The Effect of 2-Mercaptobenzimidazole-Polyaniline-CeO2 Ternary Nanocomposite Addition as a Superior Pigment for Improvement of Corrosion Resistance in Epoxy Coatings

The 2-mercaptobenzimidazole-polyaniline-ceria (MBI-PANI-CeO2) ternary nanocomposite synthesized and used as pigment into epoxy (EP) to improve protection properties of coating on mild steel. The MBI-PANI-CeO2 nanocomposite was prepared using layer by layer assembly. Initially, the PANI layer was polymerized on the surface of CeO2 nanoparticles. Then, the MBI inhibitor was adsorbed on PANI with opposite electrostatic charges. The anticorrosive performance of EP coatings was investigated using electrochemical impedance spectroscopy, salt spray test, and scanning electron microscopy by incorporating various amounts (0.5, 1, and 2 wt. %) of the MBI-PANI-CeO2 nanocomposite. The EP coating containing 1 wt. % of nanocomposite showed the highest corrosion resistance and minimum agglomeration. This coating indicated the coating resistance of 19.1 MΩ cm2, which is greater than EP and EP/CeO2 coatings. The EP/MBI-PANI-CeO2 (1 wt. %) coating showed water uptake percentage (2.09 %) about two times lower than EP/CeO2 coatings (4.56 wt. %), indicating appropriate barrier performance of inhibitor incorporated EP.

EFFECTS OF NUMBER OF PLIES ON LIGHTNING STRIKE PROTECTION OF ELECTRICALLY CONDUCTIVE LAYER-WISE HYBRID LAMINATES

With the development of composite technologies, aircraft become lighter and more fuel efficiency. The composite aircraft, however, become susceptible to lightning strike. Developing lightning strike protection (LSP) system need to couple with composite technologies. The authors present a concept of LSP using layer-wise hybrid laminates (CF/Hybrid) in this study. The aim of the study is to validate the effectiveness of layer-wise hybrid laminates structure for lightning strike application by using conventional epoxy-resin CFRP for main structure and electrically conductive layer as a cover layer. The composite laminates include two different types of resin in each layer: conductive polyaniline-based matrix (CF/PANI) and conventional epoxy resin (CF/epoxy). CF/PANI layers varied from 1, 2, and 4 layers with corresponding 7, 6, and 4 layers of CF/epoxy to find out the least effective number of CF/PANI that can prevent lightning strike damage. The specimens were characterized for their mechanical properties and underwent simulated lightning strike test to realize their effectiveness. The result of simulated lightning strike has shown that a layer of conductive CF/PANI can help to avoid catastrophic damage on CF/epoxy. With a greater number of CF/PANI, the less detectable damage in CF/PANI layer became. In the case of CF/Hybrid with 4 layers of CF/PANI shows 70% residual bending strength after the lightning strike. With the aid of nondestructive inspection tools, i.e., thermography and ultrasonic test, the mechanism of damage on the composite panels were observed and analyzed. From this study, CF/Hybrid with 4 layers shows the optimal properties for lightning strike protection.

The Effect of pH and Monomer Concentration on Polyaniline Thin Films Grown Using Electrodeposition

Polyaniline (PANI) thin films were successfully prepared from an aqueous electrolyte bath containing aniline and sulphuric acid (H2SO4) using electrodeposition method. The present study demonstrates that the properties of PANI thin film depends on the variation of pH and aniline concentration in prepared precursor. The optical and structural of PANI thin films were characterized using UV-Visible spectrometer (UV-Vis), X-ray diffraction spectrometer (XRD), Fourier Transform Infra-Red spectrometer (FTIR) and Raman spectrometer. PANI layer grown at pH 2.00 displayed green colour layer which denoted as emeraldine base (half oxidized state of PANI) while at pH 3.80 the colour of PANI layer was yellow representing the leucoemeraldine base (fully reduced state of PANI). Result obtained from FTIR confirmed the footprint of PANI and Raman spectrometer confirmed the half oxidized emeraldine base of PANI. Optical analysis using UV-Vis demonstrated the smallest energy band gap, Eg of PANI is 3.54 eV for sample with 0.50 M aniline concentration and pH 2.00. The trend shows that the bandgap of PANI is increased as the pH increased from 2.00 to 3.80. XRD result showed that all the deposited PANI layers were amorphous. Full characterization of this material is providing some information on PANI behavior due to pH and concentration in the prepared precursor.

Effect of the Polyamide Type on the Physical Properties of Layered Polyaniline Composite Films

The present work deals with the investigation of the dielectric properties of layered polyamide/polyaniline films and their correlation to the microstructure. A thin polyaniline (PANI) layer was polymerized in the subsurface of polyamide films. The dielectric relaxation spectroscopy was used to compare the electrical behaviour of flexible polyamide 6 (PA6) and polyamide 12 (PA12) surfaces loaded with PANI nanoparticles, while the roughness was investigated by the contact angle technique. Relatively high dielectric constants were recorded for PA12/PANI films compared to PA6/PANI ones due to the hydrophobic nature of the PA12 matrix. This also explained the wettability enhancement observed for PA12/PANI films up to 12 wt.% of aniline absorbed concentration, while PA6/PANI films needed no more than 9 wt.% to reach maximum wettability. This behavior was in good correlation with the microstructure of the films. SEM micrographs showed uniform surfaces for both films formed above these respective concentrations, where wettability started to decrease. The films of PA/PANI seemed to be good candidates as dielectric layers in flexible electronics. Keywords: Polymer, Polyamide, Polyaniline, Dielectric constant, Optical gap. PACS: 78.20.-ei, 78.20.-c, 68.60.-p, 82.35.Lr.

Phosphate-doped polyaniline/Al2O3 nanocomposite coating for protection of stainless steel

Purpose This work aims to prepare and characterize of protective anticorrosion phosphate-doped polyaniline (PANI) nanocomposite coatings for stainless steel (SS) in chloride solution. Design/methodology/approach PANI composite coatings were electrodeposited from aqueous sulfuric acid solution containing monomer and Al2O3 nanoparticles using cyclic voltammetry technique. Doping by phosphate was done by aging the coated steels for different periods (1–168 h) in phosphate solution. The polymer film composite was investigated by Fourier-transform infrared spectroscopy and scanning electron microscopy techniques. Potential-time, anodic polarization and electrochemical impedance spectroscopy were used to study the protection efficiency of the coatings. Findings The Al2O3 nanoparticles were incorporated into the deposited PANI layer but they decreased the deposition of polymer. The nanoparticles and the phosphate anions enhanced the protective PANI layer for passivation and protection of SS in the chloride solution. Originality/value The replacement of counter anions by phosphate ions improved significantly the PANI and its nanocomposite as protective coating of SS in chloride solution.

Printed 2D Proton Sensor for In-Situ Measurement in Glue Lines

A screen printed pH sensor was developed using a PANI layer as a proton sensitive material for the in-situ measurements of matrix cross-linking. The sensor showed a linear response in a broad pH range (3–10) and had an evident cross-talk to Cl− ions. Preliminary in-situ measurements showed a substantial signal change during the cross-linking process.

Pd nanoparticles immobilized on carbon nanotubes with a polyaniline coaxial coating for the Heck reaction: coating thickness as the key factor influencing the efficiency and stability of the catalyst

Pd/PANI@CNTs were synthesized using a low-cost and simple method. The thickness of the PANI layer is the key in determining the stability of the catalyst in the Heck reaction.

An Industry Friendly Approach for the Preparation of Magnetic and Electro-Conductive Polyaniline Composite Particles

Recently nano-sized conducting polymers have gained ample attention because of their unique properties and promising potentiality in nanomaterials and nanodevices. Among the conducting polymers, polyaniline (PANi) is the most studied conducting polymers because of its low monomer cost, ease of preparation, high conductivity in doped form, excellent environmental stability, controllable physical and electrochemical properties by oxidation and protonation. In this investigation magnetic PANi composite particles were prepared following a novel approach by using citric acid for the first time as dopant, surfactant and solubilizing agent. As synthesized citric acid doped Fe3O4 (magnetite)/PANi nanocomposites have been characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffractometer (XRD), Scanning electron microscope (SEM), Thermogravimetry analysis (TGA). Spectroscopic analyses confirmed the modification of Fe3O4 nanoparticles by PANi layer. The Magnetic susceptibility results revealed the paramagnetic behavior of Fe3O4/PANi nanocomposite particles. The electrical conductivities of Fe3O4/PANi nanocomposites increased up to certain amount of Fe3O4 and decreased thereafter.

Preparation and application of hollow ZnFe2O4@PANI hybrids as high performance anode materials for lithium-ion batteries

We firstly designed the conductive PANI layer coated hollow ZnFe2O4 nanospheres by a micro emulsion polymerization. Two strategies of hollow structure and PANI coating are attempted to relieve expansion and increase conductivity.