Preparation And Performance Of Epoxy Asphalt Compatibilizer Based On Tung Oil

Epoxy modified asphalt has become the ideal pavement material for paving steel bridge deck,advanced pavement and heavy haul road,due to its good high temperature stability and low temperature crack resistance,excellent mechanical properties and super fatigue resistance and corrosion resistance,which has attracted extensive attention of researchers.Epoxy asphalt compatibilizer is the key to achieve these excellent performances.In this paper,two kinds of epoxy asphalt compatibilizer were prepared through the different paths with tung oil as the raw material.The optimum technological conditions were determined by studing the preparation process.The structure of each target product was characterized by Fourier Transform Infrared Spectroscopy(FTIR).The thermosetting epoxy asphalt materials were prepared through vulcanization and curing reaction with the two compatibilizers respectively.The compatibilization effect of the compatibilizers on epoxy resin and asphalt system was characterized by means of segregation experiment and fluorescence microscope test.The effects of the amount of compatibilizers,the ratio of epoxy resin to asphalt and the amount of vulcanizing agent and curing agent on the mechanical properties of thermosetting epoxy asphalt system were studied by penetration,viscosity and tensile strength test.The microstructure of the thermosetting epoxy asphalt material was characterized by Scanning Electron Microscopy(SEM),and their heat resistance were characterized by thermogravimetric analysis(TGA).According to the above research,the following main conclusions are obtained:(1)With tung oil and epoxy resin as raw materials,the optimum process conditions for preparation of epoxy asphalt compatibilizer(I)by three-step reaction of saponification,esterification and epoxidation are as follows: When the saponification temperature is 70 ?,reaction time is 2 hours,and the molar ratio of tung oil to sodium hydroxide is 1: 1.2,the conversion rate of tung oil is 76.3%;When the reaction temperature is 100 ?,the reaction time is 5 hours,the molar ratio of epoxy resin to tung oil acid is 1: 2,the mass ratio of epoxy resin to toluene is 1: 2,and the amount of tetra-n-butylammonium bromide is 2.5% of the reactantmass,the esterified product had a lower epoxy value of 0.544 mol / 100 g.The optimum conditions for the epoxidation reaction are as follows: When the reaction temperature is 60 ?,the reaction time is 45 minutes,and the molar ratio of hydrogen peroxide to formic acid and tung oleate resin is 3: 1: 1,the amount of sulfuric acid is 1.5% of the total content of tung oleate resin.(2)Epoxy asphalt compatibilizer(II)was synthesized with concentrated sulfuric acid as catalyst,formic acid and hydrogen peroxide as epoxidation agents,part of the double bonds in the tung oil molecules are oxidized to epoxy groups.The optimum synthetic process conditions are as follows: Concentrated sulfuric acid is2% of the tung oil quality;n(tung oil): n(formic acid)= 1:1(molar ratio);n(tung oil): n(hydrogen peroxide)= 1:3.3(molar ratio);reaction time is 7 hours,reaction temperature is 35 ?.In this condition,the epoxy value of the epoxy tung oil is0.318 mol / 100 g.(3)By studying the influence of the amount of each component on the tensile strength of the thermosetting epoxy asphalt curing system,the ratios of the two compatibilizers in the thermosetting epoxy asphalt system are determined respectively as follows: asphalt/epoxy resin/compatibilizer(I)/curing agent =100/30/12.5/6/24,and asphalt/epoxy resin/compatibilizer(II)/curing agent=100/30/8/6/24.(4)In these ratios,the SEM photos of the thermosetting epoxy asphalt material show that both compatibilizers can significantly improve the compatibility of the epoxy resin and asphalt,make the asphalt and epoxy resin form a uniform structure after curing,tensile strengths are improved.The material has good heat resistance.