For economic and ecological concerns, bio-based polymers attracted great interest in the scientific and industrial communities in the recent years. In this context starch-based plastics appear as promising materials. Recently such materials have been developed for non biodegradables applications with a great potential in different applications as automotive parts or packaging. Nevertheless the knowledge of their mechanical behavior remains to be more precisely understood to enlarge their industrial application range. So, the present study aims to use the fracture mechanics approach (Essential Work of Fracture, EWF) to study the toughness of partially starch-based blown films and to compare it to that of polyethylene blown films. The experimental tests are carried out on double-notched samples and digital image correlation method is used to access to the deformation field around the notch and to ensure that assumptions relative to the EWF method are respected. Classic mechanical tests intension are also carried out, showing that elongation and stress at break of partially starch-based materials are higher than those of polyethylene ones. EWF characterization allows to observe and to quantify the notch propagation until the rupture giving interesting data for industrial applications.