A new flame retardant molecule was experimentally developed based on the organo-phosphorus compound DOPO (9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide), which is increasingly being tested as a basis for new PIN flame retardants, and 2-aminobenthothiazole (ABZ), a nitrogen and sulphur containing molecule.
The resulting DOPO-ABZ was tested as a PIN FR in epoxy resin, achieving 30-35% reduction in peak heat release and UL94-V0 at 7.5% loading. The flame retardant mechanism of the DOPO-ABZ is considered to be principally in the gas phase, with release of ammonia, and sulphur containing compounds and phosphorus free radicals above around 380°C. The PIN FR also significantly reduces smoke release.
“Synthesis of a Novel P/N/S-Containing Flame Retardant and Its Application in Epoxy Resin: Thermal Property, Flame Retardance, and Pyrolysis Behavior”, R. Jian et al., I&EC Research, 55, 11520-11527 http://dx.doi.org/10.1021/acs.iecr.6b03416