No abstract

The ultrasonic velocity, density and viscosity in mixtures of sorbitan sesquioleate and poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG) in different concentration ranges are measured at different temperatures (303, 313 and 323 K). From the experimental data, other related acoustical parameters such as adiabatic compressibility (β), intermolecular free length (Lf), internal pressure (πi), Rao’s constant (Ra), relaxation time (τ), acoustical impedance (Za), absorption coefficient (α/f2), free volume (Vf), cohesive energy (CE) and solvation number (Sn) have been evaluated. In aqueous solutions, surfactant molecule starts to aggregate and form micelle in concentration called as critical micelle concentration (CMC). It is one of the most important physical parameters of the surfactants. These results were interpreted in terms of surfactantpolymer complex reactions. The combinations of surfactant with polymers improve the desired properties of the product and the formation of complex was confirmed by UV and FTIR studies.

Corrosion inhibition by new triazole derivatives, 2-phosphonoacetic acid (2-PAA) and Zn 2+ on mild steel in aqueous media has been investigated by weight loss and potentiodynamic polarization, electrochemical impedance spectroscopy and atomic absorption spectroscopic methods. The results indicate that these compounds act as mixed-type inhibitors retarding the anodic and cathodic corrosion reactions. Combination of 1-(2-pyrrolecarbonyl)benzotriazole along with Zn 2+ and 2-phosphonoacetic acid shows better corrosion inhibition efficiency than other inhibitor combinations and the individual inhibitors.

The inhibition and the effect of temperature and concentration of 3-phosphonopropionic acid (3-PPA) on the corrosion of mild steel in groundwater was investigated by weight loss and potentiodynamic polarization experiments at temperatures ranging from 30 °C to 60 °C. The studied inhibitor concentrations were between 6 ppm to 18 ppm. The percentage inhibition increased with the increase of the concentration of the inhibitor. The percentage inhibition reached about 66.2% at the concentration of 12 ppm at 30 °C. On the other hand the percentage inhibition decreased with the increase of temperature.

The evaluation of various acoustical and thermo dynamical parameters which provide an idea into the nature of molecular interactions in aqueous non-ionic surfactant solutions. The measurement of ultrasonic velocity in aqueous solutions an important tool for the calculation of various acoustical parameters. These parameters have been computed through velocity, density and viscosity measurements of non-ionic surfactants (Saponin, Glucopon and Sorbitan sesquioleate) in aqueous medium. This above work was done for different concentration ranges at three different temperatures 303, 313 and 323K using Ultrasonic interferometer. The Critical Micelle Concentration (CMC) was determined to be 1.0% of Water-Saponin, Water -Glucopon, 0.8% of Water -Sorbitan sesquioleate system. These samples were characterised by UV studies.