F-KCW-Department Publications
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Item DESIGNING A CORROSION RESISTANCE SYSTEM USING MODIFIED GRAPHENE OXIDE-EPOXY MICROCAPSULES FOR ENHANCING THE ADHESION STRENGTH OF THE EPOXY COATINGS(Elsevier B.V, 2022-06-20) Priyanka D; Nalini DNew microencapsulated material with advanced corrosion resistance activity and superior adhesion strength on the steel sample was synthesized by in-situ polymerization. In this process, urea-formaldehyde was used as capsule shell material for encapsulating modified graphene oxide. The formation of microcapsules was effectively evidenced by FT-IR, SEM, and TGA-DSC analyses. Initially, graphene oxide was modified by the adsorption of Catharanthus roseus L. (C.R) leaves extract and characterized by FT-IR, SEM, EDX, and DFT studies. GO-C.R and UF-GO-C.R (microcapsules) were separately impregnated into epoxy resin and fabricated on the steel substrates. The anti-corrosion performance of UF-GO-C.R/Epoxy in comparison with neat GO-C.R/Epoxy coated sample was evaluated by electrochemical impedance spectroscopy (EIS) and salt spray test. Results reveal that UF-GO-C.R microcapsules in epoxy matrix showed the protection efficiency of 83.6 % after the immersion period of 7 days in 3.5 % NaCl solution which was relatively higher than those with neat GO-C.R. In addition, the coating loaded with UF-GO-C.R microcapsules showed improvement in the adhesion of epoxy coatings on the steel surface which was evident from the increase in peel strength (290 N) through peel-off adhesion test.Item AN AMINO ACID GRAFTED GRAPHENE OXIDE AS PROMISING MATERIAL IN POLY(UREA-FORMALDEHYDE)-EPOXY MICROCAPSULES FOR ENHANCING THE INTERFACIAL ADHESION OF EPOXY COATINGS(Asian Journal of Chemistry, 2023-02-27) Priyanka D; Nalini DNovel microencapsulated materials with superior anti-corrosion properties and improved adhesive strength on the metal substrate wereproduced by emulsion polymerization and characterized successfully. Initially, serine grafted graphene oxide was prepared and characterizedthrough various sophisticated techniques. Then, MC-GO/epoxy and MC-GO-Ser were individually impregnated into th epoxy systemand applied on the mild steel substrates. Corrosion tests were performed to evaluate the non-corrosive nature of MC-GO/epoxy and MC-GO-Ser/epoxy samples. After 7 days of exposure in saline media, MC-GO-Ser microcapsules demonstrated 80.6 % protective efficiency.Furthermore, the peel strength of 2.90 N revealed that the coating loaded with MC-GO-Ser microcapsules had improved adherence to themild steel surface. Results of urea-formaldehyde GO-Ser microcapsules showed better corrosion protection and greater adhesive strength,which is probably because of the exceptional barrier action of microcapsules against the incursion of corrosion solution onto the mild steelsurfaceItem CHEMINFORMATIC SCRUTINY OF SOME HETEROCYCLIC COMPOUNDS FOR THEIR CORROSION PROTECTIVE CAPABILITY(International Journal of Corrosion and Scale Inhibition, 2021-12-27) Ramkumar S; Nalini D; Priyanka D; Qurashi M A; Chauhan D SOver the last two decades, molecular modellings are capable of accurately predicting structures, energetics, reactivity, and other properties of molecules. Computational chemistry plays an important role in enabling chemists to: (i) explain and rationalize known chemistry of corrosion inhibitors and (ii) explore new or unknown chemicals applicable as corrosion inhibitors. In contrast to the traditional techniques of identifying and synthesizing new corrosion inhibitors in the wet lab, a prior dry-lab process is suggested by using cheminformatics tools. Once a correlation between the structure and activity or property is found, any number of compounds can be readily screened employing computational methodology. In the present work, the inhibitive performance of three important classes of heterocyclic compounds namely dithiazolidine, thioamidine, and thiourea derivatives have been calculated using quantum chemical methods. The three selected heterocyclic series contains nitrogen and sulphur in their chemical framework that were expected to be the main electron rich centres which act as the adsorption sites on the metal surface. The presence of aromatic ring together with electron donating substituents such as methyl and methoxy were found to enhance the adsorption characteristics of the studied heterocyclic systems. The global reactivity parameters and the local selectivity adsorption centres in each of the studied system were analyzed using theoretical parametersItem GLYCERAL TRINITRATE: AS POTENTIAL CORROSION PROTECTOR FOR MILD STEEL IN ACID MEDIUM ALONG WITH PAINT-COATED STEEL IN A SALINE ENVIRONMENT(Oriental Journal of Chemistry, 2021-12-21) Menaga M; Sowmya, Ramkumar; Nalini DThe importance of mild steel lies in its industrial applications, and the fight against corrosion is very important from an ecological, economic, technical, and aesthetic view. The current study involves the use of pharmaceutical drugs namely GTN towards corrosion inhibiting reaction was examined by gravimetric and electrochemical approaches. From weight loss studies, maximum I.E (%) 94.04% reached for 60 mg/L concentration of GTN for 6 hrs immersion time. The Polarization measurements showed that the behaviour of GTN as mixed nature and surface assimilation of GTN at the superficial, such that water molecules are substituted at the solution-metal boundary. The corrosion resistance property of the studied inhibitor as coating was also evaluated in NaCl which shows better progress corrosion retardation property of coating in the saline medium. Theoretical calculations were employed using DFT to correlate with the experimental observations.Item EXPERIMENTAL RESULTS WITH HYPOTHETICAL EVIDENCES FOR BEXOL AS AN EFFECTIVE INHIBITOR ON CORROSION INHIBITION OF MILD STEEL IN ACIDIC ENVIRONMENT AND ITS EPOXY COATING BEHAVIOR(Oriental Journal of Chemistry, 2020-06-03) Menaga M; Nalini D; Sowmya, RamkumarThe inhibitive ability against mild steel corrosion of pharmacologically active compound Bexol towards acid was valued by gravimetric experiments and electrochemical experiments. The results of the weight loss studies indicated inhibition efficiency was boosted with increased concentration of Bexol from 5 mg/L to 45 mg/L in the acid environment. Potentiodynamic polarization behaviour of the metal specimen in presence of Bexol exposed the mixed style inhibitive action. EIS results established that Bexol adsorb at the metal/acid junction by mere electrostatic physical adsorption mechanism to inhibit the corrosion process. Epoxy coated mild steel without and with the studied bexol was used for electrochemical studies in 3.5% of NaCl for different time intervals. The Density Functional -theory was employed to scrutinize inhibition property of the considered inhibitor. Experimental measurement obtained shows perfect fit to the theoretical calculationsItem GLYCERAL TRINITRATE: AS POTENTIAL CORROSION PROTECTOR FOR MILD STEEL IN ACID MEDIUM ALONG WITH PAINT-COATED STEEL IN A SALINE ENVIRONMENT(An International Open Access, 2021-12-21) Menaga M; Sowmya, Ramkumar; Nalini DThe importance of mild steel lies in its industrial applications, and the fight against corrosion is very important from an ecological, economic, technical, and aesthetic view. The current study involves the use of pharmaceutical drugs namely GTN towards corrosion inhibiting reaction was examined by gravimetric and electrochemical approaches. From weight loss studies, maximum I. E (%) 94.04% reached for 60 mg/L concentration of GTN for 6 h immersion time. The Polarization measurements showed that the behaviour of GTN as mixed nature and surface assimilation of GTN at the superficial, such that water molecules are substituted at the solution-metal boundary. The corrosion resistance property of the studied inhibitor as coating was also evaluated in NaCl which shows better progress corrosion retardation property of coating in the saline medium. Theoretical calculations were employed using DFT to correlate with the experimental observations.Item DESIGNING A CORROSION RESISTANCE SYSTEM USING MODIFIED GRAPHENE OXIDE-EPOXY MICROCAPSULES FOR ENHANCING THE ADHESION STRENGTH OF THE EPOXY COATINGS(Elsevier, 2022-08-10) Priyanka D; Nalini DNew microencapsulated material with advanced corrosion resistance activity and superior adhesion strength on the steel sample was synthesized by in-situ polymerization. In this process, urea-formaldehyde was used as capsule shell material for encapsulating modified graphene oxide. The formation of microcapsules was effectively evidenced by FT-IR, SEM, and TGA-DSC analyses. Initially, graphene oxide was modified by the adsorption of Catharanthus roseus L. (C.R) leaves extract and characterized by FT-IR, SEM, EDX, and DFT studies. GO-C.R and UF-GO-C.R (microcapsules) were separately impregnated into epoxy resin and fabricated on the steel substrates. The anti-corrosion performance of UF-GO-C.R/Epoxy in comparison with neat GO-C.R/Epoxy coated sample was evaluated by electrochemical impedance spectroscopy (EIS) and salt spray test. Results reveal that UF-GO-C.R microcapsules in epoxy matrix showed the protection efficiency of 83.6 % after the immersion period of 7 days in 3.5 % NaCl solution which was relatively higher than those with neat GO-C.R. In addition, the coating loaded with UF-GO-C.R microcapsules showed improvement in the adhesion of epoxy coatings on the steel surface which was evident from the increase in peel strength (290 N) through peel-off adhesion test.Item GRAPHENE OXIDE INTEGRATED INTO PROTECTIVE COATINGS AGAINST CORROSION FOR METALS AND ITS ALLOYS: A REVIEW(International Journal Corros. Scale Inhib, 2022-04-02) Priyanka D; Vinuchakravarthi S; Nalini D; Quraishi M.A; Chauhan D.SThis review aims to discuss the effect of graphene oxide (GO) derivatives incorporated protective coatings on various metals against corrosion process in alkaline environments. These coatings increased hydrophobic character and adhesion strength between the coating and metal surface. Electrochemical measurements were used more often among all other techniques to investigate the effect of inhibitor in the polymer matrix (epoxy/silane sol). In some cases, the highest inhibition efficiency was achieved by electrochemically coating GO derivatives on the metal surface. GO derivatives prepared via the adsorption of Pr3+, Ce3+ ,and Zn2+ ions have revealed a good inhibition tendency for metals in acidic solution because of the exchange of Pr3+, Ce3+, and Zn2+ with those ions (Na+, Cl–) in the corrosion electrolyte.Further, because of the adsorption of polar groups on GO onto the surface of metals, the hydrophobicity achieved by modified GO coating limits the infiltration of corrosive ions and enhances inhibitory efficiency. And, scratches were foreseen during the manufacturing of coatings on metallic substrates, and this harms the organic coatings. The defect created by impurities developed coatings deterioration that was prone to the diffusion of corrosive substances, severely reducing the coatings’ lifespan. Grafting graphene oxide with various functional groups was used to achieve self-healing behavior in organic coatings. At the defective site of the metallic substrates, self-healing by functionalized graphene oxide created dense protective coatings.Item AN AMINO ACID GRAFTED GRAPHENE OXIDE AS PROMISING MATERIAL IN POLY(UREA-FORMALDEHYDE)EPOXY MICROCAPSULES FOR ENHANCING THE INTERFACIAL ADHESION OF EPOXY COATINGS(Asian Journal of Chemistry, 2023) Priyanka D; Nalini DNovel microencapsulated materials with superior anti-corrosion properties and improved adhesive strength on the metal substrate were produced by emulsion polymerization and characterized successfully. Initially, serine grafted graphene oxide was prepared and characterized through various sophisticated techniques. Then, MC-GO/epoxy and MC-GO-Ser were individually impregnated into th epoxy system and applied on the mild steel substrates. Corrosion tests were performed to evaluate the non-corrosive nature of MC-GO/epoxy and MC-GO-Ser/epoxy samples. After 7 days of exposure in saline media, MC-GO-Ser microcapsules demonstrated 80.6 % protective efficiency. Furthermore, the peel strength of 2.90 N revealed that the coating loaded with MC-GO-Ser microcapsules had improved adherence to the mild steel surface. Results of urea-formaldehyde GO-Ser microcapsules showed better corrosion protection and greater adhesive strength, which is probably because of the exceptional barrier action of microcapsules against the incursion of corrosion solution onto the mild steel surface.Item ENHANCING THE ANTI-CORROSION AND REINFORCING PROPERTIES OF EPOXY COATINGS USING MODIFIED GRAPHENE OXIDE(Oriental Scientific Publishing Company, 2022-08-18) Thamaraiselvi N; Nalini DThe present study deals with the synthesis and anticorrosion behavior of new modified graphene oxide. Superior corrosion resistance property was exhibited by graphene oxide and modified graphene oxide on mild steel and copper substrates. Along with the corrosion resistance behavior, the reinforcing nature of epoxy coating also improved. Graphene oxide was synthesized by Hummer’s method. Graphene oxide (GO) modified with ethanol extract of Kedrostis foetidissima (KF) plant leaves. Gas chromatography-mass spectrometry (GCMS) analysis was selected to identify the chemical constituents present in the plant. GO, KF, and modified GO (GO-KF) were characterized by Fourier transforms infrared spectroscopy (FTIR) and Field Emission Scanning Electron Microscope (FESEM). Corrosion protection behavior of epoxy coating on mild steel and copper with GO and modified Graphene Oxide were studied using, Salt spray test, Peel test, and Contact angle measurements. Results revealed that the modified GO sheets act as a good reinforcing agent for epoxy coating on mild steel and copper substrate in a 3.5% sodium chloride (NaCl) environment.