Some important results about the injection molding of polyolefin blends were reported in this article.Due to the shear stress and thermal gradients

usually

injection molded parts contain a hierarchy of macromolecular arrangements and a skin-core structure.In this work

the phase morphology and interfacial structure of injection molded bars of polyolefin blends have been investigated in detail from the skin to the core

layer by layer.For preparation of injection-molded bars with high-level orientation dynamic packing injection molding technology was applied to exert oscillatory shear on the molten composite through two pistons that moved reversibly with the same frequency during the solidification stage.It was found that

under the effect of shear stress

(1) the dispersed phase of polymer blends was deformed and oriented

resulting in a change of the phase inversion as well as the mechanical properties of polymer blends;(2) shish-kebab structure instead of spherulite structure was formed;(3) the blends became homogeneous at higher shear stress

while phase separation was induced at lower shear stress;(4) epitaxial growth occurred in injection molded bar of HDPE/iPP blends.Our goal was to study the relationship between processing

morphology and mechanical properties of polymer materials in terms of the morphology controlling and structure characterization of injection-molding samples

and to provide a new way of improving the mechanical properties and service life of polymer materials through injection molding technology.