Flame retardancy and mechanical properties of ecofriendly coated hemp fabrics/epoxy composites

A new and ecofriendly chemical approach uses inexpensive waterglass solutions in order to promote the formation of a silica-based coating on hemp fabrics; this green coating is able to act as a thermal shield and to protect the latter from heat sources. The waterglass treatment improves the fire behavior of hemp fabric/epoxy composites, also in combination with ammonium polyphosphate, and favors a remarkable decrease of the heat release rate, total heat release, total smoke release and specific extinction area (respectively by 83%, 35%, 45% and 44%) as compared to untreated hemp/epoxy composites, favoring the formation of a very stable char.