Thermoplastic resins for thin film intumescent coatings - towards a better understanding of their effect on intumescence efficiency

This study investigates the role of the binder in the efficiency of intumescent coatings. It is generally known that an acid source, a carbon source and a blowing agent are the main ingredients of such paints. However, since the binder may react with these ingredients, it may significantly affect the intumescence process. To begin with, the effect of the nature of the monomers, which compose the binder, on the chemical reactivity between the binder and the intumescent additives is investigated, using thermogravimetric analysis. It is found that the thermal stability is enhanced when the copolymer is prepared with substituted styrene. Subsequently, the effect of the binder is investigated from a physical aspect. Special attention is devoted to the expansion rate and the dynamic viscosity. Finally, the efficiency of protective behaviour of the intumescent coatings prepared with the copolymers is evaluated. It is found that the thermal insulation is greatly improved when using a mixture of linear and crosslinked copolymers as the binder in inturnescent coatings particularly when these copolymers are prepared from monomers showing good reactivity with ammonium polyphosphate. (c) 2004 Elsevier Ltd. All rights reserved.