A Simple Way to Control Small-Strain Cavitation in Die-Drawn Isotactic Polypropylene

Abstract

Increasing attention has been focused on small-strain cavitation behavior of semicrystalline materials, due to the increased need of porous films with low cost and advanced chemical stability. The control of cavitation is crucial to the properties of the final product as well as the fabrication process. In this work, we proposed a simple way to regulate small-strain cavitation of isotactic polypropylene (iPP) samples via modifying the fraction of lamellae with their normal perpendicular to the stretching direction by stretching at 125 °C. Deformation at 125 °C could effectively reduce the fraction and the long period of those perpendicular lamellae in the iPP system without inducing small-strain cavitation. When successively deformed at 50 °C, the modified samples exhibited weaker ability to initiate small-strain cavitation as determined by the USAXS techniques.