Formic-oxalic synergy unlocks bamboo nanocellulose with high-thermal-stability and superior dispersion

Nanocellulose is among the most promising sustainable materials, with the potential to replace petroleum-based counterparts. However, its application process is often hindered by challenges related to reduced thermal stability and dispersibility. We firstly devised a novel strategy for preparing bamboo cellulose nanocrystals (CNCs) via the synergistic catalysis of formic acid and oxalic acid. Meanwhile, we conducted a comparative study on the thermal and dispersion stabilities of bamboo nanocellulose prepared by multiple methods, including mechanical, sulfuric acid, formic acid, oxalic acid and citric acid ones. The initial decomposition temperature of CNC prepared by this new method can reach 308.1 °C, and the maximum thermal decomposition temperature can reach 344.1 °C. The findings demonstrate that the high thermal stability of bamboo nanocellulose is primarily attributed to the ester groups grafted onto the cellulose-OH groups. Furthermore, the simultaneous introduction of carboxyl groups makes the CNCs exhibit an exceptional zeta potential of -43.87 mV, indicating excellent dispersion stability. The study underscores the critical role of surface ester group content in determining the thermal property of nanocellulose. Overall, the development of high-performance nanocellulose has been developed, contributing to the expanded application of nanocellulose in bio-based composites.