Synthesis And Thermal Properties Of DOPO-based Phosphorus-containing Flame Retardant Epoxy Resin

Flame-retardant epoxy resins are developing fast with the wide using of poxy resins.Nowadays people are paying more attention to the environment and the requirement offorbidding using halogen grows in the developed countries, development of novelnon-halogen flame-retardant becomes a focus although the commercial market is dominatedby the flame-retardant based on halogens. Among organic phosphorus flame retardants,DOPO (9,10-dihydro-9-oxa-10-phos-phaphenanthrene-10-oxide) and its derivatives isattracting a lot of attention which was found to generate less toxic gas and smoke thanhalogen-containing compounds during the fire.In this thesis, compounds DOPO-Bz1, DOPO-Bz2and the intermediate products Ba, Bp,DOPO-Ba, DOPO-Bp were synthesized and the molecular structures were investigated byFTIR, MS,1H NMR,31P NMR spectroscopic analysis. The reaction conditions of above twocompounds and their intermediate products were optimized.Eight diffident DOPO-based phosphorus-containing epoxy resins were synthesized bythe reaction DGEBA with DOPO-Bz1and DOPO-Bz2respectively and the molecularstructures were investigated by FTIR. The optimal reaction conditions were obtained on thebasis of comparison between the determination of epoxy value and theoretical epoxy value.DDM and DDS have been used as curing agents for DOPO-based phosphorus-containingepoxy resins, the inherent flame-retardant epoxy polymers were obtained. Thermal stabilityand the weight loss behavior of the cured epoxy resins were evaluated by thermogravimetricanalysis (TGA). Char yields were higher than the epoxy resins without containing phosphorus.The highest char yields of DOPO-based phosphorus-containing epoxy resins was34.36in airat550℃and the highest char yields of DOPO-based phosphorus-containing epoxy resinswas37.16in nitrogen at550℃.