Flame retardancy and thermal property of poly(ethylene terephthalate)/modified cyclotriphosphazene composites

In this study, hexachlorocyclotriphosphazene (HCCP) modified by boric acid and 3-aminopropyltriethoxysilane (KH-550) in solvent diglyme (FR-HCCP) was used as the flame retardant for poly (ethylene terephthalate) (PET) composites. The flame retardancy and thermal property of pure PET and flame-retarded PET composites were mainly investigated. The flame retardancy was investigated by limited oxygen index (LOI) and UL-94 vertical burning test. The results showed that the composites could achieved an increased UL-94 V-0 rating and LOI value 30.2, when the content of FR-HCCP was just 1%. The pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) study demonstrated that introducing FR-HCCP into PET would prevent the polymer pyrolysis during heating. TGA analysis showed that the addition of FR-HCCP could improve the char formation of the system. Roman spectra showed the order degree of residue was increasing by adding the additive. The morphology and the chemical structure of the charred residue were detected by SEM and FTIR, respectively. Results demonstrated that a good barrier was formed by the char of the composite, which protected the inside of the composite during burning. Copyright © 2015 by Editorial Board of Journal of Donghua University, Shanghai China.