Proton transport properties of poly(aspartic acid) with different average molecular weights

Yuki Nagao, Yuzuru Imai, Jun Matsui, Tomoyuki Ogawa, Tokuji Miyashita

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

We synthesized seven partially protonated poly(aspartic acids)/sodium polyaspartates (P-Asp) with different average molecular weights to study their proton transport properties. The number-average degree of polymerization (DP) for each P-Asp was 30 (P-Asp30), 115 (P-Asp115), 140 (P-Asp140), 160 (P-Asp160), 185 (P-Asp185), 205 (P-Asp205), and 250 (P-Asp250). The proton conductivity depended on the number-average DP. The maximum and minimum proton conductivities under a relative humidity of 70% and 298 K were 1.7 · 10-3 S cm-1 (P-Asp140) and 4.6 · 10-4 S cm-1 (P-Asp250), respectively. Differential thermogravimetric analysis (TG-DTA) was carried out for each P-Asp. The results were classified into two categories. One exhibited two endothermic peaks between t = (270 and 300) °C, the other exhibited only one peak. The P-Asp group with two endothermic peaks exhibited high proton conductivity. The high proton conductivity is related to the stability of the polymer. The number-average molecular weight also contributed to the stability of the polymer.

Original languageEnglish
Pages (from-to)613-616
Number of pages4
JournalJournal of Chemical Thermodynamics
Volume43
Issue number4
DOIs
Publication statusPublished - 2011 Apr

Keywords

  • Effect of molecular weight
  • Poly(aspartic acid)
  • Proton conduction

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Physical and Theoretical Chemistry

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