Search results

The purpose of this paper is to synthesize anticorrosion pigments ZnFe₂O₄ from diverse raw materials of various shapes and size of primary particles.

Anticorrosion pigments were synthesized through a high‐temperature process during a solid phase. Zinc ferrites were prepared from hematite (α‐Fe₂O₃), goethite (α‐FeO.OH), magnetite (Fe₃O₄), and specularite (Fe₂O₃) entering into reaction with zinc oxide at temperatures ranging from 600 up to 1,100°C. The nature of the initial raw material, primarily the shape of its particles, affects the shape of the particles of the synthesized zinc ferrite. The formulated zinc ferrites had a rod‐shape, lamellar, and/or isometric shape. The shape of the particles of synthesized zinc ferrites was studied with regard to its effects on the mechanical and corrosion resistance of organic coatings. The obtained pigments were characterized by means of X‐ray diffraction analysis and scanning electron microscopy. The synthesized anticorrosion pigments were used to prepare epoxy coatings and water‐borne styrene‐acrylate coatings that were subjected to post‐application tests for physical‐mechanical properties and anticorrosion properties.

The shape of the particles was identified in the synthesized pigments. X‐ray diffraction analysis revealed the degree of precipitation and lattice parameters. All of the synthesized pigments had good anticorrosion efficiency in an epoxy and in styrene‐acrylate coatings. Compared with a commercially used anticorrosion pigment, their protective power in coatings was demonstrably stronger.

The synthesized pigments can be used conveniently in coatings protecting metal bases against corrosion.

The synthesis of zinc ferrites with different particle shapes for applications in anticorrosion coatings provides a new way of protecting metals against corrosion. Of benefit is the fact that the synthesized pigments do not contain any environmentally harmful substances.

The purpose of this paper is to describe the process of synthesizing lamellarly‐shaped anticorrosion pigments having a chemically active layer whose core consists of metal aluminium on which a thin spinel film is synthesised.

Anticorrosion pigments were synthesised by reaction of metal aluminium lamellar particles whose surface was oxidised to Al₂O₃ during the first stage and by subsequent reaction with ZnO and/or MgO at 800‐1,150°C producing a thin spinel layer that is chemically bonded to the metal core of the pigment particles. Core‐shell pigments including MgAl₂O₄/Al, Mg_0.8Zn_0.2Al₂O₄/Al, Mg_0.6Zn_0.4Al₂O₄/Al, Mg_0.4Zn_0.6Al₂O₄/Al, Mg_0.2Zn_0.8Al₂O₄/Al and ZnAl₂O₄/Al were synthesised. The prepared pigments were characterised by means of X‐ray diffraction analysis and scanning electron microscopy. The synthesised anticorrosion pigments were used to prepare epoxy coatings that were tested upon application for their anticorrosion properties and resistance against a chemical environment.

The lamellar shape of the particles, as well as good‐quality coverage with a thin spinel layer, was identified in the prepared pigments. All of the synthesised pigments exhibit good anticorrosion efficiency in epoxy coatings. Compared to lamellar kaolin and metal core of aluminium without coverage, the protective function of the synthesised pigments in coatings is demonstrably better.

The synthesised pigments find convenient applications in coatings protecting metal bases from corrosion.

Synthesis of a spinel layer on the metal core of aluminium is a novel method; so is the application of these substances in coatings designed for the protection of metals from corrosion. Of great benefit is the fact that the synthesised pigments are free of any substances harmful to the environment.

This paper aims to study the effect of microcrystalline cellulose (MCC) on the mechanical property and shape memory property of water-borne epoxy (WEP).

In the present study, the MCC/WEP composites were successfully prepared by melt-blending, freeze-drying and hot-pressing. The mechanical property tests were performed using a tensile test instrument (Instron Corp, Norwood, Massachusetts, USA). dynamic mechanical analysis Q800 was performed to analyze the sample’s dynamic mechanics. The thermal–mechanical cycle tests performed on a thermal mechanical analysis (TMA) Q400 in dynamic TMA mode enabled to analysis of the shape memory properties of the MCC/WEP composites.

The results showed that the inclusion of 2 wt.% MCC led to significant improvements in tensile strength and modulus of the composites, with tensile strength increasing by 33.2% and modulus expanding by 65.0%. Although the inclusion of the MCC into WEP enhanced the shape memory property, the MCC/WEP composites still maintained good shape memory fixity and shape memory recovery ratio of more than 95.0%.

This study has a significant reference value for improving the mechanical properties of WEP and other water-borne shape memory polymers.

The purpose of this paper is to study the curing mechanisms, anticorrosive properties and protective mechanisms of three kinds of amine curing agents applied in a new kind of light colored water‐borne epoxy antistatic anticorrosive paint.

Using light color‐conductive mica, titanium oxides and environmentally‐friendly anticorrosive pigments in the two‐component water‐borne epoxy system, the light colored water‐borne antistatic anticorrosive paint was prepared. The molecular structure and curing mechanisms of the curing agents was analyzed by Fourier transform infra‐red spectroscopy, and the influence of the curing agents on anticorrosive properties and protective mechanisms was studied by electrochemical impedance spectroscopy.

The paints cured by the modified amine curing agent possessed optimal integrated properties with a coating surface resistivity of 10⁶ Ω and the best anticorrosive performance.

A novel light colored water‐borne epoxy antistatic anticorrosive paint cured by the optimal curing agent could be used in corrosion protection for oil tanks to replace the traditional oil‐based antistatic anticorrosive paints.

Just as the flow of new proprietary products has decreased so is there a lessening in announcements of new raw materials. More and more, paint companies are making do with the raw materials that they have known for the last few years. This is not to say that the coatings industry does not have an extensive armoury from which to formulate new products. It does mean however that the ingenuity of the coatings chemist will be tested as he tries to meet the exacting demands of industry without a continual flow of new polymeric materials or the other components he needs for protective coating formulation. It is an interesting point that the last three years have not produced a truly new polymer which could be useful for coatings. On the other hand numerous modifications have been proposed which are intended to facilitate the formulation of water‐borne coatings and other materials which are nonpolluting and nontoxic.

An interesting new marine coating developed in Finland is particularly useful for ice‐going vessels such as ferries which operate in cold areas and ice‐breakers. Over 30 Finnish vessels have been coated with this material which is called Inerta 160 and which was developed by Teknos‐Maalit. The coating has been licensed to International Marine Coatings and is now being tested by the U.S. Coast Guard on two ice‐breakers. Additionally the coating is said to be useful for the protection of nuclear and conventional power plants, for equipment in the chemical process industry, and on transport vehicles where there is high mechanical wear.

The paper aims to discuss the evaluation of anti-corrosive efficiency of conducting polymer, polypyrrole in water borne epoxy-polyamine coatings.

Polypyrrole (PPy) is synthesised by chemical oxidative polymerisation. The synthesised PPy is characterised by employing FT-IR, XRD, SEM and EDX analysis. The coatings are formulated using water borne epoxy cross-linked with aliphatic polyamine adduct and the effect of PPy on corrosion prevention is studied. PPy was used as anti-corrosive pigment in concentration varying from 1 to 5 wt.%. In addition to anti-corrosive property; mechanical properties, chemical resistance and weathering properties of the coatings containing PPy are studied, thereby obtaining a wholesome data about the quality and performance of these coatings.

The result obtained through various tests showed that the coating with 1 and 2% PPy exhibited excellent weathering resistance, mechanical properties and improved chemical resistance. Higher percentage loading of PPy (beyond 3 per cent) proves to be disastrous, as extended percolation networks are formed which results in rapid intense corrosion leading to fast coating breakdown.

The anti-corrosion property of the coating can be tested by means of atmospheric exposure such as Florida test which produces a real time evaluation of the anti-corrosive nature of the coating at natural condition rather than accelerated weathering, thereby providing more reliable performance data for intended application purpose.

The results find application in anti-corrosive/performance paints for industrial application.

This research paper presents the results of anti-corrosion behaviour of PPy in water borne epoxy-polyamide coating. Based on this result, a highly effective anti-corrosive coating can be formulated by the addition of small percentage of PPy in combination with other conventional pigments, thereby enhancing corrosion protection. But care must be taken so as to avoid formation of extended percolation network of PPy which leads to rapid coating breakdown.

If the paint chemist is to meet the challenges of ecology, toxicity, and government regulations generally, he must rely on two things. One of these is formulating skill, the other, new raw materials. In fact, however, there have been very few truly new raw materials in the past decade. Most of the advances have involved variations of known products and these variations have related to the needs of the paint chemist. For example there has been a strong desire to convert materials which are normally solvent‐based to forms useful in water‐borne compositions.

Magnesium ferrite pigments were evaluated as active pigments in anticorrosive water‐borne paints. The study includes the use of two different anticorrosive pigment volume concentration (APVC), 15 and 25 per cent and fixed the Q value (the pigment volume concentration/critical pigment volume concentration ratio) in both paint formulations. Epoxy and acrylated alkyd resins were used as binders. The paints were evaluated by accelerated salt spray tests, corrosion tests in condensed water and sulphur dioxide chambers and electrochemical evaluations. The results obtained were compared with reference paints containing zinc ferrite and zinc phosphate pigments. Ferrite pigments passivate the carbon steel directly in the case of neutral epoxy resin binder or indirectly due to the soaps produced as a result of reaction with the acidic acrylated alkyd resin binder. A lower per cent, i.e. 15 per cent of APVC was found to be sufficient to provide satisfactory anticorrosion protection.