Thermogravimetric studies of the metal complexes of polyacrylamide-supported amines: effect of the variables of macromolecular structure on thermal stability

Abstract

The thermal decomposition behaviour of metal complexes of amino functions supported on crosslinked polyacrylamides in different structural environments is followed. The phenomenological and kinetic aspects of the TG curves are investigated. The integral and approximation methods are used for the evaluation of the kinetic parameters. The thermal stabilities of the Cu(II) complexes of aminopolyacrylamides with 2-20 mol.% of DVB crosslinks and 4-20 mol.% of NNMBA crosslinks varied with the extent of crosslinking. The activation energy of decomposition decreases with crosslinking, reaches a minimum, and then increases. The relation between the activation energy and the extent of crosslinking fits into the general equation for a cubic polynomial. The thermal stabilities of the Cu(II) complexes of aminopolyacrylamides with DVB crosslinks are lower than the NNMBA-crosslinked system. This is due to the increased strain energy in the DVB crosslinking points. The thermal stabilities of the amino resins with 4% DVB crosslinks and 2% TTEGDA crosslinks varied with the extent of incorporation of the different metal ions, as well as the unsaturated coordination in the complex.