Synthesis and anticorrosive properties of electroactive polyimide/SiO₂ composites

In this study, a series of electroactive polyimide/SiO₂ (EPIS) composite materials containing conjugated segments of electroactive amino‐capped aniline trimer (AT) unit were successfully prepared. First of all, the amino‐modified silica (AMS) particles of ∼100 nm in diameter were synthesized by performing the conventional base‐catalyzed sol–gel reactions. Subsequently, the AMS nanoparticles were blending into the polymerization reactions between AT and 4,4′‐(4,4′‐isopropylidenediphenoxy)‐bis(phthalic anhydride), leading to the formation of EPIS composites. The as‐prepared EPIS materials in the form of coating on cold‐rolled steel (CRS) electrode were found to be much superior in corrosion protection over those of non‐electroactive polyimide and EPI materials based on a series of electrochemical corrosion measurements in saline. The significant enhancement in corrosion protection of EPIS coatings on CRS electrodes might probably be attributed to the redox catalytic property of organic EPI inducing the formation of passive metal oxide layer and the barrier property of well‐dispersed AMS nanoparticles existed in EPI matrix. POLYM. COMPOS., 35:617–625, 2014. © 2013 Society of Plastics Engineers