The effect of STFs formed with different dispersing mediums on rheological properties

This article presents a study on the rheological behavior of shear thickening fluids (STF) produced with various dispersing mediums selected according to their molecular weight, number of hydroxyl groups, branching and chain length. STF is non-Newtonian fluid behavior in which the increase in the viscosity increases with the applied shear rate. Polyethylene glycol 200, polyethylene glycol 400, 1,2-propanediol, tetraethyl orthosilicate, monoethanolamine, glycerin and diethylene glycol were used as the dispersing mediums. The steady-state rheological properties of STFs were investigated. After the rheological test, STF produced with glycerin with a concentration of 27.5% by weight gave better rheological results than STFs produced with other liquids. Although glycerin has a relatively low molecular weight, it appears that the rheological properties of glycerin are better because the STF produced with glycerin has three hydroxyl groups (3 OH−) in its structure. The critical shear rate of STF at 27.5% concentration by weight produced with glycerin is 2.39 1/s, and the peak viscosity is 732.4 Pa·s. Additionally, the weight concentration effect was also investigated. STFs were produced with polyethylene glycol 400 and 1,2-propanediol liquids at concentrations of 20%, 22.5%, 25% and 27.5% by weight. When the rheological properties of these STFs were examined, it was seen that the rheological properties improved as the concentration amount increased. For this reason, it may not be sufficient to consider only the molecular weight when choosing the dispersing medium during STF production. In addition to the molecular weight, it is necessary to consider the number of hydroxyl groups, branching and the chain length. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.