STUDIES ON PROPERTIES OF PVA FILM PLASTICIZED WITH MIXTURE OF UREA/ETHANOLAMINE

Abstract

Modified PVA films were prepared by casting method using urea/ethanolamine as a mixed plasticizer.The interactions between urea/ethanolamine and PVA molecules were investigated by FTIR spectra.The crystallinity of plasticized PVA film was measured by X-ray diffraction(XRD) method.Tm of modified PVA films was studied by differential scanning calorimetry(DSC).The mechanical properties of modified PVA films were studied by tensile testing.It was found that ethanolamine could prevent urea separating out from PVA and urea/ethanolamine mixture was a good plasticizer for PVA.FTIR spectra show that no significant structure difference between PVA and modified PVA,indicating that no chemical reaction happened between PVA and urea/ethanolamine.The shift of wavenumber shows that urea/ethanolamine can decrease the extent of inter-or intramolecular hydrogen bonds in PVA molecules.The XRD investigations show that the crystalline fraction significantly reduces with the addition of urea/ethanolamine.DSC shows that addition of urea/ethanolamine can reduce the Tm of PVA film.Tm of PVA film with 30 phr urea/ethanolamine can reduce to 199.3℃.Modified PVA films show lower degree of swelling but higher solubility than that of pure PVA film.Urea/ethanolamine mixture can soften the PVA film,resulting in lower tensile strength and higher elongation at break.The tensile strength and elongation at break for PVA film modified with 30 phr urea/ethanolamine were 23.89 MPa and 542.88%,respectively.