Studies On Reinforcment Mechanism Of Short Glass Fiber/High Density Polyethylene Composites Through Stress-Induced Reactions And Their Mechanical Properties Simulation

This thesis adopted high shearing stress-induced way, by improving the rotating speed of the twin screw extruder during melting extrusion, to induce HDPE and MAH functionalization reaction and to increase the interface adhesion between the HDPE matrix and short GF strengthen phase, hence increasing the integrative mechanical properties of the HDPE intensified by short GF effectively.By mechanical properties testing, chemical analysis and SEM analyzing, research deeply on the influences of the functionalization products grafting and relational binding intensity between the matrix and fiber interface by stress-induced intensity, disclosure the influences on the formation of the skin-core structure in the composites samples strengthened by extruding short fiber and the increasing bending, ballistic mechanical properties of the confectioning component by increasing the screw rotation, simulate the stress-strain curve and distributing well using Moldflow software. The results show that:1: In the condition of the fiber content was 30% in the course of melting extrusion at 290℃, the rotate speed of the screw increasing from 100r/min to 800r/min, acceding 2% initiator, the grafting degree of the products has improved from the 0.14% by thermal initiation to 0.77% by high shearing-stress initiation, increasing the grafting degree obviously and being propitious to the interface binding force between the GF and the matrix.2: The flowing speed of the melting can reach to 1.0～8.0g/10min by increasing the rotation of the screw extruder and shearing stress induction. It is propitious to the formation of the skin-core structure in the course of injection molding, this structure is propitious to improve the stretch-proof, resistance to bending and impact, especially for the resistance to bending and impact(because the maximal stress is on the surface), this is embodied from the bending and the impact mechanical properties of the prepared samples: the strength of the stretch, bending and notch impact test of the GF/HDPE composites was increased from21.43MPa,15.49MPa and 12.82kJ/m~2 to 0.18MPa ,29.72MPa , 19.12kJ/m~2;3: Analyzing the stretch samples by commercial software Moldflow, simulating result was agreed well with practical test. It proved that we can design the fiber intensity composites from the processing technic to the integrated mechanical properties. Then it will benefit to decrease the testing and the cost.This thesis has practical guiding significances on designing the short fiber reinforcing composites component, choosing right extruding processing parameters.