Investigation of the reaction mechanism of different epoxy resins using a phosphorus-based hardener

In this work, the fundamental kinetic and structure/property information for a novel phosphorus-based hardener, bis(4-aminophenoxy) phosphonate is cured with a range of common epoxy resins such as diglycidyl ether of bisphenol A, tri glycidyl p-amino phenol and tetra glycidyl diamino diphenyl methane (TGDDM) at various cure temperatures. The rate coefficients k1 and k 2 for the primary and secondary amine epoxide addition reactions, respectively, were determined and were found to exhibit a positive substitution effect for the TGAP and TGDDM epoxy resins. Etherification or internal cyclization were shown to be important at higher levels of cure conversion, with these reactions being more significant for the TGAP/BAPP system. Some basic structure/property relationships were established between the glass transition temperature (Tg) and epoxide conversion. The master curve obtained for the superimposition of the various cure temperatures for each epoxy demonstrated the independence of the cure mechanism with temperature.