Novel Designed PEG‐Dicationic Imidazolium‐Based Ionic Liquids as Effective Plasticizers for Sustainable Polylactide

Abstract

Main observation and conclusionA 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 (Tg) and cold crystallization temperature (Tcc) 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.