Preparation Of Modified Aluminum Hydroxidepowder And Its Properties Of Flame Retardant Warm-mixed Asphalt

In recent years,frequent fires in the construction,decoration,and transportation industries have caused serious casualties and property damage,as well as serious environmental pollution problems,especially asphalt tunnels and asphalt roads.The danger of continuous burning is huge.Asphalt contains a benzene ring structure,and the smoke released during combustion is more toxic,which can easily cause suffocation or inhalation of toxic gases.Therefore,the development of environmentally-friendly,efficient,dispersive,and compatible ultra-fine flame-retardant powder materials,modification of warm-mixed asphalt,reducing the burning performance of asphalt,is of great significance to reduce the occurrence of road asphalt fire accidents.In this study,ultra-fine aluminum hydroxide(ATH)powder flame retardant was prepared by hydrothermal synthesis.The ATH powder was prepared by using three modifiers,namely,Span-80,DL-411,and Evotherm road surface surfactant.The body was subjected to wet surface modification,and the materials were characterized by oil absorption value,absorbance,activation index,XRD,SEM,FT-IR and other characterization methods.The optimal process conditions for preparing and modifying ATH were determined,and the materials were discussed.The mechanism of controlling growth;the effects of solution pH,reaction temperature,aging temperature,aging time and other factors on the crystallinity and particle size of ultrafine ATH powders were analyzed;the wet modification of ultrafine ATH powders was clarified The influence of factors such as the best modifier amount,the best modification temperature,the best modification time,and the best stirring rate.The optimum process conditions for preparing ATH powder: 1 mol of aluminum sulfate,100 mL of deionized water,18.2 mL of sodium hydroxide,temperature 30 ?,solution titration pH 11.2,aging time 16 h,and aging temperature 45 ?.The modification results show that the surfactant Evotherm is the best modifier.After the modification,the ultra-fine ATH body almost completely floats on the water surface,the activation index reaches 99.89%,the absorbance reaches 3.199,and the oil absorption value is as low as 33.1.The best process conditions are: Evotherm dosage is 8% of ATH mass,modification temperature is 50 ?,modification time is 20 minutes,and stirring rate is 1500 r / min.The modified ultra-fine ATH powder has good dispersibility and compatibility in polymer organic materials.Its stability is better than the other two modifiers,and its flame retardancy is obvious.The modified ultra-fine ATH powder was evenly added to the warm-mixed AH-70 matrix asphalt,and the oxygen index of the mixed asphalt increased significantly.The 12% hydrotalcite and 12% Evotherm modified ATH were added to make the oxygen index from the matrix asphalt.18.8 improved to 27.6,which basically meets the requirements of self-extinguishing materials.Through thermogravimetry,scanning electron microscopy,and Fourier infrared analysis,it was found that the modified ATH was uniformly dispersed in the matrix asphalt,the thermal stability was significantly improved,and the prepared flame retardant asphalt was dispersed in the matrix asphalt by mechanical stirring.No chemical reaction occurred to produce chemical bonds.