A Journey from Processing to Recycling of Multilayer Waste Films: A Review of Main Challenges and Prospects

Abstract

In a circular economy context with the dual problems of depletion of natural resources and the environmental impact of a growing volume of wastes, it is of great importance to focus on the recycling process of multilayered plastic films. This review is dedicated first to the general concepts and summary of plastic waste management in general, making emphasis on the multilayer films recycling process. Then, in the second part, the focus is dealing with multilayer films manufacturing process, including the most common materials used for agricultural applications, their processing, and the challenges of their recycling, recyclability, and reuse. Hitherto, some prospects are discussed from eco-design to mechanical or chemical recycling approaches.

Overview of the Cast Polyolefin Film Extrusion Technology for Multi-Layer Packaging Applications

“…Transferring the film to subsequent rolls ensures control of the sheet dimensions and its even winding [ 23 ]. Depending on the purpose of the extruded foil, various additional auxiliaries are used or combined with other materials [ 24 ]. Multilayer polymeric materials are formed to provide a gas barrier [ 25 ] or suitable mechanical [ 26 ] and optical properties [ 27 ] to the films [ 28 ].…”

Design of Copolymer‐Based Blend Compatibilizers for Mixed Plastic Recycling

“…The complex/heterogeneous structures and relatively strong interfacial adhesions between distinct components within these composites also makes the separation process particularly challenging. [53,54] As weakened material properties in mixed plastic waste primarily arise from the blend phase separation, addressing this challenge necessitates an understanding about the miscibility of polymer blends, which is a key thermodynamic parameter that can be analyzed through the Gibbs free energy of mixing. Briefly, its governing relationship for multi-component polymer blends can be described as Equation ( 1)…”

“…The complex/heterogeneous structures and relatively strong interfacial adhesions between distinct components within these composites also makes the separation process particularly challenging. [ 53,54 ]…”

Hydrothermal Processing of Multilayer Plastic Film for Cascaded Valorization of Nonrecyclable Waste

“…Therefore, prevailing recycling methods, such as mechanical recycling, struggle to coprocess mixed-polymer plastics, resulting in a heterogeneous low-quality recycled product, or even process failure. , Yet multimaterial products such as multilayer plastics films are ubiquitous in many sectors including packaging and agriculture. Such films consist of several layers of different polymers and may also contain nonpolymeric materials such as paper or foil . The multilayer polymers provide enhanced functionality such as gas- and water-tight barriers and seals, light and humidity control, and impart mechanical stability and resistance against abrasion …”