Preparation And Anticorrosive Properties Of Polyaniline Redoped With Function Acid

Polyaniline(PANI) has properties of good conductivity and unique doping-dedoping. Because of the unique scratch and pitting corrosion resistance, PANI has great prospects for development in the field of metal corrosion. In this study, PANI nanofibers have been synthesized by direct mix reaction method in different acid systems. The morphology and structures of PANI have been characterized and analyzed by scanning electron microscope (SEM), Infrared Spectroscopy (IR) and Ultraviolet-visible spectroscopy (Uv-vis) spectrometers. The relationship between reaction acid system and PANI nanofibers properties have been found out by analysing to morphology and structure. PANI nanofibers was dedoped with different dedopant, the effect on morphology and structure was researched with different dedopant dedoped. The redoped PANI nanofibers with good morphology and corrosion protection of functional groups were prepared in the system which has the function of antisepsis functional group. The anticorrosion performance of the films on the mild steel was tested by electrochemical measurement technology in nature seawater, and the anticorrosion mechanism was investigated. The main results are as follows.1. Direct mix reaction is a simple and efficient polymerization method for fabricating high quality PANI in tartaric acid system. PANI nanofibers with various morphologys can be prepared in different acid systems, the morphology of PANI prepared in tartaric acid system is better than in sulfuric acid system. The nanofibers diameter is about 80-120nm and length up to several micrometers and the nanofibers forming clusters. The optimum preparation parameters of direct mix method are as folfows:tartaric acid 0.1mol/L, reaction temperature 20 ℃, reaction time 24h.2. Ammonia is a kind of ideal dedoping agent which can obtained the EB nanofibers with most similar morphology to doped PANI. While the sodium bicarbonate and sodium hydroxide can damaged the morphology in the process. Redoping can introducing functional groups into PANI. The redoped PANI nanofibers with good morphology and corrosion protection of functional groups were prepared in tannic acid system and ammonium molybdate acid system.3. The research of anticorrosion performance showed that every PANI products has certain anticorrosion ability. The open circuit potential of the samples coated PANI films shifted negatively compared to bare steel, corrosion rate generally lower. The anticorrosion efficiency of doped PANI with tartaric acid reached 59.27%. The anticorrosion efficiency of redoped PANI with tannic acid reached 64.43% and redoped PANI with molybdic acid reached 74.23%. The anticorrosion ability of redoped PANI films was better than doped PANI films, and the anticorrosion ability of redoped PANI with anticorrosion function was better than doped PANI with normal function.4. TA-EB-TNA PANI film can protect metal with high efficiency for a long time, anticorrosion efficiency can reached 86.02%, soaked in seawater for 7 days still remained at 78.84%. Under the same conditions, PANI film of tartaric acid doped has the efficiency of 68.97%, soaked in seawater for 7 days remained at 59.70%. PANI film of tartaric acid redoped has the efficiency of 74.51%, soaked in seawater for 7 days remained at 69.41%. PANI film of H2SO4-EB-TNA has the efficiency of 76.70%, soaked in seawater for 7 days remained at 63.76%.