The working principles of nitrogen-based halogen-free flame retardants mainly include the following aspects:
Release of non-flammable gases: Nitrogen-based flame retardants can release non-flammable gases such as nitrogen and ammonia at high temperatures. These gases can dilute the concentration of oxygen in the air and the flammable gases produced by the thermal decomposition of polymers, thereby preventing the occurrence of combustion. Meanwhile, these gases can also react with oxygen in the air, further consuming the oxygen on the material surface and achieving a good flame-retardant effect.
Heat absorption and cooling: Nitrogen-based flame retardants absorb a large amount of heat during the decomposition process, thereby reducing the surface temperature of the polymer. This heat absorption effect can slow down the combustion rate and even prevent the continuation of combustion.
Formation of carbon layer: Nitrogen-based flame retardants can form a carbon layer on the material surface when heated. This carbon layer can isolate heat and oxygen, further suppressing combustion and the generation of flue gas. The formation of the carbon layer helps to prevent the spread of flames and improve the flame retardant performance of the material.
Inhibiting free radical chain reactions: Nitrogen-based flame retardants can react with free radicals in combustible substances to form stable nitrogen free radicals, thereby interrupting free radical chain reactions. This interruption effect can slow down the combustion process and reduce the flammability of the material.
