Syntheses of methylene-bridged ansa-zirconocene complexes and copolymerization studies of ethylene and norbornene

Lee, Si Geun; Hong, Sung Don; Park, Young Hwan; Jeong, Boong Goon; Nam, Dae Woo; Jung, Hye Young; Lee, Hyosun; Song, Kwang Ho

doi:10.1016/j.jorganchem.2004.05.015

Cited by 15 publications

(3 citation statements)

References 44 publications

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“…Copolymerization of ethylene and NB using homogeneous metallocene catalysts has been studied by many workers in the past several years 1–27. It remains practically important to understand how the copolymer microstructures are influenced by catalysts structure and polymerization conditions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of ethylene and norbornene copolymer with metallocene catalysts and characteristic analysis

Yao

Liu

et al. 2007

J of Applied Polymer Sci

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To synthesis ethylene (E) and norbornene (NB) copolymer with high glass transition temperature and transparency, three metallocene catalysts with different symmetric structure were evaluated, respectively. The catalyst activity, NB fraction in copolymer and the transparency of copolymers produced under various conditions were investigated. It has been found that C 2 symmetric catalyst such as rac-[En(Ind) 2 ]ZrCl 2 was the best choice to produce copolymer with high NB fraction while keeping high catalyst activity. Furthermore, the effects of reaction conditions on activity of rac-[En(Ind) 2 ]ZrCl 2 and the resultant copolymer structure have also been thoroughly studied. The results indicate that increasing the NB/E ratio is the effective way to increase NB content of copolymer when NB/E ratio is less than 20. However, when NB/E ratio is over 20, further increase in NB/E ratio will lead to significant lower catalyst activity and very limited increase in NB content of copolymer.

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Section: Introductionmentioning

confidence: 99%

Synthesis of ethylene and norbornene copolymer with metallocene catalysts and characteristic analysis

Yao

Liu

et al. 2007

J of Applied Polymer Sci

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“…[ 12–18 ] The chain structure of COC materials could be controlled from random, block to alternating by fine‐tuning ligand substituents of catalysts or adjusting the feed ratio of the comonomers, which had a critical impact on the overall properties of COC materials. For example, the catalytic system [Me 2 Si(Me‐Ind) 2 ]ZrCl 2 /MAO catalyzed E–N copolymerization, and the resulting copolymers contained a large number of NNN triads or more NB sequences, [ 19–21 ] while the catalyst system [Me 2 C(Flu)(3‐R 3 Cp)]ZrCl 2 /MAO [ 22–25 ] could prevent the formation of NB microblocks, resulting in nearly isotactic and alternating E–N copolymer, which was able to raise the insertion ration of NBs. The insertion of the rigid macrocyclic comonomers into the main chain caused an increase in the modulus, tensile strength, and glass transition temperature, but the deterioration in the toughness and strain at break.…”

Section: Introductionmentioning

confidence: 99%

Viscoelasticity, Tensile Properties, and Microstructure Development in Cyclic Olefin Copolymer/Polyolefin Elastomer Blends

Pei

Zhao

et al. 2022

Macro Chemistry & Physics

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The new ethylene/cyclic olefin copolymers (COCs) are a major breakthrough in traditional polyolefins made available by metallocenes, but its high brittleness restricts the applications. Ethylene/1-octene copolymer (POE) with similar backbones is blended with COCs to compensate the rigidity of cyclic segments. Field emission scanning electron microscope photos and Raman spectra demonstrate the existence of abundant phase interfaces between POE and COC, and the phase structure changes from spherical droplets, of partial continuity to cocontinuity with rising POE components. The phase changes are considered as corresponding to the formation, expansion, and coalescence of droplets at melting state according to Van Gurp curves, Han plot, and Cole-Cole plot. Viscoelastic data show that the storage modulus, loss modulus, and complex viscosity reach a high value at medium POE contents. Furthermore, the tensile strength and fracture energy increases and then decreases, the elongation at break increases and Young's modulus reduces with the increment of POE percentage. Because of the large spherical and ellipsoidal structures and abundant interfaces, the synchronous reinforcement and toughness come true at a medium ratio of POEs. Dynamic mechanical analysis confirms the existence of the interfacial layer, and the interfacial layer becomes more pronounced with the rising POE contents exactly as the morphology and rheological findings.

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“…Cyclic olefin copolymers are versatile materials categorized as engineering thermoplastics . The random and alternative attachment of cyclo‐olefins such as cyclohexene, cycloheptene or norbornene into the polyolefinic backbone results in amorphous copolymers with high glass transition temperature, superior transparency, low shrinkage and good mechanical properties . Among them ethylene − norbornene (EN) copolymer has attracted both academic and industrial attention due to its special properties, such as high heat resistance and excellent transparency which can be optimized by altering the norbornene content.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization, rheological and thermal behavior of metallocene ethylene − norbornene copolymers with low norbornene content using pentafluorophenol modified methylaluminoxane

Manteghi

Arabi

Jahani

2015

Polymer International

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Ethylene − norbornene copolymers were synthesized using rac-ethylene bis(indenyl) zirconium dichloride/pentafluorophenol modified methylaluminoxane. First, the effect of using a modifier in combination with a low ratio of Al/Zr on the catalyst activity and co-monomer incorporation was studied. The results of copolymerization reveal a 20% co-monomer incorporation improvement and a rise of activity by 2-fold in the presence of the modifier. Rheological measurements show a higher molecular weight in copolymers synthesized using modified methylaluminoxane. The alternative and dyad block microstructures of copolymers become possible in the case of a norbornene content of more than 14 mol%. Second, the effect of co-monomer content on the rheological and thermal behavior of the synthesized copolymers was investigated. The results of the rheological study indicate a lower molecular weight in samples containing a higher norbornene content. Dynamic mechanical thermal analysis confirms the influence of different microstructures on the glass transition temperature. The crystal structure of copolymers having a higher molecular weight is emphasized using wide angle X-ray scattering and DSC even with a greater incorporation of norbornene.

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Syntheses of methylene-bridged ansa-zirconocene complexes and copolymerization studies of ethylene and norbornene

Cited by 15 publications

References 44 publications

Synthesis of ethylene and norbornene copolymer with metallocene catalysts and characteristic analysis

Synthesis of ethylene and norbornene copolymer with metallocene catalysts and characteristic analysis

Viscoelasticity, Tensile Properties, and Microstructure Development in Cyclic Olefin Copolymer/Polyolefin Elastomer Blends

Synthesis, characterization, rheological and thermal behavior of metallocene ethylene − norbornene copolymers with low norbornene content using pentafluorophenol modified methylaluminoxane

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