBP for the extraction of phosphoric acid. TBP can be used to selectively extract nitric acid.     

EXTRACTION KINETICS OF COPPER BY TRILAURYLAMMONIUM CHLORIDE IN TOLUENE FROM AQUEOUS CHLORIDE MEDIA

Abstract

The rate of extraction of copper(II) from aqueous chloride solutions by tri-n-laurylammonium chloride (TLAHC1) dissolved in toluene has been investigated. The extraction rate was evaluated as function of the chemical composition of the system. The experiments were performed by using a stirred cell with constant inter-facial area. The experiments were performed at a stirring rate of the two phases where the influence of film diffusion is minimized. The data have been interpreted by a mechanism which assumes interfacial chemical reactions between the bulk species containing copper(II) and the molecules of TLAHC1 absorbed at the interface as rate determining.     

The study of MIG weldability of heat-treated aluminum alloys

In this article, Metal Inert Gas (MIG) weldability of commercially received and aged samples of 6061-T₆ and 7075-T₆₅₁ aluminum alloys was investigated. The welding joints were prepared in ten different combinations. Microstructure, microhardness, EDX, energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were used in order to evaluate the effect of aged heat treatment on the performance of welded joints. In addition, the mechanical properties of welding joints were characterized using the tensile and microhardness tests. In conclusion, it was shown that prewelding aging heat treatment improves the mechanical properties of welding joints.