Revisiting NaOH Addition during the Amination of Cellulose Nanocrystals

There is growing recognition that both cellulose nanocrystal (CNC) source and production scheme affect their physicochemical properties and dispersion behavior. However, how these differences affect CNC surface chemistry modification has been largely unexplored. This work investigated how the combination of CNC source and counterion affects one of the most common functionalization reactions, amination. The original CNC amination scheme was developed for sulfated CNCs derived from cotton, while most current research uses commercial sulfated CNCs from wood, which contain sodium instead of hydrogen counterions. This study evaluated whether the sodium hydroxide addition, used in the original method, improves amination efficiency for commercial wood CNCs. Surprisingly, the results showed that sodium hydroxide did not enhance amination efficiency for either cotton or wood-derived CNCs. When the aminated CNCs were further functionalized with an herbicide, less than 10% of the amine groups reacted, highlighting the need for further refinement of the process.