Synthetic biodegradable aliphatic polyester/montmorillonite nanocomposites

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.