Corrosion protection properties of electroactive aniline oligomers and their epoxy cured dervatives using salt spray and cyclic tests

Electroactive polymers have been identified as novel corrosion inhibiting coatings for metals. Among all the electroactive polymers studied so far, polyaniline is the first to achieve commercial availability. However, one problem associated with large-scale commercial applications is the limited processibility. Furthermore, among the inherent drawbacks is the non-unity polydispersity in molecular weight and the existence of structural defects. Another potential problem with polyaniline is poor adhesion to metal substrates.; Aniline oligomers, on the other hand, could be prepared in well defined structures with unity or near unity polydispersity. They demonstrate enhanced solubility and processibility due to lower molecular weight. End groups could be varied to different functional groups and as a result various polymeric derivatives of aniline oligomers could be prepared. The epoxy cured amino terminated aniline has demonstrated excellent adhesion to cold rolled steel, and a far better performance than polyaniline.; In this thesis, for the first time, we have performed a series of systematic comparative exposure studies containing various aniline oligomers and their epoxy cured derivatives both as coatings and as additives against the best of commercially available conventional systems. We have successfully demonstrated the superior corrosion protection properties of aniline oligomers and their epoxy cured derivatives for practical, industrial applications. In particular, the epoxy cured amino terminated aniline trimer demonstrated outstanding corrosion protection property at low film thickness.; We performed the exposure tests based on the two widely accepted industrial standards per ASTM (A&barbelow;MERICAN S&barbelow;OCIETY FOR T&barbelow;ESTING AND M&barbelow;ATERIALS). They are: ASTM B 117-97 (Standard Practice for Operating Salt Spray (Fog) Apparatus), and ASTM D 5894-96 Cyclic Salt Fog/UV Exposure of Painted Metal, (Alternating Exposures in a Fog/Dry Cabinet and a UV/Condensation Cabinet). In order for the data to have universal acceptance, there are also grading and interpretation requirements based on ASTM. Therefore, we used ASTM D 1654-92 (Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments).