Nitrogen Flame Retardant

Nitrogen-containing compounds are a small but rapidly growing class of flame retardants with the advantage of low toxicity and solid state. Nitrogen has good synergy and can be used in combination with other flame retardants or processing aids, especially with phosphorus flame retardants. Alfa Chemistry offers an extensive catalog of nitrogen-based flame retardants.

Classification

Nitrogen-containing flame retardants mainly include three categories: melamine, dicyandiamide, guanidine salts (guanidine carbonate, guanidine phosphate, condensed guanidine phosphate and guanidine sulfamate) and their derivatives, especially phosphate derivatives.

Advantages

• High flame retardant efficiency
• Low toxicity: The nitrogen-containing organic flame retardant itself has low toxicity, and the gas released during the combustion of the material treated by it is also less toxic.
• Low corrosiveness: When nitrogen-containing organic compounds burn, they do not release corrosive gases, so the corrosiveness to equipment and materials is also greatly reduced.
• High thermal decomposition temperature: The decomposition temperature of nitrogen-containing organics is high, and the processing temperature of the material can be increased after adding the material.
• No conflict with light stabilizers in the material
• Environmentally friendly waste will not cause environmental pollution

Flame Retardant Mechanism

After the nitrogen-based flame retardant is thermally decomposed, it is easy to release incombustible gases such as ammonia, nitrogen, deep nitrogen oxides, and water vapor. The formation of these gases and the decomposition of the flame retardant absorb most of the heat, which greatly reduces the polymer surface temperature.

In addition, these non-combustible gases not only play a role in diluting oxygen in the air and the concentration of flammable gases generated by thermal decomposition of polymers, but also react with oxygen in the air to generate nitrogen, water and deep nitrogen oxides, thus consuming the oxygen of the material surface.

Applications

Their main applications are melamine in flexible polyurethane foam, melamine cyanurate in nylon, melamine phosphate in polyolefins, melamine and melamine phosphate or dicyandiamide in intumescent coatings, guanidine phosphate in textiles and guanidine sulfamate in wallpaper.

Important nitrogen-based flame retardant structures

Research Information

Based on the good synergistic effect of nitrogen elements, Luo Yong et al. synthesized a new phosphorus-nitrogen intumescent flame retardant. After the subsequent addition of MWCNTs, it was found that the combination of MWCNTs and phosphorus-nitrogen flame retardant significantly improved the flame retardancy of the LDPE matrix, with peak heat release rates and total heat release reduced by 49.8% and 51.9%, respectively. In addition, the introduction of multi-walled carbon nanotubes significantly improved the electrical conductivity and mechanical properties of the matrix. [1]

Reference

1. Yong Luo, et al. (2021). "A low-density polyethylene composite with phosphorus-nitrogen based flame retardant and multi-walled carbon nanotubes for enhanced electrical conductivity and acceptable flame retardancy," Frontiers of Chemical Science and Engineering 15, 1332–1345.