The data set of steady and transient shear data reported by Santangelo and Roland Journal of Rheology 45: 583–594, (2001) in the nonlinear range of shear rates of an unentangled polystyrene melt PS13K with a molar mass of 13.7 kDa is analysed by using the single integral constitutive equation approach developed by Narimissa and Wagner Journal of Rheology 64:129–140, (2020) for elongational and shear flow of Rouse melts. We compare model predictions with the steady-state, stress growth, and stress relaxation data after start-up shear flows. In characterising the linear-viscoelastic relaxation behaviour, we consider that in the vicinity of the glass transition temperature, Rouse modes and glassy modes are inseparable, and we model the terminal regime of PS13K by effective Rouse modes. Excellent agreement is achieved between model predictions and shear viscosity data, and good agreement with first normal stress coefficient data. In particular, the shear viscosity data of PS13K as well as of two polystyrene melts with M = 10.5 kDa and M = 9.8 kDa investigated by Stratton Macromolecules 5 (3): 304–310, (1972) agree quantitatively with the universal mastercurve predicted by Narimissa and Wagner for unentangled melts, and approach a scaling of Wi−1/2at sufficiently high Weissenberg numbers Wi. Some deviations between model predictions and data are seen for stress growth and stress relaxation of shear stress and first normal stress difference, which may be attributed to limitations of the experimental data, and may also indicate limitations of the model due to the complex interactions of Rouse modes and glassy modes in the vicinity of the glass transition temperature. Graphical abstract

中文翻译：

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劳斯熔体稳定剪切流的普遍性

Santangelo 和 Roland Journal of Rheology 45: 583–594, (2001) 在摩尔质量为 13.7 kDa 的未缠结聚苯乙烯熔体 PS13K 的非线性剪切速率范围内报告的稳态和瞬态剪切数据的数据集通过使用进行分析由 Narimissa 和 Wagner Journal of Rheology 64:129–140, (2020) 开发的单一积分本构方程方法，用于 Rouse 熔体的伸长和剪切流。我们将模型预测与启动剪切流后的稳态、应力增长和应力松弛数据进行比较。在表征线性粘弹性弛豫行为时，我们认为在玻璃化转变温度附近，Rouse 模式和玻璃态模式是不可分割的，我们通过有效的 Rouse 模式模拟 PS13K 的终端状态。模型预测和剪切粘度数据之间实现了极好的一致性，并且与第一法向应力系数数据具有良好的一致性。特别是，由 Stratton Macromolecules 5 (3): 304–310, (1972) 研究的 PS13K 以及两种 M = 10.5 kDa 和 M = 9.8 kDa 的聚苯乙烯熔体的剪切粘度数据与预测的通用主曲线定量一致Narimissa 和 Wagner 用于非缠结熔化，并在足够高的魏森伯格数 Wi 下接近 Wi-1/2 的缩放。对于剪应力的应力增长和应力松弛以及第一法向应力差异，模型预测与数据之间存在一些偏差，这可能归因于实验数据的局限性，由于在玻璃化转变温度附近 Rouse 模式和玻璃态模式的复杂相互作用，也可能表明模型的局限性。图形概要