Impedance spectroscopy of reactive polymers. 5. Impedance as a measure of chemical and physical changes in glass formers

Saša Andjelić, Jovan Mijović, Francesco Bellucci

Research output: Contribution to journalArticlepeer-review

Abstract

A study was conducted aimed at establishing the nature of chemical and physical phenomena in polymeric and nonpolymeric glass formers that can be observed by impedance measurements. Various systems were investigated that undergo a temporal evolution of structure as a result of chemical reactions and physical processes such as crystallization, vitrification, or phase separation. Distinct and systematic changes in impedance during crystallization and vitrification confirmed that these events could be monitored by impedance spectroscopy. Of particular interest was the potential use of impedance measurements in detecting gelation in crosslinking polymers. It was shown that the experimentally observed "knee" in imaginary impedance during reaction shifts with frequency and, hence, cannot be used to measure gelation. But a new insight at the molecular level was obtained by employing a novel experimental approach based on simultaneous dielectric-infrared measurements. Evidence was generated to support the formation of a hydrogen-bonded complex in the vicinity of gel point in polymer networks, which affords a vehicle for the migration of intrinsic charges and provides a contribution to the overall conductivity. This finding should be explored further because it suggests the possibility of correlating dielectric response with gelation.

Original languageEnglish (US)
Pages (from-to)641-653
Number of pages13
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume36
Issue number4
DOIs
StatePublished - Mar 1998

Keywords

  • Chemical and physical changes
  • Dielectric properties
  • Glass formers
  • Impedance spectroscopy
  • In situ monitoring
  • Reactive polymers

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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