Ching-Wei Lee Johnny, Park Jun Dong, Rogers Simon A
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign.
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign;
J Vis Exp. 2019 Apr 25(146). doi: 10.3791/58707.
We investigate the sequence of physical processes exhibited during large amplitude oscillatory shearing (LAOS) of polyethylene oxide (PEO) in dimethyl sulfoxide (DMSO) and xanthan gum in water - two concentrated polymer solutions used as viscosifiers in foods, enhanced oil recovery, and soil remediation. Understanding the nonlinear rheological behavior of soft materials is important in the design and controlled manufacturing of many consumer products. It is shown how the response to LAOS of these polymer solutions can be interpreted in terms of a clear transition from linear viscoelasticity to viscoplastic deformation and back again during a period. The LAOS results are analyzed via the fully quantitative Sequence of Physical Processes (SPP) technique, using free MATLAB-based software. A detailed protocol of performing a LAOS measurement with a commercial rheometer, analyzing nonlinear stress responses with the freeware, and interpreting physical processes under LAOS is presented. It is further shown that, within the SPP framework, a LAOS response contains information regarding the linear viscoelasticity, the transient flow curves, and the critical strain responsible for the onset of nonlinearity.
我们研究了聚环氧乙烷（PEO）在二甲基亚砜（DMSO）中以及黄原胶在水中进行大振幅振荡剪切（LAOS）时所展现的物理过程序列，这两种浓聚合物溶液在食品、提高石油采收率和土壤修复中用作增稠剂。了解软材料的非线性流变行为对于许多消费品的设计和可控制造至关重要。研究表明，这些聚合物溶液对LAOS的响应如何能在一个周期内从线性粘弹性清晰地转变为粘塑性变形，然后再转变回来的角度进行解释。通过基于MATLAB的免费软件，利用完全定量的物理过程序列（SPP）技术对LAOS结果进行分析。本文介绍了使用商用流变仪进行LAOS测量、用免费软件分析非线性应力响应以及解释LAOS下物理过程的详细方案。进一步表明，在SPP框架内，LAOS响应包含有关线性粘弹性、瞬态流动曲线以及导致非线性开始的临界应变的信息。
