Synthesis Of Aluminum Diethylphosphinate And Study On The Properties Of Synergistic Flame Retardant Polylactic Acid

In this thesis,Aluminum diethylphosphinate(ADP)was synthesized by a two-step reaction between sodium hypophosphite and ethylene at atmospheric pressure with acetone as initiator,and the products were characterized by infrared spectroscopy and thermogravimetric analysis to investigate the effect of reaction conditions on the yield of the two-step sub-reaction.And the composite of ADP and melamine polyphosphate(MPP)was applied to flame retardant poly(lactic acid)(PLA)materials,and the flame retardant properties and thermal stability of PLA were analyzed by limiting oxygen index test,thermogravimetric analysis,vertical combustion test and conical calorimetric test.The details are as follows;(1)Ethylene and initiator were passed into sodium hypophosphite solution,acetone was used as photoinitiator,and the reaction was controlled by UV lamp irradiation,and the reaction degree was judged by measuring the concentration of sodium hypophosphite in the reaction solution,and the effects of Sodium hypophosphite concentration,reaction temperature and acetone addition on the reaction yield were investigated.The optimum conditions for the free radical addition reaction were obtained as follows: the concentration of Sodium hypophosphite was 30 wt%,the reaction temperature was 50 ℃,and the amount of acetone addition was 4% of the mass of sodium hypophosphite.(2)The synthesized sodium diethylphosphinate was reacted with aluminum sulfate octadecahydrate to generate ADP,and the effects of reaction temperature,reaction time,sodium ethylphosphinate concentration,molar ratio of sodium diethylphosphinate and aluminum sulfate on the reaction yield were explored through single factor and orthogonal tests.The optimal reaction conditions for ADP were as follows: sodium diethylphosphinate concentration was 0.5mol/L;The molar ratio of sodium diethylphosphinate to aluminum sulfate was 8:1;the reaction temperature was 75 °C;The reaction time is 1h,and the yield is 97.7%.(3)ADP flame retardant and MPP flame retardant were used for PLA flame retardant modification,and the best effect was tested when the total amount of flame retardant added was 20wt% and the mass ratio of ADP to MPP was 2:1.The LOI value was 36.2%,which reached UL-94V-0 test.