Phosphorous-containing epoxy resins from a novel synthesis route

The -P(O)-H in 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was used as an active group to react with the carbonyl group in 4,4'-dihydroxy-benzophenone (DHBP) to result a novel phosphorous-containing biphenol compound (DOPO-2OH). Phosphorous-containing epoxy resins were therefore obtained from reacting DOPO-2OH with epichlorohydrin or with diglycidylether bisphenol A. The synthesized compounds were characterized with FTIR, H-1 and P-31 NMR, elemental analysis, and epoxide equivalent weight titration to demonstrate the their chemical structures. Cured epoxy resins were prepared via thermal curing the epoxy resins with various curing agents. Thermal analysis results (differential scanning calorimetry and thermogravimetric analysis) revealed that these cured epoxy resins exhibited high glass transition temperatures and high thermal stability. High char yields at 700 degreesC and high LOI (limited oxygen index) values were also found for the cured epoxy resins to imply that the resins were possessing high flame retardancy. (C) 2002 John Wiley & Sons, Inc.