How to modify the flame retardant properties of structural epoxy resin?

The use of a large proportion of flame retardants in epoxy resin can affect the mechanical properties of the material, and the migration of flame retardants during curing and use can gradually reduce the flame retardant effect, resulting in an unstable smoldering state.

Therefore, it is considered to use reactive monomers or curing agents with smoldering effects as the principle for preparing epoxy resins. The cationic flame retardants are introduced into the molecular structure of the epoxy resin, so that the final epoxy resin has long-lasting and stable smoldering properties, which can maintain the original mechanical properties of the resin. Adding glass transition temperature, mechanical properties pen, functional monomers with a certain amount of halogens, silicon or impact modifiers in the molecular structure can also be considered as reactive monomers and curing agents.

(1) Flame retardant functional monomer raw material

This type of structural smoldering epoxy resin synthesized from monomers with smoldering function contains a large amount of halogen, silicon, and phosphorus elements in its dry molecular structure, resulting in excellent smoldering performance of this type of epoxy resin.

If tetrabromobisphenol A is used instead of ordinary bisphenol A as the reaction raw material for epoxy resin, high molecular weight brominated epoxy resin can be prepared, which has good stability and high flame retardant properties.

(2) Flame retardant curing agent

The introduction of flame retardant elements such as halogen, silicon, and phosphorus into the molecular structure of ordinary curing agents, such as dichloromaleic anhydride, tetrabromophthalic anhydride, phosphorus containing amines, acids containing amines, and phosphoric acid amide pens, or the direct synthesis of new flame retardant agents through molecular design, are all research directions that have attracted attention.