The Morphology Control and Mechanical Properties of High Density Polyethylene and Polypropylene Blend under Oscillating Shear Stress Field

The improvement of mechanical properties of high-density polyethylene (HDPE) and polypropylene (PP) blend was studied by controlling the phase miscibility vs. phase separation. Because the phase morphology and crystal morphology compete with each other, it is difficult to control the degree of the micro phase separation in an ordinary way, but with the special method of oscillating packing injection molding at a low pressure, the fine structure combined with micro-phase separation and phase morphology which was studied with SEM method can be controlled to a certain extent. The high tensile strength and high toughness of HDPE/PP blends were got within the PP content in the range from 5% to 20%. The key properties of the blend were as follows: tensile strength and notched impact strength of HDPE/PP (92/8) blend specimens in the oscillating packing are 97.1 MPa and 45. 5 kJ/m2, 4. 3 times and 9. 5 times of the static packing specimens respectively.