Influence of ionic groups on the crystallization and melting behavior of segmented polyurethane ionomers

Y. Zhu, Jinlian Hu, K. W. Yeung, Y. Q. Liu, H. M. Liem

Research output: Journal article publicationJournal articleAcademic researchpeer-review


The isothermal crystallization kinetics and melting behavior of the soft segment in polyurethane (PU) ionomer/nonionomer based on PCL-4000 (poly(ε-caprolactone)) were investigated using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In general, the presence of ionic groups in PU ionomers can promote the formation of a more stable crystalline structure and lower the equilibrium melting temperature of the crystallizable phase. Comparison between the crystallization characteristics of PU nonionomers and ionomers suggests that the Coulombic Forces between ionic groups within hard segment can increase the crystallization rate and decrease the crystal size of soft segment when the total molecular weight (Mwof PU ionomer is higher than -71,000. On the other hand, the opposite effect of ionic groups on the crystallization rate is observed in PU ionomers with Mwbelow ∼20,000. The DSC thermograms illustrate that the ionic groups can significantly enhance the microphase separation in PU ionomers with higher Mwvalues. By the control and manipulation of crystallization and microstructure formation in PU ionomer, it is possible to achieve shape memory PUs with superior physical property.
Original languageEnglish
Pages (from-to)4603-4613
Number of pages11
JournalJournal of Applied Polymer Science
Issue number6
Publication statusPublished - 15 Jun 2006


  • Ionomers
  • Isothermal crystallization
  • Melting behavior
  • Phase separation
  • Polyurethanes

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry

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