The thermo-mechanical recyclability potential of biodegradable biopolyesters: Perspectives and limits for food packaging application

Up to now, recycling has been opposed to biodegradability, although these two end-of-life options are complementary. If combined in an integrated system, recycling creates an after-use economy, while biodegradability eradicates definitely the issues of environmental spreading of the persistent plastic wastes. This paper reviews the current state on recyclability of some promising biodegradable polyesters, polylactide acid (PLA), polyhydroxyalkanoates (PHAs), bio-polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT), with emphasis on mechanical recycling. The effect of the mechanical reprocessing (multiple extrusion or injection-molding) on the chemical structure and thermomechanical properties of the polymers is reported. In addition, the application of upgrading strategies such as blends and/or composites to improve polyesters recyclability are considered. A further decontamination step is studied in order to achieve food contact aptitude in mechanical recycling for food packaging application. Finally, the challenges that should be faced in the future, to promote the recyclability of biodegradable polyesters are addressed.