Supported Ziegler‐Natta catalysts for propene polymerization: Grinding and co‐grinding effects on catalyst improvement

Solid ternary MgCl2/aromatic ester (A. E.)/TiCl4 catalysts are obtained by grinding MgCl2 followed by co‐grinding MgCl2 and A. E. and then by TiCl4 impregnation. The productivity increases with grinding time up to a maximum value and the stereospecificity decreases continuously. A convenient choice of the A. E. improves the results. The productivity seems to be correlated with details of the pore size distribution. Infrared analysis of the catalyst reveals different ways of Ti‐fixation but without clear relation to the catalytic properties.