Shape memory effect of PU ionomers with ionic groups on hard-segments

Yong Zhu, Jinlian Hu, Kwok Wing Yeung, Hao Jun Fan, Ye Qiu Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

38 Citations (Scopus)


SMPU (shape memory polyurethane) non-ionomers and ionomers, synthesized with poly(ε-caprolactone) (PCL), 4, 4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO), dimethylolpropionic acid (DMPA) were measured with cyclic tensile test and strain recovery test. The relations between the structure and shape memory effect of these two series were studied with respect to the ionic group content and the effect of neutralization. The resulting data indicate that, with the introduction of asymmetrical extender, the stress at 100% elongation is decreased for PU non-ionomer and ionomer series, especially lowered sharply for non-ionomer series; the fixation ratio of ionomer series is not affected obviously by the ionic group content; the total recovery ratio of ionomer series is decreased greatly. After sufficient relaxation time for samples stretched beforehand, the switching temperature is raised slightly, whereas the recovery ratio measured with strain recovery test method is lowered with increased DMPA content. The characterization with FT-IR, DSC, DMA elucidated that, the ordered hard domain of the two series is disrupted with the introduction of DMPA which causes more hard segments to dissolve in soft phase; ionic groups on hard segment enhance the cohesion between hard segments especially at high ionic group content and significantly facilitate the phase separation compared with the corresponding non-ionomer at moderate ionic group content.
Original languageEnglish
Pages (from-to)173-186
Number of pages14
JournalChinese Journal of Polymer Science (English Edition)
Issue number2
Publication statusPublished - 1 Mar 2006


  • Cyclic tensile test
  • Cyclic thermo-mechanical investigations
  • Ionomers
  • Polyurethane
  • Shape memory effect
  • Strain recovery test

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Organic Chemistry
  • Polymers and Plastics


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