Effect of metal salt on physical properties of PVA film

Abstract

Effect of metal salt on physical properties of PVA films was investigated by preparing PVA films containing various types and contents of metal salt. The metal salts used in the present study were LiCl, NaCl, CaCl₂, BaCl₂, FeCl₂, FeCl₃ , CuCl₂, ZnCl₂, CoCl₂, and NiCl₂, respectively. Then the dried films were separately used for studying effect of each metal salt with the following techniques: UV-VIS spectroscopy, IR spectroscopy, ATR-FTIR spectroscopy, FTIR spectroscopy, Raman spectroscopy, DMTA, Tensile testing, Water absorption, Organic solvent absorption and Optical microscopy. AII of the results were mostly corresponding which can be concluded that there was interaction of metal ions with hydroxyl groups and/or residual acetate groups in PVA. The results also indicated that most of physical properties of PVA films tend to depend on metal content in the films. From UV-VIS absorption spectra, it was found that the PVA films containing some salts such as FeCl₂, FeCl₃ , CuCl₂, ZnCl₂, CoCl₂ and NiCl₂ showed different absorption band from the spectra of PVA film. Percentage of crystallinity calculated from IR spectra tended to decrease with the content of metal in the films. Tg, bending modulus, tensile properties, water and organic solvent absorption tended to depend both on types and content of metal salt in the films. In addition, optical microscopic study shows distribution of PVA films containing metal salt is more regularity after tension testing.