Thermal degradation behavior and flame retardant properties of PET/DiDOPO conjugated flame retardant composites*

Abstract

PET/DIDOPO conjugated flame retardant composites were prepared by melt blending of styrene bridged DOPO (DIDOPO) into polyethylene terephthalate (PET). The flame retardancy, rheological behavior, and thermal degradation behavior of the composite were characterized by vertical combustion test (UL-94), limit oxygen index test (LOI), rotational rheometer, and thermogravimetry (TG). The results showed that the flame retardant composite with V-0 grade was obtained when the amount of DIDOPO is 12.5wt%, and the corresponding LOI value was 56.87% higher than that of PET. The thermogravimetry-fourier infrared spectroscopy (TG-FTIR) test results showed that DIDOPO could promote the degradation of PET/DIDOPO materials, and release phosphorus-containing free radicals to quench the flame, therefore slowing down the combustion process, and mainly playing the key flame retardant role in gas-phase.

The behavior and mechanism of tris‐(3‐dopo‐propyl)‐triazine trione flame retardant polyethylene terephthalate

“…36 Above all, CR 500 in In a word, these excellent flame retardant properties can be attributed to the synergistic flame retardant effect of TAD between the gas phase and the condensed phase. In terms of gas phase, the DOPO group in TAD can release PO Á and PO 2 Á radicals to capture active radicals in the combustion area, 37 interrupting the chain reaction. In addition, inert gas from pyrolysis products will take away some heat while expelling the combustion gas from the combustion area, thereby inhibiting thermal cycling, causing an increase in LOI and a decrease in PHRR, THR, and av-EHC.…”