▎ 摘　　要

NOVELTY - Preparing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide/layered double metal hydroxide flame retardant comprises adding graphene oxide freeze-dried powder in thionyl chloride, removing excess thionyl chloride, dissolving 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives in tetrahydrofuran, injecting dispersion in acid chloride graphene oxide, adding triethylamine, centrifuging suspension, utilizing methanol to precipitate, washing to remove triethylamine, dissolving 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide, dissolving e.g. aluminum nitrate salt, heating 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide dispersion, adding metal ion, filtering, washing product with e.g. water and drying to obtain 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives grafted graphene oxide/layered double metal hydroxide flame retardant. USE - The method is useful for preparing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide/layered double metal hydroxide flame retardant. ADVANTAGE - The retardant: does not contain halogen element; is green, halogen-free and environmentally friendly. The method: has small addition amount, remarkable flame retardant effect and is environmentally friendly. DETAILED DESCRIPTION - Preparing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide/layered double metal hydroxide flame retardant comprises (a) adding graphene oxide freeze-dried powder into thionyl chloride and refluxing at 65°C for 24 hours, removing excess thionyl chloride by vacuum filtration to obtain acyl chloride graphene oxide, (b) dissolving 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives in tetrahydrofuran and stirring to obtain a dispersion, (c) injecting the dispersion into the acid chloride graphene oxide solution under stirring condition of nitrogen protection, (d) adding triethylamine to the solution, stirring and reacting for 36 hours, centrifuging the suspension and utilizing methanol to precipitate, filtering, washing repeatedly to remove excess triethylamine, drying the final product in a vacuum oven for 24 hours to obtain 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide, (e) dissolving the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide in deionized water and ultrasonically dispersing to obtain a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide dispersion, (f) dissolving divalent metal nitrate and aluminum nitrate salt in deionized water and stirring evenly, (g) heating the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted graphene oxide dispersion to 45°C and adding the metal ion solution dropwise and (h) adding dropwise 1 M sodium hydroxide solution under stirring condition, adjusting the pH value of the solution within 11±0.2, dropping the metal ion solution within 1 hour, after reacting for 0.5 hours, stop-stirring and starting to heat up until the temperature rises to 80℃ and continuously heating at this temperature for 24 hours, after completing the reaction, filtering and washing the product with deionized water and ethanol and drying in a 65℃ electric constant temperature blast drying oven for 24 hours to obtain 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives grafted graphene oxide/layered double metal hydroxide flame retardant.