Flame-retardant shape memory polyurethane/MXene paper and the application for early fire alarm sensor

Traditional fire warning sensors usually work under directly fire attack or relatively high temperature and overlook electrical safety. Therefore, it is imperative to develop an efficient early fire warning sensor with the circuit safety during flame exposure. Herein, a flame-retardant paper with thermosensitive fire-alarm response and self-cutting performance is proposed. The paper consists of shape memory thermoplastic polyurethane (SMPU) and MXene is prepared via facile electrospinning and vacuum filtering process, which can be utilized as a fire early alarm triggered by the shape memory behavior of SMPU. The SMPU/MXene paper can provide a stable detection signal and ideal early fire warning responses when the ambient temperature is above transition temperature of SMPU. Meanwhile, it is possible for SMPU/MXene paper to serve as a fuse to protect the fire alarm system from fire attacking based on the electro-activated property. Compared to SMPU paper, SMPU/MXene paper showed superior fire retardancy with a rapid self-extinguishing performance, as well as 66.0% and 49.8% reduction in peak of heat release rate (pHRR) and total heat rate (THR), respectively. This work provides a novel perspective for designing early detection fire-alarm sensors and fire-protection applications.