Effect of cationic group content on shape memory effect in segmented polyurethane cationomer

Yong Zhu, Jinlian Hu, Kwok Wing Yeung, Ka Fai Choi, Yeqiu Liu, Haiming Liem

Research output: Journal article publicationJournal articleAcademic researchpeer-review

58 Citations (Scopus)


To illustrate the importance of cationic groups within hard segments on shape memory effect in segmented polyurethane (PU) cationomers, the shape memory polyurethane (SMPU) cationomers composed of poly(ε-caprolactone) (PCL), 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO), and N-methyldiethanolamine (NMDA) or N,N-bis(2-hydroxyethyl)isonicotinamide (BIN) were synthesized. The comparison of shape memory effect between NMDA series and BIN series was made. The relations between the structure and shape memory effect of the two series of cationomers with various ionic group contents were investigated. It is observed that the stress at 100% elongation is reduced for these two series of PU cationomers with increasing ionic group content. Especially for NMDA series, the stress reduction is more significant. The fixity ratio and recovery ratio of the NMDA series can be improved simultaneously by the insertion of cationic groups within hard segments, but not for the BIN series. Characterizations with DSC and DMA suggest that the crystallibility of soft segment in SMPU cationomers was enhanced by incorporation of ionic groups into hard segments, leading to a relative high degree of soft segment crystallization; compared with the corresponding nonionomers, incorporation of charged ionic groups within hard segments can enhance the cohesion force among hard segments particularly at high ionic group content. This methodology offers good control of the shape memory characteristic in thin films and is believed to be beneficial to the shape memory textile industries.
Original languageEnglish
Pages (from-to)545-556
Number of pages12
JournalJournal of Applied Polymer Science
Issue number1
Publication statusPublished - 5 Jan 2007


  • Cationomer
  • Cyclic tensile test
  • Polyurethane
  • Shape memory effect

ASJC Scopus subject areas

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


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