Microphase separation, stress relaxation, and creep behavior of polyurethane nanocomposites

H. Xia, M. Song, Zhongyi Zhang, Mel Richardson

    Research output: Contribution to journalArticlepeer-review


    The stress relaxation and creep behavior of blank polyurethane (PU) and PU/clay nanocomposites were investigated. The relaxation time spectrum and retardant time spectrum were derived according to the generalized Maxwell model and Voigt model with a Tikhonov regularization method, respectively. The characteristic relaxation time was identified with the corresponding relaxation process. At a small strain, the relaxation was mainly attributed to uncoiling/disentangling of soft segment chain network in the soft phase, with a single characteristic relaxation time in the range of 5–100 s. The increase in the hard segment content leads to a decrease in the relaxation time, and the addition of clay leads to an increase in the relaxation time. At large strains, the multipeak relaxations occurred, and they were attributed to the breakup of interconnected hard domains and pullout of soft segment chains from hard domains, together with the disentangling of soft segment chain network in the soft phase. The creep results are consistent with those of the stress relaxation. The relaxation and creep behavior were related to microphase separation of PU. This study suggested that the relaxation spectrum can be used to examine the complicated relaxation processes for a multiphase and multicomponent polymer system.
    Original languageEnglish
    Pages (from-to)2992-3002
    Number of pages11
    JournalJournal of Applied Polymer Science
    Issue number5
    Publication statusPublished - 2007


    Dive into the research topics of 'Microphase separation, stress relaxation, and creep behavior of polyurethane nanocomposites'. Together they form a unique fingerprint.

    Cite this