Preparation Of High Conductivity Polyaniline And The Responding Study About Its Dispersion

In this paper, the highly conductive polyaniline were prepared by coagulationpolymerization and fast oxidation synthesis, respectively. In the process of thecoagulation polymerization, depending on the coagulation reaction between anilinesalts and lauryl sulfonate (SDS), lots of aggregations were generated. After thecoagulation, the aniline monomers were immobilized into the aggregations resultingin the inhibition of the diffusion of ammonium persulfate. So, the polymerization rateof aniline monomers was greatly decreased. Low polymerization rate providedenough time for the adjustment of polyaniline chains conformation and the diffusionof doping agent. In addition, many vacancies were generated when SDS leaved fromthe polyaniline chains in the process of the polymerization. Thus, the dopingefficiency of hydrochloric acid on polyaniline chains was effectively increased due toits easy diffusion among these vacancies. Therefore, the highly conductivepolyaniline was synthesized by coagulation polymerization. But, it required for a longtime to finish the polymerization, when the molar ratio of An, SDS, HCl to APS wasabout1.69:0.46:15.38:1, the product was washed by0.4mol/L HCl, the conductivityof PANI reached24.39S/cm,In the fast oxidation synthesis, we mainly considered the obvious difference oflosing electron numbers between forming benzene ring and forming quinoid ring. Itlost two electrons from aniline monomer to form benzene ring, and it lost anotherfour electrons from benzene ring to form quinoid ring. So, when the oxidizing agentwas added quickly, it is much available to generate quinoid ring at the beginning ofthe reaction. Thus, the doping efficiency was highly increased. Therefore, the highlyconductive polyaniline was also synthesized by fast oxidation synthesis. When themolar ratio of HCl, APS to An was about7.6:0.466:1, the conductivity of PANIreached27.78S/cm.Furthermore, we studied the applicability of fast oxidation synthesis in differentinorganic acid systems (phosphoric acid and sulfuric acid) to prepare highly conductive polyaniline. The highly conductive polyaniline could be achieved in twokinds of acid systems, the conductivity reached20.83S/cm and34.48S/cm.Finally, we studied the applicability of fast oxidation synthesis in different mixedacid(Na) reaction systems (hydrochloric acid(Na)+organic acid) to prepare highlyconductive polyaniline with excellent properties to disperse in organic solvent. Itshowed that this polymerization method also had some applicability in the mixedacid(Na) reaction systems. The polyaniline doped by hydrochloric acid and organicacid could obviously improve its properties of dispersion and thermal stability. So,the fast oxidation synthesis to prepare highly conductive polyaniline becomes muchmore usefully.