{"title":"Long-lasting anti-corrosion of waterborne epoxy resin synergistic modified with g-C3N4 and pH-responsive polypyrrole nanotubes","authors":"","doi":"10.1016/j.porgcoat.2024.108808","DOIUrl":null,"url":null,"abstract":"<div><div>A self-healing coating containing g-C<sub>3</sub>N<sub>4</sub>-PPynts(BTA)@PDA (CPBP) hybrids was developed to inhibit corrosion in steel. Lamellar g-C<sub>3</sub>N<sub>4</sub> and polypyrrole nanotubes were synthesized through direct pyrolysis and the methyl orange-iron chloride reactive self-degradation template method, respectively. Subsequently, benzotriazole (BTA) was incorporated into PPy nanotubes (PPynts) using the vacuum negative pressure technique. PDA (polydopamine) was then polymerized on the nanotube surface acting as a ‘gatekeeper’. Finally, g-C<sub>3</sub>N<sub>4</sub>-PPynts(BTA)@PDA hybrids were formed by attaching PPynts(BTA)@PDA(PBP) nanocontainers to g-C<sub>3</sub>N<sub>4</sub> nanosheets. The synthesized polypyrrole nanotubes exhibited superior loading capacity because of their larger size and could release encapsulated inhibitors in response to pH changes in the microenvironment. In addition, the variations in |Z|<sub>0.01Hz</sub> values of CPBP/WEC after 40 days of immersion in 3.5 wt% NaCl solution were evaluated using the EIS test, and the results showed that the failure time of CPBP/WEC was prolonged by 15 days compared with that of WEC. Moreover, the EIS test results at different pH conditions showed that the |Z|<sub>0.01Hz</sub> values decreased from 2.601 × 10<sup>9</sup> Ω cm<sup>2</sup> to 4.9 × 10<sup>7</sup> Ω cm<sup>2</sup> after 40 days of immersion at pH = 3, and decreased from 3.168 × 10<sup>9</sup> Ω cm<sup>2</sup> to 7.7 × 10<sup>7</sup> Ω cm<sup>2</sup> at pH = 11. The |Z|<sub>0.01 Hz</sub> values were both two orders of magnitude lower compared to pH = 7, but still three orders of magnitude higher than the WEC at pH = 7, which exhibited high impedance values. Meanwhile, CPBP/WEC were found to have significant self-healing properties using EIS analysis of the scratch coatings, salt spray testing, SEM and EDS analysis of the corroded areas. The experimental results indicate that the incorporation of CPBP provides a new method to improve the service life of epoxy resin.</div></div>","PeriodicalId":20834,"journal":{"name":"Progress in Organic Coatings","volume":null,"pages":null},"PeriodicalIF":6.5000,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Progress in Organic Coatings","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0300944024006003","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
A self-healing coating containing g-C3N4-PPynts(BTA)@PDA (CPBP) hybrids was developed to inhibit corrosion in steel. Lamellar g-C3N4 and polypyrrole nanotubes were synthesized through direct pyrolysis and the methyl orange-iron chloride reactive self-degradation template method, respectively. Subsequently, benzotriazole (BTA) was incorporated into PPy nanotubes (PPynts) using the vacuum negative pressure technique. PDA (polydopamine) was then polymerized on the nanotube surface acting as a ‘gatekeeper’. Finally, g-C3N4-PPynts(BTA)@PDA hybrids were formed by attaching PPynts(BTA)@PDA(PBP) nanocontainers to g-C3N4 nanosheets. The synthesized polypyrrole nanotubes exhibited superior loading capacity because of their larger size and could release encapsulated inhibitors in response to pH changes in the microenvironment. In addition, the variations in |Z|0.01Hz values of CPBP/WEC after 40 days of immersion in 3.5 wt% NaCl solution were evaluated using the EIS test, and the results showed that the failure time of CPBP/WEC was prolonged by 15 days compared with that of WEC. Moreover, the EIS test results at different pH conditions showed that the |Z|0.01Hz values decreased from 2.601 × 109 Ω cm2 to 4.9 × 107 Ω cm2 after 40 days of immersion at pH = 3, and decreased from 3.168 × 109 Ω cm2 to 7.7 × 107 Ω cm2 at pH = 11. The |Z|0.01 Hz values were both two orders of magnitude lower compared to pH = 7, but still three orders of magnitude higher than the WEC at pH = 7, which exhibited high impedance values. Meanwhile, CPBP/WEC were found to have significant self-healing properties using EIS analysis of the scratch coatings, salt spray testing, SEM and EDS analysis of the corroded areas. The experimental results indicate that the incorporation of CPBP provides a new method to improve the service life of epoxy resin.
期刊介绍:
The aim of this international journal is to analyse and publicise the progress and current state of knowledge in the field of organic coatings and related materials. The Editors and the Editorial Board members will solicit both review and research papers from academic and industrial scientists who are actively engaged in research and development or, in the case of review papers, have extensive experience in the subject to be reviewed. Unsolicited manuscripts will be accepted if they meet the journal''s requirements. The journal publishes papers dealing with such subjects as:
• Chemical, physical and technological properties of organic coatings and related materials
• Problems and methods of preparation, manufacture and application of these materials
• Performance, testing and analysis.