Complex formation of linear poly(methacrylic acid) with uranyl ions in aqueous solutions

The complex formation of uranyl ions (UO(2+)2) with poly(methacrylic acid) (PMAA) was investigated by potentiometric, conductometric, UV-visible, luminescence and FTIR spectroscopic, and thermal analysis methods. The stoichiometric ratio at complexation between polymer and uranyl ions was found to be equal to 2 polymer base units per uranyl ion. FTIR spectra of the PMAA-UO(2+)2 complex confirmed incorporation of metal ions into the polymer and showed that the electrostatic interactions play a major role in complexation. An increase of emission intensity in luminescence spectra of uranyl ions suggests influence of conformation peculiarity of the poly(methacrylic acid) chain. The thermal degradation of polycomplex starts at lower temperature as compared to pristine PMAA that is due to the lower thermal stability of PMAA-UO(2+)2 complex.