Kinetics of Isothermal Crystallization of Hydrogenated Castor Oil-In-Water Emulsions

Wednesday, November 10, 2010: 4:35 PM
250 F Room (Salt Palace Convention Center)
Dingzheng Yang, Chemical Engineering, McMaster University, Hamilton, ON, Canada and Andrew N. Hrymak, McMaster University, Hamilton, ON, Canada

Kinetics of isothermal crystallization of hydrogenated castor oil-in-water emulsions has been studied by differential scanning calorimetry with the temperature range from 55C to 70C. Polarized microscopy study showed that rosettes and fibers are the only two morphologies and kinetics of mixed morphology has been studied. Small and wide angle x-ray diffraction showed that the polymorphism does not change at this temperature range. Crystal growth rate has been obtained by microscopy method showing both fibers and rosettes grow linearly. The growth rate of rosettes at 55C, 1.03 microns per minute, is higher than that at 70C, 0.78 microns per minute, indicating higher supercooling provides larger driving force to crystal growth. Avrami model which has been widely used in kinetics study of triglyceride systems was employed to fit experimental results at different isothermal temperatures. It is found that through modification by introducing the volume fraction of each type of morphology into three dimensional and one dimensional Avrami equation, experimental results have been fitted well.

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