Influence of polyacrylamide conformation on fabric of “tunable” kaolin–polymer composite

Abstract

“Tunable” clay–polymer composites have the potential to improve the engineering properties of clay materials. The importance of these materials derives from the ability of the responsive polymer to adopt various conformations (coiled, partially extended or extended), which in turn impacts the mesoscale properties of the material. However, the influence of polymer molecule conformation on particle arrangement and overall composite behavior is not well understood. The purpose of this study is to understand the fabric development due to the conformational behavior of the polymer, and thus the clay–polymer composite, over a wide range of solids content and stress levels. The polymer molecule conformation was controlled using selected fluid pH and ionic concentrations. Results show that the polymer conformation significantly influences clay fabric formation. When the polymer molecules are likely to have extended conformation, the dominant fabric mode is face-to-face and particle mobilization increases. Both face-to-face and edge-to-edge fabric formation dominate the behavior of the composite when coiled conformation is likely, resulting in a decrease in interparticle movement. Thus, the polymer conformation can be used to manipulate both the interparticle spacing between particles and (or) aggregates and arrangement of particles.