a process for producing cellulose nanocrystals involves providing a cellulosic material , contacting the cellulosic material with an inorganic persulfate at an elevated temperature to produce cncs , and recovering the cncs . the process permits one - step production of cncs from vegetative biomasses such as flax and hemp . cellulose nanocrystals produced by the process with carboxylic groups are more uniform and have higher aspect ratios than cncs produced by prior art processes .