Seier Martina, Archodoulaki Vasiliki-Maria, Koch Thomas, Duscher Bernadette, Gahleitner Markus
Institute of Materials Science and Technology, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria.
Borealis Polyolefine GmbH, Innovation Headquarters, St. Peter Str. 25, 4021 Linz, Austria.
Polymers (Basel). 2023 Jul 6;15(13):2966. doi: 10.3390/polym15132966.
Food preservation is an essential application for polymers, particularly in packaging. Complex multilayer films, such as those used for modified atmosphere packaging (MAP), extend the shelf life of sensitive foods. These mostly contain various polymers to achieve the necessary combination of mechanic, optic, and barrier properties that limit their recyclability. As the European Union's Circular Economy Action Plan calls for sustainable products and business models, including waste prevention policies and recycling quotas, with plastic packaging being a high priority, solutions towards more sustainable multilayer packaging are urgently needed. This study evaluated and compared the recycling potential of functionally equivalent PET (polyethylene terephthalate) and PP (polypropylene) post-consumer MAP through structure analysis and recycling simulation. The structure analysis revealed that both types of MAP contained functional (stability) and barrier layers (oxygen and moisture). The recycling simulation showed that the PP-based packaging was recyclable 10 times, maintaining its mechanical properties and functionality. At the same time, the PET-based MAP resulted in a highly brittle material that was unsuitable for reprocessing into similar economic value products. The secondary material from the PP-based MAP was successfully manufactured into films, demonstrating the functional possibility of closed-loop recycling. The transition from a linear to a circular economy for MAP is currently still limited by safety concerns due to a lack of sufficient and efficient purification methods, but the proper design of multilayers for recyclability is a first step towards circularity.
食品保鲜是聚合物的一项重要应用，尤其是在包装领域。复杂的多层薄膜，如用于气调包装（MAP）的薄膜，可延长易腐食品的保质期。这些薄膜大多含有各种聚合物，以实现机械、光学和阻隔性能的必要组合，而这些性能限制了它们的可回收性。由于欧盟的循环经济行动计划呼吁采用可持续产品和商业模式，包括废物预防政策和回收配额，塑料包装是重中之重，因此迫切需要针对更可持续的多层包装的解决方案。本研究通过结构分析和回收模拟，评估并比较了功能等效的消费后气调包装用聚对苯二甲酸乙二酯（PET）和聚丙烯（PP）的回收潜力。结构分析表明，两种类型的气调包装都包含功能（稳定性）层和阻隔层（氧气和水分）。回收模拟表明，基于PP的包装可回收10次，同时保持其机械性能和功能。与此同时，基于PET的气调包装产生了一种非常脆的材料，不适合再加工成具有类似经济价值的产品。基于PP的气调包装的二次材料成功制成了薄膜，证明了闭环回收的功能可能性。由于缺乏足够有效的净化方法，气调包装从线性经济向循环经济的转变目前仍受到安全问题的限制，但为可回收性而对多层材料进行合理设计是迈向循环经济的第一步。
