Absolute Viscosities of Vegetable Oils at Different Temperatures and Shear Rate Range of 64.5 to 4835 s⁻¹

Abstract

A study was carried out to determine the effect of higher shear rates (64.5 to 4835 s −1 ) on the absolute viscosities of different vegetable oils at different temperatures (26 to 90 ∘ C). The absolute viscosities of the different vegetable oils were determined using a Lamy Viscometer RM100, a rotating viscometer with coaxial cylinder. The torque of each sample at different temperatures was recorded at different shear rates. Based on the rheograms (plot of mean shear stress against shear rate), all of the vegetable oils studied were found to be Newtonian fluids. Rice bran oil was the most viscous (0.0398 Pa⋅s at 38 ∘ C) while walnut oil was the least viscous (0.0296 Pa⋅s at 38 ∘ C) among the oils studied. The higher shear range used did not significantly affect the absolute viscosities of the vegetable oils at the different temperatures. The absolute viscosities of the vegetable oils decreased with increasing temperature and can be fitted with an Arrhenius type relationship. The activation energies for the different vegetable oils ranged from 21 to 30 kJ/mole. The peanut and safflower oils had the highest and lowest activation energies, respectively. This means that greater energy was needed to effect a viscosity change in the peanut oil.

Comparison of selected vegetable oils rheologic properties

“…For temperature dependencies of rheologic properties were used exponential functions, which is in accordance with Arrhenius equation (1). Similar results were obtained also by other authors (Diamante and Lan, 2014;Thomas et al, 2015).…”

“…The progress can be described by decreasing exponential function, which is in accordance with Arrhenius equation (1). Similar conclusions were made by authors Diamante and Lan (2014) and Thomas et al (2015). Regression coefficients and coefficients of determination are shown in Tab.…”

Physicochemical Properties and Structural Characterisation of Fatty Acids Derived from Jatropha curcas Oil Using Microwave Assisted Alkaline Hydrolysis

“…According to Diamante and Lan, liquid viscosity is amongst the important characteristics because it will determine the quality of the fatty acids. 12 In Table 1, it can be seen that the viscosity of synthesised fatty acids is 16.79 mPa.s and this value is in agreement with the data range reported by Noureddini et al (17.7 mPa·s). 13 Nevertheless, the viscosity of commerial fatty acids shows a slightly higher value as compared to the synthesised fatty acids in this study.…”

Studies on the Biolubricant Properties of Moringa Oleifera Seed Oil: Correlating Viscosity and Fatty Acid Composition

“…The M. oleifera oil had a viscosity of 0.06078 Pas at 30 o C. This is in the range of viscosities of vegetable oils like canola, rapeseed and sunflower applied as biolubricants (Fasina & Colley, 2008;Diamante & Lan, 2014). This viscosity is higher than 4.5 x 10 -2 Pas reported for D.…”