Structure, Mechanical Properties, and Rheological Characteristics of Poly(Butylene Adipate-co-Terephthalate)-Polylactic Acid Blends Modified via In Situ Maleic Anhydride Grafting.

Polylactic acid (PLA) materials face inherent limitations in many applications due to their low toughness. To address this challenge, this study employed a reactive melt-grafting method to prepare maleic anhydride (MA)-grafted poly(butylene adipate-co-terephthalate) (PBAT-MA), providing an effective approach to improve the interfacial compatibility between PLA and PBAT, thereby significantly enhancing the toughness and impact resistance of PLA and expanding its application scope. The grafting reaction process of PBAT-MA was investigated, as well as its toughening mechanism and effect on PLA. The results showed that at a maleic anhydride concentration of 2 wt%, the obtained PLA-PBAT-MA composite material exhibited the best performance, with a fracture elongation of 358.1%, 450.4% higher than that of the unmodified composite material. The impact strength was 333.9 kJ/m2, 917.3% higher than that of the unmodified composite material. This enhanced effect is attributed to the optimal MA concentration preserving the tough structure of PBAT while effectively bridging the interface between PLA and PBAT, promoting efficient stress transfer between the two phases, and ultimately achieving exceptional toughness.