Synthesis of a novel PEPA-substituted polyphosphoramide with high char residues and its performance as an intumescent flame retardant for epoxy resins

摘要: Abstract A novel polymeric intumescent flame retardant, poly(4,4′-diamino diphenyl sulfone 2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-4-methanol (PEPA)-substituted phosphoramide) (PSA), has been synthesized through solution polycondensation. The product characterized by Fourier transform infrared spectroscopy (FTIR), 1 H NMR, 13 C 31 P gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). GPC TGA suggested that PSA had sufficient molecular weight high thermal stability, with a residual char of 66.3 wt.% at 700 °C. performances its mixtures ammonium polyphosphate (APP) in enhancing the retardancy stability epoxy resins have evaluated various methods. Differential scanning calorimetry (DSC) indicated incorporation APP slightly increased glass transition temperature EP. maximum LOI value EP/PSA composites reached 32.0% passed UL 94 V-0 rating. An obvious synergistic effect between was observed LOI, CONE tests, TGA. Moreover, remarkable decreases peak heat release rate, total release, smoke were when incorporated into data showed addition greatly amount apparently reduced pyrolysis products during combustion. Additionally, structure morphology chars studied FTIR, XPS, SEM. FTIR XPS results illustrated mainly exerted condensed phase could be attributed to formation aromatic structures bridged P–O–C P–O–P bonds.