Preparation and properties of bio-based self-healing fire prevention gel reinforced with expanded graphite ligand

This study aims to facilitate fire prevention and extinguishing in coal mines through the use of peanut shells, a kind of agricultural waste. To this end, cellulose nanofibrils (CNF) extracted from peanut shells were mixed with polyvinyl alcohol (PVA), boric acid (borax), expanded graphite (EG) and NaHCO3 for preparing new self-healing PVA-borax-CNF/EG fire prevention (FP) gel. The Fourier transform infrared spectroscopy results suggest that CNF, PVA and borax have experienced copolymerization, forming many hydrogen bonds. By observing the scanning electron microscope images, it can be found that the three-dimensional structure of FP gel is orderly arranged, and the gel contains many pores and folds in which various elements are evenly and densely distributed. Product performance experiments show that the water absorption rate of PVA-Borax-CNF/EG in distilled aqueous solution is 435 times; the resistance rates of C2H4 and CO2 are 47.55% and 51.13% respectively; in addition, the combustion of PVA-Borax-CNF/EG mixed samples termination time is extended by about 109 s, indicating that it will not affect the calorific value of coal combustion. Significantly, there is a lack of studies on the action mechanism of FP gel and coal, and the FP mechanism of PVA-borax-CNF/EG is explained by the qualitative MS simulation method in this paper. PVA-borax-CNF/EG flame retardant can effectively control the oxidation of coal seams and reduce the temperature of coal, thus ensuring the physical and mental health of coal workers.