Posted on 01/02/2017 in News 32 2017
Reactive PIN FR for rigid polyurethane foam

The mineral – phosphorus PIN flame retardant, aluminium hypophosphite (AHP) was surface-reacted with melamine to generate a reactive PIN flame retardant (MCAHP) for application in polyurethane.

Analysis (FTIR, SEM) showed that the AHP was effectively coated with a melamine derivative, with external active NH2 groups. The MCAHP showed good compatibility with polyurethane foam, with smooth foam cells. DSC characterisation showed that the active groups contributed to cross-linking during the polyurethane foaming reaction, and so an increased glass transition temperature of the polyurethane foam. A 16.5% MCAHP loading in polyurethane foam enabled to achieve UL94-V0. The flame retardancy effect is considered to be the result of a well-structured char formation, generated by phosphoric acid released from AHP, water release from AHP and sublimination of melamine at c. 320°C consuming heat energy and releasing non-flammable gases which dilute fire gases.

FTIR = Fourrier transform infrared analysis. SEM = scanning electron microscopy. DSC = differential scanning calorimeter.
“Surface modification of aluminum hypophosphite and its application for polyurethane foam composites”, F. Luo et al., J. Therm Anal Calorim, 2016  Reducing fire risks from wood in buildings and furniture

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