Imogolite nanotubes (INTs) were synthesized from tetraethoxysilane, aluminum nitrate nonahydrate, and ammonia solution by the method of Arancibia-Miranda, and their dispersion was modified by 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF₆) to obtain ionic liquid (IL)-functionalized INTs (INTs-PF₆-ILs). Then, the flame retardant INTs-PF₆-ILs was complexed with ammonium polyphosphate (APP) and applied to unsaturated polyester resin (UPR). The limiting oxygen index value and the UL-94 level of the UPR/APP/INTs-PF₆-ILs composites reached 28 and V-0, respectively. The residual carbon of the composites in thermogravimetric analysis increased by 19.47%, compared with that of pure UPR. The cone calorimeter test result showed that the peak of heat release rate and total heat rate values of the UPR/APP/INTs-PF₆-ILs composites were lowered by 41 and 34% than those of the pure UPR, respectively. The effect of heat combustion and the maximum mass loss rate of UPR/APP/INTs-PF₆-ILs composites were also greatly decreased. There were no holes or folds observed on the surface of the UPR/APP/INTs-PF₆-ILs composites' residual carbon in scanning electron microscopy images. The intact residual carbon could have effectively insulated the heat and oxygen to improve the flame retardant performance.

Aiming at the calculation problem of bearing pressure of typical overlying strata structure, in this paper, mechanical calculation, field monitoring and other methods are used to study the influence range of abutment pressure. Recently, many major rock burst accidents in working surface show that with the increase of mining depth and the change of overlying strata structure, the abutment pressure distribution has become one of the problems of safe mining. The influence range, distribution of high stress area and peak position of working surface support pressure need to be solved urgently; and through theoretical analysis, this paper reveals (whole rock single-layer structure, whole rock layered structure, whole rock single-layer structure—without arch in soil layer, whole rock layered structure—without arch in soil layer, whole rock single-layer structure—with soil arching, whole rock layered structure—with soil arching) the stress transfer mode, transfer size, and arching conditions of overlying strata in different areas. The mechanical system of abutment pressure calculation for typical overburden structure is established, which provides theoretical basis for mine optimization design scheme, mining sequence, and limited personnel distance.