A (4-fluorophenyl)(phenyl)phosphine oxide-modified epoxy resin with improved flame-retardancy, hydrophobicity, and dielectric properties

The compound (4-fluorophenyl)(phenyl) phosphine oxide (4-FPO) was designed, synthesized, and used in the modification of epoxy resin (EP). The 4-FPO-modified EP was prepared by curing the reaction mixture of diglycidyl ether of bisphenol A (DGEBA) and 4-FPO in the presence of 4,4 '-diaminodiphenylsulfone (DDS). Compared with the unmodified EP, the limiting oxygen index value of the EP/4-FPO-0.6 (4-FPO-modified EP with 0.6 wt% of phosphorus) increased to 31.6%, and the sample achieved UL-94 V-0 rating. The peak of the heat release rate, average of the heat release rate, and total heat release of EP/4-FPO-0.6 were reduced by 39, 24, and 19%, respectively. Mechanism study showed that the quenching effect in the gas and barrier effect in the condensed phase were responsible for the enhanced flame-retardant properties of the 4-FPO-modified EP. The results showed that hydrophobicity and dielectric properties of the modified EP were clearly improved.