Poly(vinyl alcohol) (PVA) was structurally modified with two different types of chemicals under nitrogen atmosphere in the presence of Sb2O3 as a catalyst at 80 degrees C in an aqueous medium. An FTIR and NMR spectrum confirmed the structural modification of PVA. DSC and TGA counseled the thermal properties of structurally modified PVA. Urea modified PVA exhibited higher mechanical strength than the pristine PVA. The FTIR-relative intensities of olefin formation and ketone formation were increased with the increase of weight of water. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2059-2068, 2010