Ag-CNC nanoparticles decorated thermoplastic starch/PLA/PBAT composite film with superior antibacterial property, enhanced barrier capacity and high UV-shielding effect

Abstract

Blending thermoplastic starch (TPS) with poly (lactic acid) (PLA) and poly (butylene adipate- co -terephthalate) (PBAT) is considered as one of the most promising ways to produce fully biodegradable and renewable biopolymers. However, these composite biopolymers face challenges such as, poor mechanical performance, inferior water vapor and ultraviolet barrier resistance, and weak antibacterial property due to the incompatibility of hydrophilic TPS with hydrophobic PLA and PBAT. In this work, Ag nanoparticles were uniformly in-situ grown on cellulose nanocrystal to prepare a novel silver nanoparticles loaded-cellulose nanocrystal (Ag-CNC). Then, antimicrobial TPS/PLA/PBAT composite films with enhanced mechanical properties, superior water vapor barrier capacity and highly UV-shielding effect were fabricated by introducing Ag-CNC and oligo (lactic acid) grafting starch (OLA- g -ST, an eco-friendly compatibilizer) into TPS, PLA and PBAT matrix. As expected, the introduction of Ag-CNC significantly improved antibacterial property and UV-shielding effect (283 % increased) of TPS/PLA/PBAT composite films. Moreover, the incorporation of OLA- g -ST and Ag-CNC into the composites resulted in a notable enhancement of the mechanical properties (tensile strength and elongation at break increased by 77.95 % and 63.23 %, respectively) and water vapor barrier capacity (40.8 % increased) of TPS/PLA/PBAT composite films. Hence, the innovative fully biodegradable composite films displayed remarkable potential in the field of renewable biopolymers as well as multifunctional packages. • Fully biodegradable AOTPPFs based on TPS, PLA and PBAT were fabricated for packaging. • OLA- g -ST effectively improved the compatibility between TPS and PLA/PBAT. • Ag-CNC significantly improved antibacterial property and UV-shielding effect of AOTPPFs. • OLA- g -ST and Ag-CNC effectively enhanced mechanical properties and water vapor barrier capacity of AOTPPFs.