Morelly et al. (Macromolecules 52:915-922, 2019) reported transient and steady-state elongational viscosity data of monodisperse linear polymer melts obtained by filament-stretching rheometry with locally controlled strain and strain rate and found different power law scaling of the elongational viscosities of polystyrene, poly(tert-butylstyrene) and poly(methyl-methacrylate). Very good agreement is achieved between data and predictions of the extended interchain pressure (EIP) model (Narimissa et al. J. Rheol. 64, 95-110 (2020)), based solely on linear viscoelastic characterization and the Rouse time τ_R of the melts. The analysis reveals that both the normalized elongational viscosity and the normalized elongational stress are dependent on the number of entanglements (Z) and the ratio of entanglement molar mass M_em to critical molar mass M_cm of the melts in the linear viscoelastic regime through \( {\eta}_E^0/\left({G}_N{\tau}_R\right)\propto {\left({M}_{\mathrm{em}}/{M}_{\mathrm{cm}}\right)}^{2.4}{Z}^{1.4} \) and \( {\sigma}_E^0/{G}_N\propto {\left({M}_{\mathrm{em}}/{M}_{\mathrm{cm}}\right)}^{2.4}{Z}^{1.4} Wi \), while in the limit of fast elongational flow with high Weissenberg number \( Wi={\tau}_R\dot{\varepsilon} \), both viscosity and stress become independent of Z and M_em/M_cm, and approach a scaling which depends only on Wi, i.e. η_E/(G_Nτ_R) ∝ Wi^−1/2 and σ_E/G_N ∝ Wi^1/2. When expressed by an effective power law, the broad transition from the linear viscoelastic to the high Wi regime leads to chemistry-dependent scaling at intermediate Wi depending on the number of entanglements and the ratio between entanglement molar mass and critical molar mass.

莫雷利（Morelly）等人。（Macromolecules 52：915-922，2019）报告了通过长丝拉伸流变法在局部控制的应变和应变率下获得的单分散线性聚合物熔体的瞬态和稳态伸长率数据，发现聚苯乙烯的伸长粘度具有不同的幂律定标，聚（叔丁基苯乙烯）和聚（甲基丙烯酸甲酯）。很好的协议数据和延伸链间压力（EIP）模型的预测之间实现（64 Narimissa等，J。Rheol。，95-110（2020）），仅基于线性粘弹性表征和劳斯时间τ _[R的融化。分析表明，归一化的拉伸粘度和归一化的拉伸应力均取决于纠缠数（Z）以及通过\（{\ eta} _E ^ 0 / \ left（{G} _N {\ tau} _R \ right）在线性粘弹性状态下熔体的纠缠摩尔质量M _em与临界摩尔质量M _cm的比率\ propto {\ left（{M} _ {\ mathrm {em}} / {M} _ {\ mathrm {cm}} \ right）} ^ {2.4} {Z} ^ {1.4} \）和\（{ \ sigma} _E ^ 0 / {G} _N \ proto {\ left（{M} _ {\ mathrm {em}} / {M} _ {\ mathrm {cm}} \ right）} ^ {2.4} {Z } ^ {1.4} Wi \），而在具有高Weissenberg数\（Wi = {\ tau} _R \ dot {\ varepsilon} \）的快速伸长流动的极限下，粘度和应力均不受Z和M _em的影响/ M _cm，并接近仅取决于Wi的缩放比例的，即η _È /（g ^ _Ñ τ _{- [R}）α 无线^-1/2和σ _ë / ģ _Ñ  α 无线^1/2。当用有效幂律表示时，从线性粘弹性到高Wi态的宽泛过渡导致中间Wi处取决于化学的结垢，具体取决于缠结数和缠结摩尔质量与临界摩尔质量之间的比率。