The Preparation Of Covalent Bonded PANI/TiO₂ Nanoparticles And Its Effect On The Toughness And Anticorrosion Of Epoxy Coating

Epoxy resin(EP)for its outstanding advantages on low curing shrinkage,good adhesion,penetration resistance and anticorrosion properties has been widely used in coating industry,however epoxy resin is quite brittle,and easily failure upon crack and impact.And also with the improvement of the coating requirements for corrosion resistance,it is necessary to strengthen the anticorrosion properties of epoxy resin coating.Based on the toughening action of titanium oxide nanoparticles and the anticorrosion properties of polyaniline,the organic-inorganic hybrid material PANI-g-TiO2(PGT)was prepared,and introduced into epoxy resin in this paper,and then the mechanical properties and anticorrosion properties of epoxy resin coating was studied by adding different content and component ratios of the composite nanoparticles.and finally the toughening mechanism and anticorrosion mechanism was simply analyzed.The main researches and conclusions are presented as follows:The titanium dioxide was modified by the coupling agent ?-aminopropyl triethoxysilane(KH550)under anhydrous conditions,and then aniline was in-situ polymerized on the surface of titanium oxide to obtain the organic-inorganic hybrid nanoparticles(PGT).FTIR,XPS,TGA,SEM and XRD were used to characterize the structure and the morphology of the nanoparticles.The results showed that the polyaniline was grafted and coated on the surface of the titanium oxide.Titanium oxide and composite nanoparticles was dispersed in epoxy coating,and its properties was the characterized by adhesion,impact properties,tensile test and Izod impact test,at last the toughening mechanism was qualitative analyzed by the morphology of the fracture surface.The results showed that the tensile strength of epoxy resin with 1:0.5PGT was decreased with the increase of content,and increased with the increase of different component ratio n(PANI)/n(TiO2)at a content of lwt.%.The epoxy resin contains 1%1:0.5 PGT has the maximum tensile strength 19.86Mpa,which increased 8.2%than pure epoxy resin.The notched impact strength was increased with the increase of content,and first cdecreased,then increased with the increase of different component ratio n(PANI)/n(TiO2)at a content of 7wt.%.The epoxy resin contains 7wt.%1:2PGT has the maximum impact strength 3.2KJ/m2,which increased 10.3%than pure epoxy resin.Finally,the morphology of the fracture surface showed debonding and void most likely to be responsible for the increased toughness.The electrochemical experiment was used to analyze the corrosion behavior of metal under epoxy resin coatings with different content and different component ratio in corrosion medium.Then the anticorrosion mechanism of epoxy coating was elaborated based on the morphology and element of corrosion interface.The results showed that the coating resistance of epoxy coating contains 1:0.5PGT decreased with the increase of content,and decreased first,then increased with the increase of different component ratio n(PANI)/n(TiO2)at a content of lwt.%,After 30 days'immersion,the coating resistance of epoxy coating contains lwt.%1:0.5PGT nanoparticles was 1.94*1012O�cm2,while the maximum coating resistance of epoxy coating contains TiO2 nanoparticles was 7.76*1011.cm2,and pure epoxy coating was 1.12*10101O�cm2.A passivation film generated under the destroyed coating maybe the reason to slow down the corrosion rate of metal.The innovation of this study is to investigate how to prepare a coating with excellent tough.ness and anticorrosion from the view of inorganic-organic hybrid material,which provides a feasible approach and guiding ideas for improving the toughness and anticorrosion of organic coating.