Preparation and characterization of carboxymethyl glucuronoxylan/polyvinyl alcohol/ε-poly-(L-lysine) carbon dots/ZnCl2 composite films with antibacterial properties

Polyvinyl alcohol (PVA)-based films are widely used due to their mechanical properties and biodegradability. However, their limitations in water resistance and oxygen barrier properties hindered their further application in packaging industry. In this work, carboxymethyl glucuronoxylan/polyvinyl alcohol/ε-poly-(L-lysine) carbon dots/ZnCl 2 composite films with high mechanical properties and antibacterial properties were developed. First, carboxymethyl glucuronoxylan (CMX) and ε-poly-(L-lysine) carbon dots (PL-CD) were synthesized. The structural groups of CMX and PL-CD were confirmed by the FTIR. Then, CMX/PVA/ZnCl 2 /PL-CD composite films were prepared by casting method. With the addition of PVA, ZnCl 2 and PL-CD, the composite films demonstrated a notable improvement in mechanical properties, contact angle (tensile strength: 8.65 MPa ~ 22.4 MPa, elongation at break: 1.1% ~ 4.2%, Young’s modulus: 549.1 MPa ~ 1114.7 MPa, contact angel: 74.7° ~ 105.3°, OTR: 2.04 cm 3 /(m 2 ·day) ~ 3.67 cm 3 /(m 2 ·day)). In addition, all the composite films showed excellent antibacterial properties with the addition of PL-CD. Hence, the carboxymethyl glucuronoxylan/polyvinyl alcohol/ε-poly-(L-lysine) carbon dots/ZnCl 2 composite films holds significant promise for diverse applications in the packaging industry.