Copolymerization Of Diphenylamine Research Articles

Low potential electropolymerization and copolymerization of diphenylamine on aluminium

The main electrodeposition problem of conducting polymers on oxidizable metals is the higher potential gap between their oxidation and the electropolymerization reaction. This difference provides a dissolution of the electrode before the formation of the polymer. In this context, the present work is aimed to the electrochemical synthesis of polydiphenylamine (PDPA) and its copolymer on aluminium (Al) substrate. The electropolymerization has been performed in two different electrolytic media. We have found that the hydro-organic medium was particularly suitable for carrying out the electropolymerization of DPA on Al at a low potential, 0.6 V, instead of 1 V in the organic medium. Furthermore, the anticorrosive properties of the coatings were studied by linear polarization, open-circuit potential and electrochemical impedance spectroscopy. Finally, the copolymerization of DPA with aniline was investigated in the aim to improve the adherence and the protective performance of the polymeric film.

<i>In Situ</i> UV–Vis Spectroelectrochemical Studies on the Copolymerization of Diphenylamine and <i>o</i>-Phenylenediamine

The in situ ultraviolet-visible (UV-Vis) spectroelectrochemical study on the copolymerization of diphenylamine (DPA) and o-phenylenediamine (OPD) has been performed at a constant potential of 0.8 V using indium tin oxide (ITO)-coated glass electrodes as working electrode. And also, as a comparison, the electrochemical homopolymerizations of DPA and OPD have been investigated by using the in situ spectroelectrochemical technique. The intermediate species generated during the electrochemical homopoly-merization of DPA and OPD, and the copolymerization of DPA with OPD have been identified by using the in situ spectroelectrochemical procedure. The results reveal the formation of an intermediate in the initial stage of copolymerization through the cross-reaction of the cation radicals of DPA and OPD, and the absorption peak located at 538 nm in the UV–Vis spectra is assigned to this intermediate. To further investigate the copolymerization of DPA with OPD, cyclic voltammetry (CV) has been used to study the electrochemical homopolymerization of DPA and OPD and also the copolymerization of DPA and OPD with different concentration ratios in solution. The different voltammetric characteristics between the homopolymerization and copolymerization processes exhibit the occurrence of the copolymerization, and the difference between the copolymerization of DPA and OPD with different concentration ratios shows the dependence of the copoly-merization on the concentrations of DPA and OPD. The copolymer has also been characterized by Fourier transform infrared spectroscopy (FT-IR).

Electrochemical Synthesis and Characterization of Conducting Poly(diphenylamine-co-2-methoxyaniline)

Electrochemical growth characteristics of copolymer deposition were monitored by performing copolymerization of diphenylamine (DPA) with 2-methoxyaniline (MA) at different molar feed ratios of the comonomers. Cyclic voltammograms of the copolymer films were recorded in the background electrolyte. Reactivity ratios of the two monomers were evaluated through elemental analysis using Fineman-Ross and Kelen-Tudos equations. FT-IR spectroscopy of the copolymer revealed the compositional variations of the comonomer units in the copolymer. Thermogravimetric analysis of the copolymer shows that the thermal stability of the copolymers varies with compositions of two monomers in the copolymers.

Deposition, growth processes and characterization of poly(diphenylamine-co-N-methyl aniline)

Copolymerization of diphenylamine (DPA) with N -methyl aniline (NMA) was carried out in aqueous sulfuric acid medium by pulse potentiostatic method (PPSM). The copolymer film was grown on the surface of the working (platinum) electrode for various experimental conditions and the charge associated with film deposition was followed by cyclic voltammetry. The charge values were correlated to the amount of copolymer deposition (growth) and amount of copolymer deposited per unit time of electropolymerization (growth rate). The kinetics of the electrochemical copolymerization was followed by deducing the growth and growth rate equations in terms of charge associated with the film deposition and the conditions of electropolymerization. The deduced growth and growth rate functions indicate the dependences of concentration of DPA and NMA. The copolymer was also synthesized through oxidative polymerization and characterized by conductivity measurement, Fourier transform infra-red spectroscopy, nuclear magnetic resonance spectroscopy, ultra violet–visible spectroscopic techniques and thermogravimetric analysis.

Deposition, growth processes and characterization of poly(diphenylamine-co- N-methyl aniline)

Copolymerization of diphenylamine (DPA) with N-methyl aniline (NMA) was carried out in aqueous sulfuric acid medium by pulse potentiostatic method (PPSM). The copolymer film was grown on the surface of the working (platinum) electrode for various experimental conditions and the charge associated with film deposition was followed by cyclic voltammetry. The charge values were correlated to the amount of copolymer deposition (growth) and amount of copolymer deposited per unit time of electropolymerization (growth rate). The kinetics of the electrochemical copolymerization was followed by deducing the growth and growth rate equations in terms of charge associated with the film deposition and the conditions of electropolymerization. The deduced growth and growth rate functions indicate the dependences of concentration of DPA and NMA. The copolymer was also synthesized through oxidative polymerization and characterized by conductivity measurement, Fourier transform infra-red spectroscopy, nuclear magnetic resonance spectroscopy, ultra violet–visible spectroscopic techniques and thermogravimetric analysis.

In situ UV–visible spectroelectrochemical studies on the copolymerization of diphenylamine with ortho-methoxy aniline

UV–visible spectroelectrochemical studies on copolymerization of diphenylamine (DPA) with ortho-methoxy aniline (OMA) were carried out for different feed ratios of DPA and OMA using indium tin oxide (ITO)-coated glass as working electrode. The UV–visible spectra show clear dependencies on the molar feed composition of DPA or OMA used in electropolymerization. Derivative cyclic voltabsorptogram (DCVA) was deduced at the wavelengths corresponding to the absorption by the intermediate species and used to confirm the intermediates generated during the electropolymerization. The composition of DPA and OMA in the copolymer for the copolymers synthesized with different molar feed ratios of DPA and OMA was determined by UV–visible spectroscopy. Reactivity ratios of DPA and OMA were deduced by using Fineman–Ross and Kelen–Tudos methods and correlated with spectroelectrochemical results.

In situ UV–visible spectroelectrochemical studies on the copolymerization of diphenylamine with anthranilic acid

In situ spectroelectrochemical studies were carried out on the polymerization of diphenylamine (DPA) and copolymerization of DPA with anthranilic acid (AA). Electropolymerization was performed in aqueous 2 M H 2SO 4 by applying a constant potential (0.80 V) on indium tin oxide (ITO)-coated glass electrode. Spectral characteristics were followed for various feed ratios of the comonomers (DPA and AA) at different polymerization times. Two types of cation radicals could be observed for the electropolymerization with mixture of DPA and AA, corresponding to anilinium-type and N, N′-diphenylbenzidine-type, respectively. UV–visible spectra recorded for copolymerization inform that the peak position corresponding to DPB + showed clear dependence on AA concentration in the feed, signifying the changes in the overall oxidation states of the polymer as a result of incorporation of AA units in the copolymer. The FTIR spectral analysis of the copolymer clearly reveals the incorporation of AA units into the polymer backbone during polymerization. The presence of a band at 1650 cm −1 in FTIR spectra corresponding to the –CO group of AA units and the improvement in thermal stability of the copolymer as observed from thermogravimetric analysis (TGA) favor the incorporation of AA units in the copolymer.