The plasticization mechanism of polyacrylonitrile/1-butyl-3-methylimidazolium chloride system

The external plasticization of polyacrylonitrile (PAN) with high molecular weight was achieved, where 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was explored as a novel plasticizer. The interaction and plasticization mechanism in PAN/[Bmim]Cl system were investigated. The Fourier transform infrared spectroscopy (FTIR) results show that there exists strong hydrogen interaction between nitrile (CN) groups of PAN and unsaturated C–H of imidazolium rings in [Bmim]Cl at high temperature. The addition of [Bmim]Cl leads to the decrease in glass transition temperature, melting temperature and paracrystalline content of the system due to the high penetration efficiency of [Bmim]Cl. The rheology of the system was studied as well, which proves the occurrence of the cyclization and oxidation reactions of PAN macromolecular chains along with X-ray photoelectron spectrometer and FTIR results. The cyclization reaction is significantly influenced by the [Bmim]Cl content in whole system, which further affects the spinnability of PAN/[Bmim]Cl system and ladder structure of the prepared fibers.