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arXiv 2407.04886cond-mat.softcond-mat.mtrl-sciphysics.chem-ph
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聚合物熔体中的缠结动力学具有化学特异性

Entanglement kinetics in polymer melts are chemically specific

Benjamin E. Dolata, Marco A Galvani Cunha, Thomas O'Connor, Austin Hopkins, Peter D. Olmsted

AI总结:

该研究通过本构方程与分子动力学模拟比较,发现聚合物熔体缠结在回缩时间尺度恢复,且对流约束释放参数随Kuhn长度与堆积长度之比呈幂律变化,具有化学特异性。

摘要:

我们研究了聚合物熔体中缠结动力学的普适性。我们将近期发展的解缠结本构方程的预测,与联合原子聚乙烯和Kremer-Grest聚合物模型在剪切流和拉伸流中的分子动力学模拟进行了比较。我们确认,缠结在回缩时间尺度上恢复,而不是在蛇形时间尺度上恢复。我们发现,对流约束释放参数β与分子量无关,但随Kuhn长度b_K与堆积长度p之比增加,满足β~(b_K/p)^α,指数α=1.9;这可能表明解缠结速率与管径增大相关。这些结果或有助于揭示哪些聚合物更可能发生剪切带。

英文摘要:

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 timescale, rather than the reptation timescale. We find that the convective constraint release parameter $β$ is independent of molecular weight, but that it increases with the ratio of Kuhn length $b_K$ to packing length $p$ as $β\sim (b_K/p)^α$, 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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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