Preparation And Characterization Of PANI Synthesized By Sanding Method And P（2,3-DMA）/ZrO₂Composite

Polyaniline （PANI） is one of the most important polymer materials, due to itsexcellent and unique properties. Nowadays, the demands for production efficiency andenvironmental benefits are higher and higher, so seeking for the technique which isefficient, energy saving and less environment pollution to synthesis PANI becomes oneof the research direction of PANI. One of the important application of PANI is asadditives in anticorrosion coatings. Reports show that the electron-substitutedderivatives of PANI have better anticorrosion properties. Therefore, theelectron-substituted derivatives of PANI become the hot research area of PANI.Recent years, grinding method becomes a new method to prepare PANI, owing toits simple operation and good to the environment. However, there are also somedisadvantages, it is difficult to control the grinding speed, thus the product is notuniform. Emulsion polymerization is a classical method to synthesis PANI, the productis uniform, the polymerization rate and the molecular weight are high. But the reactiontime and water usage are high, which will result in high cost and do bad to theenvironment. Given that sanding machine has the features in good stability, simpleoperation and the product is uniform in the process of coating dispersion, sandingmethod is used to synthesis conductive PANI for the first time. It does not only offsetthe disadvantages of grinding method, but also make up the drawback of emulsionpolymerization method. The effects of sanding speed, reaction time, the concentrationof HCl, SDBS and APS on the redox performance and conductivity of PANI arediscussed by cyclic voltammetry and standard four-probe method, and the structure ofPANI is characterized by FT-IR.The results indicated that the optimal properties of PANI were achieved when thesanding speed was400r/min, the reaction time was2h, the molar ratio of HCl to Anwas4:1, the molar ratio of SDBS to An was1:1and the molar ratio of APS to An was0.8:1; The structure and electrochemical properties of PANI prepared by sandingmethod were very close to PANI synthesized by emulsion method; But the productioncost and the environmental advantage of sanding method was significant due to thereaction time was only one third of emulsion method and the total amount of water wasonly one half of emulsion method.As one of the electron-substituted derivatives of aniline, poly（2,3-dimethyl aniline） （P（2,3-DMA）） has significant anticorrosion property. However, the thermal stability ofP（2,3-DMA） is not very good, which confines its application area. In order to enhancethe thermal stability of P（2,3-DMA）, ZrO₂is added into the polymerization system of2,3-DMA to prepare P（2,3-DMA）/ZrO₂composite. The effects of ZrO₂content, theconcentration of APS and H₃PO₄, the reaction time, the reaction temperature on the tafelcurve of P（2,3-DMA）/ZrO₂composite are discussed; the structure and thermal stabilityof P（2,3-DMA）/ZrO₂composite are characterized by UV-Vis, FT-IR and TGA-DTA.When mZrO₂/m2,3-DMA=15:85, nH₃PO₄/n2,3-DMA=2.5:1, nAPS/n2,3-DMA=1.5:1, t=10h, T=30℃, the corrosion potential and yield of P（2,3-DMA）/ZrO₂composite were the highest.UV-Vis and FT-IR indicated that some interaction existed between P（2,3-DMA） andZrO₂particles rather than mechanical blend. TGA-DTA test manifested that the thermalstability of P（2,3-DMA）/ZrO₂composite was much better than P（2,3-DMA）. Therefore,the expected goal to enhance the thermal stability of P（2,3-DMA） without decreasing itsanticorrosion property was achieved, which would widen the application area of thisnew molecular polymer material.