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To study the effect of pigmentation on mechanical and anticorrosive properties of thermally sprayable ethylene vinyl acetate (EVA)/polyethylene (PE) and ethylene vinyl alcohol (EVAl)/PE coatings, red iron oxide (RIO) and titanium dioxide (TiO 2 ) pigments at varying concentration (10, 20 and 30%) were mixed using internal mixer. Pigmented compositions were characterized for mechanical properties and water vapor transmission rate (WVTR). These compositions were applied on grit blasted mild steel surface by flame spray technique and coated specimens were evaluated for adhesion strength, abrasion resistance and resistance to corrosion by exposing them in different environments. The corrosion resistance of pigmented composition was also studied by electrochemical impedance spectroscopy (EIS) technique.

Application of polymeric coatings is one of the methods for protection of mild steel against corrosion. In the present work, blends of different grades of ethylene vinyl acetate (EVA) with varying vinyl acetate (VAc) content viz. 18%, 28%, 40% and hydrolyzed EVA i.e., ethylene vinyl alcohol (EVAl) with low density polyethylene (PE) have been used as binder for development of anticorrosive coating. The blend compositions were characterized using differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA) and melt flow index (MFI) techniques for determination of melting point, degradation temperature and flow behavior respectively. The blend compositions were applied on grit blasted mild steel specimens by flame spray technique and the coated specimens were evaluated for their resistance to corrosion in salt spray, humidity and seawater. EVA/PE based compositions showed superior resistance to corrosion compared to EVAl/PE based compositions in all exposure conditions after 8 weeks. The corrosion resistance of blend compositions was also studied by electrochemical impedance spectroscopy (EIS) technique. The results indicate that EVA/PE coatings have better resistance to corrosion than EVAl/PE coatings.

Dispersion of nanoclay (NC) in polymer blend system is governed by the sequence of addition of different ingredients. In the present work nanoclay was added in different sequences to blend composition such as ethylene vinyl acetate (EVA)/low density polyethylene (LDPE) and ethylene vinyl alcohol (EVAl)/LDPE in internal mixer to get nanocomposite. It was found that sequential addition of individual polymers and nanoclay influenced mechanical properties of resulting composites. Blending sequence of PE/NC/EVA and PE/NC/EVAl gave best mechanical properties. After optimization of addition sequence, concentration of nanoclay was varied from 1 to 8% by weight in the polymer blend. The resulting composites were evaluated in terms of their mechanical properties, dispersion characteristics (XRD), water vapor transmission rate (WVTR) and water absorption (Wa). Nanocomposite containing EVA/LDPE blend with 4% nanoclay showed optimum properties. The optimized composition was applied on grit blasted mild steel specimens by flame spray technique. The coated specimens were evaluated for adhesion strength, abrasion resistance and resistance to corrosion properties.

Ethylene vinyl acetate (EVA) copolymer with varying vinyl acetate (VAc) content, viz. 18%, 28% and 40% has been hydrolyzed using alcoholic NaOH solution. Fourier Transform Infrared Spectroscopy (FTIR) analyses of hydrolyzed polymer showed the presence of both OH group and acetate group indicating that the EVA has been partially hydrolyzed. Differential Scanning Calorimeter (DSC) and Thermo Gravimetric Analyzer (TGA) of EVA and hydrolyzed EVA showed large difference in melting and decomposition temperature, respectively. Hydrolyzed EVA showed higher tensile strength and elongation at break compared to corresponding EVA. Blends of different grades of EVA and ethylene vinyl alcohol (EVAl) with low density polyethylene (LDPE) were applied on grit blasted mild steel surface by flame spray technique. FTIR analysis of blends before and after coating showed no degradation during flame spray. Measurement of adhesion strength of these coating showed that adhesion strength increased on hydrolysis of EVA.

Application of organic coatings is one of the methods for protection of mild steel against corrosion. In the present work, low-density polyethylene (LDPE) has been used as binder for development of anticorrosive coating. Since non-polar characteristics of LDPE make its adhesion poor to most substrates, polar groups have been introduced in LDPE by grafting maleic acid (MAc) using reactive extrusion method. Grafted LDPE was characterized by chemical method, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), wide angle X-ray scattering (WAXS) and melt flow index (MFI). Grafted LDPE was pigmented with different pigments such as red iron oxide, micaceous iron oxide (MIO), titanium dioxide (TiO2) and aluminium at three concentrations (i.e., 20, 30 and 40%). These compositions were applied on grit blasted mild steel specimen by flame spray technique. The coated specimens were evaluated for adhesion strength and resistance to corrosion in salt spray, humidity and seawater. Red iron oxide-based composition showed better adhesion and corrosion resistance compared to other compositions. Subsequently, corrosion resistance of red iron oxide-based compositions was studied by electrochemical impedance spectroscopy (EIS). The modified LDPE coating containing 30% red iron oxide showed higher resistance to corrosion compared to 20 and 40% red iron oxide-based compositions., © Elsevier

Low density polyethylene (LDPE) coatings are being used in an ever growing range of applications. However, non-polar characteristics of LDPE make its adhesion poor to metal substrate and so become less suitable for anticorrosive coating application. An anticorrosive coating can therefore be developed if LDPE is modified with requisite polar groups. In the present work, a polar group has been introduced in polyethylene matrix by grafting maleic acid. Grafted LDPE was characterized by chemical method, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), melt flow index (MFI), particle size analysis and hot stage optical microscopy. The presence of carbonyl peak of high intensity, high acid value and low melt flow index value confirmed grafting of maleic acid on LDPE. Change in crystallization behaviour of LDPE has been noticed after grafting. Grafted LDPE was applied on grit blasted mild steel surface by flame spray technique and adhesion study showed improved adhesion of grafted LDPE than LDPE. The coated panels were evaluated for resistance to corrosion in salt spray, humidity cabinet and seawater. The corrosion resistance of modified LDPE was also studied by AC Impedance technique. Grafted LDPE showed satisfactory corrosion resistance. Grafted LDPE was pigmented with red iron oxide and pigmented composition has shown improved resistance to corrosion in laboratory tests., © Elsevier

Grafting of maleic acid (MAc) on low density polyethylene (LDPE) was carried out using γ-irradiation technique. Preactivation method was used for grafting and a maximum grafting of 2.4% was obtained. Grafted polymer(LDPE-g-MAc) was characterized by chemical method, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermo-Gravimetric Analysis (TGA), Melt Flow Index (MFI), Tensile Property Measurement, Particle Size Analysis, and Hot Stage Optical Microscopy. Presence of carbonyl peak of high intensity, high acid value, and low melt flow index value confirmed grafting of MAc on LDPE. A marginal change in thermal and mechanical properties of LDPE was observed after grafting. Change in crystallization behavior of LDPE has been noticed after grafting. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2802–2807, 2004

In the present work low density poly ethylene (LDPE) and maleic acid grafted LDPE (LDPE-g-MAc) were pigmented with red iron oxide at three different concentrations (i.e., 20, 30 and 40 wt%). The pigmented compositions were prepared in extruder and then cryogenically grounded to bring them in powder form. These compositions were applied on grit blasted mild steel specimen by flame spray technique. Corrosion resistance of red iron oxide based compositions was studied by electrochemical impedance spectroscopy (EIS). The grafted LDPE containing 30 wt% red iron oxide showed maximum resistance to corrosion compared to 20 and 40 wt% red iron oxide based compositions.