Preparation And Characterization Of Dopped Polyaniline/dysprosium Oxide Composite Material

As a kind of new functional polymer material, polyaniline(PANI) has become one of the hottest focuses in the conductive polymer area due to its simple synthesis method, particular doping mechanism, good redox property and environmental stability, high electrical conductivity, and peculiar electrical, optical and magnetic properties. However because of big rigid of its chain backbone, strong intermolecular force, polyaniline is difficult to dissolve and melt, the poor post processability of polyaniline have badly hinder its application in every field. Modification technology by composition can not only effectively improve the processability of polyaniline but obtain multiple functionality and improve its value of practical application.Modification of polyaniline by composition with inorganics can enhance the anti-corrosive property of polyaniline coating. In the preparation process of polyaniline/inorganics composite, concentration of dopant, oxidant, inorganics, reaction time and conetent of inorganics in composite can influence the doping rate, conductivity, grain size, structure, component of composite and the anti-corrosive property of its composite coating. In this work, the effects of polymerization conditions of aniline on the properties of PANI, polyaniline/dysprosium oxide (Dy2O3) composite material (PANI/ Dy2O3) and their epoxy coating were primarily discussed.The body of the thesis is divided into two sections:â‘ Effect of conditions of emulsion polymerization of aniline on the performance of polyaniline, polyaniline/epoxy coating (P/EP), polyaniline/dysprosium oxide-mix/epoxy coating (PD-M/EP). The effects of dosage of sodium dodecylbenzene sulfonate (SDBS), Dy2O3, ammonium persulfate(APS), reaction time and the dosage of PANI on the structures and properties of PANI, P/EP coating and PD-M/EP coating were discussed by four-probe, laser granularity analytical instrument, electrochemistry workstation. The results show that the optimal conditions of PD-M/EP coating are as follows: wt PANI %=25%, nSDBS/nAn=0.8, %9%wt Dy 2O3=, nAPS/nAn=0.8, reaction time=4h, now PD-M/EP coating works best for the anti-corrosion. And the corrosion potention of PD-M/EP coating is +878mV higher than P/EP coating, thus the anticorrosive properties of coating is greatly improved.â‘¡Effect of conditions of emulsion polymerization of aniline on the performance of polyaniline/dysprosium oxide-(in-situ)(PANI/Dy2O3-I) and its epoxy coating(PD-I/EP).The effects of dosage of SDBS, Dy2O3, APS, reaction time and the dosage of PANI/Dy2O3-I on the structures and properties of PANI/Dy2O3-I and PD-I/EP coating were discussed by four-probe, laser granularity analysis, X-ray Photoelectron Spectrometry (XPS), X-ray (powder) diffraction (XRD), thermogravimetric analysis (TGA), and Tafel curve. The results show that the optimal conditions of PANI/Dy2O3-I and PD-I/EP coating are as follows: nSDBS/nAn=0.8, nDy O/nAn23=1/50, nAPS/nAn=0.8, reaction time=4h, PANI/Dy 2O3I%10%wt ?=. Now PD-M/EP coating works best for the anti-corrosion, the corrosion potention of PD-I/EP coating(0.122V) is +51mV higher than that of PD-M/EP coating, and the dosage of PANI/Dy2O3-I in PD-I/EP coating are largely decreased. XPS, XRD and FTIR analysis show that there is interaction between Dy2O3 and PANI chain in PANI/Dy2O3-I molecule. With the increase of Dy2O3 content, regularity of PANI/Dy2O3-I molecular chain is decreased, while the blue moving of its FT-IR spectra is increased. The thermal stability of PANI/Dy2O3-I under the optimal conditions is better than PANI.