Time dependent effects on the rupture of molten linear polymers in extension

The objective of the present work is to describe experimental work performed on the subject of rupture of polymer melts in uniaxial extensional flow. There are several reports on the literature dealing with the subject but nevertheless, the phenomenon of failure and rupture of polymer melts in extensional flow is still not well understood. In the present work, constant strain rate experiments in uniaxial extension were performed on commercial linear polymer melts until physical rupture of the samples was attained. Our results support the existence predicted by other authors of different flow regimes ranging from purely viscous to viscoelastic to rubbery. The time-to-rupture showed an increased dependency on the stress at rupture and for one of the materials a limiting stress was attained; simultaneously, a transition in rupture mode was observed from ductile to cohesive.