Growth Rate of Pressure-Induced Triolein Crystals

Abstract

In pressure-induced crystal growth of triolein from melt at pressures up to 300 MPa and at temperatures between 283.16 and 293.16 K, we can distinguish three different crystal morphologies. Raman spectroscopy indicates that they are related to different polymorphic structures. Switching from the most stable to a less-stable structure implies a jump in the growth rate to a maximum value. As pressure increases, the growth rate decreases indicating that the growth is transport limited. Measurements at different temperatures show that the growth rate is mainly governed by pressure. In a certain parameter range, we observe cross-nucleation to crystals with a higher growth rate. These crystals have a Raman fingerprint not yet described in the literature.