Synergistic effects of a novel silicon‐containing triazine charring agent on the flame‐retardant properties of poly(ethylene terephthalate)/hexakis (4‐phenoxy)cyclotriphosphazene composites

A novel triazine oligoimides containing silicone charring agent (TSCA) was prepared and used as charring agents in poly(ethylene terephthalate) (PET)/hexakis (4‐phenoxy) cyclotriphosphazene (PNCP) flame retardant system. Limited oxygen index, microscale combustion calorimetry, thermogravimetric analyses, and environment scanning electron microscopy tests were used to study the flame retardance and mechanism of samples. The results revealed that there was a good synergistic effect between TSCA and PNCP in flame retardant PET. The new flame retardant system induced the acid catalytic charring at higher temperature range, enhanced the formation of the integrity and stable char layer, and significantly reduced heat release capacity. Moreover, the prepared PET/PNC/TSCA composites exhibited improved thermal stability and desirable mechanic properties. POLYM. COMPOS., 39:858–868, 2018. © 2016 Society of Plastics Engineers