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This paper was prepared by melt blending high density polyethylene, linear low density polyethylene, ultra high molecular weight polyethylene and an ethylene - acrylic acid copolymer, a blend of four materials, referred to as UHLE, then prepared polyamide 6 (PA6) / UHLE blends, and its tensile behavior and fracture toughness were tested. Blends were studied by DSC tensile melting behavior before and after, by scanning electron microscopy (SEM) for PA6 and its blends aggregation structure and fracture morphology were observed, thus demonstrating the fracture process blends The energy dissipation model. Tensile Behavior tests showed that: a blend of the components PA6/UHLE the same test conditions showed significantly different tensile deformation behavior; not for post-processing and post-treated tensile test specimens also exhibit different tensile behavior. PA6/UHLE secondary blend tensile yield phenomenon exists, as UHLE content increases, the yield is caused by the secondary was becoming increasingly obvious, cold-drawn index gradually decreased. Fracture behavior of the test showed that: in impact conditions, PA6 and PA6/UHLE blends single notched specimen brittle fracture, notched impact strength with UHLE content increases gradually decreases; quasi-static three-point bending conditions, the gap length is short, neat PA6 showed brittle fracture in notched specimen length and width ratio is about 0.8, pure PA6 exhibit brittle - ductile transition of fracture behavior, PA6/UHLE blends all specimens were notched length exhibit ductile fracture behavior. With UHLE content increases, PA6/UHLE blends critical crack initiation can be reduced, but the maximum load at the crack resistance and stable crack growth resistance as UHLE content increases, first increased and then decreased, consolidate the fracture toughness parameters showed that under the conditions of high-speed impact, UHLE possible toughening PA6, the quasi-static conditions, PA6/UHLE significant increase in fracture toughness, the UHLE content of 5 wt%, the performance of the best fracture toughness. DSC results showed that after tensile deformation, DSC heating curve of the melting peak temperature moves from low temperature, which indicates that the stretching process, the specimen of the crystal morphology changed. SEM microscopic tests show, PA6/UHLE blends, UHLE PA6 dispersed phase dispersed in the matrix. Impact specimen fracture surface is smooth, UHLE granular form attached to the fracture surface or peeling, leaving holes in the fracture surface. Quasi-static conditions, the test of pure PA6 relatively smooth fracture surface, and the surface of the specimen fracture blend PA6/UHLE reticular structure, by the occurrence of plastic deformation and amplification PA6 matrix composition holes. Energy dissipation model studies show that fracture, the material of the energy dissipated mainly composed of two parts, namely the formation of new energy consumed fracture surface and crack the plastic deformation of the material around the plastic work consumed. This model can explain PA6/UHLE blends fracture toughness changes.
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