Molecular Orientation Behavior of Isotactic Polypropylene Films under Uniaxial and Biaxial Deformation at Elevated Temperatures

Abstract

In-situ molecular orientation behavior of isotactic polypropylene films prepared by quenching at 0°C was investigated under uniaxial and biaxial extension at elevated temperatures. Both the retardation value of film and the stress were simultaneously measured during stretching. The stress required to deform films depended on the stretching temperature, but the retardation was nearly independent of temperature.