Influences of molecular weight of epoxy binder on fire protection of waterborne intumescent fire resistive coating

► Epoxy emulsions with different M¯n were used as binders for intumescent coating. ► High M¯n epoxy improved thermal stability of the coating and anti-oxidation of char layer. ► Epoxy with high M¯n slowed down expansion speed of the coating under fire. ► The coating used epoxy with M¯n of 1025 g/mol as binder had good fire protection. ► Epoxy with excessive high M¯n led to formation of loose and uneven foam structure.