Phosphorus containing flame retardants in epoxy resins. Efficiency and influence on material parameters

Several star-shaped multifunctional phosphorus containing flame retardant additives were synthesized via Phospha-Michael addition, based on 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), dimethyl phosphite (DMP) and tetra-[(acryloyloxy) ethyl] pentarythrit (PETA), or the heterocyclic tris-[(acrylocloxy) ethyl] isocyanurate (TAEI) as central building block. Phosphonates are of great interest, because they are able to increase the glass transition temperature of cured resins by crosslinking in a post curing step. RTM6®, which is commercially available and used by the Aviation Industries, was selected as a premixed epoxy system. The influence on the glass transition temperature was investigated.