Abstract：Ultra-fine coal gangue power plant ash was modified with different surface modification agent, and blended with polypropylene (PP) . Ash-PP composite material was obtained by extrusion and injection molding, and its mechanical properties were also measured. The effects of modified ash on the mechanical properties and crystallization behavior of composite materials were studied by the SEM, FT-IR and DSC. The results show that the modification effect of silane coupling agent SCA1113 and SCA 503 are optimal. The tensile strength, the bending strength, and the impact strength increase from 25.70 to 29.58 MPa, 33.60 to 35.99 MPa, and 3.04 to 3.85 k J·m^-2 respectively. The modified ash in the composite plays an important role in the polypropylene because of heterogeneous nucleation effect, to increase the crystallization temperature of polypropylene and the crystallization rate, and decrease the crystallite size distribution.

Keywords：gangue power plant; ash; polypropylene; silane coupling agent; mechanical property