Toughened Polyglycolic Acid Enabled by Glycolic-Based Polyester Elastomers: Preparation, Compatibility and Performance

Poly(glycolic acid) (PGA) is considered as one of the most promising biodegradable plastics. However, its inherent brittleness limits its broader applications. In this study, a series of glycolate-based copolyesters (PPBAG) were designed and synthesized for toughening PGA. The introduction of glycolate could improve the compatibility between PPBAG and PGA. In order to achieve biobased and biodegradable elastomer toughener, four monomers were used to break the regularly of the polymer molecules and the amount of glycolate is adjusted. The improved compatibility is evidenced by a decreased size of the PPBAG dispersed phase in PGA matrix, as well as the narrowed T_g gap between the two phases. This approach ultimately yielded toughened PGA composites, achieving an elongation at break of 54.5% and a notched impact strength of 12.1 kJ/m², which represent 23.7-fold and 5.3-fold enhancements over neat PGA, respectively.