Dr Tobias Moss and Julia Eichhorn of Budenheim present challenges for thermoplastic flame retardant compounds in the context of high voltage applications and recycling for e-mobility
Driving the future : Eco-friendly phosphorus additives advancing a sustainable & circular economy
Dr Tobias Moss and Julia Eichhorn of Budenheim present challenges for thermoplastic flame retardant compounds in the context of high voltage applications and recycling for e-mobility
The EU Green Deal and its associated restrictions and concepts will impact the chemical industry dramatically . The flame retardant ( FR ) market will also be affected because some FRs will be banned , the use of certain raw materials is being restricted and necessary synergists in FR systems cannot be used any more . These extensive changes demand the development of new fire protection concepts and FRs .
FRs can have different modes of action depending on their chemistry and the elements involved ( Figure 1 ). Gas-phase active FRs react with radicals that are released by the materials and feed the fire . Halogenated and phosphoruscontaining FRs are known for their gas-phase activity . The latter can also act in the solid phase , by forming a protective layer via carbonisation and intumescence .
Mineral FRs cool the system via endothermic decomposition . Additionally , the dilution of the gas phase by the release of noncombustible gases like water decreases the number of combustible molecules . Synergistic FR systems often work via more than just one of the mechanisms described , which is why they are so effective . An example is intumescent systems , in which the phosphorus component
Action In the gas phase
Thermal feedback
Oxygen
Heat !
Interruption tt radical chain mechanism : Br , Cl , P Combustible gases Dilution by water formation : ATH ,
MHD _ �� t
Decomposition area
forms a protective layer and the nitrogen-based synergists dilute the gas phase .
There are several FRs available in the market , each with their own strengths and weaknesses . Inorganic minerals require high loadings , which result in poor mechanical performance . Halogenated FRs , while needing only low loadings , are criticised for their toxicological impact . Phosphorus , inorganic , and nitrogen ( PIN ) FRs are seen l
Heat Combustion products Smoke
_ __,
Carbonisation
Carbonaceous layer by P , N , B intrumescence , nanocomposites
Cooling ( endothermic ) & substrate dilution : ATH , MHD
Action In the condensed phase
Figure 1 - FR mechanisms & FRs involved
as potentially more sustainable solutions . However , some of these are also considered persistent or toxic , highlighting the need for new , safer alternatives .
Melamine in FRs
Melamine , a widely used chemical in fire protection , was identified as substance of very high concern ( SVHCs ) under REACH at the start of 2023 . Not only is melamine used in FR systems as a blowing agent , it is also
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