Mining Polyethylene Glycol-Based Thermosensitive Hydrogel Materials: Preparation and Flame Retardant Properties

Abstract

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.

Hydrogel and aerogel‐based flame‐retardant polymeric materials: A review

“…More examples, for example, PEGbased hydrogels for coal, are also available. 109 Zheng et al 84 added woven basalt fibers as a biobased additive combined with APP (up to 19 wt%) to enhance fire resistance of polyacrylamide hydrogels. The samples were prepared as N,N-methylenebisacrylamide (MBAA) added to the water solution of acrylamide, and also APP added to the mixture, as well as the TEMED used as an accelerator of the polymerization.…”

“…This hydrogel was tested on the coal and exhibited enhanced air‐leakage blocking by covering the burning coal surface, filling cracks and preventing re‐ignition. More examples, for example, PEG‐based hydrogels for coal, are also available 109 …”

Study on the gelation and sustained release effect of the thermosensitive material TPGS1000

“…14 With the increase of temperature, the structure of PEG will shrink. 15,16 That is, it is sensitive to temperature. Therefore, PEG is often used as the temperature-sensitive material to form PEG-based hydrogels.…”

“…Among them, PEG 1000 is the most widely studied and applied 14 . With the increase of temperature, the structure of PEG will shrink 15,16 . That is, it is sensitive to temperature.…”