Electrosynthesis of Poly(ortho-phenetidine) Coatings on Steel and Investigation of Their Corrosion Protection Properties

Poly(ortho-phenetidine) coatings on 304 stainless steel (304 SS) surface have been synthesized by using the galvanostatic technique. The electrosynthesized coatings were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), UV-visible absorption spectrometry and Scanning Electron Microscopy (SEM). The anticorrosion performances of poly(ortho-phenetidine) coatings were examined in 0.1 M HCl medium by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization technique. The corrosion rate of poly(ortho-phenetidine)-coated 304 SS was found ~10 times lower than bare 304 SS and corrosion potential increased from –0.29 V for uncoated 304 SS to –0.19 V versus Ag/AgCl (3 M KCl) for poly(ortho-phenetidine)-coated 304 SS electrode. Electrochemical measurements indicate that poly(ortho-phenetidine) coating has good inhibiting properties with an efficiency of ~93% at 1.5 mA cm^–2 applied current density in acidic corrosive media. The results of this study obviously ascertain that the poly(ortho-phenetidine) has an outstanding potential to protect 304 SS against corrosion in an acidic environment.     

Synthesis of Zinc Sulfide Nanostructures with Different Sulfur Sources via Mild Hydrothermal Route: Investigation of Crystal Phase and Morphology

In this paper, we report a facile hydrothermal route to prepare different morphologies of zinc sulfide nanostructures, using a new inorganic precursor, zinc phthalate [Zn(pht)(H₂O)]_n, and different sulfur sources. This study focuses on the effect of different sulfur sources on the crystal structure and morphology of the products. The structural and morphological studies of the products were performed by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction. The high temperature (over 1020 °C) hexagonal ZnS nanostructured spheres self-assembled from ZnS nanocrystals have been synthesized at a low temperature of 160 °C by using thioglycolic acid as sulfur source.     

Application of microwave irradiation for synthesis of novel optically active poly(amide imides) derived from diacid chloride containing epiclon and L‐isoleucine with aromatic diamines

Epiclon [3a,4,5,7a‐tetrahydro‐7‐methyl‐5‐(tetrahydro‐2,5‐dioxo‐3‐furanyl)‐1,3‐isobenzofurandione] or [5‐(2,5‐dioxotetrahydrofurfuryl)‐3‐methyl‐3‐cyclohexyl‐1,2‐dicarboxylic acid anhydride] (1) was reacted with L ‐isoleucine (2) in acetic acid and the resulting imide acid (3) was obtained in high yield. The diacid chloride (4) was obtained from diacid derivative (3) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride (4) with several aromatic diamines such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenyl methane (5b), 4,4′‐diaminodiphenylether (5c), p‐phenylenediamine (5d), m‐phenylenediamine (5e), 2,4‐diaminotoluene (5f), and 4,4′‐diaminobiphenyl (5g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed in two other different methods: low‐temperature solution polycondensation and reflux conditions. A series of optically active poly(amide imides) with inherent viscosity of 0.12–0.30 dL/g were obtained. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly(amide imides) are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2218–2229, 2004     

Optimal oxygen concentration strategy through an isothermal oxidative coupling of methane plug flow reactor to obtain a high yield of C2 hydrocarbons

An optimal oxygen concentration trajectory in an isothermal OCM plug flow reactor for maximizing C₂ production was determined by the algorithm of piecewise linear continuous optimal control by iterative dynamic programming (PLCOCIDP). The best performance of the reactor was obtained at 1,085 K with a yield of 53.9%; while, at its maximum value, it only reached 12.7% in case of having no control on the oxygen concentration along the reactor. Also, the effects of different parameters such as reactor temperature, contact time, and dilution ratio (N₂/CH₄) on the yield of C₂ hydrocarbons and corresponding optimal profile of oxygen concentration were studied. The results showed an improvement of C₂ production at higher contact times or lower dilution ratios. Furthermore, in the process of oxidative coupling of methane, controlling oxygen concentration along the reactor was more important than controlling the reactor temperature. In addition, oxygen feeding strategy had almost no effect on the optimum temperature of the reactor. Finally, using the optimal oxygen strategy along the reactor has more effect on ethylene selectivity compared to ethane.     

Removal of malachite green (a toxic dye) from water by cobalt ferrite silica magnetic nanocomposite: Herbal and green sol-gel autocombustion synthesis

Cobalt ferrite-silica nanocomposites were synthesized in the presence of various amounts of Salix alba bark extract via the self-propagating sol-gel process. The structure, morphology and magnetic property of nanostructures was investigated and the adsorbent ability for the removal of malachite green (MG) dye from water through CoFe₂O₄SiO₂ has been reported. The products were characterized by XRD, SEM, TEM, FTIR and VSM techniques. The samples that were synthesized in the presence of more extract (20 mg extract) revealed no trace of impurity in XRD pattern and indicated more spherical and agglomerated particles on SEM images; in contrast other samples indicated Co₃O₄ as impurity besides rough and irregular spherical shapes. TEM images for sample SA20 (15.41 ± 0.65 nm size) illustrated narrow size distribution which is consistent with the SEM analysis. The saturation magnetization values continuously increase with the increasing Salix alba bark extract amount and reaches to 2.89 emu/g for SA20 sample. Investigation on MG adsorption isotherm and kinetic onto the nanocomposites were carried out as well. The experimental data best fitted to the Langmuir model and revealed a monolayer adsorption capacity of 75.5 ± 1.21 mg g^?1. The adsorption kinetic was found to follow pseudo-second-order kinetic model. Consequently, prepared nanocomposite can be used as an effective magnetic adsorbent for the MG removal from water.     

Super-crosslinked ionic liquid-intercalated montmorillonite/epoxy nanocomposites: Cure kinetics,viscoelastic behavior and thermal degradation mechanism

Super-crosslinked epoxy nanocomposites containing N-octadecyl-N′-octadecyl imidazolium iodide (IM)-functionalized montmorillonite (MMT-IM) nanoplatelets were developed and examined for cure kinetics, viscoelastic behavior and thermal degradation kinetics. The structure and morphology of MMT-IM were characterized by FTIR, XRD, TEM, and TGA. Synthesized MMT-IM revealed synergistic effects on the network formation, the glass transition temperature (T_g) and thermal stability of epoxy. Cure and viscoelastic behaviors of epoxy nanocomposites containing 0.1 wt% MMT and MMT-IM were compared based on DSC and DMA, respectively. Activation energy profile as a function of the extent of cure was obtained. DMA results indicated a strong interface between imidazole groups of MMT-IM and epoxy, which caused a significant improvement in storage modulus and the T_g of epoxy. Network degradation kinetics of epoxy containing 0.5, 2.0, and 5.0 wt% MMT and MMT-IM were compared by using Friedman, Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) and the modified Coats-Redfern methods. Although addition of MMT to epoxy was detrimental to the T_g value, as featured by a fall from 94.1°C to 89.7°C detected by DMA method, and from 103.3°C to 97.9°C by DSC method, respectively. By contrast, meaningful increase in such values were observed in the same order from 94.1°C to 94.7°C and from 103.3°C to 104.7°C for super-crosslinked epoxy/MMT-IM systems.     

Enhancement of β‐Phase Crystalline Structure and Piezoelectric Properties of Flexible PVDF/Ionic Liquid Surfactant Composite Nanofibers for Potential Application in Sensing and Self‐Powering

Polyvinylidene fluoride (PVDF) is a piezo‐polymer which among its crystalline phases, the β‐phase has been researched for the improvement of piezoelectric properties. In this study, to improve the β‐phase contents and thereby the piezoelectric response of the polymer, the effect of adding self‐synthesized ionic liquid surfactant (ILS) in PVDF nanofibers is studied. This material is added in different weight percentages into the PVDF solution and the nanofibers are produced by electrospinning to prepare active piezoelectric thin layers. SEM, XRD, FTIR, and piezo‐tests are employed for assessing the effect of the ILS on the enhancement of β‐phase in electrospun nanofibers and their piezoelectric performance. The results indicate ≈98.6% β‐phase formation in the sample containing 4 wt% ILS and in comparison with the pure nanofibers, the output voltage and its power density are improved 186.9% and 275%, respectively. Considering the results, it is suggested that the ILS can improve the piezoelectric response of the polymer in the fabricated structure by simple mixing in solution compared to other additives.     

The effects of quercetin supplementation on lipid profiles and inflammatory markers among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials

Abstract

Aims: This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to determine the effect of quercetin administration on lipid profiles and inflammatory markers among patients with metabolic syndrome (MetS) and related disorders.

Methods: We searched systematically online databases including Cochrane Library, EMBASE, MEDLINE, and Web of Science to identify the relevant RCTs until November 2018. Q-test and I² statistics were applied to assess heterogeneity among included studies. Data were combined using fixed- or random-effects model and presented as standardized mean difference (SMD) with 95% confidence interval (CI).

Results: Out of 591 citations, 16 RCTs were included in the meta-analysis. The pooled findings showed that quercetin consumption significantly decreased total-cholesterol (SMD = ?0.98; 95% CI, ?1.48, ?0.49; p?<?0.001; I²: 94.0), LDL-cholesterol (SMD = ?0.88; 95% CI, ?1.35, ?0.41; p?<?0.001; I²: 92.7) and C-reactive protein (CRP) levels (?0.64; 95% CI, ?1.03, ?0.25; p?=?0.001; I²: 90.2). While, quercetin supplementation did not significantly affect triglycerides (TG) (SMD = ?0.32; 95% CI, ?0.68, 0.04; p?=?0.08; I²: 84.8), HDL-cholesterol (SMD = 0.20; 95% CI, ?0.20, 0.24; p?=?0.84; I²: 70.6), interleukin 6 (IL-6) (SMD = ?0.69; 95% CI, ?1.69, 0.31; p?=?0.17; I²: 94.5) and tumor necrosis factor-alpha (TNF-α) levels (SMD = ?0.06; 95% CI, ?0.25, 0.14; p?=?0.58; I²: 35.6)

Conclusions: In summary, the current meta-analysis demonstrated that quercetin supplementation significantly reduced total-cholesterol, LDL-cholesterol, and CRP levels, yet did not affect triglycerides, HDL-cholesterol, IL-6 and TNF-α among patients with MetS and related disorders.     

A convenient synthesis of NiO-CuS/molecularly imprinted polymer nanocomposites with highly enhanced adsorption activity and selectivity for removal of Letrozole

ABSTRACT

In this study, Novel NiO-CuS nanocomposites were prepared by simple chemical method. The goal of this project was to apply the Letrozole (Anti-estrogen drug) template molecularly imprinted polymer (MIP) for the selective removal of Letrozole from aqueous samples. The NiO-CuS nanocomposites and NiO-CuS/MIP nanocomposites were specified by field emission scanning electron microscopy, X-ray diffraction, photoelectron spectroscopy, N₂ adsorption-desorption, and thermogravimetric analysis. The performance of the NiO-CuS and NiO-CuS/MIP nanocomposites was analyzed by optimizing various removal factors. The optimized data for adsorption process were 0.01 g/L: MIP, contact time: 40 min and pH: 7.0. The data was evaluated best by pseudo 1st and 2nd order equation which revealed a chemical adsorption of letrozole onto NiO-CuS and NiO-CuS/MIP particles, respectively. The result of R² values indicated that the adsorption data followed the Langmuir isotherm equation which defined that the binding agent happened on the homogeneous sites of adsorbent.