Structure and thermal stability of microencapsulated phase-change materials

Xing Xiang Zhang, Xiaoming Tao, Kit Lun Yick, Xue Chen Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

189 Citations (Scopus)


A series of microcapsules containing n-octadecane with a urea-melamine-formaldehyde copolymer shell were synthesized by insitu polymerization. The surface morphology, diameter, melting and crystallization properties, and thermal stability of the microcapsules were investigated by using FTIR, SEM, DSC, TGA and DTA. The diameters of the microcapsules are in the range of 0.2-5.6 μ. The n-octadecane contents in the microcapsules are in the range of 65-78wt%. The mole ratio of urea-melamine has been found to have no effect on the melting temperature of the microcapsules. Two crystallization peaks on the DSC cooling curve have been observed. The thermal damage mechanisms are the liquefied n-octadecane leaking from the microcapsule and breakage of the shell due to the mismatch of thermal expansion of the core and shell materials at high temperatures. The thermal stability of materials can be enhanced up to 10 °C by the copolymerization of urea, melamine and formaldehyde in a mole ratio 0.2:0.8:3. The thermal stability of 160 °C heat-treated microcapsules containing 8.8% cyclohexane can be further enhanced up to approximately 37 °C.
Original languageEnglish
Pages (from-to)330-336
Number of pages7
JournalColloid and Polymer Science
Issue number4
Publication statusPublished - 1 Feb 2004


  • In-situ polymerization
  • Microcapsule
  • n-octadecane
  • Thermal stability

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Colloid and Surface Chemistry
  • Materials Chemistry

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