Benzyl(4-fluorophenyl)phenylphosphine oxide-modified epoxy resin with improved flame retardancy and dielectric properties

A fluorine-containing diphenylphosphine oxide derivative (benzyl(4-fluorophenyl)phenylphosphine oxide, BFPPO) was prepared and used to improve the flame retardancy and dielectric properties of epoxy resin (EP). BFPPO-modified EP thermosets were prepared by curing a mixture of BFPPO and diglycidyl ether of bisphenol A (DGEBA) with 4,4'-diaminodiphenylsulfone (DDS). The resulting EP thermosets achieved a limiting oxygen index (LOI) of 34.0% and a UL-94 V-0 rating when the phosphorus content was 0.9 wt.%. Meanwhile, BFPPO-modified EP thermosets exhibited a lower heat release rate and total heat release compared to pure EP. Mechanistic studies revealed that BFPPO exerted its flame-retardant activity by scavenging free radicals required for combustion and promoting the formation of a dense char layer that inhibited the penetration of heat and fuel and caused the concentrated release of gases. Additionally, the incorporation of BFPPO reduced the dielectric constant and dielectric loss factor of the EP thermosets at different frequencies. These results indicated the potential applications of BFPPO-modified EP thermosets in the field of advanced electronic materials.

Automated summary

A fluorine-containing diphenylphosphine oxide derivative was synthesized and used to improve the flame retardancy and dielectric properties of epoxy resin. The modified epoxy resin showed enhanced flame retardancy, lower heat release rate, and reduced dielectric loss, suggesting its potential for advanced electronic materials.