A new phosphorus flame‐retard curing agent for epoxy resin/anhydride system

Abstract A new phosphorus containing anhydride (DPO‐MA) curing agent is successfully synthesized via the addition reaction between diphenylphosphinoxid (DPO) and maleic anhydride (MA). It can improve the flame retardancy of epoxy resin (EP) without significantly deteriorating its mechanical properties. Due to the high efficiency of the gas phase flame‐retard mechanism, only 1.0 wt% of phosphorus is sufficient to increase the LOI value to 33.1% and UL‐94 to V0 rating. Cone calorimetry data shows that the peak of heat release decreases more than 42% than that of neat EP during combustion. Besides, the rigid DPO skeleton in the molecular chain can greatly improve the T g value of the DPO‐MA/EP‐1.0, which is as high as 125°C, much higher than that of neat EP. Thus, this work exhibits a great potential value for EP materials.