We reported an approach to reconstruct the complex phase morphology of impact polypropylene copolymer (IPC) with core-shell dispersed particles and to optimize its toughness in approximate shear condition. The molten-state annealing results indicate that the phase structure with core-shell dispersed particles is unstable and could be completely destroyed by static annealing

resulting in the degradation of impact strength. By using a co-rotating twin screw extruder

we found that the dispersed particle with core-shell structure could be rebuilt in appropriate condition with the recovery of excellent impact strength due to both the huge interfacial tension during solidification and the great difference in viscosity of components. Results reveal that almost all the extruded IPCs show the impact strength 60%-90% higher than that of annealed IPCs at room temperature. And the twice-extruded IPC shows the highest impact strength

446% higher than that of IPC annealed for 30 min. As for low temperature tests

the impact strength of extruded IPCs also increases by 33%-58%. According to adjusting the processing conditions including extrusion speed

extrusion frequency and temperature

an optimization of toughness was well established.