Introducing cyano-functionalized multiwalled carbon nanotubes to improve corrosion resistance and mechanical performance of poly(arylene ether nitrile) coating
Graphical abstract
The well-dispersed MWCNT-CN fillers are successfully fabricated through the decomposition of AIBN, which significantly enhances the corrosion resistance and mechanical performance of PEN coating.
Introduction
In contemporary society, industries are regarded as the cornerstone to enormously promote the economic development [1]. To support rapid development of the industries such as petrochemicals, agriculture, automobiles and ships worldwide, metallic facilities are widely used due to their numerous merits [2], [3], [4]. Nonetheless, the frustrating fact is that metals are eroded inevitably by corrosive substances including O2, H2O and ions as the service life extends, leading to the nasty industrial accidents and countless property losses [5], [6]. Thus, seeking for effective and practical approaches to prevent or retard the occurrence of metal corrosion is of vital importance.
Polymer coatings are deemed as one of the most effective and convenient methods to protect metal substrates against complex corrosive environment [7], [8]. Recently, epoxy coatings stand out as corrosion protection from numerous alternative polymer coatings, benefitting from its advantages such as great chemical resistance to severe condition, satisfying mechanical performance, strong adhesion to substrates and fair price [9], [10], [11], [12]. However, the existence of polar epoxide groups in epoxy resins would strongly interact towards water and other organic solvents, which expedites the adsorption process of corrosive solution [13]. Furthermore, micro porosities and cavities are inevitably formed in epoxy coating structure through the curing process. Under this circumstance, the adsorbed corrosive solutions could penetrate to the metal substrates more conveniently through these micro channels, descending the permeability of epoxy system [14]. As the consequence, the epoxy coatings suffer from rapid decline in barrier and mechanical performance with a short exposure time to corrosive environment, resulting in undesirable corrosion protection period [15], [16]. Therefore, exploring for durable polymeric coatings with better overall performance has become an urgent goal for researchers to achieve.
To date, an engineering polymer called poly(arylene ether nitrile) (PEN) has arisen increasing interest in extensive fields [17], [18], [19]. Ascribing to its high molecular weight, rigid backbone structure of benzene ring and controllable branch chains, PEN possess preponderances of superior resistance to corrosion and radiation, high endurance to heat as well as outstanding mechanical strength [20], [21], [22]. Further researches proved that with the polar nitrile groups could notably improve the adhesion of PEN with various substrates through interaction between nitrile and other chemical groups. Additionally, nitrile groups can also act as extra crosslinking site to generate denser structure [23], [24]. Inspired by the characteristics, it's speculated that PEN can be applied as a promising polymer barrier coating to protect metals against harsh corrosion condition.
As is shown by previous reports, the nanofillers can serve as ebullient candidates to reinforce the mechanical and barrier properties of polymer coatings ulteriorly [25], [26], [27], [28], [29]. Among various available nanofillers, multiwalled carbon nanotubes (MWCNTs) trigger intense attention in strengthening polymer coatings' mechanical and corrosion properties, because of its unique characteristic including great chemical resistance, ultrahigh aspect ratio and mechanical stability [30], [31], [32]. However, MWCNTs show chemical inertness and will restack in a short dispersion period within solution and coating matrix via π-π interaction and Van der Waals force [33], [34]. This unsatisfactory compatibility between MWCNTs and PEN matrix would eventually lead to the decline of barrier effect and corrosion resistant properties. As a countermeasure, covalent surface modification methods provide an efficient approach to ameliorate the chemical inertness of MWCNTs [35]. With polar functional groups attached to the surface of MWCNTs, the dispersibility and the compatibility with organic polymer coatings could be improved prominently, which may dramatically expand the application prospects of MWCNTs [36]. For example, Zhong et.al [37] functionalized multiwalled carbon nanotube (MWNT) with acylate groups through different in situ polymerization methods, providing better dispersibility and interfacial compatibility between MWNT and PEN resin. The results firmly confirmed that the acylate functionalized MWNT distinctly enhanced the mechanical performance and thermal resistance of PEN films. However, no research explored the corrosion mitigation of PEN coating containing cyanogen functionalized multiwalled carbon nanotubes.
In this work, through the decomposition of azodiisobutyronitrile (AIBN), carbon radicals containing cyano groups were covalently grafted onto MWCNTs to give cyano-functionalized multi-walled carbon nanotubes (MWCNTs-CN). Compared with the original MWCNTs, the cyano groups attached to MWCNTs-CN improves the interface compatibility between MWCNTs-CN and PEN, and can be cross-linked with phthalonitrile group in PEN matrix under thermal treatment to obtain a denser structure. As the result, corrosion protection properties and mechanical strength of PEN composite coatings gain prominent improvement. Besides, the enhanced corrosion mitigation mechanism was probed in detail.
Section snippets
Materials
2,6-Dichlorobenzonitrile (DCBN), 4-nitrophthalonitrile (4-NPh) were obtained from Heowns Biochem Co. Ltd. with technical grade and used without any purification. Hydroquinone (HQ, 99%) were purchased from Tianjin Bodi Chemical Co. Ltd. Azodiisobutyronitrile (AIBN) and biphenyl (BP, 99.5%) were obtained from Sigma-Aldrich. Multiwalled carbon nanotubes (MWCNTs, diameter: 3–15 nm, length: 1–15 μm) was purchased from Shenzhen Suiheng Technology Co. Ltd. N-methylpyrrolidone (NMP, 99%), dimethyl
Characterization of PEN
The 1H NMR spectrum of PEN was illustrated in Fig. 4. It could be observed that the peaks of all chemical shifts (δ) ranged from 6.5 ppm to 8.0 ppm, identifying that all hydrogens were attached on the benzene rings. The signals centered at δ of 7.24 ppm, 7.42 ppm and 7.73 ppm were attributed to the typical absorption peaks of three different hydrogens on the phthalonitrile groups. Due to the fact that phthalonitrile groups were merely used as capping group, the intensity of these signals was
Conclusion
In conclusion, MWCNT fillers were functionalized with cyano groups through free radical fragments generated from decomposition of AIBN to successfully fabricating MWCNTs-CN. Then neat PEN coating, MWCNTs/PEN coating and MWCNTs-CN/PEN coating were prepared, respectively. After introduction of MWCNTs-CN, the corresponding coating and composite film showed remarkable improvement in impact resistance and tensile strength. From EIS measurement and neutral salt spray test, MWCNTs-CN was demonstrated
CRediT authorship contribution statement
Yunqing Xia: Conceptualization, Investigation, Validation, Writing - original draft, Writing - review & editing, Formal analysis. Yi He, Xiaobo Liu: Supervision, Conceptualization, Funding acquisition, Methodology, Writing - review & editing. Lifen Tong, Guo Lin, Zhongxiang Bai: Validation, Investigation, Formal analysis, Resources. Shuai Zhang: Writing - review & editing. Shuning Liu: Data curation, Formal analysis.
Declaration of competing interest
We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work.
Acknowledgments
This work was financially supported by the National Natural Science Foundation of China (52073039, 51773028, 51903029, 21805027 and 51803020), International Science and Technology Cooperation Project (52011530027), the Fundamental Research Funds for the Central Universities (ZYGX2019J026), Major Special Projects of Sichuan Province (2020YFG0270, 2020ZDZX0020, 2019ZDZX0027 and 2019ZDZX0016), and Sichuan Science and Technology Program (2019YJ0197, 2020YFG0100, and 2019YFG0056).
References (69)
The experimental and innovative research on usability of Sulphur polymer composite for corrosion protection of reinforcing steel and concrete
Compos. Part B
(2011)- et al.
Sol–gel coatings on metals for corrosion protection
Prog. Org. Coat.
(2009) - et al.
Corrosion protection by organic coatings: electrochemical mechanism and novel methods of investigation
Electrochim. Acta
(2000) - et al.
Excellent corrosion protection performance of epoxy composite coatings filled with amino-silane functionalized graphene oxide
Surf. Coat. Technol.
(2017) - et al.
Thermal stability and water uptake of high performance epoxy layered silicate nanocomposites
Eur. Polym. J.
(2004) - et al.
A facile route of making silica nanoparticles-covered graphene oxide nanohybrids (SiO2-GO); fabrication of SiO2-GO/epoxy composite coating with superior barrier and corrosion protection performance
Chem. Eng. J.
(2016) - et al.
Corrosion performance of epoxy coatings containing silane treated ZrO2 nanoparticles on mild steel in 3.5% NaCl solution
Corros. Sci.
(2011) - et al.
Multiblock poly(arylene ether nitrile) disulfonated poly(arylene ether sulfone) copolymers for proton exchange membranes: part 2 electrochemical and H2/air fuel cell analysis
Polymer
(2017) - et al.
Thermally and chemically stable poly(arylene ether nitrile)/halloysite nanotubes intercalated graphene oxide nanofibrous composite membranes for highly efficient oil/water emulsion separation in harsh environment
J. Membr. Sci.
(2018) - et al.
Novel phthalonitrile-terminated polyarylene ether nitrile with high glass transition temperature and enhanced thermal stability
Mater. Lett.
(2014)
Covalently-grafted graphene oxide nanosheets to improve barrier and corrosion protection properties of polyurethane coatings
Carbon
Functional and smart coatings for corrosion protection: a review of recent advances
Surf. Coat. Technol.
Grafting of epoxy chains onto graphene oxide for epoxy composites with improved mechanical and thermal properties
Carbon
Corrosion protection by epoxy coating containing multi-walled carbon nanotubes
J. Ind. Eng. Chem.
Carbon nanotube-reinforced siloxane-PMMA hybrid coatings with high corrosion resistance
Prog. Org. Coat.
Fabrication and mechanical properties of well-dispersed multiwalled carbon nanotubes/epoxy composites
Compos. Sci. Technol.
Non-covalent functionalized multi-wall carbon nanotubes filled epoxy composites: effect on corrosion protection and tribological performance
Surf. Coat. Technol.
Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: a review
Compos. A: Appl. Sci. Manuf.
Dispersion and alignment of carbon nanotubes in polymer matrix: a review
Mater. Sci. Eng. R. Rep.
Multiple spectroscopic studies on the interaction of BSA with pristine CNTs and their toxicity against Donax faba
J. Lumin.
Formation of honeycomb like pores in GO-CN/PAN composite membrane
Mater. Lett.
Tuning the interfacial property of hierarchical composites by changing the grafting density of carbon nanotube using 1,3-propodiamine
Compos. Sci. Technol.
Surface and structural characterization of multi-walled carbon nanotubes following different oxidative treatments
Carbon
Surface modifications for the effective dispersion of carbon nanotubes in solvents and polymers
Carbon
Mechanical properties of epoxy composites filled with silane-functionalized graphene oxide
Compos. A: Appl. Sci. Manuf.
Polymer grafted reduced graphene oxide sheets for improving stress transfer in polymer composites
Compos. Sci. Technol.
Synergetic effects of graphene platelets and carbon nanotubes on the mechanical and thermal properties of epoxy composites
Carbon
Effects of moisture absorption and surface modification using 3-aminopropyltriethoxysilane on the tensile and fracture characteristics of MWCNT/epoxy nanocomposites
Appl. Surf. Sci.
Effect of fluorination on the mechanical behavior and electromagnetic interference shielding of MWCNT/epoxy composites
Appl. Surf. Sci.
Application of the Mott-schottky model to select potentials for EIS studies on electrodes for electrochemical charge storage
Electrochim. Acta
EIS study of corrosion behaviour of organic coating/Dacromet composite systems
Electrochim. Acta
Another approach in analysis of paint coatings with EIS measurement: phase angle at high frequencies
Corros. Sci.
Effects of carbon nanotube content on adhesion strength and wear and corrosion resistance of epoxy composite coatings on AA2024-T3
Prog. Org. Coat.
Zinc-doped silica/polyaniline core/shell nanoparticles towards corrosion protection epoxy nanocomposite coatings
Compos. Part B
Cited by (12)
Multifunctional graphitic carbon nitride/manganese dioxide/epoxy nanocomposite coating on steel for enhanced anticorrosion, flame retardant, mechanical, and hydrophobic properties
2024, Journal of Industrial and Engineering ChemistryElectrochemical deposition multi-walled carbon nanotube coatings on the surface of Ti6Al4V alloy for enhancing its biotribological properties
2023, Journal of the Mechanical Behavior of Biomedical MaterialsEffect of thermal stretching on properties of poly (arylene ether nitrile)/aramid staple fiber composites
2023, Journal of Applied Polymer Science