Crystallization Behavior and Morphology Observation
DSC thermal analysis was performed on the biodiesel using a TA Q2000 differential scanning calorimeter (TA Instruments, USA) in the range of 20 to -60 °C at a rate of 5.00 °C/min. Repeat the measurement three times and take the average to reduce the error.
To directly observes the wax crystal formation process, a photomicrograph analysis method can be used. A polarizing optical microscope DM2500 P (Leica Germany) was used to record the wax crystallization behavior of the samples at a temperature decrease rate of 1 °C/min. Micrographs of all samples were obtained at 100 times magnification.
The rheological properties of the samples from 30 °C to -60 °C were determined by a HAAKE MARS III rheometer (Germany) at a constant shear rate of 5 s-1.