A facile strategy for lightweight, anti-dripping, flexible polyurethane foam with low smoke emission tendency and superior electromagnetic wave blocking

Flexible polyurethane foam (FPUF) has been considered as an excellent material in many fields, such as furniture and electromagnetic interference (EMI) shielding products due to its lightweight and flexibility. However, there is a severe fire hazard problem for FPUF that makes it unsuitable to be used in practical. Herein, a facile method was to prepare anti-dripping FPUF via electroless plating at ambient temperature. The silver nanoparticles (SNPs) were in-situ grown on the surface along with the polydopamine (PDA) as an adhesive and template (SNP@PDA@FPUF). As a result, these FPUFs show outstanding fire safety and anti-dripping capacity, and the heat release rate reduced 80.92%. Furthermore, the amounts of carbon oxide (CO) and carbon dioxide (CO₂) decreased 75.01% and 22.4%, respectively. Above all, the EMI shielding effectiveness (SE) accomplished almost 120 dB as the increasing electroless time with a low density of 0.051 g/cm³. Furthermore, the specific EMI SE (SSE) and the absolute EMI SE (SSE/t) accomplished 2630.98 dB·cm³/g and 2434 dB·cm²/g, respectively, which was far beyond the commercial request. Therefore, this work may provide a facile way to prepare low density and EMI shielding products with high fire safety for next generation electronic products.