Comparison of transition metals in the graft copolymerization of vinyl monomers onto starch

The ability to graft acrylonitrile (AN) onto starch initiated by various transition metals such as Mn(VII), Cr(VI), V(V) and Fe(III) were compared in the existence of sulfuric acid in different concentrations. The results showed that the grafting potential of Fe(III) is the lowest, while Mn(VII) is the highest of these transition metals discussed. The catalyzing ability of varieties of acids, including perchloric acid, sulfuric acid, nitric acid and hydrochloric acid, in the graft copolymerization of acrylonitrile onto starch was studied; and the graft ability of monomers such as acrylaniide (AM), acrylic acid (AA) and methyl methacrylate (MMA), was compared. The experimental data indicates that the catalytic abilities of acids are related to their capability of providing protons. The granuluar structure of starch and it's graft copolymer were investigated with scanning electron microscopy, infrared spectroscopy, and thermogravietry.