ABSTRACT:Recently, polymer-clay hybrid materials have received considerable attention from both a fundamental research and application point of view.1-3 This organicinorganic hybrid, which contains a nanoscale dispersion of the layered silicates, is a material with greatly improved physical and mechanical characteristics. These nanocomposites are synthesized through in situ polymerization or direct intercalation of the organically modified layered silicate (OLS) into the polymer matrix. Thus, understanding the relationship between the molecular structure and the thermal stability (decomposition temperature, rate, and the degradation products) of the OLS is critical. In this study, modern thermal analysis techniques combined with infrared spectroscopy and mass spectrometry (TGA-FTIR-MS) were used to obtain information on the thermal stability and degradation products of organic modified clay. Furthermore, the thermal and mechanical properties of clay-filled PMMA nanocomposites were determined by using TGA and DSC.

Based on the engineering practice of the large section roadway in Zhaozhuang Mine, which has composite roof of mudstone and sandy mudstone, and the shale floor, and did the support optimization design of large section roadway through three-dimensional numerical simulation by using the FLAC3D. To optimize the row spacing between the bolt, it carried out nine group test of numerical simulation program to analyze, six group test of numerical simulation program to analyze the length of the anchor cable, and five group test to analyze the distance of the anchor cable. Through these, the effect of the bolt spacing, the length of the top anchor cable, the anchor cable spacing and other support parameters to the supporting are got, and putting forward an anchor - anchor cable integrated supporting parameters optimization program to match the large section of the composite roof. Results show that it is reasonable to use 950mm x 900mm of the bolt spacing in design, and 7.5 meters length in design the top anchor cable.

Since the excavation of roadway in Shuguang mine No.2 mining area, shotcrete layer has fallen off and the surrounding rock deformation was serious. For studying big deformation of roadway in Shuguang mine No.2 mining area, the paper analyzed fractured surrounding rock physical and mechanical characteristics of No.2 mining area. The results show that the uniaxial compressive strength, uniaxial tensile strength, cohesion, internal friction angle of fractured surrounding rock were very low. And the whole physical and mechanical characteristics were poor. It is the basic reason of big deformation of roadway surrounding rock physical and the important basis of late supporting of roadway.