A series of novel polyethylene glycol-dicationic imidazolium-based ionic liquids (mPEG-ILs) were synthesized by facile quaternization reaction from various elaborately designed di-imidazoles and PEG, which were then studied as green plasticizers for sustainable polylactide (PLA) material. The influences of the chain structure, content, and molecular weight of the mPEG-ILs on the plasticizing effect were systematically investigated by characterization of a series of PLA/mPEG-ILs blending systems. FTIR results show there is combination of ion-dipole interaction and hydrogen bonds interaction between PLA and mPEG-ILs, which is beneficial for the compatibility. Thermal behaviors indicate that mPEG-ILs have a significant plasticizing effect on PLA. Particularly, mPEG400-amide-IM can remarkably improve the mobility of PLA chain, leading to decreased glass transition temperature (T g ) and cold crystallization temperature (T cc ) of PLA. Tensile test results show that the ductility of plasticized PLA is greatly enhanced, and its elongation at break reaches 249.4%, which is 22 times that of neat PLA.

Herein, high-performance sustainable ternary blends were prepared via a melt blending method from completely biodegradable polyesters, namely commercial polylactide (PLA), poly(propylene carbonate) (PPC) and a series of poly(hydroxyalkanoate)s (PHAs), including poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydoxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and two types of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P 34 HB) having different 3HB molar ratios. The miscibility, phase structure, mechanical and thermal properties of the blends were investigated to deeply understand the influence of the blend compositions and species of PHAs on the structure and physical performance of the multiphase blends. Thermal and morphological analysis revealed that the PLA, PPC and PHAs components showed partial miscibility with each other, especially the blend with P 34 HB of a low 3HB ratio. Remarkable enhancement in the ductility and toughness of PLA was gained by the addition of PPC and P 34 HB. An optimum tensile strain of 171% was achieved for the PLA/PPC/P 34 HB (60/30/10) blend, while PLA/PPC/P 34 HB (60/10/30) blend showed the highest impact strength with a value of 45 kJ m À2 , which is 14 times higher than that of PLA. Synergistic toughening from the flexible PPC and P 34 HB phase with a degree of interfacial compatibilization played an effective role in enhancing the mechanical performance of the ternary blends.