Qiong Zhou

Characterization of Electrochemically Synthesized Pani on Graphite Electrode Use EIS

Polyaniline (Pani) on graphite electrode was synthesized electrochemically under galvanostatic condition at current density of 2.0 mA/cm2 from aqueous solution of 1.0 mol/L HCl and 0.25 mol/L aniline monomer. The Electrochemical Impedance Spectroscopy investigation of Pani was carried out at different stages of polymers oxidation. In the potential range 0.2V~0.7 V vs SCE, with the increase of test potential the membrane resistance decreased rapidly, and Faraday process at the polymer/solution interface weakened. When the test potential in range of -0.8V~0.2V or 0.7V~0.8V, the film has a higher membrane resistance, and lower ionic charge transfer resistance, which indicated that the ion exchange for the charge compensation at the polymer/electrolyte interface is much easier. And anticorrosion properties of Pani coating of different oxidations was investigated by salt spray test. The final visual observations of the tested coatings are in agree with the results of electrochemical impedance spectroscopy.

Effects of composite ferrotitanium on epoxy coating

Purpose – The purpose of this paper is to evaluate effects of different contents of composite ferrotitanium pigment on corrosion protection performance of epoxy resin coatings.Design/methodology/approach – Different contents of composite ferrotitanium pigment were added to the epoxy resin coatings and the corrosion performance of the coatings were investigated by electrochemical test (in 5 wt.% KCl solutions at 60°C), salt spray test and simulated test. The morphology of the coating before and after corrosion was characterised by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).Findings – The composite ferrotitanium improved anti‐corrosion properties of the coating due to complex reaction of ferrous ions and phosphates as well as introduction of nano powder to the composite ferrotitanium. The coating with 10 wt.% composite ferrotitanium pigment had better anti‐corrosion properties than that of 5 wt.%. Simulated experiment in an autoclave indicated that the composite ferrotitaniu...

The Influence of Water Content on the Morphology and Magnetic Properties of Nickel Nanoparticles Prepared in Reverse Microemulsion

Magnetic nickel nanoparticles are prepared by NaBH4 reducing agent in AOT reverse microemulsion, the influence of water content on the morphology and magnetic properties of nickel nanoparticles are investigated by TEM study, size distribution, XRD characterization and magnetization curves. The results show that spherical and polydispered particles are obtained in microemulsion. The dimension and polydispersity of particles increased with the increasing of water content. Magnetization curves clearly indicate a ferromagnetic behavior with high coercivity values. At water content of W0=41.7, the product has a high saturated magnetization 70.68 emu/g with its residual magnetizations 28.02 emu/g, higher than the sample obtained at water content of W0=13.9.

Comparative Studies on the Corrosion Protection Effect of Different Ions Selective Polyaniline Coatings

Different kinds of dopants were selected to dope polyaniline by chemical oxidative polymerization in this paper. Major characteristic peaks and microstructure of the doped polyaniline were analyzed by Fourier transform infrared spectra (FTIR) and scanning electron microscope (SEM). Measurement of membrane potential indicated that polyaniline doped with protonic acid such as sulfosalicylic acid (SSA) and hydrochloric acid (HCl) had characteristic of anionic selectivity, and polyaniline doped with cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) had characteristic of cationic selectivity. Doped polyaniline was added to the epoxy resin to obtain different ions selective coatings, such as anionic coating, cationic coating and bipolar coating. Results of electrochemical test in 5% potassium chloride (KCl) solution (at 60 °C) showed that anti-corrosion performance of the bipolar coating is better than that of cationic coating, and performance of the cationic coating is better than that of anionic coating. And the coatings contained HCl-doped polyaniline had better protection performance than those of SSA-doped because of its micro appearance and distribution.

Preparation of Epoxy/Montmorillonite Nanocomposite Coating and its Application in the High-Temperature Oil-Gas Environment with H2S

Montmorillonite was introduced into the multicomponent epoxy resin by using the intercalation polymerization. Intercalation effect of epoxy/montmorillonite composite system and the influence of the addition of montmorillonite on the glass transition temperature (Tg), mechanical properties and barrier of H2S to coating under high temperature and pressure conditions were investigated. The results showed that it was easy to intercalate epoxy resin into the organic montmorillonite layers, and the interlayer spacing of Montmorillonite was further swelled. In addition, the epoxy/montmorillonite nanocomposite coating with intercalated/ exfoliated structures were prepared. Compared to pure epoxy coating, the heat resistance and mechanical properties of epoxy/montmorillonite nanocomposite coating were slightly improved, and the barrier efficiency to H2S was substantially increased under high temperature and pressure oil-gas environment.

The Effect of Acrylonitrile Content on the Abrasion Behavior of Unfilled Nitrile Rubber

Three unfilled nitrile rubber vulcanizates with different acrylonitrile contents (28%, 33%, and 40%) were prepared. The gravimetric wear rate of testing samples increased with increasing acrylonitrile contents. The cross-linking densities of rubbers were studied by the equilibrium swelling method. The measurement of the dissipated energy between tip and rubber surface was also carried out using tapping mode atomic force microscopy and the results suggest that the cross-linking density in local areas is primary responsible to the abrasion performance of unfilled nitrile rubber with reference to the polarity of polymeric matrix.

A New Polyethylene Corrosion Protecting Coating with Ion Selectivity

Linear low density polyethylene (LLDPE) was chemically modified with grafting maleic anhydride (MAH) monomer on its backbone by melting blending. Nano-particles SiO2 was modified by cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) and anionic surfactant sulfosalicylic acid (SSA) and added to PE coating respectively. Measurement of membrane potential showed that the coating containing modified SiO2 nano-particles had characteristic of ion selectivity. The properties of the different coatings were investigated according to relative industrial standards. Experimental results indicated that PE coating with ion selectivity had better performances, such as adhesion strength, cathodic disbonding and anti-corrosion, than those of coating without ion selectivity. Crystal structure of the coatings before and after alkali corrosion was characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). Structure of the coating without ion selectivity was damaged by NaOH alkali solution, causing mechanical properties being decreased. And the structure of the ion selective coatings was not affected.

Ethylenediamine-Functionalized Carbon Nanotubes and Nylon-6 Composites

Carbon Nanotubes (CNTs) are functionalized with ethylenediamine by chemical cut and grafting process. CNTs/nylon-6 (PA6) composite is prepared by solution-evaporation method. The dispersivity of CNTs and mechanical properties of CNTs/PA6 composites are tested. Reinforced mechanism is also investigated. The results show that the ethylenediamine-functioned CNTs (s-CNTs) are well dispersed in the formic acid and the weight content of grafted ethylenediamine is about 30%. With only 2wt% addition of s-CNTs, the modulus, strength and strain of PA6 are dramatically improved by about 46%, 85%, and 200% respectively. The tensile course of s-CNTs/ PA6 composites shows that the increase of modulus were provided by both the increase of matrix crystallinity induced by s-CNTs and the recruitment of s-CNTs, and the improvements of strength and strain were attributed to the malleable integration between the s-CNTs and matrix, which was formed with s-CNTs, crystal matrix based on the tubes and the partial entanglements of tubes.