TEMPO-mediated 'living' free-radical approach to ABA triblock dendritic linear hybrid copolymers

Todd Emrick, Wayne Hayes, Jean Frechet

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


Dumbbell-shaped ABA triblock copolymers composed of benzyl ether dendrons and polystyrene as the A and B blocks, respectively, were prepared using 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) -mediated 'living' free-radical polymerization. A new bis-dendritic unimolecular initiator, compound 3, was employed to study the efficiency of ABA triblock formation under standard TEMPO-mediated polymerization conditions. By this design, the central B block of the ABA triblock copolymer was grown into the bis-dendritic unimolecular initiator. The ABA triblock copolymer products were separated from their by-products, AB diblock copolymers, by column chromatography on silica gel. The isolated copolymers were characterized using gel permeation chromatography and proton nuclear magnetic resonance spectroscopy as complimentary techniques. That the dendritic-linear AB diblock copolymer was obtained in a mixture with ABA triblock material indicates that TEMPO-terminated dendron counter-radical 5 is an imperfect mediator of this free-radical polymerization.

Original languageEnglish (US)
Pages (from-to)3748-3755
Number of pages8
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Issue number20
StatePublished - Oct 15 1999

ASJC Scopus subject areas

  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry


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