Enhanced Flame Retardancy of Unsaturated Polyester Resin via Simultaneously Using a Novel DOPO-Based Organic Flame Retardant and Modified Silicon Carbide

Unsaturated polyester (UP) resin is widely utilized in the construction and automotive industries. The flammable nature of UP must be constrained when its products are manufactured. A novel organic flame retardant has been synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and triallyl isocyanate (TAIC). This DOPO-TAIC additive has been used to reduce the flammability of a matrix. Additionally, this flame retardant was then combined with dopamine-modified silicon carbide (M-SiC) to further diminish the flammability of UP. The limiting oxygen index (LOI) value combustion of a UP/DOPO-TAIC/M-SiC blend was 30.8% when the filler contents of DOPO-TAIC and M-SiC was 15 wt.% and 30 wt.%, respectively. These materials exhibited a UL 94 V-0 rating for combustion. Compared to the values for combustion of the neat UP, the peak heat release rate (Pk-HRR) and total heat release rate (THR) for this blend were reduced by 51% and 35%, respectively. The mode of action for flame retardant of UP blends containing DOPO-TAIC and M-SiC has been composed. The presence of a flame retardant containing P-Si elements can significantly reduce flammability compared to that of unmodified resin.