Flame-Retardant and Electromagnetic Interference Shielding Hierarchical Composites by Interfacial Integration of TPU/APP@ZrCu-MOF/SCF and Functionalized Polyester Fabric

Developing flexible textiles with effective electromagnetic interference (EMI) shielding is highly attractive for wearable devices and electronic protection applications. However, achieving both excellent flame retardancy and EMI shielding performance in flexible textile systems remains a great challenge due to the inherent flammability of textiles and the poor durability of modified coatings. In this work, thermoplastic polyurethane (TPU) incorporating a metal–organic framework-encapsulated ammonium polyphosphate (APP@ZrCu-MOF) and short carbon fibers serves as the outer layers. The polyester (PET) fabric modified by the alternating deposition of MXene and reduced graphene oxide is used as the intermediate layer. These components are assembled into a flexible multilayer composite by employing an air-assisted hot-pressing technique. Among the prepared composites, TMS4P3 exhibits markedly improved fire safety, which has a high limiting oxygen index of 29.5%. Compared with the unmodified PET/TPU composite, the peak heat release rate, total heat release, peak smoke production rate, and total smoke release of TMS4P3 decrease by 44.9, 41.4, 60.0, and 42.7%, respectively. In addition, TMS4P3 exhibits average EMI shielding effectiveness values of 30.4 and 31.9 dB in the X and Ku bands, respectively. This study provides a promising approach for broadening the applications of PET fabrics and TPU and offers an effective strategy for the fabrication of multifunctional flexible composites.