Simultaneously improved electromagnetic interference shielding and flame retarding properties of poly (butylene succinate)/thermoplastic polyurethane blends by constructing segregated flame retardants and multi-walled carbon nanotubes double network

Simultaneous improvement on the electromagnetic interference (EMI) shielding and flame retardancy of polymer composites is dependent on the controllable distribution of functional fillers. Herein, a facile method to control distribution of multi-walled carbon nanotubes (MWCNTs) and flame retardants in poly (butylene succinate)/thermoplastic polyurethane blends by constructing segregated structure was reported. High-efficiently conductive networks could be easily constructed in segregated structure, resulting in a low percolation threshold of 0.22 wt%. High EMI shielding effectiveness of similar to 45 dB could be achieved in segregated samples with 2.5 wt% MWCNTs which far exceeds commercial requirement. Furthermore, the segregated samples also exhibited excellent flame retardancy and the UL-94 rating reached V-0 with prompt self-extinguishment and disappeared melt-dripping. More importantly, this unique network could provide synergistic enhancement for the flame retardancy which increases with the increasing of MWCNTs loading. Accordingly, this work provided a promising route to fabricate various high-performance EMI shielding polymer composites with excellent flame retardancy.