Studies on curing kinetics and thermal behavior of phosphorylated epoxy resin in the presence of aromatic amide-amines

摘要

This article describes the synthesis of some novel aromatic amide-amine curing agents by reacting 1 mole of p-amino benzoic acid with 1 mole of each of 1,4-phenylene diamine (P), 1,5-diamino naphthalene (N), 4,4′-(9- fluorenyllidene)-dianiline (F), 3,4′-oxydianiline (O), and 4,4′-diaminodiphenyl sulphide (DS) and were designated as PA, NA, FA, OA, and SA, respectively. The aromatic amide-amines so synthesized were characterized with the help of spectroscopic techniques, viz., Fourier Transform Infrared, proton nuclear magnetic resonance, and carbon nuclear magnetic resonance. The curing kinetics of the epoxy resins obtained by reacting amines with diglycidyl ether of bisphenol-A blended with tris(glycidyloxy)phosphine oxide in a ratio of 3:2, respectively, were investigated by DSC technique using multiple heating rate method (5, 10, 15, 20°C/min). Activation energies were determined by fitting the experimental data into Kissinger and Flynn-Wall-Ozawa Kinetic models. The activation energies obtained through Flynn-Wall-Ozawa method were slightly higher than Kissinger method but were comparable. However, both the energies were found to be dependent on the structure of amines. The thermal stability and weight loss behavior of isothermally cured thermosets were also investigated using thermogravimetric analysis in nitrogen atmosphere.