Mohd Rashid

Polyaniline/Palm Oil Blend for Anticorrosion of Mild Steel in Saline Environment

The corrosion protective performance of polyaniline/palm oil (PAni-PO) blend coated on mild steel in 3% NaCl aqueous solutions has been evaluated by electrochemical methods, namely, open circuit potential (ocp), potentiodynamic polarization, and EIS spectroscopy. The surface of mild steel was covered by a dark green protective layer due to the physical interaction between the coating and steel. The permanent shifts of ocp and potentiodynamic polarization towards higher positive value of oxidation potential by about 800 mV and by a decrease in corrosion current density by sixfold in magnitude and an increase of 10 orders of magnitude in charge transfer resistance are due to protective coating.

Oxidative Copolymerization of Aniline with o- and p-Nitroaniline by Ammonium Per Sulfate: Kinetic and Pathway

The kinetic study on the oxidation of aniline with o- and p-nitroaniline by ammonium persulfate (APS) has been carried out. The course of copolymerization was investigated by UV-vis spectroscopy and structural characterization was studied by FTIR spectral analysis. The electronic spectra of the copolymers poly(aniline-co-p-nitroaniline) and poly(aniline-co-o-nitroaniline) show hypsochromic shift. The shift has been observed in the bands corresponding to π → π* transition as well as in the exciton transition. The presence of nitro-group not only affects the oxidative polymerization window but also brings about the remarkable changes in the optical and electronic properties of parent polymer polyaniline. The poly(aniline-co-nitroaniline) has been shown multiple color transition (yellow → lightgreen → darkgreen) as the pH of the system changes with progress of polymerization reaction. The increase in absorbance recorded at various time intervals with increasing concentration of aniline, o- and p-nitroaniline, which indicates the growth of polymer formation. The first order kinetics is suggested as the degradation curve is consistent well byan exponential decay of APS. The resulting first-order rate constant was used to calculate the rate of poly(aniline-co-nitroaniline) formation using the rate equation –d[A]/dt = kcn. The reaction shows first-order dependence for each reactant.

Synthesis and characterization of electrically conducting copolymers of poly(aniline-co-o-iodoaniline)

Functionalized copolymers of poly(aniline-co-o-iodoaniline) have been synthesized by the chemical oxidative polymerization method by using o-iodoaniline (o-IA) and aniline (AN) as monomer units by changing their molar feed ratio in acid aqueous medium. The physical properties viz; solubility, electrical conductivity have been studied to characterize them. The copolymers possess better solubility than unsubstituted homopolymer in organic solvent such as N-methyl-2-pyrrodinone (NMP). The conductivity of the pressed pellets of as-synthesized copolymers depends upon the content of o-IA in the polyaniline (PANI). The structural confirmation of the copolymer has been explained by Fourier transform infrared spectroscopy study which suggest that AN and o-IA units are uniformly distributed along the polymer chain and thus, the physical properties of copolymers may possibly be tailored by varying the molar feed ratio in copolymerization reactions. The conductivity of the copolymer decreases upon increasing the o-IA content in molar feed, because the introduction of –I- as a functional group reduces the extent of conjugation of the polymer chain.

Biosynthesis of Self-Dispersed Silver Colloidal Particles Using the Aqueous Extract of P. peruviana for Sensing dl-Alanine

We report the biosynthesis of silver nanoparticles (AgNPs) in a single step using edible fruit aqueous extract of P. peruviana that essentially involved the concept of green chemistry. Yellowish-brown color appeared upon adding the broth of P. peruviana to aqueous solution of 1 mM AgNO3 which indicates the formation of AgNPs. The maximum synthesis of these nanoparticles was being achieved in nearly 2 hrs at 28°C. The synthesis of AgNPs was followed by AgNPs UV-visible spectroscopy. Particle size and morphology of AgNPs were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. These studies revealed that the AgNPs characterized were spherical in shape with diameter ranging from 31 to 52 nm. The energy dispersive X-ray spectroscopy showed that the AgNPs present are approximately 63.42 percent by weight in the colloidal dispersion. The absorption spectra of the AgNPs in absence and presence of dl-alanine show a distinguish shift in surface plasmon resonance (SPR) bands. Thus, these nanoparticles may be used as a chemical sensor for dl-alanine present in the human blood.

Electropolymerization of poly(aniline-co-p-toluidine) on copper and its application as a corrosion inhibitor

Purpose – This paper aims to compare the inhibitive effects of polyaniline (PAni), poly(p-toluidine) and poly(aniline-co-p-toluidine) in hydrochloric acid (HCl) solution. Design/methodology/approach – The electrochemical deposition of PAni, poly(p-toluidine) and poly(aniline-co-p-toluidine) on pure copper metal was studied potentiodynamically. The copolymer deposited was characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV)-visible spectroscopy and scanning electron microscopy (SEM). The corrosion inhibition studies on copper electrode were performed using electrochemical methods, viz, open circuit potential (OCP) measurements, potentiodynamic polarization scans and electrochemical impedance spectroscopy (EIS) tests, conducted in 0.1 M HCl solution. Finding – The results of the study reveal that the copolymer of poly(aniline-co-p-toluidine) at the optimum concentration of 1 × 10−3 M has better corrosion inhibition efficiency as compared to PAni and poly(p-toluidine). Research l...

Synthesis and Characterization of Conducting PANI/PNA Blend Polymer Doped with ZrO2 and CdO Nanocrystals

Composites of ZrO2 and CdO nanocrystals with conducting polyaniline/p-nitroaniline blended in different ratios have been prepared and investigated by UV-vis spectrophotometer, luminescence spectrophotometer and structural characterization of copolymer was studied by FTIR method. A decrease in nanocrystals photoluminescence (PL) has been observed with the increase in the concentration of PANI/PNA in the composites. A phenomenon of quenching is observed in the nanocrystals by luminescence.

Synthesis and Characterization of Polyaniline, Poly(3-fluoroaniline), and Poly(aniline-co-3-fluoroaniline) Derivatives Obtained by Chemical Oxidative Polymerization Methods

ABSTRACT The syntheses of thermally stable, conducting polyaniline, poly(3-fluoroaniline), and poly(aniline-co-3-fluoroaniline) derivatives by chemical oxidative polymerization methods are described. By varying the mol% of 3-fluoroaniline in the monomer feed, a series of new poly(aniline-co-3-fluoroaniline) derivatives with different chemical compositions were prepared by chemical oxidative copolymerization methods using ammonium persulfate as oxidant in the presence of hydrochloric acid as the dopant. The chemical oxidative copolymerization of aniline with 3-fluoroaniline affords poly(aniline-co-3-fluoroaniline) derivatives with increased solubility properties, greater thermal stability, improved morphological control, and enhanced electrical characteristics, which promotes the processibility of the different fluorine-functionalized polyaniline derivatives when compared with the parent polyaniline homopolymer. Poly(3-fluoroaniline) and the different poly(aniline-co-3-fluoroaniline) derivatives show better solubility and thermal stability than the polyaniline homopolymer, due to the incorporation of the F atoms along the fluorine-functionalized polyaniline backbone. Furthermore, the poly(3-fluoroaniline) homopolymer is thermally more stable than the polyaniline homopolymer due to the presence of the C–F bonds of the 3-fluoroaniline units along the polymer backbone. The electrical conductivity of the different poly(3-fluoroaniline) derivatives is dependent on the 3-fluoroaniline content in the polymer derivative and the morphology of the specific copolymer. The poly(3-fluoroaniline) homopolymer exhibits the lowest electrical conductivity. In addition, the electrical conductivity of the different poly(aniline-co-3-fluoroaniline) derivatives decreases with increasing 3-fluoroaniline content in the copolymer. The different polymer derivatives were characterized by proton nuclear magnetic resonance (1H NMR) spectrometry, fourier transform infrared (FTIR) spectroscopy, ultraviolet visible (UV–Vis) spectroscopy, thermogravimetric analyses, scanning electron microscopy, and electrical conductivity measurements. GRAPHICAL ABSTRACT

Nanotransition Materials (NTMs): Photocatalysis, Validated High Effective Sorbent Models Study for Organic Dye Degradation and Precise Mathematical Data’s at Standardized Level

The present work describes the synthesis of copper oxide nanoparticles (CuONPs) via a solution process with the aim of applying the nano-adsorbent for the reduction of methylene blue (MB) dye in alkaline media. These NPs were characterized via Field emission scanning electron microscopy (FE-SEM), X-ray diffraction, high-resolution Transmission electron microscopy (TEM), and ultra violet UV-visible spectroscopy to confirm their morphology and crystalline and optical properties in order to design an adsorption-degradation process. The photocatalytic CuONPs exhibited dynamic properties, great adsorption affinity during the chemisorption process, and operated at various modes with a strong interaction between the adsorbent and the adsorptive species, and equilibrium isotherm, kinetic isotherm, and thermodynamic activities in the presence of UV light. All basic quantities, such as concentration, pH, adsorbent dose, time, and temperature, were determined by an optimization process. The best-fitted adsorption Langmuir model (R2 = 0.9988) and performance, including adsorption capacity (350.87 mg/g), photocatalytic efficiency (90.74%), and degradation rate constant (Ks = 2.23 ×10−2 min−1), illustrate good feasibility with respect to sorption-reduction reactions but followed a pseudo-second-order kinetic on the adsorbent surface, reaching an equilibrium point in 80 min. The thermodynamic analysis suggests that the adsorption reaction is spontaneous and endothermic in nature. The thermodynamic parameters such as enthalpy (∆H°), entropy (∆S°), and Gibbs free energy (∆G°) give effective results to support a chemical reduction reaction at 303 K temperature. The equilibrium isotherm and kinetic and thermodynamic models with error function analysis explore the potential, acceptability, accuracy, access to adsorbents, and novelty of an unrivaled-sorption system.

N-cetyl-N,N,N trimethyl ammonium bromide (CTAB)-stabilized polyaniline: a corrosion inhibitor for mild steel

Purpose The purpose of this study is to compare the inhibitive effect of polyaniline (PAni) and N-cetyl-N,N,N trimethyl ammonium bromide (CTAB)-stabilized PAni in a hydrochloric acid (HCl) medium. Design/methodology/approach PAni has been deposited potentiodynamically on mild steel in the presence of CTAB as a stabilizing agent to achieve high corrosion inhibition performance by the polymer deposition. The corrosion inhibition studies of CTAB-stabilized PAni inhibitor in 0.1 M HCl acidic solution was carried out by electrochemical methods, namely, open-circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy technique. Findings The results of electrochemical studies have shown that the CTAB-stabilized PAni inhibitor has higher corrosion efficiency than PAni on mild steel in 0.1 M HCl solution. The maximum per cent efficiency evaluated using the potentiodynamic polarization method is approximately 91.9. Originality/value CTAB-stabilized PAni has never been studied as a corrosion inhibitor for mild steel in an acidic medium. The investigations demonstrate relatively the better corrosion inhibition efficiency and high dispersion of the polymer in the acidic medium.

Synthesis and characterization of electroactive novel poly-2-cynoaniline

Uniform needle-like structures of poly-2-cynoaniline are formed without the use of any template by electrochemical oxidative polymerization method on copper electrode in acidic medium. The structural characterizations are performed by FT-IR, UV-Visible spectroscopy and X-ray diffraction studies. The morphology of the polymer is demonstrated by scanning electron microscopy (SEM). The framework of the needle-like structure, which is seen at low and high magnifications appeared as nanorods of 50–80 nm diameter and of length up to a few micrometres to form a scaffold of interconnected nanorods. Thermogravimetic analysis (TGA) indicates that poly-2-cynoaniline is thermally more stable than polyaniline. The conductivity of pressed pellet of the as-synthesized polymer measured at room temperature of 25 °C by four-probe measurement method was found to be 9.1824 × 10−5 S/cm. The polymer is easily dispersed in some organic solvents and shows high solubility.