Effect of pressure on the flow behavior of polybutene
Effect of pressure on the flow behavior of polybutene
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DOI：
10.1002/polb.23472
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发表时间：
2014-05
期刊：
影响因子：
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通讯作者：
A. Ponjavic;L. Mare;J. Wong
中科院分区：
文献类型：
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作者：
A. Ponjavic;L. Mare;J. Wong
采用新开发的光漂荧光成像测速技术，研究了亚微米厚聚合物熔体在高压条件下的流变性。特别地，研究了雷诺方程解的有效性和局限性，它提出了一个线性的贯穿厚度的速度剖面。聚丁烯（PB）以点接触的方式在两个表面之间剪切。在这项工作中提出的结果表明，存在一个临界压力，低于该压力，通过厚度的速度分布接近线性。然而，在较高的压力下，剖面呈s形，类似于部分塞流。s型曲线与线性曲线的偏离随着压力的增加而增加，这表明发生了二级相/玻璃化转变。这种转变的性质是通过检测PB挤压膜的压力依赖动力学独立证实的。流动型转变的临界压力随分子量的变化而变化，这与聚合物熔体的压力诱导玻璃化转变一致。©2014 Wiley期刊公司j .变异较大。科学。B部分：Polym。物理学报，2014,52,708-715
The rheology of submicron thick polymer melt is examined under high normal pressure conditions by a recently developed photobleached-fluorescence imaging velocimetry technique. In particular, the validity and limitation of Reynold equation solution, which suggests a linear through-thickness velocity profile, is investigated. Polybutene (PB) is sheared between two surfaces in a point contact. The results presented in this work suggest the existence of a critical pressure below which the through-thickness velocity profile is close to linear. At higher pressures however, the profile assumes a sigmoidal shape resembling partial plug flow. The departure of the sigmoidal profile from the linear profile increases with pressure, which is indicative of a second-order phase/glass transition. The nature of the transition is confirmed independently by examining the pressure-dependent dynamics of PB squeeze films. The critical pressure for flow profile transition varies with molecular weight, which is consistent with the pressure-induced glass transition of polymer melt. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 708–715