Comparison of selected vegetable oils rheologic properties

The article is focused on measuring and comparison of rheologic parameters of selected vegetable oils. Determined were these properties: density, dynamic, kinematic viscosity and fluidity. Measurements were performed in approximate temperature range (5 - 32) °C on two samples of vegetable oils: sunflower oil and olive oil. Density of vegetable oils was determined by oscillation method using digital densimeter Anton Paar DMA 4500 M at different temperatures. For dynamic viscosity measurement was used rotational viscometer Anton Paar DV-3P, which principle is based on dependency of sample resistance against the probe rotation. Other rheologic parameters as kinematic viscosity and fluidity were determined according to the definitions. Results of measurements are shown as graphical dependencies of rheologic parameters to the temperature. Temperature dependencies of vegetable oils dynamic and kinematic viscosity had decreasing exponential shape which is in accordance with Arrhenius equation and temperature dependencies of fluidity had an increasing exponential shape for both samples. Dependencies of samples density on temperature were characterized by decreasing linear function in measured temperature range. Similar results were obtained by other authors. From measured values can be seen that dynamic viscosity of olive oil is higher than viscosity of sunflower oil. This proportion is caused by different composition of oils.