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An innovative way to improve fire-retardant properties of different polymers by applying intumescent coatings on their surface has been studied. Two polymers have been investigated: polypropylene and polycarbonate. The surfaces were first subjected to a flaming treatment in order to clean them and to increase their wettability and thus improve the adhesion of the coatings. Two different formulations were then applied: a transparent intumescent varnish, based on an acrylic resin, and an intumescent coating based on polyvinylacetate resin. Different parameters have been obtained using several fire tests. The cone calorimeter, the limiting oxygen index and UL94 tests have been carried out to evaluate the fire-retardant properties obtained for both the intumescent coating and the intumescent varnish. Results clearly evidence an outstanding improvement of the fire-retardant properties using intumescent coatings without any incorporation of flame retardants in the bulk. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with the thermal degradation and fire performance of polysilazane (PZane) based coatings. PZanes are silicon–nitrogen backbone polymers and can be used in a wide range of applications. In this study, the fire performance of PZane coating as virgin or formulated materials were evaluated using a homemade fire testing methodology similar to the “Torch Test” fire testing method. It was shown that the performance of the PZane coating can be improved incorporating fire retardant additives. Degradation of the coating is then investigated. The mechanism of degradation of the PZane was elucidated analyzing the gas and condensed phases during the degradation. It was shown that the degradation occurs in three steps leading to the formation of SiN4 and charring at high temperature. The kinetics of degradation of the three steps of degradation was also modeled in order to predict the degradation of the PZane coating in a fire scenario. [Copyright &y& Elsevier]

Abstract: Fire retarded poly(ethylene terephthalate) (PET) has been obtained by the incorporation of octamethyl polyhedral oligomeric silsesquioxane (OMPOSS) and Exolit OP950, a phosphinate-based compound, in recycled PET. The presence of Exolit OP950 only leads to intumescence explaining the improvement of the flame retardancy. The addition of OMPOSS leads to a synergistic effect considerably increasing the fire retarding performances of the polymer in terms of cone calorimetry and limiting oxygen index even if a small thermal stabilisation as well as a very poor dispersion of OMPOSS and OP950 into the matrix has been observed. [Copyright &y& Elsevier]

Abstract: It is known that acid source, carbon source and blowing agent are the main ingredients of an intumescent paint. Melamine and halogenated additives, such as polychlorinated alkanes (PCAs) are used as blowing agents, however, the legislation tends to prohibit the use of halogenated coumpounds for environmental reasons. The aim of our study is to investigate the mode of action of melamine and PCAs in an intumescent formulation. Their interactions are also studied. It is found that the combination of PCAs and melamine leads to more efficient systems. Spectroscopic analyses (FTIR and solid state 13C NMR) led us to conclude that when the intumescent paint was heated melamine condensed to create melem via Diels-Alder-type reaction. Melem could then react with PCAs leading to the stabilisation of the PCA-melamine mixture. The proposed mechanism of action led us to propose a method for the substitution of PCAs. [Copyright &y& Elsevier]

This study investigates the role of the binder in an intumescent paint. In fact, it is generally known that acid source, carbon source and blowing agent are the main ingredients of such a paint. However, since the binder may react with these ingredients, it is also a very important component of an intumescent paint. To begin with, the effect of the nature of the monomers composing the polymeric binder, on the chemical reactivity between the binder and the intumescent additives is investigated using thermogravimetric analysis, solid state NMR and FTIR analysis. It is found that the thermal stability increases when the copolymer is based on substituted styrene. Subsequently, the efficiency of protective behaviour of the intumescent coatings is evaluated varying the nature of the binder resin. It is found that the thermal insulation is greatly improved when using a mixture of a linear copolymer presenting a good reactivity with the acid source and a cross-linked copolymer as binder in the intumescent paint. [Copyright &y& Elsevier]

This work deals with the mechanism of degradation of vinyl acetate/butyl acrylate (VA/BA) copolymers varying the VA/BA ratio. It is shown that for higher VA contents, the degradation starts at comparatively lower temperature but a more thermally stable material is formed. The mechanism of degradation of VA/BA copolymers is then compared with PVA and PBA homopolymers. It appears that the fractions of degradation (gases, high boiling products and residue) for VA/BA copolymer is a combination of those of polyvinyl acetate (PVA) and polybutyl acrylate (PBA). However, a slight stabilisation occurs when VA/BA are co-polymerised together compared with a VA and BA combination. Moreover, the comparison of the thermo-oxidative degradation with the pyrolysis demonstrates that the mechanisms are similar at least up to 450 °C. [Copyright &y& Elsevier]

Self-stratifying coatings are promising coating systems based on incompatible polymer blends which can produce polymer/polymer laminate. A complex multi-layer or gradient coating structure is formed from one single coat, providing an undercoat and finishing coating. The preferential distribution of concentration through the film thickness greatly eliminates the interfacial adhesion failure without compromising the advantages of a multi-layer system, and thus favors an industrial eco-efficient process. Powder, waterborne and solventborne coating systems are able to stratify: the most well-known and effective systems are described in this review. Finally, this concept constitutes a great possible versatile process for a broad range of applications and could thus favor the development of new products, taking into account the reduction of solvent and labor cost [ABSTRACT FROM AUTHOR]