PBAT Applications

A mismanagement of the disposal of short term polymers after use joined with the impossibility to handle the problem only by mechanical recycling due to still inefficient waste management programs, the composition of some plastic formulations (i.e., blends, composites, nanocomposites, etc.), and the fact that plastics cannot be recycled forever [1], as well as the resistance to degradation by many plastic materials, have led to plastic hoarding in the environment [2,3,4,5]. In this context, the production of biodegradable polymers has considerably increased during recent years, particularly for short term applications, such as food packaging materials [5,6], while resulting in a necessary alternative to deal with the environmental problem produced by the accumulation of plastics in the environment. Naturally occurring microorganisms offer the opportunity to enzymatically degrade biodegradable polymers into small molecules (carbon dioxide and water) [7]. However, biodegradable polymers present reduced overall performance with respect to traditional petroleum-based counterparts, such as higher sensitivity to humidity and thermal degradation, as well as poor barrier and mechanical performance, which hinder its massive industrial exploitation [8,9,10]. Among biodegradable polymers, biopolyesters are positioned in the packaging sector as the most suitable polymers to replace petrol-based plastics in food packaging applications; thus, there are many research studies focused on improving biopolyesters' performance, including poly(lactic acid) (PLA), polyhydroxyalkanoates (PHAs) and its derivatives [11], poli(ε-carpolactone) (PCL), and poly(butylene adipate-co-terephthalate) (PBAT) [12,13,14]. Aliphatic biopolyesters, such as PLA and PHB, have been, to date, the most promising biodegradable polymers for biodegradable or compostable food packaging products [7]. However, aliphatic biopolyesters present some drawbacks for food packaging applications with respect to their petrochemical counterparts such as sensitiveness to hydrolytic degradation, which is highly influenced by ambient moisture and temperature, leading to low thermal stability [7,15,16]. Additionally, for food packaging purposes, their poor barrier properties and inherent unfavourable physical and mechanical properties, such as their limited stretchability, have limited their commercial utility [7,17]. Thus, many research efforts have been focused on biopolyesters modification for extending their industrial application as flexible materials with improved barrier and hydrophobicity performance, such as blending, the addition of fillers and/or nanofillers, surface plasma treatment, or copolymerization [16,18,19]