Effect of 9,10-Dihydro-9-Oxa-10-Phosphaphenanthrene-10-Oxide on Liquid Oxygen Compatibility of Bisphenol A Epoxy Resin

In this study, bisphenol A epoxy resin (DGEBA) was chemically modified by 9,10-dihydro-9-oxa-10-phosphaphenanthrene- 10-oxide (DOPO), and the molecular structure of the modified epoxy resin was characterized by Fourier transform infrared spectra. The effects of DOPO on liquid oxygen compatibility of DGEBA were calculated using mechanical impact method. The results indicated that epoxy resin (EP-P1)/4,4-diaminobisphenol sulfone (DDS) was compatible with liquid oxygen. When compared with EP/DDS, differential scanning calorimetry and thermogravimetry analyses showed that EP-P1/DDS and EP-P2/DDS had much higher glass transition temperatures and char yield. X-ray photoelectron spectroscopic analysis suggested that phosphorus atoms on the surface of EP-P1/DDS and EP-P2/DDS could act in the solid phase to restrain the incompatible reaction, which was in accordance with the flame-retardant mechanism of phosphorus-containing compounds. The compatibility mechanism of EP-P1/DDS was further proposed. (C) 2014 Wiley Periodicals, Inc.