The essential work of fracture (EWF) method [1] is gaining acceptance for the toughness determination of ductile polymer sheets and film.EWF tests are easy to perform and the data reduction is also very simple.This guided researchers to adapt this technique also for systems where it does not work [1-2].Thus the published results scatter and do not allow us to make any useful conclusion in respect to the structure-toughness relationships in thermoplastic nanocomposites.