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Herein, we are reporting the synthesis of polythiophene, polypyrrole, and reinforced nickel oxide (NiO) hybrid nanocomposites by an in-situ chemical oxidative polymerization of thiophene and pyrrole in the presence of NiO nanoparticles. The polymerized nanocomposites were thoroughly characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) studies, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The concentration of polymer-NiO hybrids varied between different ratios of PTh, PPy and NiO contents. A maximum dielectric constant of ≈ 1×106 was observed at a higher ratio of polymer-filler contents. The PTh-PPy-NiO hybrid nanocomposite structure and crystallinity were verified by X-ray diffraction (XRD), and the FTIR approach demonstrated a robust interaction between PTh, PPy, and NiO particles. The surface morphology analysis revealed that NiO particles were successfully integrated with PTh, PPy during the polymerization process by forming a network. The dielectric constant values of the resultant nanocomposites were obtained from capacitance measurements. The dielectric constant for the higher concentration ratio of polymer-NiO hybrids was much higher than that of the pristine PTh, PPy matrix. A significant increase in dielectric loss and AC conductivity was observed for the higher concentration of PTh-PPy-NiO ternary nanocomposites. These PTh-PPy-NiO hybrid nanocomposites can potentially be useful in developing high-performance composite materials in the electronic field. Herein, we are reporting the synthesis of polythiophene, polypyrrole, and reinforced nickel oxide (NiO) hybrid nanocomposites by an in-situ chemical oxidative polymerization of thiophene and pyrrole in the presence of NiO nanoparticles. The concentration of polymer-NiO hybrids varied between different ratios of PTh, PPy, and NiO contents. A maximum dielectric constant of ≈ 1×106 was observed at a higher ratio of polymer-filler contents. The dielectric constant for the higher concentration ratio of polymer-NiO hybrids was much higher than that of the pristine PTh, PPy matrix. A significant increase in dielectric loss and AC conductivity was observed for the higher concentration of PTh-PPy-NiO ternary nanocomposites. These PTh-PPy-NiO hybrid nanocomposites can potentially help develop high-performance composite materials in the electronic field. [ABSTRACT FROM AUTHOR]

The current research work deals with the synthesis of a novel composite material of carboxylic graphene oxide‐carboxymethyl chitosan (COOH‐GO‐CMC) composite by ultrasound and microwave‐assisted processes. The composite was characterized by Fourier Transform Infra‐red spectroscopy, X‐ray Powder Diffraction, Raman Spectroscopy, Scanning Electron Microscopy, and X‐ray Photoelectron Spectroscopy. The synthesized composite was used to remove heavy toxic metal ions (HTMIs) such as uranium (U6+), lead (Pb2+), chromium (Cr6+), and cadmium (Cd2+) ions from aqueous solutions. The HTMIs removal study was carried out to verify the effects of pH, contact time, amount of adsorbent dose, initial concentration, and temperature. The linear and nonlinear Langmuir and Freundlich adsorption isotherms were fitted to the data of removal studies, and it was observed that the linear Langmuir adsorption isotherm (R2 > 0.99) was the best‐fitted model. The maximum adsorption capacities of COOH‐GO‐CMC were found to be 74.62, 416.66, 76.92, and 53.47 mg g−1 for U6+, Pb2+, Cr6+, and Cd2+ ions, respectively. The kinetics studies, including four types of models (linear and nonlinear pseudo‐first‐order, linear and nonlinear pseudo‐second‐order, Intraparticle diffusion, and Elovich kinetic models), were tested, and the results showed that the linear pseudo‐second‐order kinetics model (R2 > 0.99) was the best‐fitted model. The thermodynamic studies reveal that the adsorption of HTMIs is a spontaneous (ΔG < 0) and exothermic (ΔH < 0 and ΔS > 0) process in nature. [ABSTRACT FROM AUTHOR]

In this study, the microwave-assisted novel composite of carboxylic graphene oxide-chitosan (COOH-GO-CTS) was prepared by using carboxylic functionalized graphene oxide (COOH-GO). The prepared composite was characterized by FTIR, SEM, XRD, XPS and Raman spectroscopy successfully. The composite was used as an adsorbent material for the removal of heavy metals such as uranium (U), lead (Pb), chromium (Cr), and cadmium (Cd). Batch adsorption was carried out to study the effects of pH of the medium, initial concentration of heavy metals, amount of adsorbent dosage, contact time, and temperature. The removal percentages for U, Pb, Cr, and Cd were observed to be 92.4, 94.6, 90.2, and 90.6% at 5, 5.5, 3, and 5 pH, respectively. Adsorption isotherms were performed for Langmuir and Freundlich adsorption, and it was observed that the Langmuir adsorption isotherm well fitted (R2 > 0.99) the present adsorption study. The maximum adsorption capacities of the composite for U, Pb, Cr, and Cd were found to be 64.93, 384.61, 68.49, and 49.50 mg g−1, respectively. The heavy metal adsorption kinetics were also performed, and it was observed that the pseudo-second order was well fitted (R2 > 0.99) the present study. Further, the themodynamic studies confirmed the adsorption of the heavy metals to be endothermic and spontaneous in nature. [ABSTRACT FROM AUTHOR]

Present manuscript deals with the comprehensive solventless coupling of carbon dioxide and epoxides to yield cyclic carbonates catalyzed by cobalt complex [Co-HPEED]. Different spectroscopic techniques are used to characterize this cobalt complex, which confirm its square planar geometry. The cobalt complex shows high catalytic activity toward the formation of cyclic carbonates. We found that the types of co-catalysts, temperature and time affect the rate of formation of cyclic carbonates to great extent. Finally, a mechanism appropriate for the formation of cyclic carbonates has been given based on our experimental results. [ABSTRACT FROM AUTHOR]

In the present study, the cobalt (II) complex [Co-HMBED] has been prepared and characterized by spectrochemical techniques, which confirmed its square planar structure. The catalytic activity of the cobalt complex was evaluated towards solvent-free conversion of CO2 and styrene oxide into cyclic styrene carbonate and polymerization of lactide. This perspective describes the synthesis, characterization and catalytic studies of Co-HMBED complex; towards coupling of styrene oxide and CO2 to produce cyclic styrene carbonates and polymerization of lactide. [ABSTRACT FROM AUTHOR]

Palm-epoxy hybrid composites were fabricated by incorporating palm leaf stem stalk (PLSS) powder at levels of 0 wt%, 5 wt%, 10 wt%, and 15 wt%. Physical, mechanical, and erosion characteristics of these composites were investigated. Incorporation of filler powder had a positive effect on the hardness and impact strength and a negative effect on the tensile and flexural strength of the composites. The erosion test varied the impact angle (45° to 90°), impact velocity (40 m/s to 80 m/s), and erodent particle size (40 µm to 100 µm). The erosion experiments were statistically designed using Taguchi's orthogonal arrays. It was found that the erosion rate of palm-epoxy composites decreased with increasing filler powder content, and that the composite filled with 15 wt% PLSS had the highest erosion resistance. The surface morphology of the eroded samples were examined using scanning electron microscopy. [ABSTRACT FROM AUTHOR]

In the present study, salicylaldimine zinc complex (Zn- HMBED) was synthesized and its reactivity for the ring-opening polymerization ( ROP) of lactide was studied. The zinc complex was prepared by the reaction of zinc solution with one molar equivalent of salicylaldimine Schiff base ligand in methanol under a nitrogen atmosphere. Further, the complex was characterized by various spectroscopic methods, which showed tetrahedral geometry. X-ray diffraction studies were used for the structure determination of the Schiff base. It was observed that the zinc complex is highly active towards the ROP of lactide. The rate of polymerization is heavily dependent on the initiator used. The zinc complex allows controlled ROP as revealed by the linear relationship between the percentage conversion and the number-average molecular weight. Finally, a mechanism for the ROP of lactide is proposed by use of the above zinc complex. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Poly(etheretherketone) PEEK, is a versatile polymer having a wide range of applications in different fields because of its good mechanical properties, thermal stability, toughness, etc. However, nowadays its application as a fuel cell membrane is an emerging research area. Thus, suitable selection and modification of PEEK is necessary. The synthesis of the sample membrane and design of the fuel cell should be properly carried out to meet the market need. This chapter will introduce different applications of PEEK and modified PEEK with particular emphasis on fuel cells. Basically, sulfonated PEEK (SPPEK) has been observed to be more advantageous for fuel cell applications because of its good proton conductivity. The various synthesis methods, sample preparation methods and evaluation of fuel cells will be presented in this article. [ABSTRACT FROM AUTHOR]

In the present work, the -ONNO- tetradentate Schiff base ligand N, N′-bis (2-hydroxy-3-methoxybenzaldehyde) propylenediamine, [HMBPD] was synthesized. Further, complexation of this ligand with copper [HMBPD-Cu] was carried out and their reactivity for the ring-opening polymerization (ROP) of lactide (LA) has been studied. This monomeric copper complex is prepared by the reactions of copper solution with one molar equivalent of HMBPD Schiff-base ligand in ethanol under nitrogen atmosphere. This copper complex has been characterized by different spectroscopic methods, which showed square planner geometry. The copper complex is highly active towards ROP of LA. The rate of polymerization is heavily dependent on the initiator used. The copper complex allows controlled ring-opening polymerization as shown by the linear relationship between the percentage conversion and the number-average molecular weight. On the basis of literature reports, a mechanism for ROP of lactide has been proposed. [ABSTRACT FROM AUTHOR]