Though Ziegler-Natta catalysts for propylene polymerization prepared by spherical Mg(OEt)₂ precursor have been shown high performances for industrial application, it’s still uncertain how the performances originate. In this paper, effects of preparation method on particle morphology were investigated in comparison of Mg(OEt)₂-based catalyst with MgCl₂ grinding one. The particle morphology and the polymer growth are different between the catalysts mainly due to the difference of the spatial Ti distribution in the particles. Mg(OEt)₂-based catalyst has uniform spatial distribution of active Ti species over the catalyst particles, leading to well-controlled initial fragmentation and subsequent homogenous polymer particle growth. Buy this Article