Metallocene/methylaluminoxane catalysts are able to design copolymers with tailored architectures. It is possible to copolymerize ethene with higher α‐olefins and cyclic olefins. The terpolymer of ethene/1‐hexene/norbornene shows a better flexibility than the ethene/norbornene copolymer by a similar high transparency. The influence of the comonomer concentration on activity, molecular weight, and glass transition temperature is given as well as the comparison to 1‐hexene/norbornene and propene/norbornene copolymers. Hexene/norbornene copolymers were found to have a predominant alternating microstructure.
small amount of n-octadecyl bromide, 2.74 g. (67%) of unreacted triphenyl-2-phenylethylgermane and 0.63 g. of product boiling over the range 180-185°at 0.005 mm. Recrystallization of this latter fraction from methanol gave 0.5 g. (28.6%) based on unrecovered starting material) of n-octadecyldiphenyl-2-phenylethylgermane, m.p. and mixture m.p. 34.5-35.5°.Cleavage of tri-n-hexylphenylgermane. (Attempted,). A mixture of 2.03 g. (0.005 mole) of tri-n-hexylphenylgermane, 0.3 g. (0.043 g.-atom) of lithium and 7 ml. of ethylene glycol dimethyl ether was stirred for 24 hr. to yield a deep red solution giving a positive Color Test I. The solution was pipetted into a dropping funnel and added to 1.7 g. (0.01 mole) of n-hexyl bromide dissolved in 20 ml. of GDME.After stirring 5 min., Color Test I was negative. Water was added and the mixture extracted with ether. The ether portions were dried and the solvents distilled to leave a residue which was distilled under reduced pressure to give 1.3 g. (65%) of starting material, b.p. 186-188°( 0.7 mm.), 1.4959.
Summary: Syndiotactic polymers of 1‐pentene, 1‐hexene and 1‐octene were obtained with the CS‐symmetric metallocene catalysts [Ph2C(Cp)(2,7‐tert‐Bu2Flu]ZrCl2 and [(4‐MePh)2C(Cp)(2,7‐tert‐Bu2Flu)]ZrCl2, which have already been proven to give high molar masses and excellent tacticities in propene polymerisation. The monomers were polymerised in bulk and in solution processes at temperatures between 0 and 60 °C using methylaluminoxane as a cocatalyst. The effects on catalyst activity as well as on polymer microstructure and molar mass were determined. Polymers with high syndiotacticities and molar masses (up to 550 000 g · mol−1 in the 1‐octene polymerisation) compared to other metallocenes were obtained.
magnified image
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.