Behaviour of a simple crystallisation model in tube and channel flow

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• 作者：Roger I. Tanner ; Chitiur Hadinata and Duane LeeWo
• 关键词：Shear ; induced crystallisation ; Tube flow ; Poly(butene ; 1) ; Amorphous ; frozen model
• 刊名：Rheologica Acta
• 出版年：2009
• 出版时间：June, 2009
• 年：2009
• 卷：48
• 期：5
• 页码：499-507
• 全文大小：377.3 KB

文摘

A formulation describing the rheology of crystallising polymers is discussed. For some semi-crystalline polymers where spherulites form as part of the crystallisation process, the use of a suspension-type model is appropriate. Whilst it is possible to so describe simple shearing and elongational rheology during on-going crystallisation with such models, the flow through a capillary tube is much more complex and numerical solution is usually necessary. To give some insight into this complex flow, a ‘step function’ or ‘amorphous-frozen’ model of the viscosity changes due to crystallisation has been devised so that a semi-analytical approach is feasible. We use this simple model and compare the results with recently published experiments in tubes and channels at high (O(103 s − 1)) shear rates using poly(butene-1). A direct correlation between simple shear and tube flow crystallisation onset times is found.