Synthesis of a Novel Intumescent Flame Retardant and Its Application in EVM

Received 19 January 2011; accepted 16 May 2011DOI 10.1002/app.34924Published online 16 January 2012 in Wiley Online Library (wileyonlinelibrary.com).ABSTRACT: A novel phosphorous-nitrogen structurecontaining intumescent flame retardant, 4,4-diaminodi-phenyl methane bi(2,2-dimethyl-1,3-propanediol) phos-phoramidate (DBDPP) was synthesized and characterized.Thermal stability and flammability properties of ethylenevinyl-acetate copolymer rubber(EVM)/DBDPP compositeswere investigated by thermogravimetric analysis (TGA),limiting oxygen index (LOI) test and UL-94 measurement,respectively. The results showed that the addition ofDBDPP enhanced the thermal stability and flame retard-ancy of EVM significantly. The weight of residues improvedgreatly with the addition of DBDPP. SEM investigationsrevealed that a strong charred layer was formed fromEVM/DBDPP composites during combustion. It is con-firmed that the char structure was a critical factor for flameretardancy of EVM rubber.