A simple strategy to significantly improve the anticorrosion and aging resistance of epoxy coatings by adding polyaniline modified multi-walled carbon nanotubes

IF 6.3 2区化学 Q1 POLYMER SCIENCE Polymer Degradation and Stability Pub Date : 2024-10-08 DOI:10.1016/j.polymdegradstab.2024.111027

Yijian Gao , Shasha He , Jinyi Hu , Chonggang Wu , Zhenyu Chen , Hongyu Cen

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Abstract

Epoxy coatings are widely used for corrosion protection of metals, but under extremely harsh environments, the epoxy polymer chains such as the CO bonds of epoxy ether and aromatic ether, and the -OH in the epoxy chain structure can also undergo aging and degradation, leading to the failure of the coating in service. How to extend the anti-aging capability of epoxy resins while maintaining their other properties unchanged has become a major challenge in the practical application of epoxy coatings. In this study, the polyaniline (PANI) modified multi-walled carbon nanotubes (MWCNT@PANI) were synthesized by polymerization in-situ and added to epoxy resin as an anti-aging filler. The various measurements have been adopted to characterize the composition and structure of MWCNT@PANI, and the anticorrosive performance of the composite coating for carbon steel were evaluated via salt spray, chemical aging and UV light aging. Results showed that the impedance value of the blank epoxy coating decreases by at least two orders of magnitude after the salt spray tests, and the contact angle decreases by about 30° and gradually changes from hydrophobic to hydrophilic, indicating a significant decline in corrosion resistance. In contrast, the composite coating confirmed the excellent anti-aging performance, while the impedance values increased by approximately 2–5 orders of magnitude compared to that in blank epoxy coatings, and remained around 10¹⁰ Ω·cm². Given the dense encapsulation of MWCNT@PANI, the dispersion stability between the filler and EP can be improved, and the effective corrosion resistance performance was also supported by molecular dynamic simulation. Besides that, the ability of free radical quenching along with the labyrinth effect and hydrophobic interaction have also been investigated to explain the anticorrosion and anti-aging mechanism.

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通过添加聚苯胺改性多壁碳纳米管大幅提高环氧涂料防腐和抗老化性能的简单策略

环氧涂料被广泛应用于金属防腐，但在极端恶劣的环境下，环氧聚合物链，如环氧醚和芳香醚的 CO 键以及环氧链结构中的 -OH 也会发生老化和降解，导致涂层在使用中失效。如何在保持环氧树脂其他性能不变的情况下延长其抗老化能力，已成为环氧涂料实际应用中的一大难题。本研究采用原位聚合法合成了聚苯胺（PANI）改性多壁碳纳米管（MWCNT@PANI），并将其添加到环氧树脂中作为抗老化填料。采用多种测量方法表征了 MWCNT@PANI 的组成和结构，并通过盐雾、化学老化和紫外光老化评估了碳钢复合涂层的防腐性能。结果表明，盐雾试验后，空白环氧涂层的阻抗值至少下降了两个数量级，接触角下降了约 30°，并逐渐从疏水变为亲水，表明耐腐蚀性能显著下降。相比之下，复合涂层证实了其优异的抗老化性能，而阻抗值则比空白环氧涂层增加了约 2-5 个数量级，并保持在 1010 Ω-cm2 左右。鉴于 MWCNT@PANI 的致密包覆，填料与 EP 之间的分散稳定性得以提高，分子动力学模拟也支持其有效的耐腐蚀性能。此外，还研究了自由基淬灭能力以及迷宫效应和疏水相互作用，以解释其防腐和抗老化机理。

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来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

期刊介绍： Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology. Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal. However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.