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首页> 外文期刊>Journal of Applied Polymer Science >Effects of microstructures on the viscoelastic and rheological properties of metallocene-catalyzed cyclo-olefin copolymers: A preliminary study
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Effects of microstructures on the viscoelastic and rheological properties of metallocene-catalyzed cyclo-olefin copolymers: A preliminary study

机译：微观结构对茂金属催化的环烯烃共聚物粘弹性和流变性能的影响：初步研究

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摘要

We characterized metallocene-catalyzed cyclo-olefin copolymers (mCOCs) with similar heat distortion temperatures but dramatic differences in melt-flow indices to understand how the molecular conformation affected their rheological and viscoelastic properties. The mCOC conformations were identified with C-13-NMR, whereas the viscoelastic and rheological properties were measured with cone-and-plate and high-pressure capillary rheometers. Our preliminary results showed that the mCOC rheological and viscoelastic properties might depend strongly on the conformation rather than the norbornene content, molecular weight, and molecular weight distribution. mCOCs containing -NNN- locks (where N represents norbornene) exhibited stronger molecular entanglements than those having no -NNN- blocks, as reflected in lower crossover frequencies and higher crossover torque. Furthermore, the existence of larger rigid -NNN- blocks resulted in higher molten viscosities and flow activation energies. (C) 2002 Wiley Periodicals, Inc. [References: 20]
机译：我们对茂金属催化的环烯烃共聚物（mCOC）进行了表征，它们具有相似的热变形温度，但熔体流动指数存在显着差异，以了解分子构象如何影响其流变学和粘弹性。 mCOC构象用C-13-NMR鉴定，而粘弹性和流变特性用锥板式和高压毛细管流变仪测量。我们的初步结果表明，mCOC的流变和粘弹性可能很大程度上取决于构象，而不是降冰片烯含量，分子量和分子量分布。包含-NNN-锁（其中N代表降冰片烯）的mCOC与没有-NNN-嵌段的mCOC相比，表现出更强的分子纠缠度，这体现在较低的交叉频率和较高的交叉扭矩上。此外，较大的刚性-NNN-嵌段的存在导致较高的熔融粘度和流动活化能。 （C）2002 Wiley Periodicals，Inc. [参考：20]

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