Through a combined approach of experiment and simulation, this study quantifies the role of entanglements in determining the mechanical properties of glassy polymer blends. Uniaxial extension experiments on 100-nm films containing a bidisperse mixture of polystyrene enable quantitative comparison with molecular dynamics (MD) simulations of a coarse-grained model for polymer glasses, where the bidisperse blends allow us to systematically tune the entanglement density of both systems. In the MD simulations, we demonstrate that not all entanglements carry substantial load at large deformation, and our analysis allows the development of a model to describe the number of effective, load-bearing entanglements per chain as a function of blend ratio. The film strength measured experimentally and the simulated film toughness are quantitatively described by a model that only accounts for load-bearing entanglements.

中文翻译：

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聚合物玻璃中的承重缠结

通过实验和模拟相结合的方法，本研究量化了缠结在确定玻璃态聚合物共混物的机械性能中的作用。对含有聚苯乙烯双分散混合物的 100 nm 薄膜进行单轴延伸实验，可以与聚合物玻璃的粗粒度模型的分子动力学 (MD) 模拟进行定量比较，其中双分散混合物使我们能够系统地调整两个系统的纠缠密度。在 MD 模拟中，我们证明并非所有缠结在大变形时都承载大量载荷，并且我们的分析允许开发一个模型来描述每条链的有效承载缠结数作为混合比的函数。