Proposição de um fluido não-newtoniano com comportamento shear-thickening visando aplicações na área de polimento

Abstract

Non-Newtonian fluids, specifically those exhibiting shear-thickening behavior, are a class of materials with specific properties and diverse applications, which are slowly beginning to be explored in contemporary times. This work aims to propose a new dilatant and address one of its specific applications, related to the polishing process, through a method known as Shear-Thickening Polishing. The project initially proposed the development of a shear-thickening fluid in two situations: (i) a starch and water suspension, a fluid well-known in the literature for exhibiting this behavior, and (ii) a fluid of sodium clay particles dispersed in polyethylene glycol. Rheological viscosity analyses, in controlled shear rate mode, and thixotropic analyses were performed to verify the existence of the shear-thickening phenomenon in the produced suspensions. The polishing process was performed manually using two suspensions of the best-known dilatant fluid (corn starch and water), and its analysis was done visually, which proved ineffective. Synthesis by the coprecipitation method produced micrometric particles of cerium trioxide with distinct morphologies (tubular and plate-like), the presence of agglomerates, and some morphologies resembling a rectangular and slender geometry. The use of clays (sodium and kaolinite) resulted in fluids with shear-thickening behavior, while, from the corn starch suspensions, it was possible to verify the presence of shear-thickening behavior, along with the two known transition types for this behavior. Finally, manual polishing with corn starch suspensions did not produce visual results.