||Anti-Corrosive Paint Systems Based on Conducting Polymers
||Petersen, Marie Louise (Materialeteknologi og -udvikling, Institut for Produktion og Ledelse, Danmarks Tekniske Universitet, DTU, DK-2800 Kgs. Lyngby, Denmark)
||Møller, Per (Materialeteknologi og -udvikling, Institut for Produktion og Ledelse, Danmarks Tekniske Universitet, DTU, DK-2800 Kgs. Lyngby, Denmark)
||Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
||The corrosion protection of anti-corrosive paint systems based on conducting polymers is
examined in the following four application areas: shopprimers, ballast tank protection, protection
in off-shore environment and protection of aluminium. The conducting polymers used as an
additive are polyaniline and polythiophene. Five possible hypotheses for the protection
mechanism of conducting polymers are stated, and the aim is to examine the credibility of these
For shopprimer applications, no improvement of the corrosion protection is established by the
addition of polyaniline to a conventional shopprimer. In some of the applied shopprimers,
polyaniline seems to accelerate the degradation of the paint film instead. The main explanation for
these observations is a very low dispersibility of polyaniline in the paint.
For protection of ballast tanks, addition of polyaniline to a conventional paint system seems to
increase the resistance to cathodic disbonding. The assumption is made that polyaniline acts as an
amphoteric material and reacts with the hydroxide ions, which are produced in the cathodic
reaction. During this reaction, polyaniline is reduced to a non-conductive base form.
For protection in off-shore environment, no improvement of the corrosion resistance is
established by adding polyaniline to a conventional zinc primer. The effect of the cathodic
protection is lowered, therefore polyaniline is not a suitable conductor between the zinc particles.
Some positive effect is registered in the water based paint system with the addition of
polythiophene in the primer. It is evaluated that a higher degree of dispersibility is the main
explanation for this observation.
Finally, the protective character of a conventional polyaniline containing primer is examined on
aluminium. The efficiency is compared to other surface treatments that are especially designed for
protection of aluminium. The results show that the polyaniline containing primer has a low
adhesion to the substrate material, and the resistance to filiform corrosion is also not acceptable.
The best corrosion protection is established by a conventional coating system with an anodizing
Creation date: 2007-07-19
Update date: 2011-09-27