In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene

E. N. Brown, M. R. Kessler, N. R. Sottos, S. R. White

Research output: Contribution to journalArticlepeer-review

Abstract

Microencapsulated healing agents that possess adequate strength, long shelf-life and excellent bonding to the host material are required for self-healing materials. Urea-formaldehyde microcapsules containing dicyclopentadiene were prepared by in situ polymerization in an oil-in-water emulsion that meet these requirements for self-healing epoxy. Microcapsules of 10-1000 μm in diameter were produced by appropriate selection of agitation rate in the range of 200-2000 rpm. A linear relation exists between log(mean diameter) and log(agitation rate). Surface morphology and shell wall thickness were investigated by optical and electron microscopy. Microcapsules are composed of a smooth 160-220 nm inner membrane and a rough, porous outer surface of agglomerated urea-formaldehyde nanoparticles. Surface morphology is influenced by pH of the reacting emulsion and interfacial surface area at the core-water interface. High yields (80-90%) of a free flowing powder of spherical microcapsules were produced with a fill content of 83-92 wt% as determined by CHN analysis.

Original languageEnglish (US)
Pages (from-to)719-730
Number of pages12
JournalJournal of Microencapsulation
Volume20
Issue number6
DOIs
StatePublished - Nov 2003

Keywords

  • Dicyclopentadiene
  • In situ polymerization
  • Microcapsule
  • Self-healing
  • Surface morphology
  • Urea formaldehyde

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Pharmaceutical Science
  • Chemical Engineering(all)
  • Pharmacology

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