Reactive-Mechanical Processing for Recycling of Multilayer Films Waste Based on Polyolefins From Packaging

Multilayer films based on polyethylene are extensively used for packaging to confer desirable properties that cannot be achieved by a single film. Since packaging is discarded as soon as the inside products are consumed, gigantic amounts of waste are generated globally every year, around 40 million tons for polyethylene alone. The mixture of different polymer components in the waste leads to the formation of incompatible polymer blends with depreciated properties when the material is mechanically recycled. Thus, the conventional recycling of multilayer films from packaging waste is a challenge. In this study, the aim was to evaluate the reactive-mechanical recycling of multilayer films using controlled shear rate and zeolite ZSM-5 as catalyst to induce structural changes and material compatibility. Waste from multilayer films and virgin polymers (reference) was processed at nitrogen flow in an internal mixer for different times after polymer plasticization. Then, the materials were characterized by thermal, rheological, mechanical, and dynamical-mechanical analyses. There was an improvement in performance of mechanical properties for determined processing conditions, which should be related to structural changes induced on the polymers by controlled shear rate and presence of zeolites ZSM-5. Reactive-mechanical processing showed great potential as a viable alternative for mechanical recycling of multilayer film waste from packaging.