Influence of Modified Poly(Glycolic acid) on the Physical and Mechanical Properties of PLA/PBAT/mPGA Multi-phase Blends

PGA is currently getting great attention as a potential biodegradable polymer due to its biodegradability, high gas barrier, and high thermal stability; however, its low processability and brittleness are key factors to be overcome for various applications. The purpose of this study was to investigate the feasibility of poly(glycolic acid) (PGA) as a packaging material for a bio-based poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend with improved properties. The optimized PLA/PBAT blend composition was determined with balanced mechanical properties along with microstructural observation. The PGA was first modified with a chain extender to improve its processability, and then it was introduced to PLA/PBAT blends with various compositions via the melt processing method. The melt strength of PGA was found to be improved about 90% with the addition of 0.5 phr of chain extender, achieving better processability. The Young’s modulus and tensile strength of the PLA/PBAT/mPGA blend showed no statistically significant differences, which is an interesting finding as compared to other ternary blend system. For barrier properties, the O₂ and H₂O permeabilities showed no statistically significant difference among ternary blends except the PLA/PBAT blend, but H₂O permeability showed a decrease tendency with a value of about 27% as compared to the PLA/PBAT blend. In addition, the morphological observation was also performed to assess the structure-properties relationship in the multi-phase blends system.