Phase Transition and Polymorphic Behavior of Binary Systems Containing Fatty Alcohols and Peanut Oil

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• 作者：Fabio Valoppi ; Sonia Calligaris ; Alejandro G. Marangoni
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4209-4215
• 全文大小：473K
• 年卷期：0
• ISSN：1528-7505

文摘

This study reports a detailed characterization of the phase transition behavior and polymorphism of fatty alcohols with different chain lengths in peanut oil. Upon crystallization, fatty alcohols nucleated into rotator phases, which then transformed into well-defined crystal polymorphs. At concentrations greater than 30%, fatty alcohol crystals were in the monoclinic γ-form with a lamellar thickness that decreased as the length of the carbon chain of the fatty alcohols decreased. At concentrations lower than 30%, on the other hand, fatty alcohol crystals formed an orthorhombic β′-form. In this case, two main crystal families with lamellar thicknesses were detected. In particular, the thicker family range was from 5.95 to 4.96 nm moving from 1-docosanol to 1-hexadecanol while the thinner family range was from 4.98 to 3.68 nm. The thicker crystal population progressively decreased, while the thinner crystal population increased, suggesting an interconversion between these species. The kinetics of these changes increased crystallizing the systems at 20 °C. Ultrasmall-angle X-ray scattering was used to characterize nanoscale structure and mesoscale crystal aggregation. It was found that crystal aggregates were characterized by a diffuse surface with crystallites in the range of 125–765 nm and a mass fractal dimension for crystals aggregation of 2.26–2.7.