Synthesis of phosphazene-triazine bi-base sulfonate and its applications in flame-retardant modified polycarbonate

A phosphazene-triazine bi-base sulfonate compound (CPNS) was synthesized using hexachlorocyclotriphosphazene, cyanuric chloride, and sodium p-hydroxybenzene sulfonate as raw materials. The chemical structure was determined by FTIR, H-1 NMR P-31 NMR (NMR stands for nuclear magnetic resonance), and elemental analysis of P, Na. To study the flame retardant properties of CPNS, a series of modified polycarbonate (MPC) with different ratios of CPNS were prepared. The flame retardant performance and thermal stability of CPNS/MPC were characterized by limiting oxygen index (LOI), UL-94 vertical burning test, cone calorimetry test, and TG. Results show that when CPNS is added to 0.3%, the CPNS/MPC can pass the UL94 V-0 level with an LOI value of 35.3% and reduce the peak heat release rate by 16.89% during the combustion. TG results show that adding 0.1% CPNS can decrease the initial decomposition temperature of the MPC by 68 degrees C in nitrogen and 27 degrees C in air. The reduction of the initial decomposition temperature means that the flame retardant promotes the isomerization reaction of polycarbonate accelerates the formation of an intermediate char on the surface. Investigation of intermediate char residue's morphology and chemical structure demonstrates that CPNS promotes the formation of more complete and compact char residue, which acts not only there is increased opportunity for radical recombination reactions in the condensed phase but also as physical barriers to inhibit the transfer of heat and oxygen, resulting in good flame retardant properties.

Automated summary

By synthesizing and studying a novel phosphazene-triazine bi-base sulfonate compound (CPNS), it was found that adding a certain proportion of CPNS in modified polycarbonate can significantly improve the flame retardant properties of the material and reduce the heat release rate during combustion. At the same time, CPNS can also promote the formation of more complete and compact carbon residue during the combustion of polycarbonate, further enhancing the flame retardant effect.