A tunable alkaline/oxidative process for cellulose nanofibrils exhibiting different morphological, crystalline properties

This study describes a two-step alkali/oxidation process to efficiently convert waste sugarcane bagasse (SCB) into cellulose nanofibrils (CNF) whose structures have been characterized using a range of analytical techniques (SRWAXS, IR, TEM and DLS). Increasing the concentration of the NaOH solution from 10 to 16 wt% in the first step results in a gradual increase in cellulose II content from 0 to >99 %, which also produces a corresponding increase in fiber crystallinity index from 32 to 61 %. Varying the concentration of NaClO used in the second oxidative step enables the morphologies of the CNF to be reliably controlled, with fiber lengths decreasing from micrometer to nanometer levels as the amount of NaClO oxidant used is increased. This simple two-step alkaline/ oxidative treatment process enables SCB to be converted into CNF exhibiting different polymorphic and morphological properties, thus enabling their economic and reproducible production as nanostructured materials for numerous applications.

Automated summary

This study presents a two-step alkali/oxidation process to efficiently convert waste sugarcane bagasse into cellulose nanofibrils with controlled morphologies. By adjusting the concentrations of NaOH and NaClO, the cellulose content, crystallinity index, and fiber length can be effectively tailored, allowing for the production of CNF with different properties and applications.