Effects of delignification in the production of plant-based cellulose nanofibers for optically transparent nanocomposites

The pulp-making procedures prior to nanofibrillation require considerable chemical treatments to leach the matrix substances. In particular, the sodium chlorite (NaClO2) solution treatment is cyclically applied to remove lignin. In this study, we clarified the effects of delignification in the production of cellulose nanofibers and nanocomposites through a comparison of plants with lignin (2 year old lignified mature bamboo culms) and without lignin (immature bamboo shoot culms). We concluded that the NaClO2 treatment might have degraded the cellulose nanofibers, as we found that the morphology and properties of the cellulose nanofibers extracted from mature bamboo had no advantages over the nanofibers from immature bamboo. In addition, the light transmittance of the cellulose nanocomposites from immature bamboo was higher even at lower wavelengths.