Synthesis of PTFE@PFAC core-shell composite particle as a highly efficient anti-dripping agent for PC

• The fabrication process of PTFE@PFAC particles is simple and has the possibility of industrial production. • The addition of fluorine-containing shell can improve the interface compatibility and force between the PTFE particles and PC matrix. • The anti-dripping property of composite can be significantly improved with only a small amount of PTFE@PFAC particles (0.5 wt %). • The PTFE@PFAC particles can serve as a universal anti-dripping agent for general and engineering plastics. Polycarbonate (PC) is kind of engineering plastics which is widely used in the fields such as automotive manufacturing and building materials due to its excellent transparency, high strength and good reprocessing ability. However, the anti-dripping performance of PC is poor and the PC is prone to producing molten droplets during the burning process, which can cause the spread of fire. This drawback severely limits the application range of PC. Owing to its excellent fiber forming ability, thermal stability and chemical stability, polytetrafluoroethylene (PTFE) could be applied as a kind of anti-dripping agent in the production of thermoplastic resins. In this work, a kind of novel fluorinated acrylate coated PTFE composite anti-dripping agent (PTFE@PFAC particle) was successfully prepared with the PTFE as the core layer and methyl methacrylate, butyl acrylate, and fluorinated acrylate as the shell layer. The diameter of the PTFE@PFAC particle is in the range of 200–250 nm. After melt blending with PC, PC/PTFE@PFAC composite was successfully prepared. It is found that the addition of a certain amount of PTFE@PFAC particles has little influence on the processability, transparency, crystallinity, tensile strength and thermal stability of PC/PTFE@PFAC composites. Surprisingly, the addition of a small amount of PTFE@PFAC (0.5 wt %) can significantly improves the anti-dripping and flame retardance properties of the composite, which was reflected in the extension of anti-dripping time, the increase of ultimate oxygen index, the significant reduction of heat release rate and the total smoke production. Furthermore, the PTFE@PFAC particle could also be used as an efficient anti-dripping agent in the preparation of PP composite.