Flexible thermoplastic polyurethane/reduced graphene oxide composite foams for electromagnetic interference shielding with high absorption characteristic

Abstract Lightweight and flexible thermoplastic polyurethane/reduced graphene oxide (TPU/RGO) composite foams for electromagnetic interference shielding (EMI SE) were fabricated through a supercritical CO2 foaming method. The hydrogen-bond interaction formed through in-situ reduction by L-ascorbic acid in samples contributed to good interface adhesion and good flexibility of foamed samples. Multistage cellular were formed after scCO2 foaming, in this way, the density of samples was effectively reduced and the size of cells depends on the content of RGO. And the constructing of segregated structure in TPU/RGO composites contributed significantly to the electrical conductivity of samples. Shielding effectiveness of 21.8 dB was achieved with only 3.17 vol% RGO loading owing to the multistage cellular structure with good conductive network. In addition, the introduction of cellular structure enhanced the electromagnetic shielding absorption characteristic of the samples. This result demonstrated a promising method to fabricate flexible and lightweight composite foams for absorption-dominated electromagnetic interference shielding.