Modification of poly(propylene) by grafted polyester‐amide‐based dendritic nanostructures with the aim of improving its dyeability

Fiber‐graded poly(propylene) was modified by polyester‐amide‐based dendritic nanostructures with the aim of improving its dyeability. Two different dendritic polymers were used and the dendritic nanostructures were formed in situ via reactive blending with maleic anhydride‐modified poly(propylene). Samples were chosen exploiting a 4‐component mixture design. Thermal, morphological, and rheological characterizations showed domains with different size and distribution were formed and primary properties of the dendritics determined the characteristics of the resulted domains. Morphological parameters were quantified by digital analysis of scanning electron microscope images. Thermal and rheological behavior also demonstrated good agreements with the inferred morphology of the formed dendritic domains. The modified samples were then dyed with dispersed dyestuffs. A variety of substantivities were obtained, and some of the modified samples showed a significant enhancement in dyeing properties. A predictive model was developed for K/S ratio, where K and S are absorption and scattering coefficients of the Kubelka‐Munk one constant theory, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Sonochemical Synthesis of a Nanocrystalline Tin(IV) Complex based on a Bulky Anthracene Carboxylate Ligand: Spectroscopic and Photophysical Properties

In order systematically investigate the effect of ligand with a large conjugated π-system on the structure and optical properties of tin complex, anthracene-9-carboxylic acid (L¹) is selected as a primary ligand, and quinoline-2-carboxylic acid (L²) used as second ligand to incorporate with anthracene-9-carboxylic acid to construct a new tin(IV)-carboxylate coordination complex under thermal gradient condition. Prepared complex was fully characterized based on its ¹H and ¹³C NMR, IR and UV spectra and elemental analysis. The molecular structure of complex was determined by single-crystal X-ray analysis. The nanocrystalline complexes of the prepared complex were successfully obtained at 30, 50 and 60 °C by a facile sonochemical route. The new nanocrystalline complexes were characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analysis. The photoluminescence properties of the nanocrystalline complexes and crystalline bulk complex in the solid-state indicated that the size of the complex particles has a remarkable effect on the optical properties of it. Absorption and emission peaks of the nanocrystalline complexes blue shifted significantly in comparison with those of in the single-crystal form. Application of the prepared complex in fabrication of an organic light-emitting diode has been demonstrated. The current–voltage (I–V) characteristics and the electroluminescence (EL) properties of the complex have been investigated. The EL of the compound exhibits green emission at 552 nm.     

Sonoelectrochemical synthesis of a nanoscale complex of lead(II) and 2-methyl-8-hydroxyquinoline: spectroscopic, photoluminescence, thermal analysis studies and its application in an OLED

A new lead complex, [Pb(mq)₂], (mq = 2-methyl-8-hydroxyquinoline) was prepared via an electrochemical route from the oxidation of lead metal in the presence of 2-methyl-8-hydroxyquinoline in a fast and facile process. The complex was fully characterized by means of NMR and IR spectra and elemental analysis. The nanostructure of the prepared compound was obtained by sonoelectrochemical process and studied by scanning electron microscopy, atomic force microscopy, X-ray powder diffraction, IR spectroscopy and elemental analysis. Thermal stability of single crystalline and nanosize samples of the prepared compound was studied by thermal gravimetric and differential thermal analysis. The photoluminescence properties of the prepared compounds, as single crystals and as nanorods, have been investigated. The results showed a good correlation between the size and the shape of the complex particles and emission wavelength. The prepared complex was doped in PVK:PBD blend as guest and its application in the fabrication of OLED was studied. The ratio of lead complex was modified and was equal to 8 (w/w %) in PVK:PBD (100:40).     

Wavelet PSO‐Based LQR Algorithm for Optimal Structural Control Using Active Tuned Mass Dampers

This study presents a new method to find the optimal control forces for active tuned mass damper. The method uses three algorithms: discrete wavelet transform (DWT), particle swarm optimization (PSO), and linear quadratic regulator (LQR). DWT is used to obtain the local energy distribution of the motivation over the frequency bands. PSO is used to determine the gain matrices through the online update of the weighting matrices used in the LQR controller while eliminating the trial and error. The method is tested on a 10‐story structure subject to several historical pulse‐like near‐fault ground motions. The results indicate that the proposed method is more effective at reducing the displacement response of the structure in real time than conventional LQR controllers.     

The effect of pressure on removal of carbon monoxide in biofilter

Solubility of carbon monoxide in water is very important for its biological oxidation or removal process of gaseous pollutants. Present research shows the effect of pressure on solubility of carbon monoxide in liquid phase and its removal process by a biofilter. The results are considered as laboratory research on carbon monoxide elimination. In this method a pressurized trickle-bed biofilter was used to increase pressure in the reactor. The biofilter was filled with Leca-stones and inoculated with microorganisms. When the system’s pressure is increased, the solubility of carbon monoxide will be increased, respectively, and it causes a better reaction of the microorganisms for removing of gaseous pollutants. The efficiency was improved significantly by increasing the pressure in the reactor.     

Evaluation of Microstructure and Mechanical Properties in Dissimilar Austenitic/Super Duplex Stainless Steel Joint

To study the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super duplex (ER2594) and an austenitic (ER309LMo) stainless steel filler metal. While the austenitic weld metal had vermicular delta ferrite within austenitic matrix, super duplex stainless steel was mainly comprised of allotriomorphic grain boundary and Widmanstätten side plate austenite morphologies in the ferrite matrix. Also the heat-affected zone of austenitic base metal comprised of large austenite grains with little amounts of ferrite, whereas a coarse-grained ferritic region was observed in the heat-affected zone of super duplex base metal. Although both welded joints showed acceptable mechanical properties, the hardness and impact strength of the weld metal produced using super duplex filler metal were found to be better than that obtained by austenitic filler metal.     

Copper corrosion in sodium dodecyl sulphate solutions and carbon nanotube nanofluids: A modified Koutecky–Levich equation to model the agitation effect

Copper corrosion in sodium dodecyl sulphate (SDS) solutions and carbon nanotube (CNT) nanofluids were studied by potentiodynamic polarization. For the corrosion current densities calculations, Koutecky–Levich equation was modified to model the combined charge and mass transport. 0.005 M SDS reduced the copper corrosion current density by 81%. Higher SDS concentrations enhanced corrosion. Stirring SDS solutions increased the corrosion current density by ∼75%. By adding CNT to SDS solution, the corrosion current density first decreased and then remained constant. Stirring CNT nanofluids didn’t change the corrosion current density. An adsorbed CNT layer on copper controlled the corrosion process in CNT nanofluids.     

The Effect of Silicon Percentage and Shot Peening Operation on Mechanical Properties of Hadfield Steel Containing 17% Manganese

Protection of Metals and Physical Chemistry of Surfaces - The present study examines the effect of shot peening on the wear behavior of austenitic high- manganese steels in both low and high...     

Plasticized poly(vinyl chloride) composites: Influence of different nanofillers as antimigration agents

In this study, plasticized poly(vinyl chloride) (PVC) composites with different nanofillers, including single‐walled carbon nanotubes (SWCNTs), organoclay, TiO₂, and ZnO nanoparticles, were prepared, and their effects on plasticizer migration were investigated. Scanning electron micrographs revealed the dispersion quality of the nanofillers in the polymer matrix. It had a significant influence on the performance of the nanofillers in the process of plasticizer migration. Migration and exudation tests showed that the nanofillers could efficiently hinder plasticizer migration. On the basis of these results, we concluded that carbon nanotubes were the best antimigration agent in the plasticized system. This was ascribed to the high aspect ratio of the SWCNTs and the good interactions between them and the plasticizer. Also, TiO₂ nanoparticles showed a better performance compared to the ZnO nanoparticles. This was due to the more homogeneous dispersion of the TiO₂ in the polymer matrix and the higher surface area of the particles. The differential scanning calorimetry thermograms were in good agreement with the migration tests. The lowest change in the glass‐transition temperature was observed for the composite filled with SWCNTs. This indicated that a lower amount of the plasticizer migrated from PVC. The thermogravimetric analysis curves showed that the incorporation of the nanofillers improved the thermal stability of the PVC. The results could be useful for determining the efficiency of plasticized PVC in applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42559.