Flow‐Induced Birefringence of Concentrated Polyisoprene Solutions
Flow‐Induced Birefringence of Concentrated Polyisoprene Solutions
复制标题
浓聚异戊二烯溶液的流动引起的双折射
DOI：
10.1122/1.550026
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发表时间：
1989
影响因子：
3.3
通讯作者：
M. Doi
中科院分区：
文献类型：
--
作者：
D. S. Pearson;A. D. Kiss;L. Fetters;M. Doi
在一系列聚异戊二烯浓缩液上进行了恒定剪切流动开始后测量双折射的实验。在机械流变仪上测量了稳态剪切应力。从这两个实验中得到的数据证实了双折射和应力在延伸到非牛顿区域的剪切速率范围内是线性相关的(应力-光学定律)。在高剪切速率下的瞬时响应过程中，还观察到了有趣的非线性效应。剪应力和第一法向应力在达到其稳态值之前都经历了极大值。原始的Doi-Edwards模型没有预测到法向应力的最大值，但对他们的理论进行了修正，包括了链的伸展，这与我们的结果定性地一致。
Experiments measuring the birefringence following the inception of a steady shearing flow were conducted on a series of concentrated polyisoprene solutions. The steady‐state shear stress was also measured in a mechanical rheometer. The data obtained from the two experiments confirmed that the birefringence and stress were linearly related (stress‐optical law) over a range of shear rates that extended far into the non‐Newtonian region. Interesting nonlinear effects were also observed during the transient response at high shear rates. Both the shear stress and the first normal stress pass through maximums before reaching their steady‐state values. A maximum in the normal stress is not predicted by the original Doi‐Edwards model but a modification of their theory which includes chain stretching is in qualitative agreement with our results.