Radiation effects on microcrystalline cellulose in 1-butyl-3-methylimidazolium chloride ionic liquid

The radiation processing of cellulose in ionic liquids (ILs) demands a comprehensive knowledge of radiation effects on cellulose in ILs. Herein, gamma radiation-induced degradation kinetics of microcrystalline cellulose (MCC) in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was studied by viscometry. The intrinsic viscosity of MCC in [Bmim]Cl decreased slightly with increasing dose; while chemical structure and crystalline state of cellulose has no obvious change up to 300 kGy. The radiation degradation rate constant (k) of MCC in [Bmim]Cl was 2.60 × 10−7/kGy, lower than that of solid cellulose, but higher than that in N-methylmorpholine-N-oxide (NMMO) solvent. Furthermore, k value decreased to 1.12 × 10−7/kGy in dimethyl sulfoxide (DMSO)/[Bmim]Cl system due to the free radicals scavenging of DMSO. The radicals generated during irradiation play main role in the radiation degradation of MCC in [Bmim]Cl. This work provides a new way to control the average molecular weight of cellulose by radiation-induced degradation of cellulose in ILs.