Esterification and Acidolysis Controlled Multifunctional PBAT/Thermoplastic Starch (TPS) Films with Nano Mica Exfoliated by Critic Acid: Regulable Degradation, Excellent UV Resistance, Enhanced Interfacial Compatibility, and High Water Vapor Barrier

Multifunctional value-added biodegradable materials are significant for addressing issues of plastics waste in a green, cost-effective, and energy-saving way. In this work, the nano mica (Mica) was both exfoliated and interfacial double esterified by critic acid (CA) in a facile one-step method to achieve multifunctional biodegradable polybutylene adipate/terephthalate (PBAT)/thermoplastic starch (TPS) films. As a result, the obtained composite with 1 phr Mica (P4T6-1Mica) demonstrated excellent comprehensive performances under the coordination of esterification and acidolysis of CA. The crystallinity and tensile strength of P4T6-1Mica were 240 and 56% higher than those of original composite (P4T6C0.5), attributed to the heterogeneous nucleation of Mica and improved interfacial compatibility. P4T6-1Mica also exhibited a lower water vapor transmission rate (WVT) of 73.39 g/m 2 ·24 h, representing a 39.3% improvement over P4T6C0.5. The decreased WVT was assigned to the hindering paths caused by CA esterification and acidolysis and the original barrier of Mica. At 10 weeks, the biodegradation rates for P4T6C0.5, P4T6-1Mica, and P4T6-2Mica were 56.3, 37.5, and 33.1%, respectively, indicating regulable biodegradation. The incorporation of exfoliated Mica even enhances UV resistance and transmittance of the film. The design of double esterification and a one-step process offers sustainable, affordable, and energy-saving approaches for developing multifunctional biodegradable materials to address plastic pollutions.