Modified nano-lignocellulose preparation by azolidinone and its application in polylactic acid composite film and paper coating

Cleverly combining the hydrophobicity and flexibility of polylactic acid (Ling et al.) with the high barrier properties of nanocellulose (CN) will create a promising raw material for degradable membrane materials and paper-plastic composites. However, compatibility and dispersibility of CN with PLA (Polylactic acid) are the main challenges of this study. Herein, a deep eutectic solvent (DES) composed with oxalic acid and choline chloride was utilized to retain lignin and cellulose within lignocellulose and oxazolidinones was employed to aminate the retained lignin to enhance compatibility between LCNF (Nano-lignocellulose) and PLA (Polylactic acid). The results indicated that the synthesized Nano-lignocellulose exhibits excellent dispersion stability and good interfacial compatibility with PLA. The PLA/LCNF composite solvent not only demonstrated favorable dispersion stability but also enhanced the tensile strength of the composite film by 31.60 %, improved the thermostability and antibacterial performance simultaneously. As the barrier coating, the contact angle of the coated paper is significantly larger than that of filter paper, indicating a excellent hydrophobicity and water stability. Additionally, the bursting resistance of the coated paper improved by 24.48 %, while the tearing strength increased by 9.20 %. The LCNF/PLA coating effectively covers the surface of the paper fibers, fills internal pores, and significantly enhances barrier performance, with water vapor and oxygen barrier rates increasing by 96.82 % and 98.65 %, respectively. • This DES removed hemicellulose selectively, promoted cellulose esterification and microfiberization. • Azolidinone-modified Nano-lignocellulose improved its compatibility with polylactic acid. • The PLA/LCNF composite membrane had excellent mechanical and antibacterial properties. • The PLA/LCNF coating significantly improved the paper's barrier and antibacterial properties.