Glycogen nanoparticles as a potential corrosion inhibitor.

Biological macromolecules are proven to be potential green corrosion inhibitors because of their outstanding structural features and eco-friendliness. This study is aimed at enhancing their corrosion mitigation capabilities by converting them into nanoparticles. This is the first work where nanoparticles of biological macromolecules are exploited for corrosion mitigation studies. Glycogen nanoparticles (GLY-Np) were synthesized by microwave-mediated nanoprecipitation method and characterized by ATR-FTIR, XRD, UV-Visible Spectroscopy, FESEM analysis, EDX, TEM, and Zeta potential measurements. They are used as an eco-friendly inhibitor for corrosion control of zinc in sulfamic acid (NH2SO3H). The electrochemical study was a primary experimental tool employed for corrosion rate measurement. Conditions were optimized to obtain maximum inhibition efficiency by varying concentrations of inhibitor and temperature. Activation and thermodynamic parameters were evaluated and discussed in detail. A suitable adsorption isotherm was proposed to fit the experimental results. Adsorption of the inhibitor was confirmed by SEM, EDX, and AFM techniques. The inhibition efficiency of 92% was obtained for 0.02 gL-1 GLY-Np. Thus, GLY-Np turned out to be an effective green inhibition with economic benefits.

Maltodextrin for corrosion mitigation of zinc in sulfamic acid: Electrochemical, surface and spectroscopic studies.

Maltodextrin (MLD), a biopolymer was introduced as a novel green inhibitor to mitigate the corrosion of zinc in sulfamic acid medium by weight loss and by electrochemical methods. Conditions were optimized to obtain maximum inhibition efficiency. Thermodynamic parameters were evaluated. The surface morphology was studied by SEM, EDX, AFM analysis. Adsorption of inhibitor was re-affirmed by FT-IR spectroscopy, Atomic absorption spectroscopy (AAS), Raman spectroscopy and powder X-ray diffraction (XRD) analysis. Maximum efficiency of 72% was observed for the addition of 400 ppm of MLD. Surface morphology and spectroscopic studies confirmed the adsorption of MLD onto the surface of zinc. Results obtained by classical and electrochemical methods are in good agreement with one another. Maltodextrin emerged as an effective eco -friendly green inhibitor.

Pullulan as a potent green inhibitor for corrosion mitigation of aluminum composite: Electrochemical and surface studies.

This work emphasizes the corrosion inhibition ability of pullulan, an environmentally benign fungal polysaccharide on acid corrosion of 6061Aluminum-15%(v) SiC(P) composite material (Al-CM). The electrochemical measurements such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) studies were carried out for the corrosion inhibition studies. Conditions were optimized to obtain maximum inhibition efficiency, by performing the experiment at varying concentrations of inhibitor, in the temperature range of 308K- 323K. Surface morphology studies were done to reaffirm the adsorption of inhibitor on the surface of composite material. Pullulan acted as mixed type of inhibitor with a maximum efficiency of 89% at 303K for the addition of 1.0 gL-1 of inhibitor. Evaluation of kinetic and thermodynamic parameters revealed that inhibitor underwent physical adsorption onto the surface of Al-CM and obeyed Freundlich adsorption isotherm. The surface characterization like SEM-EDX, AFM confirmed the adsorption of pullulan molecule. Pullulan can be considered as effective, eco friendly green inhibitor for the corrosion control of Al-CM.

Carbohydrate biopolymer for corrosion control of 6061 Al-alloy and 6061Aluminum-15%(v) SiC(P) composite-Green approach.

The acid corrosion control of 6061Aluminum alloy and 6061Al-15%(v) SiC(P) composite material (Al-CM) was carried by using inulin - a carbohydrate polymer as a green inhibitor. Potentiodynamic polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) techniques were adopted. Concentration of inulin was in the range of 0.2gL-1-1.0gL-1, and studies were done in the temperature range of 303-323K. The adsorption of inhibitor on the surface of Al alloy and Al-CM was confirmed by physical techniques such as Scanning electron microscopy (SEM), energy-dispersive X-Ray analysis (EDX), and atomic force microscopy (AFM) analysis. The studies showed that inhibition efficiency of inhibitor increased with increase in concentrations of inulin and decreased with increase in temperature. The adsorption of inulin on metal surface obeyed Langmuir adsorption isotherm through physical adsorption on both alloy and on Al-CM. Results obtained from potentiodynamic polarization method and electrochemical impedance spectroscopic methods were in good agreement with one another.

In vitro evaluation of cytotoxicity and corrosion behavior of commercially pure titanium and Ti-6Al-4V alloy for dental implants.

PURPOSE: The aim of this study was to investigate the cytotoxicity in human gingival fibroblast by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and corrosion behavior by potentiodynamic polarization technique of commercially pure titanium (Ti 12) and its alloy Ti-6Al-4V (Ti 31). MATERIALS AND METHODS: In the present in vitro study, cytotoxicity of Ti 12 and Ti 31 in human gingival fibroblast by MTT assay and the corrosion behavior by potentiodynamic polarization technique in aqueous solutions of 0.1 N NaCl, 0.1 N KCl, and artificial saliva with and without NaF were studied. RESULTS: The independent t-test within materials and paired t-test with time interval showed higher cell viability for Ti 12 compared to Ti 31. Over a period, cell viability found to stabilize in both Ti 12 and Ti 31. The effects of ions of Ti and alloying elements aluminum and vanadium on the cell viability were found with incubation period of cells on samples to 72 h. The electrochemical behavior of Ti 12 and Ti 31 in different experimental solutions showed a general tendency for the immersion potential to shift steadily toward nobler values indicated formation of TiO2 and additional metal oxides. The multiphase alloy Ti-6Al-4V showed more surface pitting. CONCLUSION: The commercially pure Ti showed better cell viability compared to Ti 31. Less cell viability in Ti 31 is because of the presence of aluminum and vanadium. A significant decrease in cytotoxicity due to the formation of TiO2 over a period of time was observed both in Ti 12 and Ti 31. The electrochemical behavior of Ti 12 and Ti 31 in different experimental solutions showed a general tendency for the immersion potential to shift steadily toward nobler values indicated formation of TiO2 and additional metal oxides. Ti 31 alloy showed surface pitting because of its multiphase structure.