Effect of Magnesium Oxide Nanoparticles on Rheological and Volumetric Properties of Solutions Containing Polyethylene Glycol

Polyethylene glycols, PEGs, with molar masses of 2000 and 6000 g/mol were dissolved in PEG with a molar mass of 400 g/mol to prepare the homogeneous solutions. Rheological properties and density values for these solutions have been measured. Nanoparticles of MgO were added to these solutions and dispersed by an ultrasonic bath for making homogeneous nanofluids. The UV-Vis spectroscopy, zeta potential, and dynamic light scattering have been used to specify the stability and particle size distribution of colloidal solutions studied. Density values of prepared nanofluids have been measured at different temperatures. The excess molar volumes were calculated from density data for highlighting the interparticle interactions occurred in nanofluids. Polynomial equation and Singh et al. model were used for fitting the excess molar volume values of binary and ternary systems, respectively. Fluid flow and suspense structure of MgO nanoparticles in solutions of PEG400, PEG400-PEG2000, and PEG400-PEG6000 were studied by measuring the rheological properties at T=298.15 K. Bingham plastic and Herschel-Bulkley equations have been used for modeling the dependence of shear stress on shear rate. Carreau-Yasuda model has also been modified for modeling the viscosity values.