Expandable graphite embedded in flexible polymer surfaces for fire detection in multiple modes

Abstract Fire detection sensors are a necessary facility to ensure fire safety. The long fire response time and the false fire alarms caused by a single fire response mode are urgent problems for fire detection sensors. Here, a strategy of embedding expandable graphite (EG) in the sample surface of a styrene‐butadiene‐styrene block copolymer/intumescent flame retardant is used to endow the sample with fire detection in multiple modes and early warning functions, thus shortening the fire warning time and preventing the false fire alarms. The EG improved the flame retardancy of the samples from failing to V‐0 in the vertical burning rating test. The EG also gave the samples the ability to sense tensile and bending deformation. The negative temperature effect of the EG resistance gave the sample an early warning capability for fires with warning temperatures as low as 200°C. The rapid expansion of EG exposed to flame into graphite worms was used for the rapid response of the sample to fire (response time < 1 s). The Seebeck effect with response voltage of up to 0.3 V was used for fire detection of samples based on the temperature difference of EG on the sample surface caused by the flame. This study has potential application prospects for rapid fire warning in buildings.