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Mechanism of aging effects on viscoelasticity in ethylene-methacrylic acid ionomer studied by local thermal-mechanical analysis

Published online by Cambridge University Press:  31 January 2011

Harsha P. Kulkarni
Affiliation:
Department of Physics and Astronomy and Curriculum in Applied and Materials Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-3255
Gregory Mogilevsky
Affiliation:
Department of Physics and Astronomy and Curriculum in Applied and Materials Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-3255
William M. Mullins
Affiliation:
Department of Mathematics, University of North Carolina, Chapel Hill, North Carolina 27599-3255
Yue Wu*
Affiliation:
Department of Physics and Astronomy and Curriculum in Applied and Materials Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-3255
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

A unique atomic force microscope-based local thermal-mechanical analysis (LTA) technique was used to study the influence of room temperature aging on viscoelastic properties of ethylene-methacrylic (E/MAA) acid ionomers. This approach permits easy access to structural relaxation effects on viscoelasticity at a short aging time, for instance, before the occurrence of secondary crystallization differential scanning calorimetry (DSC) melting peak. A Burger model along with finite element method yields quantitative analysis of viscoelastic properties versus the aging time. Creep curves were obtained with LTA after various times of aging at room temperature upon cooling from the melt. Measurements were carried out at both 30 and 70 °C. The results reveal the effects of structural relaxation upon aging in the ion-rich amorphous region, the influence of secondary crystallites on the viscoelastic properties, and shed light on the processes associated with aging in E/MAA ionomers.

Type
Articles
Copyright
Copyright © Materials Research Society 2009

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