Synthesis And Application Of Aluminum Salts Diethyl Phosphinic Acid As Flame Retardant

In this paper,aluminum salts of diethylphosphinic(ADP)was synthesized by two synthetic routes.The effects of synthesis time and synthesis temperature on the yield were investigated.The structure and properties of the final product were characterized by infrared spectroscopy and thermo-gravimetric analysis(TGA).The flame retardancy and thermal stability of the soft wire material were investigated by applying ADP to the soft wire material.The details are as follows:The first synthetic route is to synthesize aluminum salt of diethyl phosphinic acid was three-step method.Firstly,bis(α-hydroxy)ethyl phosphinic acid was synthesized through the reaction between sodium hypophosphite monohydrate,hydrochloric acid and acetaldehyde.With red phosphorus and hydriodic acid as reducing agents,the diethyl phosphinic acid was prepared.Finally,Aluminum salts of diethyl phosphinic acid was synthesized through the reaction between diethyl phosphinic acid and aluminum sulfate.The structure of the product was characterized by infrared spectroscopy.The thermal behavior of the final product was characterized by thermo-gravimetric analysis(TGA).The results showed good thermal stability.The yield of each step of the reaction was improved by changing the feed ratio and reaction temperature.But the yield of the final product,aluminum salts of diethylphosphinic,was low.The second synthetic route is Grignard reagent method.Pyrophosphoryl chloride is synthesized by hydrolysis of phosphorus oxychloride and a small amount of water in the early stage.Then the pyrophosphoryl chloride was used to react with Grignard reagent,and then the intermediate was obtained by reaction with water.Finally,aluminum salts of diethylphosphinic was obtained by reaction with aluminum sulfate solution.The effects of reaction time and reaction temperature on the yield of the final product were investigated.And the yield was 99.5%.Fourier transform infrared spectroscopy was used to characterize the product.And the spectra showed that the characteristic peaks of aluminum salts of diethyl phosphinic acid.The thermal stability of products was tested by thermo-gravimetric analysis and the results showed the good thermal stability.Aluminum salts of diethyl phosphinic acid as flame retardant,melamine cyanurate(MCA)as flame retardant additive,and polyphenylether(PPO)as flame retardant char forming agent were used to prepare flame retardant thermal plastic elastomers.The flame retardant properties and thermal stability of the thermal plastic elastomer wereinvestigated.The vertical firing of the material ranks UL94 V-0,showing excellent flame retardant.