Functionalization of poly (butylene adipate-co-terephthalate) and its toughening effect on poly (lactic acid)

In the study, poly (butylene adipate-co-terephthalate) (PBAT) was grafted with glycidyl methacrylate (GMA) in the presence of the co -monomer N -vinyl pyrrolidone (NVP), and then it was employed to enhance the toughness of poly (lactic acid) (PLA). It was found the functionalized PBAT had a better toughening effect on PLA than neat PBAT. The PLA/PBAT-GMA (70/30) blend undergoes brittle -ductile transition when the graft monomer ratio of GMA:NVP:DCP exceeds 2:2:0.2. The impact strength of PLA/PBAT-GMA (3:3:0.3) blend reached 65.7 kJ/m(2), with an elongation at break of 210.9 %. Additionally, rheological tests showed that the entanglement ability of chain segments was enhanced, it was ascribed to the improvement of the compatibility between PLA and PBATGMA owing to the compatibilization reaction between the epoxy functional groups in PBAT-GMA and the carboxyl groups in PLA, resulting in the formation of a new copolymer. DMA tests revealed that the Tg of PLA and PBAT-GMA were close to each other, confirming the improved compatibility of the PLA/PBAT-GMA blends. This offers a novel method for preparing super -though PLA.