A strong, excellent water resistance, and anti-ultraviolet poly(vinyl alcohol)/lignocellulose/poly(butylene adipate-co-terephthalate) composite with "sandwich" structure.

Renewable materials derived from lignocellulose are promising materials for different practical applications, including biomedical, food, and agricultural fields. However, the poor mechanical performance and wet stability restrict their applications. Herein, we fabricated PVA/lignocellulose/PBAT (PVA/CLM/PBAT) composite with a "sandwich" structure. Cellulose-lignin mixture (CLM) was prepared by deep eutectic solvent (DES) pretreatment of corn straw. It served as a reinforcing scaffold of Poly (Vinyl Alcohol) (PVA) film for improving mechanical properties, UV blocking and decrease water permeability. Poly (butylene adipate-co-terephthalate) (PBAT) was used as "protector" with PVA/CLM composites by solvent coating method. The tensile strength of PVA/CLM/PBAT is 63.92 MPa. The results show that 27.93 MPa of tensile strength and 179.98 % of elongation at break of PVA/CLM/PBAT are achieved after immersing in water for 2 h, which was remarkable higher than that of PVA/CLM without PBAT coating (4.78 MPa and 111.43 %, respectively). The bonding strength of PVA/CLM/PBAT is 2.44 ± 0.06 N/15 mm. The hydrogen bonds, π-π interaction between PBAT, PVA, and CLM enhance the bonding strength of PVA/CLM/PBAT composites. The water absorption rate of PVA/CLM/PBAT is only 4.4 % after 20 h, which showed a remarkable water resistance. 25 wt% CLM content in PVA/CLM/PBAT composite can fully shield ultraviolet at 200-800 nm, indicating that the remarkable UV shielding capability.