Coordination and morphology of metal/polyetherurethane complexes

Based on infrared spectra, differential scanning calorimetry, and quantum chemical calculations, this study investigated the effects of the species of metal (MnCl2, FeCl3, CoCl2, CuCl2, GaCl3), their interaction sites and binding strength on the morphologies of polyetherurethane (PU). The calculated frequency and binding energy were consistent with the experimental results, suggesting that most of the binding strength (95%) is associated with the charge transfer from the lone pairs (on the nitrogen in NH and the oxygen in CO and COC) in the PU ligand to the metal. MnCl2, CoCl2, and CuCl2 are more soluble in soft segments of PU than GaCl3 and FeCl3 via coordination with one or two polyether ligands and can significantly raise the glass transition temperature of PU. Conversely, GaCl3 and FeCl3 interact more strongly with hard-segment NH of PU than MnCl2, CoCl2, and CuCl2 and markedly reduce the melting temperature of PU.