Synthesis and characterization of phosphorus- and silicon-containing flame-retardant curing agents and a study of their effect on thermal properties of epoxy resins

Two amines, one phosphoric acid tris-(5-amino-naphthalene-1-yl) ester and another bis-(5-amino-naphthalene-1-yl) dimethyl silane, were synthesized and their structures were characterized with the help of elemental analysis, FTIR, H-1 NMR, C-13 NMR, and P-31 NMR spectroscopic techniques. These amines are used as reactive flame retardants as well as curing agents to blend with commercial epoxy resin diglycidyl ether of bisphenol A (DGEBA). The thermal properties of these epoxy thermosets (EPs) were investigated by thermogravimetric analysis and the flame retardancy was tested according to the LOI and UL 94 tests. The results indicate that all epoxy thermosets exhibit excellent flame retardancy, moderate changes in T (g), and 5% decomposition temperature in the range of 344-435A degrees C.