ABSTRACT Polylactic acid (PLA)‐based biodegradable polymers have potential for active packaging in the food industry. Extensive research has been conducted on the fabrication of PLA films to overcome their brittleness and improve their performance. However, studies on the fracture behavior of these films are very limited. Given the importance of fracture behavior, this study was designed to investigate the fracture behavior of PLA composite films by blending them with neroli and thyme essential oils, as well as spherical and rod‐shaped zinc oxide nanoparticles. The fracture behavior was analyzed using SEM images along with ImageJ software, following the essential work of fracture technique. Results from SEM revealed that the films exhibited ductile fracture characterized by cavity formation, followed by crazing and crack propagation. The shape of the cavities was found to be less circular before fracture, which transformed to more rounded after fracture with distinct visibility. The percentage of porosity increased after fracture, indicating the development and coalescence of more cavities when the material underwent deformation and failure. The specific essential work of fracture ( w e ) for the film containing rod‐shaped nanoparticles, which was one of the two control films for the active films, had the highest value (16.66 kJ/m 2 ), indicating that this film absorbed more energy in the elastic region compared to other films. The shape factor multiplied by the specific nonessential work of fracture ( βw p ) for the film containing spherical‐shaped nanoparticles, which was one of the two control films for the active films, had the highest value (6.08 MJ/m 3 ).
Tajari et al. (Tue,) studied this question.