methods for forming thermal oxidative barrier coatings for organic matrix composites include applying a bond coat having nano - particles dispersed in a polyimide matrix to a hot side surface of a component and overlying the bond coat with a thermal barrier layer comprising a silsesquioxane or an inorganic polymer . the nano - particles may include clay platelets , graphite flakes or a polyhedral oligomeric silsesquioxane . the bond coat may be applied as a liquid . the thermal barrier layer may be applied as a liquid , film , prepreg , molding compound , or a spray .