Copolymerization and characterization of ethene–1-hexene copolymers prepared by using the (Me5Cp)2ZrCl2–MAO catalyst system

✍ Scribed by Sven Rudolph; Jürgen Giesemann; Jörg Kressler; Tammo J. Menke; Heike Menge; Peter Arends

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 289 KB
• Volume: 74
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19991010)74:2<439::aid-app27>3.0.co;2-h

✦ Synopsis

It is demonstrated that the catalyst system bis(pentamethylcyclopentadienyl)-zirconium dichloride (Me 5 Cp) 2 ZrCl 2 -methylaluminoxane (MAO) is able to produce random copolymers of ethene and 1-hexene. The 1-hexene incorporation in the copolymers is extremely small. Even in the case of a molar ratio of [ethene] to [1-hexene] of 1/20 in the monomer feed, only 1.4 mol % 1-hexene are incorporated according to 13 C nuclear magnetic resonance (NMR) spectra. Nevertheless, the physical properties of the random copolymers change significantly in this small range of 1-hexene incorporation, from a high-density polyethene to a linear low-density polyethene. Thus, the melting temperature, the degree of crystallinity, the density and lamella thickness, and the long period of the alternating crystalline and amorphous regions decrease with increasing 1-hexene content in the random copolymers. Blends of high-density polyethene prepared with the system (Me 5 Cp) 2 ZrCl 2 -MAO and an elastomeric random copolymer of ethene and 1-hexene are phase-separated and show good compatibility, as demonstrated by transmission electron microscopy.