Studies on Morphology Evolution of Polypropylene/Poly (Ethylene-co-1-octene) Blends at Different Shear Rates

Abstract

The transient state of the phase morphology of polypropylene with poly(ethylene-co-1-octene) blends during melt mixing are investigated by the pattern analysis of scanning electron microscope (SEM). The results show that morphology develops mainly at the initial stages of mixing. During the intermediate mixing stage, a dynamic equilibrium is established between breakup and coalescence of domains. The mixing time required for reaching equilibrium stage reduces as shear rate increases. The fractal analysis indicates that the development of the dispersed phase during melt mixing process evolves with dynamical self-similarity partly through the competitions of break-up and coalescence of dispersed phase.

Keywords:

• Morphology evolution
• Poly(ethylene-co-1-octene)
• Polypropylene
• Shear rate

ACKNOWLEDGMENTS

The authors gratefully acknowledge the financial support of National Natural Science Foundation of China (No. 02490220) and Research Foundation for the Excellent Youth Scholars of Shanghai (SHU-10057).