A new type of efficient
and anti-extinguishing materials to inhibit
coal spontaneous combustion is required because of the current situation
of the short activity cycle of existing anti-extinguishing technology.
Now, polyethylene glycol (PEG) was used as a water-absorbing monomer
to polymerize various substances to prepare an AB-type mining thermosensitive
hydrogel that was obviously thermoresponsive. The thermosensitive
hydrogel, which is low-cost and stable, can be stored for a long time,
and it is prepared by compounding A and B components. The orthogonal
experiments determined the optimal ratio of component A, while the
controlling variable experiments determined the optimal ratio of component
B. The thermal stability and flame-retardant properties of the AB-type
thermosensitive hydrogel were analyzed during the process of natural
oxidation of coal, and the temperature responsiveness of thermosensitive
hydrogels was investigated at different temperatures. The results
showed that the optimal ratio of polyethylene glycol:methyl cellulose:sodium
carboxymethyl cellulose:guar gum of component A was 6:6:1.2:1.5; and
the ratio of bentonite:kaolin:Mg(OH)2 of component B was
2:1:1. When the ratio of component A to component B was 1:2, the AB-type
thermosensitive hydrogel shows the best flame retardant properties.
When this ratio of gel was applied to coal samples, the weight loss
was just 6%, and the reduction of CO was as high as 72.6%. The gel,
which was convenient for transportation in mining pipelines, had strong
fluidity at low temperatures and rapid temperature response. As the
temperature rose, a phase transition occurred gradually, and after
the phase transition, a high-viscosity solid substance was formed,
whose viscosity was approximately 11 times that of the room temperature.
It plugged the pores effectively, and in the high-temperature region,
the occurred phase transition gathered to extinguish the fire. It
is a new type of high-efficiency anti-extinguishing material with
excellent properties.