Enhancing Thermal Insulating and Flame Retardancy of Electromagnetic Shielding Polyester-Based Nonwoven Fabric

Electromagnetic radiation pollution poses significant threats to both electronic equipment functionality and human health, necessitating the advancement of electromagnetic shielding materials. Among them, electromagnetic shielding nonwoven fabrics offer notable advantages, such as lightweight, affordability, simplicity in production, and versatility in application. This study focuses on utilizing polyester fiber (PET) as the base material, surface-modified with polyethylenimine (PEI), and impregnated with nanocarbon material slurry. Subsequently, electromagnetic shielding nonwoven fabrics are fabricated via a hot-pressing process. The micromorphology and electromagnetic shielding performance of the resulting fabrics were characterized through SEM observation and vector network analyzer measurement. Results demonstrate that employing a mixed solution of carbon nanotubes (CNTs), graphene (Gr), and polypyrrole (PPy) in a mass ratio of 6:1, alongside hot pressing at 240 °C with three layers, yields polyester fiber-based nonwoven fabrics with exceptional electromagnetic shielding effectiveness, achieving a shielding coefficient of up to 65 dB. Meanwhile, polyester nonwoven fabrics showed significant flame retardancy and prolonged burning time after impregnation with electromagnetic shielding materials, and the burning time of PET nonwoven fabric impregnated with CNTs/Gr/PPy was prolonged to 61 s. This research underscores the electromagnetic shielding prowess of polyester fiber-based nonwoven fabrics and their wide-ranging applications in electrical circuit protection, military equipment, and beyond, and offers insights for their large-scale production.