Synthesis Of High Temperature Resistant Epoxy Resin And Its Application In Graphene Anticorrosive Materials

Epoxy resins,as a kind of thermoset resin,have a wide range of applications in the fields of coatings,electronics,adhesive,and aerospace,because of their outstanding adhesion,strong weatherability,and excellent mechanical properties.However,epoxy resin has poor temperature resistance,which causes damage to electronic devices and affects the normal operation of the circuit.Although the conventional heat-resistant agent can improve the heat resistance of the epoxy resin,the compatibility between the heat-resistant agent and the epoxy resin is poor,resulting in a decrease in the mechanical properties and the glass transition temperature of the epoxy resin.In this paper,epoxy resin(DEPFS)with high temperature resistance is synthesised by reacting diazobisphenol fluorene with diphenyldichlorosilane and epichlorohydrin.By adjusting the ratio of DEPFS in E-51 epoxy resin,the epoxy resin system(E-51-DEPFS)with high temperature resistance,high glass transition temperature,enhanced reinforcing and toughening is obtained after curing.First,diazofluorenone was synthesized by the oxidation of potassium permanganate to the phenanthroline,The diazobisphenol fluorene was prepared by reacting phenol with diazofluorenone,The diphenyldi(9,9-di-(4-hydroxyphenyl)4,5-diazafluorenoxy-silane)was synthesized through the nucleophilic substitution reaction between diazobisphenol fluorene and diphenyldichlorosilane.A novel silicon-containing reactive epoxy resin,diphenyldi(9,9-di-(4-(2,3-epoxypropoxy)phenyl)4,5-diazafluorenoxysilane)(DEPFS),was prepared by ring-opening reaction with epichlorohydrin.Secondly,DEPFS was added to E-51 epoxy resin in different proportions and cured to form a mixed epoxy resin(E-51-DEPFS).The effects of DEPFS content on the temperature resistance,glass transition temperature and mechanical properties of E-51 epoxy resin were studied.The results show that with the increase of DEPPS content,the residual carbon content of E-51-DEPFS epoxy resin reaches 24.8%at 800?,the glass transition temperature reaches 187?,and the tensile strength and modulus reach77.37 MPa and 1507.71 MPa,respectively,and an elongation at break is as high as8.26%.However,the pure E-51 epoxy resin has a residual carbon content of only 11.2%at 800?,a glass transition temperature of 153?,a tensile strength and modulus of32.28 MPa,766.13 MPa,and an elongation at break of only 6.04%.Eventually,different types of graphene were added to E-51-30%DEPFS epoxy resin,and the effects of graphene powder,graphene paste and graphene oxide on the corrosion resistance of E-51-30%DEPFS epoxy resin were explored.The results show that the graphene paste has the best anti-corrosion performance for E-51-30%DEPFS epoxy resin when the same amount of graphene is added.Further,adding 0.5wt%graphene paste,the adhesion and resistance of E-51-30%DEPFS epoxy coatings are as high as 6.08 N cm^-2and 5.3×10³W,respectively,after immersion for 168 h.By measuring the electrochemical impedance and electrical resistance of the coating,it was confirmed that the addition amount of the graphene slurry was 0.5 wt%,and the corrosion resistance was excellent.It shows that the sheet structure of graphene can effectively increase the corrosion path and prolong the time for corrosive ions to reach the substrate.Therefore,graphene paste can significantly improve the corrosion resistance of E-51-30%DEPFS.