A series of poly(ethylene oxide) (PEO)/organoclay nanocomposites have been prepared via a solvent casting method. Using three different organoclays modified with the alkylammonium salts, the effect of surfactants on organoclay surfaces in polymer/organoclay nanocomposites was investigated by focusing on two major aspects:  internal structure analysis and rheological measurement of the nanocomposites. The d spacings of both the pure PEO and intercalated organoclay were examined via X-ray diffraction analysis, and the microstructure of these nanocomposites was examined by transmission electron microscopy. Rheological properties of these nanocomposites exhibited different behavior with different modifier concentrations and surfactant sizes (chain lengths). To analyze the non-Newtonian flow behavior, we fitted shear viscosity data via the Carreau model, showing that steady shear viscosity and power-law behavior increase with organoclay content. Hysteresis phenomenon was also enhanced with organoclay content, and the increase in the storage/loss moduli and interactions among organoclay platelets were observed with organoclay content. The enhanced thermal stability of the nanocomposites by organoclay was also observed.

Biodegradable aliphatic polyesters (BAPs), synthesized from diols and dicarboxylic acids, and organophilic montmorillonite (OMMT) were intercalated by a solvent-casting method using chloroform as a cosolvent to produce nanocomposite (BAP/OMMT). The d spacings of both BAP and BAP/OMMT were examined by X-ray diffraction analysis, and the microstructure of BAP/OMMT was examined by transmission electron microscopy. Melting temperature changes and residuals were measured by thermal gravimetric analysis. Tensile strength and elongation were also examined with a universal testing machine. Increases in both the thermal stability and the mechanical strength of BAP/OMMT were observed for several different OMMT loadings. The rheological properties of the BAP/OMMTs were also examined with a rotational rheometer having a parallel-plate geometry. The shear viscosity at low shear rate exhibited a Newtonian plateau even at high loading and showed a higher degree of shear thinning at higher shear rate. Both the Newtonian plateau and the enhanced power-law behavior were correlated with a scaling function.

The organophilic montmorillonite clay and poly(ethylene oxide) (PEO) nanocomposites were intercalated by a solvent casting method using chloroform as the cosolvent. The prepared nanocomposites were characterized by an X‐ray diffraction method to examine their microstructure. Rheological properties of both the PEO/clay nanocomposites and the immiscible PEO/clay blends were investigated via a rotational rheometer in steady shear mode with a parallel plate geometry. The shear thinning viscosity data were fitted with the Carreau model, which showed that steady shear viscosity increases with increasing clay loading. The hysteresis phenomenon is observed to be enhanced with clay loading. PEO/clay nanocomposites exhibit higher zero‐shear‐rate viscosity and sharper shear thinning behaviors than immiscible PEO/clay blends.

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Nanocomposites with synthetic biodegradable aliphatic polyesters (BAP) were synthesized by the solution intercalation method with addition of organically modified montmorillonite. The hybrid structural evolution, caused by nanoscopic interaction between matrix polymer and layered silicate, was analyzed using viscoelastic properties obtained from oscillatory rheological measurements. Changes of viscoelastic properties to more solid-like, especially in the terminal region, were explained by both formation of specific BAP chain mesostructures with organoclay incorporated and a rheological percolation threshold. This behaviour was analyzed via a modified Cole-Cole plot evaluating the structural changes with filler concentration as well as the frequency dependence of dynamic modulus, complex modulus, and phase angle. Furthermore, the stress relaxation behaviour successfully demonstrated structural changes and critical concentration of nanocomposites with a jump shift of the longest relaxation time towards longer time.

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