Stereochemistry of the radical polymerization of vinyl pentafluorobenzoate

Weihong Liu, Yasuhiro Koike, Yoshi Okamoto

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The free-radical polymerization of vinyl pentafluorobenzoate (VPBz) was carried out under various conditions in order to compare its stereochemistry to that of the vinyl benzoate (VBz) polymerization using similar conditions. Contrary to the stereochemistry of the radical polymerization of VBz, VPBz favors syndiotactic propagation. The poly(VPBz) obtained in hexafluoroisopropanol (HFIP) with nBu3B-air at -30°C has a triad syndiotacticity (rr) of 52% which achieved the highest syndiotacticity reported for the radical polymerization of vinyl esters. The stereochemistry difference for the VPBz polymerization was ascribed to the electron-withdrawing effect of the fluorine on the aromatic ring. The solvent effect of enhancing the rr specificity in HFIP may be related to the hydrogen-bonding between HFIP and VPBz or the growing species. It was also found that the glass transition temperatures (Tg) of the VPBz polymers apparently increased with an increase in their diad syndiotacticities (r): the Tg of poly(VPBz) with r=72% was 79°C, which was 25°C higher than that of poly(VPBz) with r=56% obtained in toluene.

Original languageEnglish
Pages (from-to)5491-5495
Number of pages5
JournalPolymer
Volume45
Issue number16
DOIs
Publication statusPublished - 2004 Jul 21

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Keywords

  • Radical polymerization
  • Stereochemistry
  • Vinyl ester

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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