Coal-induced in-situ gelation of an injectable P(SA-co-IA) dust suppressant for source control of coal dust

Coal-induced APS activation enables in-situ gelation within the coal matrix. • DSS retains multiscale penetration before gelation at approximately 63 h. • EPR and APS-consumption tests support coal-induced radical generation. • Total and respirable dust generation fell by 76.46% and 88.91%. • Gelation, pore plugging, and bonding enabled durable source dust control. To address rapid moisture loss after conventional coal seam water injection and the poor coordination between penetration and gelation of traditional gel dust suppressants, an injectable P(SA-co-IA) semi-interpenetrating polymer network (semi-IPN) dust suppressant with coal-induced in-situ gelation was developed. A prepolymer solution containing short-chain P(SA-co-IA) prepolymers and residual reactive monomers was supplemented with ammonium persulfate (APS) and N,N′-methylenebisacrylamide to obtain the dust suppressant solution (DSS). After entering the coal matrix, intrinsic electron-donating functionalities activated APS, triggering radical generation and in-situ crosslinking. L NMR showed that DSS penetrated multiscale pores and approached a stable distribution after approximately 60 h. With an additional APS dosage of 8.47 wt%, gelation occurred at approximately 63 h, providing a compatible penetration–gelation window. Peroxide concentration tests, EPR, FTIR, rheological measurements, gel fraction, and SEM–EDS confirmed coal-induced APS activation and semi-IPN hydrogel formation. After 12 h, the water evaporation rate of DSS-treated coal was approximately 30%. After 72 h, total and respirable dust-generation rates decreased by 76.46% and 88.91%, respectively. BET, SEM, and molecular dynamics simulations indicated that pore plugging, surface coating, hydrogen-bond adsorption, and particle bonding enhanced coal structural stability and reduced dust generation at the source. Download: Download high-res image (243KB) Download: Download full-size image