Miroslav Kohl

The Effect of Polypyrrole on Corrosive Properties of Organic Coatings Containing High Amounts of Zinc Metal Particles

The objective of this paper concerns reducing the zinc metal content in organic coatings while preserving their high mechanical efficiency. The two goals can be achieved by using conductive polymer as components of the protective coating. Polypyrrole (PPy) was investigated as the conductive polymer. PPy was specified using physico-chemical parameters. As a binder, the epoxy ester resin was used. Organic coatings were prepared by combining zinc metal with PPy. The anticorrosive efficiency of the prepared films was evaluated using the results of direct corrosion tests.

ANTICORROSION PROPERTIES OF ORGANIC COATINGS CONTAINING POLYPHENYLENEDIAMINE PHOSPHATE

The present work was aimed at the synthesis of polyphenylenediamine, its description and determination of parameters whose knowledge is required for the formulation of organic coatings pigmented with this compound. Polyphenylenediamine phosphate was prepared by oxidation polymerization in acidic environment. Phosphoric acid was used as the doping acid. Based on the results, pigmented organic coatings containing polyphenylenediamine at volume concentrations of 0%, 0.5%, 1%, 3%; 5%, and 10% were formed. The effect of the conductive polymer on the organic coatings‘ corrosion properties was examined via accelerated corrosion tests. From the results of an accelerated corrosion test it follows that if added to an epoxy-ester coating, this pigment improves appreciably the coating‘s corrosion resistance, especially at low pigment volume concentrations.

Synthesis of Me2 TiO4 and MeFe2 O4 spinels and their use in organic alkyd resin-based anticorrosion coatings

Abstract The anticorrosion properties of paints containing mixed metal oxide-based pigments were examined. Spinels with the cation combinations Ti-Zn-Mg or Fe-Zn-Mg were synthesized. Core-shell pigments with zinc oxide and magnesium oxide layers were also prepared. The pigments were synthesized from the oxides or carbonates by the high-temperature solid-phase process. The anticorrosion and physico-mechanical properties of film of paints based on an alkyd resin modified with soy oil and containing the pigments at a volume concentration of 10% were investigated. The highest anticorrosion efficiency was observed with the ferrite-based pigments. The anticorrosion efficiency was found to increase with increasing Zn contents of the pigments.

Anti‐Corrosive Properties and Physical Resistance of Alkyd Resin–Based Coatings Containing Mg‐Zn‐Fe Spinels

The anti‐corrosive and physical properties of organic coatings containing spinel pigments Mg0.2Zn0.8Fe2O4 wer studied. Pigments exhibiting different particle morphol‐ ogies were synthesized by high‐temperature solid phase reactions. Core‐shell pigments containing Fe‐Mg‐Zn ferrite shells deposited on non‐isometric particles of mineral cores consisting of layered silicates were also prepared. The pigments were used in paints, the pigment volume concentrations in the binder being 5, 10 and 15%. Anti‐corrosive efficiency was investigated for paint films containing one of three ferro‐spinel (Mg0.2Zn0.8Fe2O4)‐based pigments or one of two core‐shell pigments consisting of Fe‐Mg‐ Zn shell and lamellar silicate‐based cores. The paint properties were examined by accelerated corrosion tests and by physico‐mechanical tests. The relationships between the pigment particle shape and the paint properties were examined. The effect of the pigment particle morphology on the mechanical properties of the paint films was also investigated. The dependence of the paint film properties on the pigment volume concentration was studied and the optimum concentrations providing the most efficient anti‐corrosive protection were determined for each pigment.

Anticorrosive efficiency of alkyd resin-based coatings containing Mg–Zn–Fe mixed oxide-based pigments

Abstract Mixed oxide-based pigments Mg–Zn–Fe with different particle morphologies were prepared by high-temperature solid phase reactions. The core shell pigments containing ferric oxide and non-isometric particles of layered silicates were also prepared. The pigments were tested in paints, the pigment volume concentrations in the modified alkyd resin based binder being 5%, 10%, and 15%. The paint properties were examined by accelerated corrosion tests and by physico-mechanical tests. The effect of the pigment particle morphology on the surface hardness of the paint films was also studied. The influence of pigment volume concentration on the coating properties, and the optimum concentrations providing the most efficient anticorrosive protection were processed. A higher anticorrosion efficiency was observed for the paints with pigments possessing the lamellar particle shape.

Corrosion protection by organic coatings containing polyaniline salts prepared by oxidative polymerization

The aim of this work was to describe polyaniline salts synthesized and to assess the mechanical and anticorrosion properties of alkyd resin-based coating materials pigmented with them, in dependence on the pigment volume concentration and type. Polyaniline salts were prepared by oxidative polymerization in the solutions of inorganic (hydrochloric, phosphoric, and sulfuric) and organic (p-toluenesulfonic and 5-sulfosalicylic) acids. Polyaniline salts were characterized by thermal analysis and spectroscopic methods. Electrical conductivity was also measured by the van der Pauw method, and the molecular weight of the polyaniline was determined by gel permeation chromatography. Furthermore, the particle size of the solid salts was measured, and the morphology was studied by scanning electron microscopy. Subsequently, the parameters required to formulate pigmented organic coatings, i.e., density and critical pigment volume concentration were determined. A soybean oil-based fast drying alkyd resin of medium oil length was used as the binder for the organic coating material. Organic coatings containing the polyaniline salts at pigment volume concentrations 0%, 1%, 5%, 10%, and 15% were formulated and subjected to a standard accelerated cyclic corrosion tests. The organic coatings (paint films) were also subjected to mechanical tests and to the electrochemical test by potentiodynamic polarization studies.Graphical Abstract

Properties of Metal Oxide Pigments Surface Modified with Polyaniline Phosphate and Polypyrrole Phosphate in Corrosion Protective Organic Coatings

The objective of this work was to describe the properties of metal oxide–based pigments whose surface has been coated with a conductive polymer, if used as pigments in organic coating materials. The perovskite‐type pigments were synthesized by high‐temperature solid‐phase reaction, and their surface was modified with a conductive polymer, specifically polyaniline phosphate or polypyrrole phosphate, by chemical oxidative polymerization. The pigments’ structure and physicochemical properties were examined by XRD, XRF, and SEM. The composite pigments (pigment/ conductive polymer) were dispersed in a solvent‐type epoxy‐ester resin binder to obtain a series of paints whose anticorrosion properties were assessed by means of corrosion tests in simulated corrosion atmospheres and by the linear polarization method. The anticorrosion and mechanical properties of the paints were compared with those of a paint containing the routinely used zinc phosphate hydrate pigment as a reference material. The pigments were found to possess a high anticorrosion efficiency, comparable to or higher than that of the commercially available zinc phosphate–based anticorrosion pigment. The highest anticorrosion efficiency was observed with the paints containing the Ca–Ti, Sr–Ti, and Sr–Mn perovskite pigments modified with polypyrrole phosphate.