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Article: Biaxial Stress Relaxation of High Impact Polystyrene (HIPS) Above the Glass Transition Temperature.
- Article from:
- Polymer Engineering and Science
- Article date:
- March 1, 2001
- Author:
CopyrightCOPYRIGHT 2001 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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SCOTT R. HUMMEL [*]
A procedure was developed and experiments were performed to measure the biaxial stress relaxation of High Impact Polystyrene (HIPS) sheets above the glass transition temperature. Tests were performed at various temperatures and strain magnitudes. The data were normalized to unity at time zero to isolate the time dependence of the stress from the strain dependence. The results show that the time dependent biaxial stress relaxation properties were independent of the magnitude of the stress or strain for small strains. The stress relaxation curves were fitted to a Prony series and it was found that time-temperature superposition could be applied ...