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The purpose of this paper is to prepare cheap and environmentally friendly water soluble polyester coatings through the glycolysis of poly(ethylene terephthalate) (PET) waste.

A secondary value-added polyester coatings were prepared from PET waste. The first step was the de-polymerisation of PET waste by 2,2-dimethyl-1,3-propanediol with different molar ratios in the presence of different concentrations of zinc acetate as trans-esterification catalyst. The de-polymerised product was characterised by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (¹HNMR), differential scanning calorimetry and hydroxyl values. The polyesters were successfully synthesised by esterification of the glycolysed product with adipic acid, isophthalic acid, 2,2-dimethyl-1,3-propanediol and trimellitic anhydride in different ratios. FTIR and ¹HNMR were used qualitatively and quantitatively to elucidate the structure of the prepared polyesters. Hydroxyl value and the physical properties of the prepared polyesters were also investigated. Two different curing agents were used to prepare the coatings based on the prepared polyesters.

Useful coating products were obtained by chemical (glycolysis) of post consumed PET wastes. The 2,2-dimethyl-1,3-propanediol was found to be good glycol in the glycolysis of PET. It was noticed that the rate of glycolysis increases with increasing the amount of catalyst, time of glycolysis and amount of 2,2-dimethyl-1,3-propanediol. N,N-Dimethylethanol amine was a good neutralising agent used for the preparation of water soluble coatings based on glycolysed product of PET.

The use of waste products like PET waste in water soluble coating systems will bring down the costs of the coatings and will also open a new market of recycled plastic materials and, hence, may provide a potential solution to the problems of solid waste management. It is an attractive option for environmentally friendly and efficient disposal of plastic waste.

The paper provides a potential way to use undesirable PET waste as industrial raw material. The coatings prepared are eco-friendly, soluble in water that can replace other expensive polyester coatings that are soluble in organic solvents and not environmentally coatings.

This paper aims to enhance the barrier properties and active protection of a water-based silane coating on mild steel through nanoclay and zinc acetylacetonate simultaneously included into the formulation.

The corrosion protection performance of the silane sol-gel coatings with no additive, zinc acetylacetonate, nanoclay and nanoclay + zinc acetylacetonate was monitored using electrochemical impedance spectroscopy during 5 h of immersion in a sodium chloride solution. Moreover, the surface of coatings was analyzed using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (FESEM-EDX) and water contact angle measurements.

In electrochemical impedance spectroscopy analysis, the impedance at low frequencies, coating resistance and charge transfer resistance were the parameters considered which indicated the superiority of silane coating formulated with both nanoclay and zinc acetylacetonate. According to the results of FESEM/EDX and water contact angle measurements, the superiority was linked with the enhancement in the barrier properties in the presence of nanoclay, as well as function of the corrosion inhibitor at coating–substrate interface.

According to the literature, there is no research conducted to study the impact of the simultaneous use of nanoclay and zinc acetylacetonate on the barrier properties and active protection of an eco-friendly silane sol-gel coating including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane on mild steel in a sodium chloride solution.

The purpose of this paper is to develop a kind of novel and high‐performance rheological additive, an eco‐friendly composite of anatase nano‐TiO₂ particles and xanthan gum (NTX), for interior wall coatings.

NTX was prepared through heating and refluxing the mixture of TiO₂ hydrosol and xanthan gum, and five interior wall coating samples were fabricated with different NTX contents. The morphology of nano‐TiO₂ hydrosol and NTX were characterised with TEM, and the stability and rheological properties of these coating samples were studied.

TEM images showed a core‐shell structure of NTX, and that nano‐TiO₂ particles in it were encapsulated by xanthan gum, which was anticipated to weaken Van der Waals force among nano‐TiO₂ particles thus preventing the aggregation of nano‐particles. All of the five coating samples were found to be non‐Newtonian pseudo‐plastic fluid, and showed excellent stability and thixotropic property.

This paper focused on the preparation, the characterisation of NTX additive and the study of the rheological behaviours of the coating samples with NTX. Some other aspects, such as coating durability, photocatalytic ability and film properties, will be studied in the future.

It was proven that NTX was an effective eco‐friendly rheological additive for interior wall coatings. Consequently, this paper threw light on developing eco‐friendly interior wall coatings.

A kind of novel and effective rheological additive was developed for interior wall coatings in the study reported in the paper. A method was also developed to introduce functional nano‐particles into coating in a good dispersion state.

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.

This study aims to synthesize pigment and resin from agro-wastes and use them in the formulation of eco-friendly surface coatings.

The pigments and resin were synthesized through a chemical modification of agro-wastes. The pigments were characterized by infrared spectroscopy (FTIR) and were screened for their antimicrobial activities. The physicochemical characteristics of the cashew nutshell liquid (CNSL)-modified resin were evaluated. These precursors and other natural additives were used to formulate surface coatings, and their drying and adhesive properties were evaluated using international testing methods.

It was observed that the curing of the CNSL-modified resin depended on time and temperature. The pigments exhibited antimicrobial activity against E. coli and S. aureus and had high melting points, affirming their stability. The chemically modified precursors successfully yielded surface coatings with acceptable drying times and adhesion to the base substrate.

The use of agro-wastes as the main components of the surface coatings implies waste valorization, a reduction in production costs and the creation of job opportunities for sustainable development. To increase the chemical, physical, corrosion resistance and antimicrobial qualities of paint compositions, chemically modified peanut skin extracts and CNSL can be used as pigments and resins, respectively. This could be a green approach to achieving the targets of Sustainable development goals 11 and 12.

The paper outlines a prospective approach to use unwanted waste (peanut skin, cashew nutshells) and other natural additives as industrial raw materials. These novel surface coating precursors are cost-effective, readily available, eco-friendly and could replace conventional precursors.

This paper aims to access the protective function of hybrid sol-gel coatings deposited on 304L stainless steel substrate in silane solutions containing a mixture of tetraethoxysilane, methyltriethoxysilane and glycidyloxypropyltrimethoxysilane with different pH values during various immersion periods.

The 304L stainless steels coated through 10 and 30 s of immersion in the silane solutions with pH values of 2.1 and 2.8 were exposed to NaCl solution. The corrosion resistance of the coated substrates was studied through taking advantage of electrochemical noise method as well as atomic force microscopy (AFM), water contact angle and field emission-type scanning electron microscopy (FESEM) surface analysis.

The electrochemical current noise, PSD (I) plot, noise resistance and characteristic charge as parameters extracted from electrochemical noise method indicated the superiority of eco-friendly silane coating deposited on the substrate surface during 10 s exposure to the solution, due to the film uniformity and homogeneity as confirmed by FESEM and AFM. Moreover, immersion of the stainless steel in the silane solution with pH 2.1, characterized by higher hydrolysis ratio, led to more effective corrosion control in the NaCl electrolyte according to the results of electrochemical noise and FTIR measurements.

The noise resistance and characteristic charge as electrochemical noise parameters were only used in this research to evaluate the protective behavior of the water-based silane sol-gel coatings. Future studies should examine the correlation between electrochemical noise data and the parameters extracted from other electrochemical methods, e.g. electrochemical impedance spectroscopy.

The data obtained in this research may provide an effective approach based on electrochemical noise method to screen the silane sol-gel coatings for protection of metallic substrates against corrosion.

According to the literature, no report can be found studying the effect of immersion time on a silane solution, including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane, as well as the silane solution pH on the corrosion resistance of 304L stainless steel in NaCl solution through electrochemical noise method.

The purpose of this investigation was to develop sustainable resource-based anticorrosive coating material using Pongamia glabra seed oil and tannic acid (TA), as well as to improve the coating properties.

TA-modified fatty amide diol was synthesized by condensation polymerization. First, Pongamia glabra seed oil was converted to fatty amide diol (Pongamia oil fatty amide, PFA) that was further modified by TA with different parts per hundred of resin (10, 15 and 20) to develop a polyether fatty amide (PFA-TA). The confirmation of reaction between TA and PFA was carried out using Fourier transform infrared spectroscopy. The thermal behavior of PFA-TA was studied by thermogravimetric analyses. Coatings of several PFA-TA resins were applied to steel (i.e. plain carbon steel) coupons to investigate their physico-mechanical and anticorrosive performance. The corrosion protection performance was observed using AC impedance and polarization tests.

TA-modified fatty amide coatings showed the highest scratch hardness of 2.5 kg, flexibility (1/8 inch) and gloss at 45° was 60-62. Among all compositions, PFA-TA15 showed the best physico-mechanical and anticorrosion performance. Corrosion tests of coated panels were examined in different corrosive media (3.5 wt per cent HCl, 3.5 wt per cent NaOH and 5.0 wt per cent NaCl) using potentiodynamic polarization and AC impedance measurements. PFA-TA may find application as an eco-friendly protective coating, and thermal analyses revealed that it can be safely used up to 300°C.

This paper provides the development of protective coatings for steel from non-edible seed oil and TA to utilize sustainable resources.

The purpose of this paper is to evaluate the water vapour permeability and mechanical properties of a solventless epoxy – nano‐platelet nano‐composite system compatibilised with an amino‐silane.

The performance of a nano‐platelet reinforced coating composite was studied with reference to the water vapour permeability and mechanical properties. The effect of addition of coupling agent on these properties was also studied.

The addition of nano‐platelets to the solventless epoxy system resulted in an increased water vapour permeability which was reduced on the addition of coupling agent. The talc‐based films showed a better performance as compared to the montmorillonite based coatings. The mechanical properties of the films increased though the addition of coupling agent showed a larger increase. The gloss of the coatings was compromised on addition of nano‐particles. Comparing coupling agents, the primary amine based silane showed better performance and lower tactoid formation as compared to the secondary amino silane based coupling agent.

The addition of nano‐particles to solventless and other eco‐friendly coatings needs to be studied further. Various other coupling agents could be studied to further improve the performance of these coatings.

The formulation developed could be used to reduce the water vapour permeability and performance of solventless epoxy coatings, which could be used as anti‐corrosive coatings.

The study of performance of nano‐particles in solventless epoxy coatings and their effect on water vapour permeability could increase performance of these reduced VOC coatings.