Synthesis And Application Of A Series Of Secondary Phosphorus (phosphonate) Flame Retardants

With the rapid development of society,the high performance polymer material rapidly influx into people's production and living.However,the majority of the polymer material is flammable.It is easy to cause fire unless we addition flame retardant.Therefore the development and application of flame retardant in polymer materials have already become the research focus of researchers.Hypophosphite were a series of halogen-free and environmental protection flame retardants and were developed in recent decades years.They have many excellent performance,such as high content of phosphorus,high flame retardant performance,low price,low toxicity or non-toxic and have no effect on the colour and lustre of the material.They can be used as ideal flame retardants of polyurethane?PU?,polyvinyl chloride?PVC?,polyethylene terephthalate?PET?and poly(butyl glycol terephthalate?PBT?materials.This paper studied and synthesised calcium hypophosphite,iron hypophosphite,barium hypophosphite,zinc hypophosphite,magnesium hypophosphite,aluminium hypophosphite and aluminium phenylphosphinate flame retardand.And studied the effect of the reaction temperature,the reaction time and the material ratio on the yield of the product by the orthogonal experiments,obtained the optimum process condition.Calcium hypophosphite:the material ratio of n?CaCl2?and n?NaH2PO2·H2O?being1:2.5,the reaction temperature being 60 ?,the concentration of sodium hypophosphite being 7 mol/L,the reaction time being 2 h,the yield of calcium.hypophosphite was up to 94.7%.Iron hypophosphite:the material ratio of n?FeCl3?and n?NaH2PO2 H2O?being 1:3.4,the reaction temperature being 90?,the concentration of sodium hypophosphite being 5 mol/L,the reaction time being 3 h,the yield of iron hypophosphite was up to 98.1%.Zinc hypophosphite:the material ratio of n?ZnCl2?and n?NaH2PO2 H2O?being 1:2.4,the reaction temperature being 75 ?,the concentration of sodium hypophosphite being 8 mol/L,the reaction time being 3 h,the yield of zinc hypophosphite was up to 60.3%.Magnesium hypophosphite:the material ratio of n?MgO?and n?H3PO2?being 1:2.5,the reaction temperature being 75 ?,the reaction time being 2 h,the yield of magnesium hypophosphite was up to 30.7%.Aluminium hypophosphite:the material ratio of n?Al2?SO4?3·18H2O?and n?NaH2PO2 H2O?being 1:7.5,the reaction temperature being 90 ? the concentration of sodium hypophosphite being 9 mol/L,the reaction time being 3 h,the yield of aluminium hypophosphite was up to 98.5%.Aluminium phenylphosphinate:the adding temperature of dichlorophosphaness being 0?5 ?,the reaction temperature being 90 ?,the reaction time being 3 h,the concentration of the aluminum sulfate being 3 mol/L,the yield of aluminum phenylphosph-imate was up to 89.6%.IR,¹HNMR,³¹P NMR and ICP were used to characterize their chemical structures,consistent with their target molecules.TG and SEM were used to detect the thermal stability and particle size of product,the results show that they have smaller particle size and good thermal stability,which can meet the demand of the decomposition temperature of ideal flame retardant.Aluminium hypophosphite was coated by phenolic resin,which can effectively reduce the bibulous rate of aluminium hypophosphite.The application of aluminium hypophosphite on the rigid polyurethane foam plastics was studied,and discussed the effect of additive amount of aluminium hypophosphite on the limit oxygen index,the tensile strength and other performances.