Journal of Engineering Sciences / Журнал інженерних наук
Permanent URI for this collectionhttps://devessuir.sumdu.edu.ua/handle/123456789/34326
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Item Comparative study of rheological properties of polyvinyl alcohol and polyethylene glycol(Sumy State University, 2021) Javanbakht, T.Hydrogels are promising biomaterials for diverse applications that require studying their rheological properties. While some properties of hydrogels have been investigated, their comparative analysis for a deeper understanding of their rheological properties is required to determine their mechanical behavior. Polyvinyl alcohol (PVA) and polyethylene glycol (PEG) are among the hydrogels with diverse applications in engineering. This study aims to provide comparative data on their rheological properties. Both PVA and PEG showed steady shear viscosity as their viscosity did not show a huge change with time. Their shear viscosity increased with shear strain. PEG showed more shear thickening behavior than PVA. While the shear viscosity of PVA reached a plateau, that of PEG continued to increase. This was attributed to the sensitivity of PEG to its deformation because of the junction separations after the application of mechanical force on the polymer. Furthermore, the slow increase in the shear viscosity of both polymers was observed with the increase of the shear rate. This increase was 2.4 % for PVA and 8.7 % PEG, respectively. As these polymers are among the candidates for the preparation of nanocomposites, the results of this study can provide the required information for their applications in engineering.Item Rheological properties of superparamagnetic iron oxide nanoparticles(Sumy State University, 2021) Javanbakht, T.; Laurent, S.; Stanicki, D.; Salzmann, I.The present study focuses on the rheological properties of polyethylene glycol (PEG) modified, positively charged, and negatively charged superparamagnetic iron oxide nanoparticles (SPIONs) at different temperatures. We hypothesized that the surface properties of these nanoparticles in the water did not affect their rheological properties. These nanoparticles had not the same surface properties as SPIONs-PEG had not to charge on their surface whereas positively charged and negatively charged ones with amine and carboxyl groups as their surfaces had positive and negative surface charges, respectively. However, their rheological behaviors were not different from each other. The comparative rheological study of SPIONs revealed their pseudo-Newtonian behavior. The viscosity of SPIONs decreased with the increase in temperature. At low shear rates, the shear stress of SPIONs was independent of rate and increased with the increase of rate. Moreover, at high shear rates, the shear stress for PEG-SPIONs was more than those for positively charged and negatively charged SPIONs. These measurements also revealed that at high shear rates, the shear stress of samples decreased with the increase of temperature. The shear stress of samples decreased with the increase of shear strain and the temperature. We also observed that all the samples had the same amount of shear strain at each shear stress, which indicated the exact resistance of SPIONs to deformation. Furthermore, the shear modulus decreased with time for these nanoparticles. These results suggest that these nanoparticles are promising candidates with appropriate properties for fluid processing applications and drug vectors in biomedical applications.