Preparation Of Modified GO With 8-hydroxyquinoline Terminated Aniline Trimer And Its Application In Anticorrosion Coatings

In the era of marine economy,the rich resources in the ocean attract people to dig and use.However,the harsh marine environment is prone to cause serious corrosion of marine equipment and facilities,which causes great potential safety hazards and huge economic losses.It is urgent to solve the problem of marine corrosion.Among many anticorrosion strategies,anticorrosion coatings are considered to be the most economical and effective means to delay the corrosion of metal materials.At the same time,graphene with the two-dimensional lamellar structure has the ability to block corrosive medium,and can be used as the filler for anticorrosion coatings to improve the anticorrosive performance.However,the stacking form of graphene limits its wide application.In this paper,the 8-hydroxyquinoline terminated aniline trimer was synthesized as a dispersant for graphene oxide.The non-covalently modified graphene oxide exerts a good barrier effect in the coating.Meanwhile,it makes the coatings self-healing in acid environments and improves acid corrosion resistance of the coatings.Our main work is shown as follows:?1?The 8-hydroxyquinoline terminated aniline trimer?QAAT?was synthesized from 8-hydroxyquinoline?8-HQ?and aniline trimer?AT?,and the influences of protic solvent types and reaction time on the yield of QAAT were studied.QAAT and graphene oxide?GO?were ultrasound treated at a dosage of 20:1 to obtain the stable dispersion of GO-QAAT.GO-QAAT was proved to be p H responsive,which laid a foundation for later verification that GO-QAAT could enable self-healing properties of anticorrosion coatings under acid conditions.?2?GO-QAAT was introduced into the epoxy coating system to explore the influence of the dispersion stability of GO-QAAT and the amount of addition in the coating on the performance of the epoxy coating.When the addition amount of GO-QAAT was 0.1%,the epoxy coating had the best anticorrosive performance.Its impedance modulus at 0.01 Hz after 96 h immersion(|Z|_{0.01Hz 96h})could maintain at32.5 k?cm²,and the corrosion current density(I_corr)was only 0.049?A/cm².Compared with other samples,its water contact angle could reach 80.8°,which was the most hydrophobic coating.Meanwhile,it showed excellent flexibility and impact resistance in the impact test.In addition,the epoxy coating with GO-QAAT had self-healing properties in acid environments to improve its acid resistance,which combines the corrosion inhibition of 8-HQ with the"maze effect"of GO.?3?The benzoxazine monomer with silane coupling agents?B-TMOS?was synthesized from 3-aminopropyltrimethoxysilane and bisphenol A.The polybenzoxazine?PB-TMOS?was obtained by heat curing.It had been proved that PB-TMOS had better corrosion resistance than anticorrosive epoxy coatings due to its advantages of compact structure and low surface energy.The|Z|_{0.01Hz 96h}of it was 1order of magnitude higher than that of pure epoxy coating which could reach 243 k?cm²,and I_corrdropped to 0.037?A/cm².Its water contact angle could reach 93.6°and the hydrophobicity was greater than that of pure epoxy coating.Then,GO-QAAT was added to the obtained polybenzoxazine system.It can be found that when the amount of GO-QAAT was 0.1%,the barrier properties of GO-QAAT and the self-healing performance in acid environments made the polybenzoxazine coating have better anticorrosive performance and acid resistance.In addition,GO-QAAT/polybenzoxazine coatings showed good adhesion to the substrate in the adhesion test.