THE RELATIONSHIP BETWEEN THE LINEAR (OSCILLATORY) AND NONLINEAR (STEADY-STATE) FLOW PROPERTIES OF A SERIES OF POLYMER AND COLLOIDAL SYSTEMS
THE RELATIONSHIP BETWEEN THE LINEAR (OSCILLATORY) AND NONLINEAR (STEADY-STATE) FLOW PROPERTIES OF A SERIES OF POLYMER AND COLLOIDAL SYSTEMS
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DOI：
10.1007/bf00656927
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发表时间：
1992-01-01
影响因子：
2.4
通讯作者：
WALTERS, K
中科院分区：
文献类型：
--
作者：
ALHADITHI, TSR;BARNES, HA;WALTERS, K
线性（振荡）和非线性（稳态）粘度之间的Cox-Merz经验关系已被证明对许多聚合物体系有效。本文给出了粘弹性系统的线性（G ′）和非线性（N1）弹性性质之间的等价关系。与Cox-Merz关系一样，它使用弹性和粘性参数的组合。储能模量的修正形式则等于Cox-Merz复数粘度。它可以用来与（半）法向力在数值上相等的圆频率和剪切rate. ESTA新的表达式和Cox-Merz规则进行了测试的聚合物和胶体系统的范围。结果发现，这两个表达式的工作所考虑的聚合物系统，但失败的胶体系统。在后者中，粘度和弹性的稳态值始终较低，用复数粘度和我们的新弹性表达式代替它们只会使情况变得更糟。对于聚合物体系，我们认为这是一个普遍而非普遍的观察结果，因为我们知道聚合物体系服从Cox-Merz粘度规则和我们的弹性规则的例外情况。对于胶体系统，我们发现任何一个系统都遵守这两条规则。
The Cox-Merz empirical relationship between the linear (oscillatory) and nonlinear (steady-state) viscosities has been shown to be valid for many polymeric systems. Here, we present an equivalent expression to relate the linear (G') and nonlinear (N1) elastic properties of viscoelastic systems. Like the (Cox-Merz relationship, it uses a combination of elastic and viscous parameters. The modified form of the storage modulus is then equivalent to the Cox-Merz complex viscosity. It can be used to correlate with (half) the normal force at numerically equal circular frequency and shear rate, respectively.This new expression and the Cox-Merz rule are tested for a range of polymeric and colloidal systems. It is found that both expressions work for the polymeric systems considered, but fail for the colloidal systems. In the latter, the steady state values of viscosity and elasticity are consistently low, and replacing them by the complex viscosity and our new elastic expression only makes matters worse.For polymer systems, we suggest this is a general but not universal observation, since we are aware of exceptions to the rule that polymeric systems obey the Cox-Merz rule for viscosity and our rule for elasticity. For colloidal systems we find that either rule is obeyed for any of our systems.