Thermal Characteristics of PVA-PANI-ZnS Nanocomposite Film Synthesized by Gamma Irradiation Method

Gamma irradiation is employed for in situ preparation of PVA-PANI-ZnS nanocomposite. The irradiation dose is varied from 10 to 40 kGy at 10 kGy intervals. The XRD result confirms the formation of crystalline phases corresponding to ZnS nanoparticles, PVA and PANI. Field emission scanning electron microscopy shows the formation of agglomerated PANI along the PVA backbone, within which the ZnS nanoparticles are dispersed.UV-visible spectroscopy is conducted to measure the transmittance spectra of samples revealing the electronic absorption characteristics of ZnS and PANI nanoparticles. Photo-acoustic(PA) setup is installed to investigate the thermal properties of samples. The PA spectroscopy indicates a high value of thermal diffusivity for samples due to the presence of ZnS and PANI nanoparticles. Moreover, at higher doses, the more polymerization and formation of PANI and ZnS nanoparticles result in enhancement of thermal diffusivity.     

Nitric acid in the presence of supported P2O5 on silica gel: an efficient and novel reagent for oxidation of sulfides to the corresponding sulfoxides

This paper describes an efficient and easy method for oxidation of sulfides 1 to their corresponding sulfoxides 2 with nitric acid in the presence of supported P₂O₅ on silica gel under solvent-free conditions in high yields.     

A simple and rapid spectrophotometric method for determination of ultra trace amounts of thallium(III) with 4-(4'-N,N-dimethylaminophenyl) urazole as a new reagent

A simple and selective spectrophotometric method is proposed for the determination of ultra trace amounts of Tl(III). The reported method is based on the oxidation of 4-(4'-N,N-dimethylaminophenyl)urazole (DAPU) to the corresponding triazolinedione (TAD) by Tl(III) at pH 4.0. The reaction was monitored spectrophotometrically by measuring the increasing color of TAD compound at 514 nm by the fixed-time method. At a given time of 2.0 min at 30 degrees C, the working range of calibration was 5.0 x 10(-8) - 2.0 x 10(-5) M Tl(III) and detection limit of 5.0 x 10(-8) M was obtained. The influences of pH, reagent concentration, ionic strength and temperature were studied. The effect of diverse ions on the determination of Tl(III) by the proposed method was also investigated. Thallium in real samples was determined by this method, with satisfactory results.     

First principles study of electronic properties,interband transitions and electron energy loss of <Emphasis Type="Italic">α</Emphasis>-graphyne

The electronic and optical properties of α-graphyne sheet are investigated by using densityfunctional theory. The results confirm that α-graphyne sheet is a zero-gap semimetal. Theoptical properties of the α-graphyne sheet such as dielectric function,refraction index, electron energy loss function, reflectivity, absorption coefficient andextinction index are calculated for both parallel and perpendicular electric fieldpolarizations. The optical spectra are strongly anisotropic along these two polarizations.For (E ∥x), absorption edge is at 0 eV, while there is noabsorption below 8 eV for (E ∥z).     

Optimized mercapto-modified resorcinol formaldehyde xerogel for adsorption of lead and copper ions from aqueous solutions

Journal of Sol-Gel Science and Technology - Resorcinol formaldehyde (RF) xerogel was modified by mercapto functional groups for removal of Pb(II) and Cu(II) ions from aqueous solutions. The...     

The first heterogeneous Sonogashira coupling reaction of aryl halides with terminal alkynes catalyzed by diatomite‐supported palladium(II) salophen complex

We report here our observation that, using appropriate reaction conditions, the Sonogashira reaction can be performed without the need for copper catalyst and solvent. Our approach involves the use of diatomite‐supported palladium(II) salophen complex as a catalyst and triethylamine as a base. The methodology works, to differing extents, for aryl iodides and bromides. This heterogeneous catalyst can be reused at least five times without any decrease in activity. Copyright © 2011 John Wiley & Sons, Ltd.