Characterization of cellulose II nanoparticles regenerated from 1-butyl-3-methylimidazolium chloride

► The crystalline structure of cellulose was converted from cellulose I-II with decreased crystallinity after a combined 1-butyl-3-methylimidazolium chloride [BMIM]+[Cl]− and high pressure homogeneration treatment. ► The regenerated cellulose II nanoelements had both elongated fiber and spherical structures. ► Measured length and width data of the elongated cellulose II nanoelements followed asymmetrical log-normal distributions. ► The cellulose II nanoelements had a two-step thermal pyrolysis process.