The role of magnesium chloride as support for Ziegler—Natta catalysts
Polimery 2000, No 9, 608
SummaryStructural examination data are presented for various supports. Porosimetry (Table 2) and particle size distribution studies on MgCl2, MgCl2(THF)2, Al2O3 as supports, carried out prior to and after ball-milling (Figs. 2, 3), suggest that MgCl2 is beneficial as carrier because it is more liable to pretreatment (ball-milling, presence of a Lewis base) and allows its mass to be better utilized and its surface to produce catalytically active centers. Prolonged ball-milling of MgCl2 was found to result not only in comminuted particles but also in increased specific area and larger pore volume. Studies on synthesis conditions of a vanadium precursor supported on MgCl2(THF)2 showed prolonged ball-milling to be indispensable to prepare a high-activity catalyst. Various Ziegler—Natta catalysts were compared in terms of the activity to polymerize ethylene, supported on MgCl2 or Al2O3 that had been ball-milled for 24 h (Table 4).