Preparation And Research Of Solvent-Free Coatings Based On Conductive Polymer Materials

With the rapid development of our country’s economy,the consumption of iron and steel and additional metal materials is increasingly increasing,which in the long-term use process,a major problem is corrosion.Corrosion will not only cause great economic losses,but also lead to equipment failure,serious safety accidents and heavy casualties.In order to ensure the performance of metal materials and improve the reliability of the system,we should take scientific anti-corrosion measures.Coating coatings are widely used in the field of metal anticorrosion.With the development of the national economy and the enhancement of people’s environmental awareness,the traditional anticorrosion coatings have been unable to meet the market demand.Nowadays,the development and utilization of solvent-free coatings has become a hot issue at home and abroad.In this paper,we develop solvent-free coatings based on conductive polymer materials using a solvent-free epoxy system as a formulation basis,through orthorhombic design and single-factor experiments,using a modern approach to secondary doping that enables the fabrication of composite functional nanomaterials of polyaniline and graphene/carbon nanotubes.The details are as follows:（1）In the perchloric acid system,using the polyaniline secondary doping method,the graphene grown in situ was doped with polyaniline,and the carbon nanotubes were doped with polyethylene,the cost eigenstates were reduced after ammonia hydrolysis doping,combined to form new functional composite materials.By scanning SEM,TEM,FT-IR,UV-Vis,characterizing the morphologies and structures of different products,testing the corrosion resistance of different products in 3.5wt%Na Cl solution through the electrochemical workstation,and the results show that:graphene/polyaniline composites and carbon nanotubes/polyaniline composites were treated by the method of secondary doping,and can avoid the aggregation of nanomaterials,and can improve the product performance effectively,break through the bottleneck of producing composite materials with graphene/carbon nanotubes and polyaniline simultaneously,compared with conventional graphene/carbon nanotube composite,the anti-corrosion effect increased by 56.51%and the gradual release efficiency reached 81.79%and the impedance value was 1893.6Ω·cm².（2）The epoxy resin and curing agent system for solvent-free coatings were selected and developed by single-factor experiment.In this system,five kinds of fillers and five kinds of functional fillers were screened,according to the pigment volume concentration（PVC）of each filler,can make 10 solvent-free epoxy coatings with a single filler.The effects of resins,curing agents,and pigment fillers on the basic physical properties and the anti-corrosion properties of coatings have been investigated by means of basic physical performance tests,ac impedance tests,neutral salt spray tests,and metallographic microscopy,among other four methods.The results show:excellent antiseptic properties of the pure resin coating formed after cross-linking and curing with phenolic epoxy MY9512 and phenolic amine NX-2003D.And under the system,barium sulfate and ceramic powder can provide excellent physical properties to the coating,the coating prepared by mica iron oxide and calcium exchange Si O₂ was soaked in 3.5%wt%Na Cl solution for 1800h,its impedance value can still be maintained above 2×10⁸Ω·cm².In this way,it can provide a long-term anti-corrosive effect to the coating.（3）Using barium sulfate and ceramic powder as filler,mica iron oxide,calcium exchange Si O₂ as coating rust prevention filler,according to different ratios,combining the four fillers to make a new solvent-free epoxy coating with good basic physical properties and excellent anti-corrosion properties.The influence of the choice of film forming material,pigment volume concentration,and different fillings on the physical properties of the coating and its resistance to corrosion was investigated using four methods:basic physical properties testing,ac impedance testing,neutral salt spray testing,and metallographic microscopy.The results show that:when the ratio of film forming material to pigment filler is 6:4,the ratio of filling filler to rust prevention filler is 1:1,the ratio of ceramic powder to barium sulfate is 2:1,and the ratio of mica iron oxide to calcium for Si O₂ is 3:1,the basic physical properties of the coating are excellent,the coating viscosity is moderate,and it is convenient for construction.Besides,the coating has the strongest corrosion resistance under this formula,after soaking in3.5%wt%Na Cl solution for 1800h,it can still maintain 3.470×10¹⁰Ω·cm².It has excellent anti-corrosion properties and the 720h salt spray test again verified that the formula has excellent anti-corrosion properties.（4）Made the solvent-free epoxy coatings based on secondary doped graphene/carbon nanotube polyaniline composites with different proportions,and explored the effect of the amount of polyaniline nano functional material on the corrosion resistance of the solvent-free coating.The results show that the coating already exhibits excellent anti-corrosion properties,film density,excellent scratch resistance,and some self-passivation capability for a polyaniline nanocomposite of 1wt%.In addition,it can improve the corrosion resistance of the coating After soaking for 1800h,the impedance value is 5.557×10¹⁰Ω·cm²,and there is no corrosion shift after 1000h salt spray test.The optimal coating formula is:the mass ratio of film forming material to pigment filler is 6:4,the mass ratio of filler to rust prevention filler is 1:1,the mass ratio of ceramic powder to barium sulfate is 2:1,the mass ratio of mica ferric oxide to calcium to exchange Si O₂ is 3:1,the secondary doped graphene/carbon nanotube polyaniline is1wt%,and the coating formula is 1wt%.Active diluents range from 6wt%to 8wt%,and auxiliaries from 1wt%to 2wt%.