Crystallization and prevention of supercooling of microencapsulated n-alkanes

Xing Xiang Zhang, Yao Feng Fan, Xiaoming Tao, Kit Lun Yick

Research output: Journal article publicationJournal articleAcademic researchpeer-review

226 Citations (Scopus)

Abstract

Microencapsulated n-alkanes (n-octadecane, n-nonadecane, and n-eicosane) were synthesized by in situ polymerization using urea-melamine-formaldehyde polymer as shells. Microcapsules 5.0 and 10.0 wt% of 1-tetradecanol, paraffin, and 1-octadecanol were used as nucleating agents. The fabrication was characterized using Fourier transform infrared, light microscopy, and scanning electron microscopy. The crystallization and prevention of supercooling of the microcapsules are studied using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction. The crystal system of the microencapsulated n-alkane is the same as that of the bulk. The enthalpies of the microcapsules containing 70 wt% n-alkanes are approximately 160 J/g. The melting temperature of the n-alkanes in the microcapsule is the same as that in the bulk. There are multiple peaks on the DSC cooling curves that are attributed to liquid-rotator, rotator-crystal, and liquid-crystal transitions. The DSC cooling behavior of microencapsulated n-octadecane is affected by the average diameters. The measured maximum degree of supercooling of the microencapsulated n-octadecane is approximately 26.0°C at a heating and cooling rate of 10.0°C/min. The degree of supercooling of microencapsulated n-octadecane is decreased by adding 10.0 wt% of 1-octadecanol as a nucleating agent.
Original languageEnglish
Pages (from-to)299-306
Number of pages8
JournalJournal of Colloid and Interface Science
Volume281
Issue number2
DOIs
Publication statusPublished - 15 Jan 2005

Keywords

  • Crystallization
  • Microcapsules
  • n-Alkanes
  • Nucleating agents
  • Supercooling

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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