Synthesis and characterization of copolymers of ethylene and 1-octadecene using the rac-Et(Ind)2ZrCl2/MAO catalyst system

✍ Scribed by Raúl Quijada; Ana Narváez; René Rojas; Franco M. Rabagliati; Griselda Barrera Galland; Raquel Santos Mauler; Rosario Benavente; Ernesto Pérez; José M. Pereña; Antonio Bello

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 66 KB
• Volume: 200
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/(sici)1521-3935(19990601)200:6<1306::aid-macp1306>3.0.co;2-4

✦ Synopsis

The copolymerization of ethylene and 1-octadecene using a bridged metallocene was studied in order to observe the effect of the comonomer on the catalytic activity. A noticeable increase in activity is seen as the concentration of 1-octadecene in the reaction medium increases. 13 C NMR analysis shows 6.4 mol-% incorporation of comonomer at the highest 1-octadecene concentration in the feed used here. The molecular weight of the copolymers shows a drastic decrease that may be attributed to chain termination by transfer or b-elimination of the comonomer. As to the molecular weight distribution, it remains within a narrow range, as expected with metallocene catalysts. The melting temperature and the enthalpy of melting of the copolymers show a decrease with increasing comonomer content. As usual for ethylene copolymers, the X-ray crystallinities are higher than those determined from the enthalpy of melting.