Effect of multifunctional flame retardant tougheners on the flame retardant and mechanical properties of polycarbonates

In order to balance the effect of flame retardant modification and mechanical modification of polycarbonate (PC), the flame retardant toughening agent with silicone-phosphorus-containing acrylate core-shell structure (ACR) prepared by seed emulsion polymerization was used to modify PC materials in this paper. When 4wt%ACR was added to PC, the limiting oxygen index (LOI) of 4%ACR/PC could reach 31.7%, the vertical combustion test reached UL-94 V-0 level, and the cone calorimeter test showed that the combustion heat release and smoke density were reduced by 43.2% and 20.5%, respectively. At the same time, the tensile strength of 4%ACR/PC was similar to that of pure PC, and the impact strength was increased by 9.4%. Thermogravimetric-infrared spectroscopy, Raman spectroscopy and post-combustion residue scanning electron microscopy analysis showed that the flame retardant effect was mainly due to the synergistic effect of phosphorus-silicon and the catalytic charring effect of phosphorus on PC. The impact cross-section SEM images showed that the toughening effect is reflected in the fact that the ACR core layer silicone rubber can absorb impact energy and inhibit or terminate the generation of cracks.