Metal complexes of partially phosphorylated poly(vinyl alcohol) - Functions and applications

The highly phosphorylated poly(vinyl alcohol)s (P-PVAs: degree of phosphorylation 70 mol-%) were synthesized by the reaction of PVA, dicyandiamide, urea and orthophosphoric acid in DMF solution. A range of P-PVAs having differents contents (3.3 to 70 mol-%) of phosphoric acid groups can be obtained by the change of reaction time via the same procedure. The complex formation of Cr(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions with P-PVA thus obtained was investigated by means of potentiometric titration and spectroscopy. By chemical crosslinking reaction of P-PVA with glutaraldehyde, novel anionic polyelectrolyte gels were easily prepared. The degree of swelling and the hardness of hydro-gels can be changed by varying the crosslinking reaction condition. The ion exchange capacity and metal ion selectivities of a cation exchange resin prepared from P-PVA hydrogel have been estimated. Flame-retardation of metal-P-PVA complexes have also studied. The Ni(II)-P-PVA complex showed a good name-retardation. The molecular composites of the P-PVA salts of cations such as K+ or R4N(+) (R = CM3 etc.) were also prepared. These composite polymers showed single ionic conductivity (sigma RT > 10(4)S . cm(-1)).