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Article: Physical aging kinetics of syndiotactic polystyrene as determined from creep behavior.
- Article from:
- Polymer Engineering and Science
- Article date:
- September 1, 1997
- Author:
CopyrightCOPYRIGHT 1997 Society of Plastics Engineers, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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INTRODUCTION
The cooling of an amorphous polymer through the glass transition [T.sub.g] results in a non-equilibrium glassy state that then proceeds to spontaneously evolve towards a temporally distant equilibrium (1, 2). Associated with the evolution of the state variables of, e.g., volume or enthalpy, are observable changes of macroscopic properties such as viscoelastic response, yield strength, impact resistance, etc. (3), which has come to be referred to as physical aging. One anticipates similar behavior for the glassy response of semicrystalline polymers. However, it has been observed that for semicrystalline polymers physical aging persists even above the ...