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Microphase separation, stress relaxation and creep behavior of polyurethane nanocomposites

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journal contribution
posted on 05.03.2007 by Hesheng Xia, Mo Song, Zhongyi Zhang, Mel Richardson
The microphase separation of polyurethane (PU) nanocomposite was studied. The result suggests that the addition of clay leads to a decrease in the size of hard domain and an increase in the degree of microphase separation. The stress relaxation and creep behavior of blank 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. 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 5~100s. 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 multi-peak relaxations occurred, and they were attributed to the breakup of interconnected hard domains and pull-out of soft segment chains from hard domains, together with the disentangling of soft segment chain network in the soft phase. The creep results are in consistent with that of the stress relaxation. The relaxation and creep behavior were related to microphase separation of polyurethane. This study suggested that the relaxation spectrum H() can be used to examine the complicated relaxation processes for a multi-phase and multi-component polymer system.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Materials

Pages

389945 bytes

Citation

XIA et al, 2007. Microphase separation, stress relaxation and creep behavior of polyurethane nanocomposites. Journal of Applied Polymer Science, 103(5), pp. 2992-3002

Publisher

© John Wiley & Sons

Publication date

2007

Notes

This article was published in the journal, Journal of Applied Polymer Science [© John Wiley & Sons] and is also available at: www3.interscience.wiley.com/cgi-bin/jhome/30035.

ISSN

0021-8995

Language

en

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