Synergistic Reinforcement of Poly(butylene adipate- co -terephthalate) Composite Films by Sequentially Modified h-BN@ZnO Fillers with Polydopamine and Octadecylamine

Abstract

Inspired by the brick-and-mortar architecture of natural nacre and mussel-adhesion chemistry, a biomimetic synergistic strategy was proposed to fabricate multifunctional poly(butylene adipate-co-terephthalate) (PBAT) composite films with a nacre-like architecture. This strategy integrates hexagonal boron nitride (h-BN)@ZnO hybrid filler construction with polydopamine (PDA) and octadecylamine (ODA) regulation of the filler-matrix interface. In this design, ZnO nanoparticles acted as physical spacers to suppress h-BN aggregation, while the PDA-ODA bilayer strengthened the interfacial adhesion through chain entanglement and hydrogen bonding. With only 1 wt % modified filler, the composite film attained a tensile strength of 42.2 MPa, 29.5% higher than that with unmodified h-BN, while retaining an elongation at a break of 543%. The synergistic ultraviolet (UV) protective mechanism involving PDA and ZnO endowed the films with excellent aging resistance. After 144 h of accelerated aging, the tensile strength retention of the film containing 5 wt % filler was 78.5% higher than that of neat PBAT. Meanwhile, the water vapor barrier performance was improved by 20.8%, the UV-shielding efficiency increased by 91.1%, and the hydrophobicity and thermal conductivity were also markedly enhanced. The film containing 3 wt % filler extended the shelf life of high-moisture fruits to more than 7 days. Under soil-burial conditions, the film with 1 wt % filler exhibited a mass loss of over 50% after 120 days, substantially exceeding that of neat PBAT, indicating that this material can degrade rapidly when it is discarded in soil. This biomimetic strategy provides an effective route for expanding the application potential of PBAT-based films.