Research on polyethylene glycol-based thermo-responsive inhibitor shell composite materials

Exposure of salt inhibitors to air leads to moisture evaporation, reducing coal moisture content and weakening the inhibitory effect on coal’s spontaneous combustion. To address this, a thermo-responsive secundina sphere inhibitor (TRSSI) was proposed, utilizing PEG 10,000 as the main phase change material for the outer shell. The salt inhibitor was encapsulated within this phase change shell, releasing the internal inhibitor when the coal surface reached the phase change temperature. By reducing PEG 10,000’s water solubility through a physical blending method, the retention rate of the matrix material increased from 23.5% to 99%. Three flame-retardant additives were selected for mechanical performance, and a silane coupling agent improved interfacial adhesion, raising the shell’s maximum stress from 1.3 MPa to 3.88 MPa and achieving a compressive strength of 21.56 N, thus meeting transportation requirements. Infrared spectroscopy demonstrated that PEG 10,000 inhibits coal oxidation by promoting stable group formation within coal, and temperature-programmed experiments indicated the TRSSI shows a superior inhibitory effect on coal’s low-temperature oxidation compared to single inhibitor liquids. This research provides the necessary theoretical knowledge and experimental conditions for subsequent large-scale laboratory experiments involving the spreading of small spheres on coal seams.