As a long-term project aimed at developing super polyolefin blends, in this paper we summarize our work on the mechanical reinforcement and phase morphology of polyolefin blends achieved by dynamic packing injection molding (DPIM). The main feature of this technology is that the specimen is forced to move repeatedly in the model by two pistons that move reversibly with the same frequency during cooling, which results in preferential orientation of the dispersed phase as well as the matrix. The typical morphology of samples obtained via DPIM is a shear-induced morphology with a core in the center, an oriented zone surrounding the core and a skin layer in the cross-section areas. Shear-induced phase dissolution at a higher shear rate but phase separation at low shear rates is evident from AFM examination of LLDPE/PP (50/50) blends.The super polyolefin blends having high modulus (1.9-2.2 GPa), high tensile strength (100-120 MPa) and high impact strength (6 times as that of pure HDPE) have been prepared by controlling the phase separation, molecular orientation and crystal morphology.
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