Preparation and characterization of films based on zirconium sulfophenyl phosphonate and chitosan

Zirconium sulfophenyl phosphonate (ZrSP), Zr(O₃P-C₆H₄SO₃H)₂, was synthesized and characterized to prepare nanocomposites based on chitosan (CS). The effects of ZrSP on the structure, morphology, and thermal properties, as well as the mechanical properties of the films were investigated by Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and tensile tests. FTIR spectroscopy revealed that electrostatic interactions had been formed in the nanocomposites, which improved the compatibility between CS and ZrSP. XRD and SEM results indicated the ZrSP nanoparticles were uniformly distributed in the chitosan matrix at low loading, and obvious aggregations existed at high loading. In addition, compared with neat CS, the values of tensile strength (σ_b), elongation at break (ε_b), and water resistance of CS/ZrSP-3 containing 0.6 wt % ZrSP had been improved by 60.0%, 69.7%, and 41.8%, respectively.