Thermally Conductive and Absorption‐Dominant EMI Shielding in Metallic Foil‐Supported Thermotropic Polyarylate/Carbonyl Iron Particle Composite Laminates

ABSTRACT

Metallic foil‐supported polymer composites that integrate enhanced thermal transport with absorption‐dominant electromagnetic interference (EMI) shielding are highly attractive for advanced electronic systems. In this study, asymmetric hybrid laminates composed of a thin aluminum (Al) foil and a thermotropic polyarylate/carbonyl iron particle (TP/CIP) composite layer were developed and systematically evaluated. The TP/CIP composites exhibited uniform filler dispersion, strong interfacial integrity, and preserved polymer matrix stability. Increasing CIP content enhanced the dielectric response and X‐band shielding effectiveness of the TP/CIP composites, resulting in a thickness‐normalized shielding effectiveness of ~18 dB/mm for TCIP80. Despite high filler loading, the composites maintained through‐thickness electrical insulation (10 ⁻¹¹ –10 ⁻⁸  S/cm) and demonstrated significantly improved thermal conductivity, increasing from 0.300 to 1.195 W/(m K) (~300% enhancement). Upon lamination with a 20 μm Al foil, the shielding behavior transitioned from reflection‐dominant to absorption‐dominant as the TP/CIP layer thickness increased. At TCIP80 layer thicknesses of 480 μm or greater, the absorption coefficient exceeded both 0.5 and the corresponding reflection coefficient. The optimized TCIP80‐960@Al laminate exhibited a total shielding effectiveness of ~54.9 dB, an absorption coefficient of ~0.73, and a reflection coefficient of ~0.27. This transition is attributed to reduced front‐surface reflection and enhanced electromagnetic attenuation within the TP/CIP layer. These findings establish thickness‐engineered TP/CIP‐on‐Al laminates as promising candidates for thermally conductive, electrically insulating, and absorption‐dominant EMI shielding in high‐frequency applications.