Phase morphology and rheological behavior of polymer/layered silicate nanocomposites

Abstract

Rheological behavior of polymer/layered silicate nanocomposites an strongly dependent not only upon their microstructure but also upon the interfacial characteristics. Different phase morphology (intercalated or exfoliated) of polymer/clay is obtained according to interfacial characteristics between polymer chains and clay. In intercalated structure, the presence of randomly oriented anisotropic stacks of silicate layers is responsible for the enhancement of both moduli. The PS/clay nanocomposites exhibit a slight enhancement at low frequency because of its simple intercalated structure and little interaction. On the other hand, the PS-co-ma/clay nanocomposites have a similar intercalated structure but exhibit a distinct plateau-like behavior at low frequency since the PS-co-ma has a strong attractive interaction with the silicate layers. Finally, PE-g-ma/clay nanocomposites display an exfoliated structure, which exhibit both a distinct plateau-like behavior at low frequency and enhanced moduli at high frequency. Percolation structure as well as large interfacial area between polymer chains and clay are responsible for the theological behavior.