Toughness response of amorphous (co) polyesters using the essential work of fracture approach

摘要

The essential work of fracture (EWF) is an easy to perform approach to determine the plane stress fracture toughness of ductile polymeric sheets and films. Amorphous polyesters and copolyesters are the most suitable model materials for EWF studies as they undergo full ligament yielding prior to the subsequent necking+tearing process. This behavior allowed us to partition between the yielding- and necking-related EWF parameters. The EWF method was applied to study the fracture behavior of amorphous (co)polyesters as a function of external (testing-related) and internal (material-related) parameters. It was claimed that the yielding-related specific essential work of fracture term represents the inherent toughness of the materials accordingly. This material parameter is controlled by characteristics of the entanglement network which is in close analogy with the toughness response of chemically crosslinked rubbers.