Effect of novel copolyamide charring agents on flame-retarded polypropylene

In this article, two novel copolyamide charring agents, ES-6 and M-170, were served as charring agents or synergist with ammonium polyphosphate (APP) and dipentaerythritol (DPER) for the flame-retarded polypropylene (PP). The flame-retardant system was characterized by limiting oxygen index (LOI), tensile strength, Izod impact strength, thermogravimetric analyses, differential scanning calorimeter (DSC), and scanning electron microscope (SEM). Compared with polyamide 6 (PA6), ES-6 and M-170 had better dispersion and compatibility in the PP matrix and enhanced mechanical properties. Meanwhile, as low melting point polyamides, ES-6 and M-170 could decrease processing temperature and effectively inhibit side reaction, especially the degradation of APP. In addition, the synergistic effect between ES-6 and DPER was also investigated. The results showed that the synergistic system containing ES-6 had better flame retardancy and mechanical performance in comparison with the system only using DPER or the system containing PA6. POLYM. COMPOS., 2013. (c) 2013 Society of Plastics Engineers