Abstract:

Highly efficient flame-retarded epoxy resin （EPM） was prepared by using a self?made flame retardant bis｛4-［4-（4-aminobenzyl）phenylamino］ ［（6-oxydibenzo［c，e］［1，2］oxophenanthrene?6?yl） methyl］ phenyl｝ phenyl phosphonate （DOP?DDM） compounding with metal oxide. The flame retardant performance of the resultant EPM was evaluated using limiting oxygen index （LOI）， vertical combustion （UL 94） and cone calorimetric combustion test， and its thermal performance was investigated through thermogravimetry and dynamic thermal mechanical analyses. The flame retardant mechanism was analyzed by combining thermogravimetry analysis with infrared spectroscopy， scanning electron microscopy and Raman spectroscopy. The results indicated that the introduction of DOP?DDM reduced the initial degradation temperature of the EPM without any effect on glass transition temperature and increased the residual char yield， storage modulus， loss modulus， and flame retardant properties. When 4.7 wt % of DOP-DDM was incorporated， the resultant EPM achieved a phosphorus content of only 0.37 wt % but a high LOI of 33.5 % with a UL 94 classification of V?0. Its peak heat release rate， total heat release and total smoke release decreased by 23.2 %， 17.8 % and 12.4 %，respectively.When 3.7 wt % DOP-DDM was combined with 1.0 wt % Al₂O₃， the EPM exhibited a reduction not only in peak heat release rate and total smoke emission but also in CO and CO₂ toxic gases by 7.7 % and 17.2 %， respectively.

Key words: flame-retardant epoxy resin, high-efficiency phosphorus-containing flame-retardant, flame-retardant mechanism