Indirect method for determining degree of branching in hyperbranched polymers

Larry J. Markoski, Julie L. Thompson, Jeffrey S. Moore

Research output: Contribution to journalArticlepeer-review


In an attempt to relate architecture to physical properties through a systematic study of degree of branching (DB), we recently reported the copolymerization of a series of AB/AB2 monomers ranging from 0 to 1 mole fraction AB monomer content (xAB). However, the DB of copolymers with 0.25 < xAB < 1.0 were not measurable by standard 1H NMR due to severe aggregation and lack of dispersion. To indirectly measure the DB of the whole series, a reaction scheme involving nonpolymerizable small molecules that contain the A, B, and B2 functionalities ((A + B)/(A + B2) model reaction), whose products represent the linear and dendritic connectivities in the AB/AB2 copolymer products, was devised. By control of the stoichiometry and utilization of reaction conditions identical to those of the polymerizations, the products representing hyperbranched polymer units were produced and their ratios were monitored by 1H NMR and/or HPLC to indirectly determine the DB. In all reactions the A functionality was consumed in 2.5 min or less (pA = 1 at 2.5 min) and no detectable side products were observed in either analytical technique. Excellent agreement in DB was observed for copolymer compositions that could be measured and the corresponding model reactions, validating our indirect method for measuring DB in our AB/AB2 ether-imide copolymers.

Original languageEnglish (US)
Pages (from-to)1599-1603
Number of pages5
Issue number5
StatePublished - Feb 26 2002

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry


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