Pyrolysis of fire retardant anhydride-cured epoxy resins

Anhydride-cured epoxies are in general the preferred one in epoxy sealants and putties as encapsulation materials for integrated circuits and semiconductor-based electronic systems. Thermal recycling of brominated plastics is an eco-efficient waste management options available for end-of-life WEEE items. Thermal behaviour of epoxy ester resins prepared on the purpose of using brominated and unbrominated epoxy monomers based on bisphenol A and phthalic anhydride as hardener has been investigated in thermogravimetry and in Py-GC/MS. Similarly to what is observed in amine hardened epoxies, the presence of bromine reduces the thermal stability of the network. First reaction to occur is the ester pyrolysis followed by hardener evaporation, and volatilization or rearrangement or loss of the glycidyl end groups from the glycidyl species. Debromination of aromatic structures and scission of the isopropyl bridge of bisphenol A take place at higher temperatures.