PC is a universal engineering plastic with high light transmittance and comprehensive mechanical, electrical, and heat resistance properties. It has been widely used in industries such as electronics, electrical appliances, machinery, automobiles, and construction.

PC has self extinguishing properties and its flame retardant performance is better than that of general plastics, but further flame retardant modification is still needed in some situations where high flame retardant requirements are needed.

At present, the commonly used halogen-free flame retardants for PC include phosphate, sulfonate, and organosilicon, among which sulfonate, especially potassium perfluorobutyl sulfonate (PPFBS), has the most significant flame retardant effect on PC.

The experimental results show that adding 0.01% (mass fraction, the same below) can increase the P C oxygen index from 26% to 35%, adding 0.1% can increase the P C oxygen index to 39%, and the vertical combustion can reach U L 94V-0 (3mm), with little effect on the optical and mechanical properties of P.

Furthermore, from the DTG curve, the maximum thermal decomposition rate of FRPC is lower than that of PC, indicating that the addition of PPFBs reduces the thermal decomposition rate of PC.

A lower decomposition rate is beneficial for blocking the formation of carbon layers and preventing further decomposition of PC, thus improving flame retardancy.

The activation energy of PC changes relatively smoothly throughout the entire degradation stage, and the degradation process is divided into three stages.

The first stage is when the conversion rate is less than 20%, mainly due to the breakage of PC end groups. As the number of end groups decreases, the degradation reaction gradually shifts to the main chain of the molecule, and the activation energy gradually increases;

The conversion rate of 20% -90% is in the second stage, mainly due to the breakage, rearrangement, and cross-linking of the molecular main chain. The change in activation energy is relatively gentle, and the increase is not significant;

The third stage is when the conversion rate is greater than 90%, mainly involving the continued decomposition of small chain segments and the decomposition of cross-linked carbon precursors, with a rapid increase in activation energy.

Compared with the FRPC system, there is a significant difference in the change of activation energy. In the first stage of degradation reaction (conversion rate<20%), the activation energy is lower than that of pure PC, indicating the catalytic effect of PFBS on the thermal degradation of PC; In the second stage (conversion rate 20%~80%), the activation energy of the system is higher than that of pure PC and increases with the degree of reaction, indicating that the main chain breakage position of PC in the system has changed, and the crosslinking degree of decomposition products gradually increases; The third stage (conversion rate>90%) mainly involves the decomposition of cross-linked carbon precursors, and the activation energy of the system rapidly increases, much higher than that of the pure PC system. This indicates that PPFBS is conducive to the formation of highly cross-linked stable carbon precursors in PC, thereby forming a stable carbon layer and effectively improving the flame retardant performance of PC.