Experimental Design of Fire-Retarded Formulations. Low Viscosity Polyester Resins

Fire formation and development can be defined as a specific num ber of combustion reactions which take place in situ depending on several factors. It is important to notice two different processes: first, material reaction to fire and second, emission of fumes from the material subjected to overheating where optical density and toxicity are factors of concern. An improvement in fire behav ior can be achieved by means of fire retardants and smoke suppressants. Fire re tardants can act chemically by interfering with combustion radical chain reactions or physically by several methods, including developing a layer which protects the material from ignition on the surface of the substrate, giving off non- flammable gases (water vapor, hydrochloric acid, etc.) in order to dilute flamma ble ones or displace the oxygen from the fire area in the gas phase and enhancing certain reactions (halides, phosphoric acid, etc.) such as endothermic reactions and surface dehydrations. On the other hand, smoke suppressants such as zinc compounds can also act physically and chemically (by formation of metal halides or oxyhalides in red-ox reactions) in the condensed and gas phases.