Synergistic effect of maltodextrin/sodium polyacrylate to prepare cellulose nanocrystals with excellent water redispersibility

Cellulose nanocrystals (CNCs), which are abundant in OH groups, form hydrogen bonds and are difficult to be redispersed after dehydration and drying, losing unique nano-effects. In this study, we propose a simple and green method to overcome aggregation. The results demonstrate that Re_{(15MDX-0.3PAAS)}-CNCs prepared by simultaneously adding 15 % maltodextrin (MDX) and 0.3 % sodium polyacrylate (PAAS) are the same as original CNCs. Characterization results indicate that the presence of MDX and PAAS has no significant effect on the chemical and crystalline structure of original CNCs. The Z-average and Zeta potential of Re_{(15MDX-0.3PAAS)}-CNCs after redispersion are 113 nm and - 46.1 mV, respectively, which are consistent with original CNCs measurement. TEM shows that only a small amount of MDX is observed on the Re_{(15MDX-0.3PAAS)}-CNCs surface, its size structure is not obviously different from original CNCs. This is mainly because MDX and PAAS are selected as hydrogen bonding blocking agent and dispersant, and stabilizer, respectively. Electrostatic repulsion is formed between CNCs and PAAS during the drying and dehydration of CNCs, which promotes the complete adhesion of MDX to the CNCs surface and prevents the formation of hydrogen bonds between OH groups in CNCs. The above-mentioned method is beneficial for CNCs to maintain excellent nano-effects.