Rheology and phase separation of polymer blends with weak dynamic asymmetry

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• 作者：Wei Yu^a ; ^{wyu@sjtu.edu.cn"" rel=""nofollow} ; Runming Li^b ; Chixing Zhou^a
• 关键词：Rheology ; Phase separation ; Dynamic asymmetry
• 刊名：Polymer
• 出版年：2011
• 出版时间：26 May 2011
• 年：2011
• 卷：52
• 期：12
• 页码：2693-2700
• 全文大小：764 K

文摘

Rheological methods have been frequently used to study the phase separation behavior of partially miscible polymer blends. Usually the binodal temperature can be determined from the failure of time–temperature superposition (TTS) principle in isothermal experiments, or the deviation of the storage modulus from the apparent extrapolation of modulus in miscible regime in non-isothermal experiments. However, these methods are shown in this work to be not widely applicable even in blends with weak dynamic asymmetry due to the thermo-rheological complexity. A rheological model which is an integration of the double reptation model and the self-concentration model is found to describe the linear viscoelasticity of miscible blends quite satisfactorily, from which it is possible to follow the contribution from the miscible blends even in the two phase regime. Then, the binodal temperature is readily defined as the deviation of experimental data from such model prediction for miscible blends. Such method is successfully applied in a model polymer blend (poly(methyl methacrylate)/poly(styrene-co-maleic anhydride), PMMA/SMA) with weak dynamic asymmetry.