Synthesis Of A Novel Phosphorus-Silicon Flame Retardant And Its Application In Pet

In this study, three kinds of phosphorus-containing flame retardants were synthesized and applied in PET (Polyethylene terephthalate), named HAPP-Na, DDP and DOPO-Si.Their chemical structures were characterized by IR and NMR. The flame-retardant property of FRPET (flame-retardant PET) had been estimated with the Limiting Oxygen Index (LOI) and UL-94. The thermal property of FRPET was investigated by the Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry Analysis (DSC) , while the carbon layers and elements of FRPET were characterized by the Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis System(EDS). The flame retardant mechanism of the novel co-polyester phosphorus-silicon containing was investigated.DOPO-Si has the best flame retardant effect for the synergistic effect of phosphorus and silicon with LOI value of 27.4 and good anti-dripping property, while DDP and HAPP-Na both have certain flame retardant effect without conspicuous anti-dripping property. In addition, DOPO-Si can facilitate the carbon forming process of the matrix, since silica in DOPO-Si have positive effect for the densification and stabilization of the carbon layers, which lead to the accumulation of carbon residue.The thermal degradation kinetics, TGA and EDS characterization demonstrate that the flame retardant mechanism of novel co-polyester with both phosphorus and silicon containing is the synergistic effect of the condensed phase and the gas phase.