Phosphonium ionenes from well-defined step-growth polymerization: Thermal and melt rheological properties

Sean T. Hemp, Musan Zhang, Mana Tamami, Timothy Edward Long*

*この研究の対応する著者

研究成果: Article査読

42 被引用数 (Scopus)

抄録

Step-growth polymerization of ditertiary phosphines with dibromoalkanes enabled the synthesis of novel phosphonium ionenes. In situ FTIR spectroscopy monitored the increase in absorbance as a function of time at 1116 cm -1, which corresponded to the polymeric P+-Ph stretch. Aqueous size-exclusion chromatography (SEC) provided absolute molecular weights and confirmed expected molecular weight growth for difunctional, step-growth polymerization. Phosphonium ionenes exhibited improved thermal and base stability compared to ammonium ionenes, which was attributed to the propensity of the ammonium cation towards Hofmann elimination. Melt rheology examined phosphonium ionene viscous flow and the influence of charge density on melt viscosity as a function of shear rate and temperature. Time-temperature superposition (TTS) resulted in both master curves and pseudomaster curves depending on phosphonium ionene composition. Two primary relaxations occurred: (1) onset of long-range segmental motion at Tg, and (2) relaxation attributed to electrostatic interactions. Higher charge densities shifted these two relaxations to longer time scales and increased flow activation energies. Phosphonium ionenes also readily bound pDNA effectively (± ratios of 1), and base stability suggested applications in energy generation.

本文言語English
ページ(範囲)3582-3590
ページ数9
ジャーナルPolymer Chemistry
4
12
DOI
出版ステータスPublished - 2013 6 21
外部発表はい

ASJC Scopus subject areas

  • バイオエンジニアリング
  • 生化学
  • 生体医工学
  • ポリマーおよびプラスチック
  • 有機化学

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