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

Abstract

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. 13C 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 β‐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.

Recent Advances in Olefin Polymerization Using Binary Catalyst Systems

“…[22] These catalyst precursors were chosen since iron catalyst 20 is highly selective for the production of 1-alkenes, [23] and metallocenes 21 and 3 are known for their ability to copolymerize ethylene and higher 1-olefins. [24] The polymerization reaction performed in toluene at 60 8C using an Al/Fe molar ratio of 2 000 showed that increasing the Fe/Zr ratio leads to a reduction in productivity. 13 C NMR data revealed that the degree of branching increased with increasing Fe/Zr ratio.…”

“…Additional studies with respect to the production of stereoblock poly(propylene) by using in-situ mixtures of metallocene catalysts with different stereoselectivity were recently performed by Brintzinger et al [28] Propene polymerization reactions were performed using metallocene catalysts 22, Me 2 Si(2-Me-4-t Bu-C 5 H 2 ) 2 ZrCl 2 (24) and Me 2 Si(2-MeInd) 2 ZrCl 2 (25) in the presence of either MAO or triisobutylaluminium (Al i Bu 3 )/triphenylcarbenium tetrakis(perfluorophenylborate) ([Ph 3 C][B(C 6 F 5 ) 4 ], trityl borate) as the cocatalyst.…”

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State 13C NMR Spectroscopy

“…Isotactic poly(propylene)-co-hexenes of varying comonomer incorporation, PP6-A and PP6-B, were synthesised using the metallocene rac-[Me 2 Si(2-Me-Ind) 2 ]ZrCl 2 catalyst and MAO cocatalyst. [45] Melt-state NMR was performed on three dedicated solidstate Bruker Avance NMR spectrometers: a narrow-bore DRX700, a wide-bore DSX500 and a wide-bore DSX300. These operated at 1 H and 13 C Larmor frequencies n 1 H (n 13 C ) of 700.13 (176.05), 500.13 (125.75) and 300.23 (75.49) MHz respectively.…”

Copolymerization of 4-methyl-1-pentene with α,ω-alkenols

“…The activity decreased while the 9D1O feeding amount increased (run 5-7). The so-called 'comonomer effect' has been observed in several manners for the ethylene copolymerization with α-olefin [30,31]. The incorporation of 9D1O into the polymer chain improved the solubility of the resulteding polymer in the reaction mixture; therefore the resistance of the mass and heat transfer would be reduced, leading to the increased activity.…”