Preparation and Performance of a Caffeic Acid Nano‐Modified Dual‐Network Gel Composite Inhibitor

ABSTRACT To address the short lifespan and persistent effects of existing flame‐retardant materials, this study developed a novel dual‐network composite gel‐based inhibitor integrating physical barrier properties, chemical inhibition, and nano‐flame retardancy. Nano‐titanium dioxide (TiO 2 ) was used as a cross‐linker to prepare a nanocomposite gel using acrylamide (AM) and N ‐isopropylacrylamide (NIPA). This was then combined with polyacrylic acid (PAA) to form a dual‐network gel. Caffeic acid (CA), a compound with antioxidant properties, was then grafted onto the gel to form the P(AM‐NIPA)@TiO 2 /PAA‐CA dual‐network gel‐based inhibitor. Scanning electron microscopy (SEM) micromorphology revealed abundant wrinkles and pores on the gel surface, enhancing its water absorption capacity. Fourier transform infrared spectroscopy (FTIR) analysis revealed that CA was successfully grafted into the gel network, as evidenced by the peak at 1150 cm −1 , indicative of ether bond formation. X‐ray photoelectron spectroscopy (XPS) revealed a 3.26% increase in the peak ether bond area in the treated coal, indicating the effective suppression of reactive functional groups. Diffuse reflectance infrared spectroscopy revealed that the composite inhibitor effectively passivated reactive functional groups such as free hydroxyl groups and inhibited the oxidative degradation of aliphatic groups. This research may provide a new approach to comprehensive spontaneous coal combustion prevention and control.