Generation of Tough Poly(glycolic acid) (PGA)/Poly(butylene succinate- co -butylene adipate) (PBSA) Films with High Gas Barrier Performance through In situ Nanofibrillation of PBSA under an Elongational Flow Field

Poly(glycolic acid) (PGA) is derived from glycolide obtained by fermenting pineapples or sugarcane, which has excellent gas barrier properties and a small carbon footprint. PGA is a potential substitute for the current aluminum-plastic composite films used in high barrier packaging applications. However, its poor ductility and narrow processing window limit its application in food packaging. Herein, poly(butylene succinate- co -butylene adipate) (PBSA) was used to fabricate PGA/PBSA blend films through an in situ fibrillation technique and blown film extrusion. Under the elongational flow field used during the extrusion process, a unique hierarchical structure based on the PBSA nanofibrils and interfacially oriented PGA crystals was obtained. This structure enhances the strength, ductility and gas barrier properties of the PGA/PBSA blend film. In addition, an epoxy chain extender (ADR4468) was used as a compatibilizer to further enhance the interfacial adhesion between PGA and PBSA. 70PGA/0.7ADR exhibited a very low oxygen permeability (2.34×10 −4 Barrer) with significantly high elongating at break (604.4%), tensile strength (47.4 MPa), and transparency, which were superior to those of petroleum-based polymers. Thus, the 70PGA/0.7ADR blown films could satisfy the requirements for most instant foods such as coffee, peanuts, and fresh meat.