Flame retardancy of polymers

Lucie Tibiletti will defend his PhD thesis entitled ” Modification of unsaturated polyester resins to improve fire resistance” on July, 19th 2011 at Ecole des mines d’Ales.

ABSTRACT :

Unsaturated polyesters are thermoset resins particularly appreciated for their low cost and easy processing. Nevertheless one of their main drawbacks is their poor fire resistance. The aim of this PhD thesis was to prepare new resin formulations with an improved fire behaviour. The first part of this work was dedicated to the grafting of phosphorous monomers in the polyester matrix. Methacrylic and styrenic monomers were synthesized and used to replace of part of the styrene in the resin. Resin thermal stability was decreased, but on the whole their fire behaviour was improved. Condensed phase and gas phase effects of phosphorus were highlighted. In a second part, a screening of various kinds of particles with different sizes was performed. Calorimetric tests revealed that, while the effect of these particles used alone is limited, a decrease of resin flammability could be achieved with specific combinations. Finally, commercial phosphorous additives were associated with submicronic fillers. From all the additives tested, ammonium polyphosphate stands out, with a powerful impact on the resin fire reaction and especially a much increased charring. However, its combination with inorganic particles was not conclusive.

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