Viability of milk pouch recycling into monolayer blown films

Abstract

Due to the wide versatility and properties of plastics, they have replaced many other materials in food packaging and other products. Multilayer films are highly used in the food industry since they bring together the properties of several polymers in the same container. However, the marked growth has not been accompanied by an adequate recovery and recycling plan, currently leading to a large volume of garbage and no adequate solutions for the mismanaged plastic waste. Through this work, the feasibility of recycling of commercial multilayer milk pouch is explored. The main goal is to obtain films with good enough performance to be used in applications such as e-commerce envelopes. To this aim, different processing conditions were applied, and blends with a compatibilizer and virgin polyethylene in varying content were evaluated. Obtained blown films were physically characterized by performing FTIR, thermal, water permeation and rheological tests. Finally, mechanical and fracture performance was deeply characterized in both quasi-static and dynamic loading conditions in order to assess the overall performance of films. It was found that the analyzed properties of the multilayer and recycled films are highly dependent on their composition. The addition of only 2% of the correct compatibilizer can improve mechanical behavior. However, it was also found that a large amount of compatibilizer has a negative impact on films' performance, since it can agglomerate and act as stress concentrator inhibiting plastic deformation.