Synthesis and performance of a new temperature-sensitive and super-absorbent fire prevention hydrogel based on ultrasonic method

To prevent spontaneous combustion of coal, a new type of temperature-sensitive, highly absorbent, fire-extinguishing hydrogel has been developed. Using Xylan and carboxymethylcellulose sodium as the matrix, free radical copolymerization with N-isopropylacrylamide and 2-acrylamido-2-methylpropane sulfonic acid was performed under ultrasonic vibration to obtain the final product. The experimental results show that the resulting hydrogel has high fluidity and good water absorption at low temperatures. After being subjected to high temperatures, this hydrogel undergoes a phase change, its viscosity increases, its volume decreases, and water in the gel is discharged. It can cool, cover, and block spontaneously combustible coal more efficiently, overcome the shortcomings of traditional hydrogels that have high viscosity and poor fluidity and that also easily block pipelines. The base material used is a biodegradable material that can avoid secondary pollution to the environment. In addition, the microscopic reaction and structure of the product were analyzed by using infrared spectroscopy, X-ray diffraction, thermogravimetry and scanning electron microscopy. The gel performance was tested by examining the viscosities, swelling kinetics, resistance rates, which proved that the product has strong temperature responsiveness, high water absorption rate, and obvious fire extinguishing effect. The gelation and flame retardant mechanisms of thermosensitive hydrogels were profoundly elucidated from the molecular level by molecular dynamics simulation technology.