Comparison of poly(ethylene-co-acrylic acid) loaded Zn2+–montmorillonite nanocomposites and poly(ethylene-co-acrylic acid) zinc salt

Novel nanocomposite films based on poly(ethylene-co-acrylic acid) (PEAA) and zinc montmorillonite (Zn2+–MMT) were fabricated using a solution casting method with water as the solvent. Transmission electron microscopy indicated that Zn2+–MMT was distributed finely in the PEAA matrix. X-ray diffraction indicated that an ion exchange process occurs between Zn2+–MMT and PEAA. The nanocomposites filled with a low Zn2+–MMT loading increased the tensile strength and elongation at break. The significant improvements in these mechanical properties were attributed to the fine dispersion of Zn2+–MMT in the polymer and the covalent interaction between the polymer chains and Zn2+ cations. Thermogravimetric analysis and differential thermal calorimetry confirmed that PEAA formed a network through the presence of Zn2+ cations. A poly(ethylene-co-acrylic acid) zinc salt (PEAAZn) film by hot pressing was introduced for comparison. Zn2+–MMT improved the mechanical properties of the PEAA significantly compared to that of PEAAZn.