Abstract
In industrial crystallization, control of crystal morphologies becomes a very important subject. For organic compounds, each face has a different growth mechanism and a growth rate because they have different orientation of molecules. Therefore, growth rates of particular faces are controlled by noncrystallizing components. However morphology control by noncrystallizing components were not enough to be understood. This paper described the influence of p-CNB on the m-CNB crystal as relationships between the additive concentration and the supercooling, and the dynamic behavior of the crystal morphology when the supercooling was stepwise changed. The m-CNB crystal has the round face on +z direction under the presence of p-CNB. Form the experimental results the crystal morphology depended on not only the additive concentration but also the supercooling. When the supercooling was changed from the condition that the rounded face appeared to the condition that it did not appear, the rounded face disappeared slowly and there was a time period that the maximum length of +z direction was not changed. The driving force of the crystals growth was used for the repair of the rough face. In the region that the rounded face appeared, it was observed that the maximum length of +z direction decreased temporarily after the change of supercooling. From these results, new knowledge of the influence of noncrystallizing component on crystal morphology was obtained.
