Title:
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Development of novel curing agents for epoxy resins
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A series of complexes incorporating diamine (o-phenylenediamirre, 2-aminobenzylamine, anthranilamide, OPD, 2-ABA and Anth respectively) ligands and containing the acetato and chloro transition metal salts of Ni and Cu has been prepared and characterised using elemental analysis and spectroscopic methods. Infrared data show that complexation of the amino nitrogen atoms occurs to a high degree. The same curing agents have been incorporated into two commercial epoxy resins recognised as "industry standards" (MY721 and MY750), and their cure properties and shelf life assessed alongside commercial curative systems. Thermal FTIR, ESR, and Uv-vis spectroscopy coupled with principal component analysis have been utilised to determine the initial dissociation of the ligands from the metal centre. Thermogravimetry (TG) of the samples has been used to determine the temperature at which the ligand begins to fully dissociate from the metal centre. The current work demonstrates that while complexes based on copper(ll) and nickel(ll) and containing OPD ligands may be prepared and incorporated into commercial epoxy resins, there are some advantages associated with using 2-ABA (as the diamine ligand) due to the higher complex solubility and better processing characteristics that it imparts to the formulated system. In general, the 2-ABA based complexes disperse well within commercial epoxy systems and display good storage stability over prolonged periods of time (up to 67 days at ambient temperature). Initial studies have been carried out to elucidate the mechanisms by which the complexes react with the epoxy resin and the kinetic parameters associated with that reaction.
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