A facile and large-scale approach to prepare macroscopic segregated polyether block amides/carbon nanostructures composites with a gradient structure for absorption-dominated electromagnetic shielding with ultra-low reflection

Conductive polymer composites have been utilized commonly as efficient electromagnetic interference (EMI) shielding materials. However, they inevitably bring distinctly secondary electromagnetic radiation. Moreover, current EMI shielding materials with low reflection also face problem of complex preparation. Therefore, it is urgent to obtain EMI shielding materials with ultra-low reflection via a simple and large-scale method. Herein, a design strategy for combining segregated structure with gradient structure was proposed to obtain EMI shielding material of ultra-low reflection. A facile, eco-friendly and large-scale approach was employed to prepare macroscopic segregated polyether block amides (PEBA)/carbon nanostructures (CNS) composites consisting of large-size PEBA beads (∼3.4 mm) via direct hot compression. The obtained nanocomposites exhibited a low percolation threshold of 0.024 wt%, good electrical heating performance with 113 °C saturation temperature and absorption-dominated EMI shielding of ∼22.9–55.3 dB with 0.1–0.5 wt% CNS, along with low R coefficient of ∼0.28–0.42. To further reduced R coefficient, the gradient structure was prepared via compression molding, which endowed gradient PEBA/CNS composites with ultra-low R coefficient of 0.071 with EMI shielding of ∼33.0 dB at 0.2 wt% CNS content. The design strategy provided an eco-friendly and large-scale method to obtain EMI shielding material with ultra-low reflection.