The Influence of Molar Mass Distribution on the Complex Moduli of Polymer Melts
The Influence of Molar Mass Distribution on the Complex Moduli of Polymer Melts
复制标题
摩尔质量分布对聚合物熔体复模量的影响
DOI：
10.1122/1.550038
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发表时间：
1989
影响因子：
3.3
通讯作者：
G. Schindlauer
中科院分区：
文献类型：
--
作者：
G. Eder;H. Janeschitz;S. Liedauer;A. Schausberger;W. Stadlbauer;G. Schindlauer
测定了一系列聚丙烯熔体的复模数，并绘制了凝胶渗透色谱图。作者之一(A.Schausberger)提出的模型被用来关联摩尔质量分布数据和动态力学数据。结果表明，储能模数对分布的高摩尔质量尾部的变化非常敏感，因此凝胶渗透色谱(GPC)很难用来检验聚合物熔体流变学分子理论的有效性。似乎不到0.5%的大分子的总质量分数对模数-频率曲线的几乎整个形状都是决定性的。只有适当地将摩尔质量分布外推到高摩尔质量区域(假设尾部为对数正态)，才能在预测的频率依赖关系和观测到的频率依赖关系的形状之间进行有利的比较。
The complex moduli of a series of polypropylene melts were measured together with their gel permeation chromatograms. A model, as proposed by one of the authors (A. Schausberger), was used to correlate the molar mass distribution data with the dynamic mechanical data. It turns out that, in particular, the storage modulus is so sensitive to variations in the high molar mass tail of the distribution that gel permeation chromatography (GPC) is hardly a method which can be used to check the validity of molecular theories on polymer melt rheology. It seems that a total mass fraction of less than a half percent of large molecules is decisive for almost the whole shape of the modulus versus frequency curve. Only a proper extrapolation of the molar mass distribution into the high molar mass region (assumption of a lognormal tail) leads to a favorable comparison between the shapes of predicted and observed frequency dependences.