Factors Influencing the Fire-Resistance of Epoxy Compositions Modified with Epoxy-Containing Phosphazenes

Abstract

The flame resistance of epoxy compositions based on resin D.E.R.-330, isomethyltetrahydrophthalic anhydride, and new epoxy-containing aryloxycyclotriphosphazenes according to GOST (State Standard) 28157-89 (analog of the test UL-94) was studied. Thermogravimetric analysis and microstructural investigations of the coke residue formed during combustion were performed. It was found that an increase in the phosphazene content of cured compositions increases significantly their flame resistance, and this is connected with both increase in the amount of porous coke residue, which is the barrier against flame propagation and flame heat transfer onto the sample, and increase in size of pores arising in coke residue. The data obtained can be used to create tough and flame-resistant composite materials for microelectronics, the aircraft and other industries.