Scaling of Structural Characteristics of Gelled Model Waxy Oils

The structural properties of gelled model waxy oils with different wax concentrations (5–20 wt %) were investigated through a differential scanning calorimetry (DSC) test, rheological measurement, and scaling model for colloidal gels. The wax precipitation curves obtained from the DSC test show that the concentration of precipitated wax crystals φW increases gradually with the decrease of the temperature, and most of the waxes dissolved in the oil phase precipitate at −20 °C. The gelation point increases gradually with an increasing wax concentration from 22 °C at 5 wt % to 26 °C at 10 wt %, then to 32 °C at 15 wt %, and 34 °C at 20 wt %. The structure of gelled waxy oils, similar to the structure of colloidal gels, transits from a strong-link regime to a weak-link regime with the increase of φW, and the value of φW at the transition point is around 1.8 wt % for all of the tested model waxy oils. In the strong-link region, G′E increases while γE decreases with an increasing φW. In the weak-link region, both G′E and γE increase with an increasing φW. The ln G′E ∼ ln φW and ln γE ∼ ln φW relations can be divided into three parts at wax concentrations of ≤10 wt %; at wax concentrations of 15–20 wt %, the relations can be divided into two parts. In the strong-link region, the fractal dimension D of gelled waxy oil was calculated through parameters A and B. In the weak-link region, the fractal dimension D was calculated through parameter B because of the good linear relationship between ln γE and ln φW. The fractal dimension D increases from very small values (less than 1) to high values (approaching 3) with an increasing φW, indicating the continuous development of the microstructure of the gelled waxy oils with an increasing φW.