Synthesis and Property of Flame Retardant Epoxy Resins Modified with 2-（Diphenylphosphinyl）-l,4-benzenediol

2-（Diphenylphosphinyl）-1,4-benzenediol（DPO-HQ） was synthesized by the reaction of diphenylphos- phine oxide（DPO） with 1,4-benzoquinone（BQ）, and characterized by Fourier transform infrared（FTIR）, and nuclear magnetic resonance（1H NMR, 13C NMR, 31p NMR） spectrometries. The thermal stability of DPO-HQ was investi- gated by thermogravimetric analysis（TGA）. Flame retardant epoxy resin was synthesized based on DPO-HQ. The thermal properties and burning performance of cured epoxy resins were measured by differential scanning calorime- try（DSC）, thermogravimetric analysis（TGA）, limited oxygen index（LOI） and vertical burning test（UL-94V）. The morphologies of cured epoxy resins after combustion were investigated by scanning electron microscopy（SEM） and electron probe microanalysis（EPMA）. Moreover, the thermal stability（both in air and in N2） of DPO-HQ and its cured epoxy resin was compared with that of 10-（2,5-dihydroxyphenyl）-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- oxide（DOPO-HQ） and its cured epoxy resin. The thermal stability of DPO-HQ is comparable with that of DOPO-HQ, while the thermal stability of cured epoxy resin based on DPO-HQ is better than that based on DOPO-HQ.

Synthesis and Property of Flame Retardant Epoxy Resins Modified with 2-(Diphenylphosphinyl)-1,4-benzenediol

2-(Diphenylphosphinyl)-1,4-benzenediol(DPO-HQ) was synthesized by the reaction of diphenylphosphine oxide(DPO) with 1,4-benzoquinone(BQ), and characterized by Fourier transform infrared(FTIR), and nuclear magnetic resonance(¹H NMR, ¹³C NMR, ³¹P NMR) spectrometries. The thermal stability of DPO-HQ was investigated by thermogravimetric analysis(TGA). Flame retardant epoxy resin was synthesized based on DPO-HQ. The thermal properties and burning performance of cured epoxy resins were measured by differential scanning calorimetry(DSC), thermogravimetric analysis(TGA), limited oxygen index(LOI) and vertical burning test(UL-94V). The morphologies of cured epoxy resins after combustion were investigated by scanning electron microscopy(SEM) and electron probe microanalysis(EPMA). Moreover, the thermal stability(both in air and in N₂) of DPO-HQ and its cured epoxy resin was compared with that of 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO-HQ) and its cured epoxy resin. The thermal stability of DPO-HQ is comparable with that of DOPO-HQ, while the thermal stability of cured epoxy resin based on DPO-HQ is better than that based on DOPO-HQ.