Study On Doped Polyaniline

Polyaniline were synthesized in water by oxidation, in which Aniline (An) unrefined is monomer and Ammonium persulfate is oxidant. In aniline polymerization process several kinds of different dopants were added by one-step method. The effects of different reaction conditions on polyaniline properties were studied and optimum condition was obtained. The polyanilines containing different dopants were characterized. The conclusions were gotten as follows.The optimum conditions for aniline polymerization with the dopant of the solution blended with hydrochloric acid and LAS at the proportion of 1/1 (LAS-HCl) are that the mole ratio of LAS and An is 1/1, and that of APS and An is also 1/1, the temperature of the polymerization is about 20℃, the proper reaction time is about 6 hours.The thermal stability of the polyaniline doped with LAS-HCl has been improved a lot in contrast with that doped with HCl, and the start thermal decomposition temperature is about 200℃, the thermal weightlessness is 2.9% at 250℃, and only 5% at 281℃, the conductivity decreases at one order of magnitude after being kept in vacuum at 250℃ for 30 minutes.The polyaniline were synthesized respectively with the dopants of the solution blended with hydrochloric acid and PSVS (PSVS-HCl) and the solution blended with hydrochloric acid and SVS (SVS-HCl), The conductivity of the polyaniline doped with PSVS-HCl do not change much in contrast with the one doped with SVS-HCl, but the productivity increases a little. The thermal stability of the polyaniline doped with PSVS-HCl was not improved.And the polyaniline were synthesized respectively with the dopants of the solution blended with hydrochloric acid and PSSS (PSSS-HCl) and the solution blended with hydrochloric acid and SSS (SSS-HCl), the start undoped temperature of the polyaniline doped with PSSS-HCl increases from 222℃ to 282℃ comparing to that of the one doped with SSS-HCl, while the productivity and conductivity of the polyaniline doped with PSSS-HCl increase very much too.When the assistant solvent is ethanol and the dopant is DBSA, the optimum conditions for aniline polymerization by one-step method are that the mole ratio ofDBSA and An is 1.2, the mole ratio of APS and An is 1.0, and the volume ratio of ethanol and water is 1/1.The thermal stability of the polyaniline is not influenced using ethanol as assistant solvent, and by this way the production increases and the bad factors such as frothiness and agglomeration in the polymerization process are removed.