Non-Universal Feature in Uniaxially Extensional Rheology of Linear Polymer Melts and Concentrated Solutions: A Review
Non-Universal Feature in Uniaxially Extensional Rheology of Linear Polymer Melts and Concentrated Solutions: A Review
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线性聚合物熔体和浓缩溶液单轴拉伸流变学的非普遍特征：综述
DOI：
10.1016/j.progpolymsci.2020.101325
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Y. Matsumiya and H. Watanabe
中科院分区：
文献类型：
--
作者：
Y. Matsumiya;H. Watanabe;N. Sukhonthamethirat;and V. Vao-soongnern;Y. Matsumiya and H. Watanabe
聚合物液体的流变行为一般被认为是由一些与时间无关的分子参数（如Rouse弛豫时间和每条链的缠结数）决定的，而与聚合物和溶剂（如果有的话）的化学结构以及聚合物浓度无关。这种普遍性得到了广泛的剪切下进行了50多年的实验和连续的理论发展的粗粒分子模型的支持。然而，最近的实验和理论研究揭示了这种普遍性的故障在拉伸流动行为的纠缠和未纠缠的聚合物。从这些研究中产生的一个关键概念是减少链段摩擦的高度取向/拉伸的聚合物链在快速拉伸流动下的熔体。这种摩擦降低的幅度随着聚合物和溶剂的化学结构以及聚合物浓度而变化，即使与时间无关的分子参数保持相同，这导致拉伸行为的非普遍性。本文综述了线性聚合物在单轴拉伸流动下的实验和理论研究结果，并讨论了剩余的问题，特别是摩擦的概念。
Rheological behavior of polymeric liquids has been considered to beuniversallydetermined by a few time-independent molecular parameters (such as the Rouse relaxation time and the entanglement numberperchain)irrespective ofthe chemical structure of the polymer and the solvent (if any) and the polymer concentration. This universality has been supported by extensive experiments under shear conducted over 50 years and the successive theoretical development of coarse-grained molecular models. Nevertheless, recent experimental and theoretical studies have revealed the breakdown of this universality in the extensional flow behavior of both entangled and unentangled polymers. A key concept resulting from those studies is the reduction of segmental friction of highly oriented/stretched polymer chains in melts under fast extensional flow. The magnitude of this friction reduction changes with the chemical structure of the polymer and solvent as well as the polymer concentration even if the time-independent molecular parameters remain the same, which results in the non-universality in the extensional behavior. This review article summarizes these experimental and theoretical findings for linear polymers under uniaxially extensional flow, and discusses remaining problems in particular for the concept of friction.