| As a widely used polypropylene material still has problems such as easy deformation,high molding shrinkage,low temperature fracture,easy oxidation and low heat deflection temperature,inorganic fillers can effectively improve the material properties.As a kind of coal-based solid waste,coal gasification fly ash mainly consists of silica-aluminum-iron-calcium components,and its resource utilization method has become the focus of research.In order to develop the value potential of coal gasification fly ash as inorganic filler,this paper selects the actual gasification fly ash produced by a Shell gasifier and studies the chemical properties of fly ash such as particle size distribution,chemical composition,crystal minerals,microscopic morphology and micro-zone chemical composition and stability by modern analytical testing techniques to determine its value potential as polypropylene inorganic filler.Further,the gasification fly ash polypropylene composites were prepared by twin-screw extruder,and the effects of different coupling agent concentrations and fly ash additions on the macroscopic and microscopic mechanical properties of the composites were investigated by universal testing machine and nanoindentation technique.The effects of coal gasification fly ash as inorganic filler on the properties of polypropylene materials were analyzed.The main conclusions of this topic are as follows.The nature of gasification fly ash has common characteristics in terms of particle size distribution,composition,crystal structure,valence bonding,etc.However,there are still some differences in the performance of fly ash due to the differences in raw coal and operation conditions.The inorganic components are mainly silicon,aluminum,iron and calcium,with a total content of>85%;the particle size distribution of fly ash is mainly characterized by"two-peak or multi-peak distribution",with regular spherical particles and irregular particles.The surface properties of fly ash are unstable,with a certain degree of adhesion and easy to agglomerate phenomenon.With the increase of modified fly ash addition,the density,water absorption and Vicat softening temperature of the composites changed significantly,and the reaction between fly ash and polypropylene matrix after modification by silane coupling agent formed new Si-O-Si bonds,which increased the interfacial compatibility and adhesion between fly ash and polypropylene.The mechanical properties of the composites were influenced by fly ash.In terms of macromechanics,the mechanical properties and rheological properties of the three fly ash-prepared materials showed a trend of first increasing and then decreasing,and the maximum tensile strength,bending strength and rheological properties of the materials were 43 MPa,30.4 MPa and 13.08 g.（10 min）-1,respectively,when fly ash was added at5%;in terms of micromechanics,the modulus of elasticity and hardness reached 1.95GPa and 0.113 GPa respectively at 5%addition of fly ash,and the mechanical properties were better than those of the polypropylene material without filler.Due to the effect of fly ash itself and the atmosphere makes the thermal stability of the composites have a difference,the initial and final decomposition temperature of the composites in inert atmosphere is delayed backward;in oxidizing atmosphere,due to the participation of oxygen atoms in the reaction,the metal atoms in the fly ash have catalytic effect,which reduces the initial pyrolysis activation energy of the material and is not conducive to the stability of the composites,but with the increase of the fly ash addition,the effect of fly ash is greater than the catalytic effect,and the thermal stability of the material is enhanced.Figure[44] Table[22] Reference[109]... |
