Polylactic acid films reinforced with chitin nanocrystals: Biodegradation and migration behavior

Polylactic acid (PLA) is a widely recognized sustainable alternative to conventional petroleum-based plastics for food packaging. To enhance its properties that currently trail those of conventional packaging materials, the addition of chitin nanocrystals (ChNC) has been considered. This has led, amongst others to stronger materials. For their ultimate application, it is also important to evaluate these materials in terms of food safety and environmental impact. In this study, we investigate the biodegradation of and migration from ChNC/PLA nanocomposites. The solution casting method was used to prepare PLA and ChNC/PLA nanocomposites, and overall migration (OM) tests were carried out with food simulants (10 % ethanol and isooctane). Additionally, we evaluated the biodegradability (crude chitin powder, ChNC, and nanocomposites) based on ISO norm no 14851:2019. The OM tests demonstrated that the migration levels from ChNC-PLA composites were below the allowed limit (60 mg/kg). The biodegradability of ChNC was comparable to that of crude chitin powder and microcrystalline cellulose, and interestingly, when incorporated in PLA films did not impact the biodegradability of PLA in a negative way. In summary, the migration and biodegradation of ChNC/PLA nanocomposites exhibit encouraging potential for their future utilization in food packaging.