Determination of the tear properties of thermoplastic polyester elastomers (TPEEs) using essential work of fracture (EWF) test method

In this paper, three commercial thin thermoplastic polyester elastomer (TPEE) samples are prepared by the injection molding process. Essential work of fracture (EWF) tests, which have been extended to cover the ductile tearing of polymeric materials that neck before fracture, in both the machine direction (MD) and the transverse direction (TD) are executed based on the ESIS TC-4 protocol as well as conventional trouser tear tests. Through an examination of the EWF test results, the tear properties of TPEE samples can be determined quantitatively. Partitioning of the test results is attempted for identifying the contribution of yielding and necking/tearing on the overall tear properties of TPEE samples. In addition, the fracture surfaces of TPEE samples following EWF tests are investigated through scanning electron microscopy (SEM). The root causes of the differences in tear properties are studied using the morphology of the fracture surfaces of TPEE samples.