Polymer Bulletin, Vol.43, No.2-3, 231-238, 1999
Study of the MgCl2 recrystallization conditions on Ziegler-Natta catalyst properties
Magnesium dichloride supported titanium catalysts were prepared by dissolving anhydrous MgCl2 in 1-hexanol/isooctane. Then recrystallization took place through different techniques such as evaporation of the solvent, quick cooling, precipitation with silicon tetrachloride and precipitation with titanium tetrachloride. The FT-IR analysis showed that several degrees of dealcoholation took place as a result of the adducts of MgCl2. XROH. Moreover, it was found that the most active catalysts in the polymerization of ethylene were those obtained recrystallizing MgCl2 by precipitation with SiCl4. On the other hand, those directly recrystallized with TiCI4 were the least reactive and the ones that produced polyethylenes with the highest molecular weights and the lowest degrees of crystallinity.