Effect of Fire Retardants on Flame Propagation through Glass Fiber-Reinforced Epoxy Resin in a Counter-Flow of Oxidizer
E. A. Sosnin1,2, A. A. Paletsky1, A. A. Chernov1, A. G. Shmakov1, I. V. Kulikov1,3, A. A. Shcherbinina1,3, S. A. Trubachev1
1Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
3Novosibirsk State Pedagogical University, Novosibirsk, Russia
Keywords: flame retardants, fire resistance, flame propagation, polymer, epoxy resin, thermocouple measurements
Abstract
A study was conducted on the flammability characteristics of 0.35 and 1 mm thick glass fiber-reinforced epoxy resin plates with additives of the phosphorus-containing flame retardant DOPO-THPO, graphene, and graphene oxide. The fire resistance of the plates was determined using the oxygen index test and the UL-94 HB test. The tests revealed no significant effect of flame retardant additives on fire resistance. The mechanism of action of the flame retardants was further investigated in experiments on horizontal flame propagation towards the oxidizer flow with different oxygen concentrations. It was found that the addition of 2 wt. % graphene + 4 wt. % DOPO-THPO leads to a decrease in the flame propagation velocity of 0.35 mm thick samples. However, an increase in the concentration of DOPO-THPO additive to 6 ÷ 8 wt. % had the opposite effect. The effect of the addition of 8 wt. % graphene oxide was higher than that of the addition of a mixture of graphene and DOPO-THPO. No effect of flame retardants on flame propagation velocity was detected for 1 mm thick specimens. This is presumably due to the specimen thickness, which corresponds to the thermal limit of thickness. Furthermore, temperature profiles in the condensed and gas phases during flame propagation were determined.
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