Shape memory effect and reversible phase crystallization process in SMPU ionomer

Yong Zhu, Jinlian Hu, Ka Fai Choi, Qinghao Meng, Shaojun Chen, Kwok Wing Yeung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

28 Citations (Scopus)


It is the first attempt to reveal the effect of reversible phase crystallization process on shape memory effect in shape memory polyurethane (PU) ionomer. Thereof the cyclic tensile testing was conducted with various cooling time to fix the temporary deformation for assessing shape memory function. The crystallization process of the reversible phase, poly (ε-caprolactone) (PCL) in shape memory PU ionomers composed of different ionic group contents, 1,4-butanediol, 4,4′-methylenebis(phenyl isocyanate) and PCL, was investigated by using isothermal crystallization kinetics under the thermal routine similar to that for the cyclic tensile testing. The results demonstrate that the ionic groups within hard segments significantly slow down the crystal growth of the reversible phase. When the physical crosslink is strong enough, the crystallization rate would be a predominant factor determining the shape fixity ratio after various cooling time. Instead, when physical crosslink is weakening, the influence of crystallization rate is much less on the cooling time dependence of fixity.
Original languageEnglish
Pages (from-to)328-333
Number of pages6
JournalPolymers for Advanced Technologies
Issue number4
Publication statusPublished - 1 Apr 2008


  • Crystal growth
  • Ionomer
  • Isothermal crystallization
  • Polymers
  • Shape memory materials
  • Shape memory polyurethane

ASJC Scopus subject areas

  • Polymers and Plastics


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