Synthesis of highly spherical Ziegler-Natta catalyst by employing Span 80 as an emulsifier suitable for UHMWPE production

A set of MgCl2.EtOH adducts was synthesized by employing two different weight fractions of span 80 (0.5, and 1.0 wt.%) as an emulsifier during adduct preparation step by melt quenching method. Spherical morphology of the prepared adducts was explored using scanning electron microscopy. Further characterization results revealed that emulsifier containing adducts had similar crystalline structure, higher ethanol content and smaller particle sizes. Prepared adduct samples were employed in TiCl4/MgCl2 (Ziegler-Natta) catalysts synthesis which subsequently tested in slurry-phase ethylene polymerization in the presence of triethylaluminium as a cocatalyst. The ethylene polymerization results disclosed that, using emulsifier caused to high active catalyst samples in comparison with emulsifier-free one, where catalyst activity increased up to 40% by using 1.0 wt.% of emulsifier. And as a significant achievement, molecular weight results showed that, synthesized catalysts in the presence of emulsifier led to the production of ultra-high molecular weight poly ethylene with M-v > 1.5 x 10(6) g/mol at low ethylene pressure of only 2 bar. The production of ultra-high molecular weight poly ethylene together with small particle size feature make the catalyst containing 1 wt.% emulsifier as a good candidate for industrialization step through slurry-phase plants.