A study of the inhibition properties of gallic acid/lignin-modified hydrogel inhibitor prepared via graft copolymerization

In view of the shortcomings of pure hydrogels, such as a single inhibition effect and poor stability at high temperatures, this study aims to develop a new composite hydrogel inhibitor and to study its inhibition mechanism. To this end, gallic acid and lignin were added to modify the hydrogel, and a gallic acid/lignin-modified hydrogel (GA/LG-PAA) inhibitor was prepared. By scanning electron microscope, it was discovered that inhibited coal samples treated with gallic acid hydrogel (GA-PAA) and GA/LG-PAA had bigger particles. By using thermogravimetric analysis, it was found that after the inhibition treatment with GA/LG-PAA, the coal samples' characteristic temperature points have increased to different degrees. Among these, the dry cracking temperature was increased by 53.87 degree celsius, the ignition temperature was increased by 20.23 degree celsius, and the burnout temperature was increased by 19.79 degree celsius. Thermogravimetric experiments therefore showed that GA/LG-PAA had the best inhibition effect. Through infrared diffuse reflection experiments, it was found that the peak areas of methylene, carbonyl, carbon-carbon double bond, ether bond and other functional groups were all increased in coal samples after inhibition. The GA/LG-PAA inhibited spontaneous combustion by forming ether bonds. The results show that GA/LG-PAA can effectively inhibit coal spontaneous combustion.