Control of molecular weight and molecular weight distribution in ethylene polymerization with metallocene catalysts

✍ Scribed by Taek Kyu Han; Hong Ki Choi; Dong Wook Jeung; Young Soo Ko; Seong Ihl Woo

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 528 KB
• Volume: 196
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1995.021960816

✦ Synopsis

Abstract

The molecular weight (MW) and the molecular weight distribution (MWD) of polyethylene (PE) prepared with various metallocene catalysts were investigated. The weight‐average molecular weight (M~w~) of PE prepared with dicyclopentadienyltitanium dichloride/aluminoxane (Cp~2~TiCl~2~/MAO) was about 4,0 · 10^5^, while that of PE obtained with dicyclopentadienylzirconium dichloride/aluminoxane (Cp~2~ZrCl~2~/MAO) is about 1,0 · 10^5^. PE of bimodal MWD was obtained with the mixed catalyst Cp~2~TiCl~2~/Cp~2~ZrCl~2~. Narrow MWD PE was obtained with the mixed catalyst Cp~2~ZrCl~2~/Et(ind)~2~ZrCl~2~, because each catalyst produced an M~w~ of 1,0 · 10^5^. However, the change of temperature during the polymerization with the mixture Cp~2~ZrCl~2~/Et(ind)~2~ZrCl~2~ produced PE with a bimodal MWD and a value of the ratio of weight‐ to number‐average molecular weights of M~w~/M~n~ = 4.