Long-Chain Fatty Acid–Modified Cu-MOFs for Constructing Multifunctional PBAT/PLA Composite Films: Interfacial Regulation, Intelligent Responsiveness, and Hydrothermal Stability

Abstract

The Poly (butylene adipate-co-terephthalate) (PBAT) and Poly (lactic acid) (PLA) blend system has garnered significant attention due to its excellent biodegradability and complementary properties. However, the inherent incompatibility between the two polymers has somewhat limited its further development. In this study, Cu-MOF was successfully synthesized via a hydrothermal method. It was surface-modified using organic acids with different carbon chain lengths and incorporated into the PBAT/PLA polymer matrix to enhance interfacial compatibility. Results indicate that incorporating M-Cu-MOF as a functional filler into PBAT/PLA composite films enhances multiple properties. Among these, SA-Cu-MOF composite films exhibit optimal comprehensive performance: a water contact angle of 101°, and reduced water vapor and oxygen transmission rates by 30.75% and 62.19%, respectively. Additionally, the films exhibited excellent antibacterial activity, ammonia visualization response capability, and enhanced hydrothermal degradation rates. Long-chain organic acids influenced the macroscopic properties of M-Cu-MOF/PBAT/PBAT composite films by affecting the microstructure and dispersion of Cu-MOF. These results demonstrate that the Cu-MOF surface modification strategy based on regulating the carbon chain length of organic acids provides an effective approach for constructing high-performance, multifunctional, and controllably degradable PBAT/PLA green packaging films.