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Chapter 8
Improved Synthesis and Corrosion Properties of Poly(bis-(dialkylamino)phenylene vinylene)s (BAMPPV) Nicole Anderson, David J. Irvin, Jennifer A . Irvin, John D . Stenger-Smith, Andrew Guenthner, Cindy Webber, and Peter Zarras Naval Air Warfare Center Weapons Division, Department of the Navy, Code 4T4220D, 1 Administration Circle, China Lake, CA 93555
Abstract: An alternative material for corrosion protection on 2024 T3 aluminum alloy in aqueous alkaline environments has been synthesized and tested. The alternative material is a poly(phenylene vinylene) derivative called poly(bis-(N— methyl-N-hexylamino)phenylene vinylene) (BAMPPV). The synthesis of this material is discussed including improvements in overall yield of polymer and reduction in the side products. The BAMPPV was coated onto 2024 T3 A l alloy plates using a draw down method and an atomization andflamedeposition process. The material has performed well in both neutral and alkaline (pH=8) environments and has shown excellent adhesion to the 2024 T3 aluminum alloy. A comparison of panels coated with BAMPPV to panels coated with chromate conversion coatings using B117 salt-fog tests (pH=7) showed similar performance results.
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U . S . government work. Published 2003 American Chemical Society
Zarras et al.; Electroactive Polymers for Corrosion Control ACS Symposium Series; American Chemical Society: Washington, DC, 2003.
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Introduction Current methods o f corrosion protection, including marine coatings that contain hexavalent c h r o m i u m , volatile organic compounds ( V O C s ) and other heavy metal conversion coatings, are coming under increasing scrutiny from the E P A ( / ) . N e w coatings and coating methods are needed to replace existing coating systems that are not environmentally friendly. Estimates from the United States D o D indicate that corrosion costs billions o f dollars annually for the m i l i t a r y (2). Initial studies based on conductive polymers have demonstrated their corrosion-inhibiting properties (3,4). Polyaniline ( P A N I ) , one o f the most w i d e l y studied conductive polymers, has been demonstrated as a corrosionprotective coating i n acidic environments ( 5 ) . There is a need for a more versatile coating that w i l l protect in neutral and basic environments as w e l l as acidic environments. E n v i r o n m e n t a l l y benign applications o f coatings f o r marine environments are under development using conductive polymers. Our efforts have focused on using conductive polymers based on poly(phenylene vinylene)s. Synthetic strategies for the synthesis of poly(bis-(N,N,d i a l k y l a m i n o ) p h e n y l e n e vinylene)s, developed b y N A W C W D , have been p r e v i o u s l y reported (6). One o f these materials, p o l y ( b i s - ( N - m e t h y l - N hexylamino)phenylenevinylene) ( B A M P P V ) , has shown promise as a corrosion inhibiting coating on 2024 A l T3 aluminum alloy in simulated seawater (7-11). Q u a n t i t a t i v e evidence was obtained f r o m these i n i t i a l studies u s i n g potentiostatic and galvanostatic techniques (12-14). The polymers were prepared via a seven-step synthesis w i t h overall yields between 10-20% (Scheme I ) . The current paper w i l l examine current attempts to reduce the number o f synthetic steps and increase the overall yield. In addition to the time and cost o f materials for the 7-step synthesis o f B A M P P V , there is also the issue o f the quantity and type o f waste produced from each o f the respective steps. The reduction o f waste materials generated from the synthesis o f B A M P P V was accomplished by m o d i f y i n g the 7-step synthesis (Scheme I I ) and developing t w o alternative m e t h o d s f o r the p r o d u c t i o n o f p o l y ( b i s - ( N - m e t h y l - N - h e x y l a m i n o ) phenylenevinylene). Each o f these methods can reduce cost and waste generation. Additionally, this paper w i l l present new data regarding the physical and corrosion properties o f B A M P P V . Immersion tests using simulated seawater and neutral ( p H = 7.0) salt-fog experiments are presented.
Experimental Materials and Methods D i m e t h y l l,4-cyclohexanedione-2,5-dicarboxylate was purchased from Acros Chemical and used as received. A l l other chemicals were purchased from A l d r i c h Chemical and used as received. Bruker Instruments 200 M H z N M R ( f o r monomers and intermediates) and 400 M H z N M R ( f o r p o l y m e r s )
Zarras et al.; Electroactive Polymers for Corrosion Control ACS Symposium Series; American Chemical Society: Washington, DC, 2003.
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