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This study aims to present the fabrication of the two-layer system, coating it on steel surface and evaluating the system’s anti-corrosion performance using the ASTM Standard Salt-Spray Test: B117 and the technique of Electrochemical Impedance Spectroscopy (EIS).

A synthesized electroactive polyaniline (PANi) was utilized in this study to make a PANi-based primer, with which a two-layer coating system was fabricated by overlaying the primer with a polyurethane top-coat.

In the Salt-Spray test, the two-layer PANi/polyurethane system exhibited higher corrosion resistance than the two-layer control epoxy/polyurethane system. In particular, the PANi/polyurethane system tended to mitigate the production of rust on substrate surface and demonstrated higher delamination resistance. The EIS analysis confirmed the high corrosion resistance and delamination resistance of the two-layer PANi/polyurethane system based on parameters obtained using the best-fit equivalent circuits.

The demonstrated anti-corrosion capacity of this new PANi/polyurethane system laid a solid base for industrial applications.

This novel coating system is expected to achieve improved corrosion protection for steels than the conventional zinc-rich three-layer coatings.

The study aims to synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion.

Polyesteramide polyol has been synthesised from phthalic anhydride and fatty amide of mustard oil. Aminolysis of mustard oil had been carried out with diethanolamine. The novel polyurethane dispersion had been synthesised using a polyesteramide polyol as a precursor. Isophorone diisocyanate was used as an isocyanate component and polyurethane dispersion (PUDs) had been synthesised by an anionic method where DMPA was introduced to introduce –COOH groups as via grafting to the resin backbone. Triethylamine was used for neutralisation and, hence, for further dispersion in water. Hydroxyl ethyl methacrylate was used for the synthesis to introduce unsaturation in the backbone of PUDs. The coating was made by an UV curing process. The coating was characterised for mechanical properties, chemical properties, thermal properties as well as stain resistance.

The polyurethane dispersion formed through it has ester and amide linkage present in it. The acetone process is used for its synthesis. The nuclear magnetic resonance spectroscopy confirms the successful formation of polyesteramide polyol and PUDs. Even though long aliphatic chains present in polyol which may impart hydrophobicity the synthesis PUDs well dispersed in water. It is observed as the coating made from it have hardness and scratch resistance properties. The coating also exhibits good stain resistance properties.

The method is an easy one to synthesise polyurethane dispersion from polyesteramide polyol, which is based on ester and amide linkage.

To the best of the authors’ knowledge, this is the first report on synthesised polyurethane dispersion from polyesteramide polyol. The polyesteramide resin already proves its excellence and upcoming technology in the coating industry. Here, they are incorporated into the synthesis of polyurethane dispersion.

The insulation resistance of polyurethane and poly (para dichloroxylelene) conformal coating was characterised following exposure to hygrothermal environment. Three types of test specimens were used—the standard Y type pattern, the ‘comb’ pattern and the ‘twin’ conductor type. The PCB with the comb pattern has been found to be the best testing specimen for the evaluation and comparison of conformal coating materials and processes. Using this type of PCB, the effects of predrying and thickness in polyurethane coated PCBs have been studied. While predrying has proved to be beneficial for preventing degradation of insulation resistance upon exposure to hygrothermal conditions, only marginal improvement of resistance is obtained when the polyurethane coating thickness has been doubled from 50 to 100 µm. Tin‐plated copper exhibited enhanced insulation resistance compared with bare copper for both polyurethane and polyxylelene coatings. Finally, a thin polyxylelene coating has demonstrated improved moisture barrier properties compared with a thicker polyurethane coating as determined from the resistance degradation with exposure duration to heat and humidity.

The purpose of this work was to study the effect of different wood surface preparations on the wetting and adhesion of coating.

In this research, six different chemical preparations to evaluate the photostability and properties of wood coating. Also, the effect of the same wood treatments on the properties of the coating, i.e. wetting, adhesion and the permeability of two types of coatings, was investigated.

As a result, benzoyl chloride and chromic acid were found to be the most effective photostabilizing preparations. Solvent-based polyurethane was more compatible with the prepared wood surfaces compared with water-based alkyd coatings.

Chemical modifications of wood surfaces affected the wetting of various coatings.

Various surface properties could be changed using preparation that affects important coating properties.

Unfortunately, the properties of transparent wood coatings used outdoors disappear through the early years of use, essentially due to the wood substrate’s photodegradation.

Wood is a widespread substrate because of its comfortable handling, availability, proper cost of preparation and its good mechanical strength because of its density. Architects and designers tend to use wood in the construction of green buildings. However, this material is disposed to weathering while using outdoors and it should be solved.

The reasons why a coating is selected as suitable for use on a pipeline would normally depend upon two major factors. Firstly, the performance of the available coatings has to be evaluated according to their technical characteristics. Secondly, price, which is more often influenced by application techniques rather than actual material cost.

The purpose of this paper is to formulate two component polyurethane coatings based on acrylic polyol, to study the effects of variable nanosilica loadings in these coatings on different morphological, optical, mechanical, corrosion resistance and weather resistance properties and to study the intercalation of acrylic polyol molecules into nanosilica crystals by XRD technique.

Two component polyurethane coatings were synthesised using acrylic polyol and isocyanate HDI. The nanosilica was incorporated in polyurethane formulation at the weight ratios of 1%, 3% and 5% based on total weight of polyol and isocyanate. The performance of nanocoatings was compared for variable loads of nanosilica for different properties such as morphological, optical, mechanical, corrosion resistance, weather resistance and were studied for intercalation of acrylic polyol into nanosilica crystals by XRD technique.

Improvement in the properties of polyurethane coatings is achieved with the incorporation of nanosilica. The improvement is the result of inherently high properties of inorganic nanosilica. Tensile strength, scratch hardness, abrasion resistance, corrosion and weathering resistance show significant improvement in performance with the incorporation of nanosilica. Properties are found to deteriorate beyond a certain loading of nanosilica; hence it is important to optimise loading level. The optimal range for high performance was found to be in the range of 1% to 3%. The improvement was a result of synergistic behaviour and good interfacial interaction between polyurethane and nanosilica at optimal levels.

The method used for incorporation of nanosilica into polyurethane was direct incorporation method. The other method of incorporation, i.e. in situ addition and its effect on properties can also be studied.

With the addition of optimal loading level of nanosilica to polyurethane coatings, properties can be enhanced up to the mark. The addition is relatively easy and cost effective.

The paper proves the significance of incorporation of nanosilica on original properties of polyurethane coatings and widens the area of applications of two component polyurethane coatings from acrylic polyol by strengthening them in their properties. The coatings can be applicable in high performance topcoats especially for automotive topcoats.

Stress corrosion cracking at the weld areas in the interior of blast furnace stoves has become a world wide problem which has been accentuated by the higher operating temperatures and pressures now used. This paper describes the work carried out to evaluate various protective coatings proposed for application to the interior of the stove shell plates to prevent the stress corrosion. A heat and chemical resistant polyurethane primer‐pitch polyurethane top coat has given superior results to all coatings tested, particularly when applied over a hot sprayed ceramic.

The primary purpose of this work is to prepare the renewable source-based polyurethanes coatings which can be used to substitute petroleum-based materials. In the secondary purpose, the paper included improvement in the properties of said PU coatings using modified nano TiO₂ for industrial PU coatings.

The authors have synthesised low molecular weight polyols (monoglycerides) based on vegetable oils such as castor, linseed, coconut, mustard, sunflower and rice bran oils. These monoglycerides were successfully utilised in the preparation of polyurethane coatings. In order to improve the performance of these coatings, modified nano TiO₂ was incorporated into them. The particle size of TiO₂ was determined by transmission electron microscopy. Coatings prepared were characterised for their properties such as gloss, scratch resistance, impact resistance, flexibility, cross cut adhesion and chemical resistance. The thermal stability of coatings was also studied by thermo gravimetric analyzer.

The polyurethane coatings prepared from six monoglycerides of different oils with polymeric diphenyl methane diisocyanate showed good chemical resistance and thermal stability. Coating properties like impact resistance, flexibility and adhesion were excellent for all of the prepared samples of PU coatings. PU coatings with excellent hardness up to 5B were found with the modification of nano TiO₂ by silane coupling agent. The authors successfully prepared the renewable source-based (monoglycerides of oil) PU coatings.

Practically the authors are able to convert renewable source that is vegetable oils into polyurethane coatings which may have strong potential to be used as industrial surface coating. The properties of the PU coatings were evaluated before and after the incorporation of different concentration of surface-modified nano TiO₂ which revealed that the presence of 1 percent nano TiO₂ showed significant enhancement in coating properties.

The beauty of this work includes synthesis of polyurethanes coatings from renewable source material (monoglycerides of vegetable oils) to substitute petroleum-based materials. The incorporation of silane-modified TiO₂ nanoparticles in renewable source-based PU coatings is another originality of the work. This article is also representing comparative study of various vegetable oils on PU coatings.

The paper's aim is to synthesise ultraviolet (UV) curable polyurethane acrylate based on polyester polyol and to study change in its mechanical, chemical, optical and weather resistance properties with varying amount of nanosilica. It also seeks to determine its optimum loading levels for property maximisation.

New UV curable polyurethane acrylate has been synthesised using polyester polyol, blend of isophorone diisocyanate and toluene diisocyanate and hydroxyl ethyl acrylate. This resin was incorporated with nanosilica (1‐3 per cent) on the basis of total solids. The newly synthesised material was characterised by fourier transform infrared spectroscopy, gel permeation chromatography, X‐ray diffraction and scanning electron microscopy. The mechanical, chemical and optical properties of the coating films were studied and compared.

The hardness, tensile strength and abrasion resistance show significant enhancement with increasing amount of nanosilica. It is also found that UV cured polyurethane acrylate nanocoating exhibited improved weather resistance. The optimum concentration of nanosilica for better performance is found to be 3 per cent of total solids. The improvement is the result of inherent nature of nanosilica.

Nanosilica used in present context is having 10 nm mean diameter and near about 600 m²/g surface area. Nanosilica having different particle size, surface area and surface modification can be used to improve more specific properties.

Addition of nanosilica particles to polyurethane acrylate coating is a simple and inexpensive method resulting in phenomenal increase in properties.

The new organic‐inorganic hybrid nanocoating with improved weather resistance was synthesised. These coatings could find applications in demanding fields such as automotive topcoats.

An important development in the urethane coating area is the use of polyisocyanates, in combination with hydroxylated acrylic resins, to provide room‐temperature‐curing coatings. These new formulations, according to Klein and Elms [Journal of Paint Technology, 43, November (1971) p. 68], demonstrate lightfastness, good outdoor durability and solvent resistance when the acrylic resin is coreacted with an aliphatic polyisocyanate. The acrylic resins are copolymers which contain either the hydroxypropyl or hydroxybutyl ester of acrylic or methacrylic acid as one component. Hydroxypropyl acrylate acetoacetate extends the potlife of this two‐component coating. The authors describe work in which glass transition temperature is used as a means for selecting the correct hydroxylated acrylic resins for use in the system. If the glass transition temperature is between 22 and 54°C, a flexible coating with good impact resistance results, but the system requires baking. At a glass transition temperature of 54° and a hydroxyl value of 26, a composition results which dries rapidly at ambient temperatures and which provides good hardness and mar resistance. The coreactant in this instance is an aliphatic diisocyanate composition based on hexamethylene diisocyanate.