Modifying The Nano-sized Inorganic Silica Particles And Studying Its Application In Epoxy Resin Based Composite Coatings

Polymer materials are widely used in various products due to their lightweight,low cost and easy molding characteristics.However,the shortcomings of polymer materials such as insufficient hardness,easy aging,and poor weather resistance are magnified in use.Therefore,the research on polymer materials suitable for different scenarios has also received increasing attention.Inorganic silica nanoparticle has high hardness,aging resistance,good weather resistance and other characteristics.Also,inorganic silica nanoparticle has a variety of structures,which can be applied to different application scenarios,so it is also widely concerned.In this thesis,three different inorganic silica nanoparticle products were prepared and mixed with epoxy resin systems by physical blending to prepare three composite materials with different properties.The main content of this thesis is as follows:(1)Two kinds of silica sol with epoxy group and without epoxy group were prepared by sol gel method.The silica sol was characterized by FTIR,XRD and other tests.The two prepared silica sols were added to the epoxy resin to prepare a silica sol/epoxy composite coating.The thermal stability,surface morphology,wear resistance,mechanical properties,dielectric properties,and hydrophobicity of the composite coating were characterized by means of DSC,laser confocal microscopy,rotary wear tester,and contact angle measuring instrument.The results show that silica sol with epoxy groups can participate in the curing process of epoxy resin,forming a more dense three-dimensional network structure;Adding silica sol to epoxy resin can reduce the surface roughness of the composite coating while increasing its hardness,which is beneficial to enhancing the wear resistance of the coating;Due to the low dielectric constant of silica sol,the appropriate addition of silica sol to epoxy resin can effectively reduce the dielectric constant and dielectric loss of the composite coating.(2)The modified fumed silica powder was prepared by modifying fumed silica using OTMS.The microstructure and properties of modified fumed silica were characterized by FTIR,SEM,nitrogen adsorption and desorption tests.The prepared modified fumed silica was doped into epoxy resin to prepare a modified fumed silica/epoxy composite coating.The hydrophobicity,surface morphology,and mechanical properties of the composite coating were characterized by laser confocal microscopy and contact angle testing instruments,and its hydrophobic mechanism was analyzed.The results show that the fumed silica powder modified by OTMS cannot be dispersed in water;Modified fumed silica with hydrophobicity forms a multi-level hydrophobic structure on the surface of the composite coating.Therefore,after increasing the doping ratio,the hydrophobicity of the composite coating exhibits an enhanced trend,up to 131 °.(3)The mesoporous silica was prepared by hydrothermal method.The corrosion inhibitor BTA was loaded into the mesoporous silica,and then the mesoporous silica was hydrophobically modified by OTMS to prepare modified mesoporous silica loaded with BTA.The loading process was analyzed through nitrogen adsorption and desorption,SEM,TEM,and other tests.The prepared powder is doped into the epoxy resin system to prepare a composite coating.The hydrophobicity and corrosion resistance of the composite coating were analyzed by means of SEM,contact angle measuring instrument,impedance analyzer,and other equipment.The results show that the composite coating exhibits good hydrophobicity and corrosion resistance after adding appropriate amount of samples.