Novel Designed Peg-Dicationic Imidazolium-Based Ionic Liquids As Effective Plasticizers For Sustainable Polylactide

Main observation and conclusion 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.