Benjamin E. Dolata*, Marco A. Galvani Cunha, Thomas O’Connor, Austin Hopkins and Peter D. Olmsted*,
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引用次数: 0
摘要
我们研究了聚合物熔体中纠缠动力学的普遍性。我们将最近开发的解缠构成方程的预测结果与联合原子聚乙烯和 Kremer-Grest 模型的分子动力学模拟结果进行了比较。我们证实,缠结是在回缩时间尺度上恢复的,而不是在回缩时间尺度上恢复的。我们发现对流约束释放参数 β 与分子量无关,但它会随着库恩长度 bK 与堆积长度 p 的比值 β ∼ (bK/p)α 而增加,指数 α = 1.9,这可能表明解缠速度与管直径的增加有关。这些结果可能有助于揭示哪些聚合物更容易发生剪切带化。
Entanglement Kinetics in Polymer Melts Are Chemically Specific
We investigate the universality of entanglement kinetics in polymer melts. We compare predictions of a recently developed constitutive equation for disentanglement to molecular dynamics simulations of both united-atom polyethylene and Kremer-Grest models for polymers in shear and extensional flow. We confirm that entanglements recover on the retraction time scale, rather than the reptation time scale. We find that the convective constraint release parameter β is independent of molecular weight, but that it increases with the ratio of Kuhn length bK to packing length p as β ∼ (bK/p)α, with an exponent α = 1.9, which may suggest that disentanglement rate correlates with an increase in the tube diameter. These results may help shed light on which polymers are more likely to undergo shear banding.
期刊介绍:
ACS Macro Letters publishes research in all areas of contemporary soft matter science in which macromolecules play a key role, including nanotechnology, self-assembly, supramolecular chemistry, biomaterials, energy generation and storage, and renewable/sustainable materials. Submissions to ACS Macro Letters should justify clearly the rapid disclosure of the key elements of the study. The scope of the journal includes high-impact research of broad interest in all areas of polymer science and engineering, including cross-disciplinary research that interfaces with polymer science.
With the launch of ACS Macro Letters, all Communications that were formerly published in Macromolecules and Biomacromolecules will be published as Letters in ACS Macro Letters.