Grattoni Carlos A., Al-Sharji Hamed H., Yang Canghu, Muggeridge Ann H., Zimmerman Robert W.
T. H. Huxley School of Environment, Earth Sciences and Engineering, Imperial College of Science, Technology and Medicine, London, SW7 2BP, United Kingdom
J Colloid Interface Sci. 2001 Aug 15;240(2):601-607. doi: 10.1006/jcis.2001.7633.
Gels produced by crosslinking polyacrylamide solutions with chromium (III) have been characterized by dynamic rheology studies. To vary the gel strength, different polymer concentrations were used, while keeping the temperature, salinity, and crosslinker concentration constant. Both the loss and storage moduli increased with the polymer concentration for this gel system. The storage modulus at the end of the gelation was used to characterize the gel strength. Steady-state water flow experiments through gel-filled capillary tubes were performed, with the aim of linking the gel strength and flow behavior. The permeability was found to be a function of the water flow rate (velocity) and polymer concentration. Two parameters were used to characterize the flow behavior, intrinsic gel permeability and elasticity index, which are each functions of the polymer concentration. However, only one parameter is needed to fully identify the flow and rheological gel properties, as the elasticity index and storage modulus are linked by a power-law relationship. The loss modulus and intrinsic permeability are correlated with the storage modulus and elasticity index, respectively. A theoretical model for this behavior linking both gel properties based on the dual domain structure was used to demonstrate that the flow and rheological behavior of the gel are indeed related and that the gel strength controls the water permeability. Implications for prediction of flow of water through gels emplaced in a porous medium are discussed. Copyright 2001 Academic Press.
通过将聚丙烯酰胺溶液与铬（III）交联制备的凝胶已通过动态流变学研究进行了表征。为了改变凝胶强度，使用了不同的聚合物浓度，同时保持温度、盐度和交联剂浓度不变。对于该凝胶体系，损耗模量和储能模量均随聚合物浓度的增加而增大。凝胶化结束时的储能模量用于表征凝胶强度。进行了通过填充凝胶的毛细管的稳态水流实验，目的是将凝胶强度与流动行为联系起来。发现渗透率是水流速率（速度）和聚合物浓度的函数。使用两个参数来表征流动行为，即固有凝胶渗透率和弹性指数，它们各自都是聚合物浓度的函数。然而，由于弹性指数和储能模量通过幂律关系相连，因此只需一个参数就可以完全确定流动和流变凝胶特性。损耗模量和固有渗透率分别与储能模量和弹性指数相关。基于双域结构的将两种凝胶特性联系起来的这种行为的理论模型被用于证明凝胶的流动和流变行为确实相关，并且凝胶强度控制着水渗透率。讨论了对预测水在多孔介质中放置的凝胶中的流动的影响。版权所有2001年学术出版社。
