Late-State Ripening Dynamics of a Polymer/Clay Nanocomposite
Late-State Ripening Dynamics of a Polymer/Clay Nanocomposite
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DOI：
10.1021/ma901665m
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发表时间：
2010-01
期刊：
影响因子：
5.5
通讯作者：
Xiaoliang Wang;Pingchuan Sun;G. Xue;H. Winter
中科院分区：
文献类型：
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作者：
Xiaoliang Wang;Pingchuan Sun;G. Xue;H. Winter
人们发现物理凝胶有一种非常简单的粘弹性松弛模式，超过其凝胶点，就会慢慢成熟到稳定的结构状态。该材料是一种纳米复合材料，由两种成分组成，即有机粘土和末端官能化聚合物，它们按规定的比例混合。当新组合时，聚合物嵌入粘土廊道中，并最终使粘土剥落。剥落发生时无需施加流动。纳米复合材料快速通过凝胶点，并且随着熟化时间tr的增加，其特征模量Gc(tr)和弛豫时间λc(tr)分别按数量级增长和衰减。令人惊讶的是，我们发现他们的乘积 Gc(tr)λc(tr) 在嵌入和剥离这两个截然不同的结构化过程中保持不变。对于流变实验，Gc(tr)λc(tr)=常数意味着动态力学数据可以在45°以下通过对数/对数移位相互合并。
A remarkably simple viscoelastic relaxation pattern was found for a physical gel that, beyond its gel point, slowly ripens toward a stable structural state. The material is a nanocomposite that consists of two components, an organoclay and an end-functionalized polymer, which get mixed at prescribed ratio. Whenfreshlycombined,thepolymerintercalatesintotheclaygalleriesandeventuallyexfoliatestheclay.The exfoliation occurs without applying flow. The nanocomposite quickly passes through the gel point and, with increasing ripening time, tr, its characteristic modulus Gc(tr) and relaxation time λc(tr) grow and decay by ordersofmagnitude,respectively. Surprisingly, theirproduct,Gc(tr)λc(tr),is foundtoremainconstant during the two vastly different structuring processes of intercalation and exfoliation. For the rheological experi- ments,Gc(tr)λc(tr) = constant means that dynamic mechanical data can be merged into each other by log/log shifting under 45� .