Flame Retardant, High Strength, Transparent Bio-Based Derivative Modified Epoxy Thermoset Resins

Over the last few decades, phosphorus-containing flame retardants have received considerable attention in improving the flame retardancy of epoxy resins (EP).

However, to obtain satisfactory flame retardancy, most phosphorus-containing flame retardants are added at high levels, resulting in deterioration of the mechanical properties of the flame retardant EP materials.

The addition of FA-bis-DOPO improved the mechanical strength, energy storage modulus and glass transition temperature of the flame-retardant epoxy materials because FA-bis-DOPO is rigid and reactive with the epoxy matrix, thus increasing the crosslink density of the material.

The ultimate oxygen index of the EP material containing 5.0 wt% FA-bis-DOPO was 31.0%, which is UL-94 V0, while the ultimate oxygen index of the non-UL-94 tested EP material was 23.5% and failed the UL-94 test, indicating that FA-BIS-DOPO has a high flame retardant efficiency.