Universal Relaxation Behavior of Entangled 1,4-Polybutadiene Melts in the Transition Frequency Region
Universal Relaxation Behavior of Entangled 1,4-Polybutadiene Melts in the Transition Frequency Region
复制标题
1,4-聚丁二烯熔体在跃迁频率范围内的普遍弛豫行为
DOI：
10.1021/ma5024632
复制
发表时间：
2015
期刊：
影响因子：
5.5
通讯作者：
R. Larson
中科院分区：
文献类型：
--
作者：
Seung Joon Park;Priyanka S. Desai;Xue Chen;R. Larson
对文献中线性聚丁二烯、星形聚丁二烯、H聚丁二烯和梳形聚丁二烯的线性粘弹性 G' 和 G'' 主曲线进行了比较，发现在转变频率区域内吻合良好，其中 G' 和 G'' 超过了平台模量，而与分子量和支化结构无关。因此，在 T = 25 °C 时平衡时间的 τe = (3.7 ± 0.93) × 10–7 s 值可以通过将 Rouse 预测拟合到跃迁频率数据来确定，并减去由 Kohlrausch-Williams-Watts (KWW) 表达式表示的玻璃模式的影响。尽管低温转变因子存在很大差异，但在过渡区域中多个数据集之间获得了良好的一致性，这显然是由于样品间 1,2 含量的微小差异所致。 1,2 含量的这些变化也会引起平台模量 GN0 和缠结分子量 Me 的微小变化，这对线性聚合物只有很小的影响，但对于长链支化聚合物可能会导致很大的变化......
Linear viscoelastic G′ and G″ master curves for linear, star, H, and comb 1,4-polybutadienes from the literature are compared and found to agree well in the transition frequency region, where G′ and G″ exceed the plateau modulus, irrespective of molecular weight and branching structures. A value of τe = (3.7 ± 0.93) × 10–7 s for the equilibration time at T = 25 °C can therefore be determined from fitting Rouse predictions to the transition frequency data, after subtracting effects of glassy modes represented by the Kohlrausch–Williams–Watts (KWW) expression. Good agreement among multiple data sets was obtained in the transition region despite large variations in low-temperature shift factors, evidently due to small sample-to-sample variations in 1,2 content. These variations in 1,2 content can also cause small changes the plateau modulus GN0 and the entanglement molecular weight Me, which should have only a small effect on linear polymers but for long-chain branched polymers could lead to large variations...
影响因子：
5.5
作者：
M. Shivokhin;E. Ruymbeke;C. Bailly;D. Kouloumasis;N. Hadjichristidis;A. E. Likhtman
通讯作者：
M. Shivokhin;E. Ruymbeke;C. Bailly;D. Kouloumasis;N. Hadjichristidis;A. E. Likhtman