Conductivity Polyaniline And Its Composites Based On Ionic Liquid:Preparation And Characterization

Since polyacetylene as the first successful synthesis of conductive polymers in1970s, conductive polymer materials have attracted more and more attention by scholars both at home and abroad, because of its unique physical and chemical properties. Among the conducting polymers, polyaniline (PANI) is considered to be one of the most prospects in commercial application of conductive polymer materials due to its numerous advantages, such as diversity structure, special type proton doping, good oxidation reducing, good environmental stability, excellent physical properties, the cheap raw material, the high electrical conductivity, the synthesis method simple and easy control, and so on. In this paper, it is PANI-based that a series of "polymer-clay" conductive composite materials are prepared in ionic liquids (ILs) via in situ chemical oxidation polymerization.In this thesis, conductive CMMIm-PANI prepared using a chemical oxidation method with sulfamic acid (SA) as the doping agent and ammonium persulfate (APS) as oxidant in1-methyl-3-alkylcarboxylic acid imidazolium chloride ([CMMIm]Cl) ILs. The impact of preparation conditions (dopant amount, oxidant amount, ILs amount and reaction time) on the conductivity of CMMIm-PANI was studied and the structure and properties of CMMIm-PANI was studied at same time. Results showed that the conductivity of CMMIm-PANI is2.5S/cm when the mass of SA is1g, the mass of APS is1.7g, the mass of [CMMIm]Cl is5g and the reaction time is2h. In addition, the environmental stability of CMMIm-PANI is better because of ILs.Based on the above work,"polymer-clay" conductivity composites named CMMIm-PANI-attapulgite (ATP) was prepared based ILs. The composites were prepared using untreated ATP via in-situ chemical oxidation polymerization method in ILs. The impact of preparation conditions (ATP amount) on the conductivity of composites was studied, and structure, properties and the conductive structure model were also studied. Results showed that, the conductivity of CMMIm-PANI-ATP composites is10S/cm when the mass of ATP is0.15g (namely mATP/mAn=0.15). The results are further indicated that PANI which coated on the surface of rodlike crystal ATP helped the formation of conductive path among ATP crystals which overlapped each other in ILs. In addition, conductivity of CMMIm-PANI-ATP composites is higher than the CMMIm-PANI.Further, based ILs PANI-montmorillonite (MMT) conductive composites which named CMMIm-PANI-MMT were prepared via in-situ chemical oxidation polymerization method. The impact of preparation conditions (MMT amount) on the conductivity of composites was studied, the change of layer spacing of MMT in the ILs, and structure, properties and the conductive structure model were also studied. Results showed that the MMT layer spacing increases from1.27nm to1.27nm when MMT dispersed in the ILs2h, and the conductivity of CMMIm-PANI-MMT composites is5S/cm when the mass of MMT is0.05g (namely mMMT/mAn=0.05). This description ILs effectively promotes the increase of the inter-layer space of MMT, and aniline monomers are more likely to enter interlayer. The aniline monomers were polymerization both adsorption on the surface and between layers of MMT at the same time. Therefore, the better coated structure making the conductivity of composites increasing.For comparison with the two clays above (the structure of ATP is rodlike, the structure of MMT is lamella), the based ILs PANI-silica fume (SF) conductive composites which named CMMIm-PANI-SF were studied. CMMIm-PANI-SF were prepared via in-situ chemical oxidation polymerization method. Different silicon dioxide content of SF, and SF usage on the influence of the conductivity of composites were studied in the synthesis, and structure, properties and the conductive structure model were studied, respectively. Results showed that the conductivity of CMMIm-PANI-SF composites is1.6S/cm when SiO2>70%and the mass of SF is0.2g (namely msF/mAn=0.2), and the other is0.91S/cm when SiO2>90%and the mass of SF is0.07g (namely mSF/mAn=0.07).Innovation of this paper:first introducing ILs in polymerization of PANI via in situ-chemical oxidation method, and the composites has good conductivity and stability. We use ILs not only as the proton source but also as the modifier to employ ATP, MMT and SF in based ILs "polymer-clay" synthesis, respectively, what’s more, conductivity of composites are higher. And analysis the synthetic mechanism of "polymer-clay", from the different shape of clays effect on the properties of conductive composites. And provide a good experimental basis on how to improve the conductivity in this type of materials in the future.