Lightweight, Highly\nEfficient,\nand Recyclable Absorption-Dominated\nElectromagnetic Interference Shielding Foams Based on Molecularly\nDesigned Polyamide Elastomer/Carbon Nanotube Nanocomposites

Abstract

In this study, a\npolyamide elastomer system with excellent foamability\nwas synthesized. Single-walled carbon nanotube (SWCNT) fillers were\ncombined to fabricate a series of nanocomposites. Following supercritical\ncarbon dioxide (sc-CO₂) foaming, a high-quality nanocomposite\nfoam system was successfully manufactured. With the incorporation\nof only 2.5 wt % SWCNT, the foamed product exhibited excellent absorption-dominated\nelectromagnetic interference (EMI) shielding performance with a specific\nshielding effectiveness (SSE) value of 209.8 dB cm³ g^–1, which was resulted from the synergistic effect induced\nby the three-dimensional conductive network of SWCNT and multiple\nreflections inside the micropores. Deformation tests were conducted,\nin which the nanocomposite foam was bent or twisted 1000 times; the\nfoam stably retained its EMI shielding capacity at more than 95% of\nthe original performance. The nanocomposite foam was both recyclable\nand refoamable, indicating its higher sustainability than traditional\nfoaming products with chemical residues or cross-linking. This study\nprovides insights into the development of high-efficiency EMI shielding\nfoams for lightweight electronic applications.