Study on the Properties of Proanthocyanidins Modified Temperature Sensitive Gel Composite Inhibitor for Inhibiting Coal Spontaneous Combustion

To address the disadvantages of the single inhibition effect, poor inhibition effect and short inhibition life of the inhibitors used in coal mining, a temperature-sensitive gel composite inhibitor was developed in this study. Polyacrylic acid (PAA), n-isopropylacrylamide (NIPA) and proanthocyanidin (OPC) were used as raw materials. The inhibition property and mechanism of the temperature-sensitive gel composite inhibitor were studied using scanning electron microscopy (SEM), infrared spectroscopy (IR), temperature sensitivity tests and thermogravimetric analysis (TGA). The results indicate that OPC/P(NIPA-co-AA) is able to fill the coal interstitial space and isolates oxygen to weaken the oxygen-coal reaction. The absorption peak of the chemically stable ether bond increases, and the content of methyl and methylene groups that can easily react with oxygen decreases in the OPC/P(NIPA-co-AA)-inhibited coal sample, indicating that the stability of the inhibited coal sample is improved. The sensitive temperature of OPC/P(NIPA-co-AA) is around 55°C, and the composite inhibitor reduces the temperature of water loss when the coal heat storage reaches the sensitive temperature, which improves the physical inhibitory effect. The ignition temperature of the OPC/P(NIPA-co-AA)-inhibited coal sample is 6.94°C higher than that of the raw coal, whereas the oxidation reaction of the OPC/P(NIPA-co-AA)-inhibited coal sample is more difficult. The temperature-sensitive gel composite inhibitor exhibits good inhibitory performance in both physical and chemical aspects, and it can significantly inhibit the spontaneous combustion of coal.