Cationic Reduced Graphene Oxide as Self-Aligned Nanofiller in the Epoxy Nanocomposite Coating with Excellent Anticorrosive Performance and Its High Antibacterial Activity

Amine functionalised graphene embedded polyvinyl alcohol (PVA) and PVA-chitosan hydrogel composites

A novel amine-functionalized graphene oxide (AFG) doped polyvinyl alcohol (PVA)/chitosan (PVA-Ch) composite film was developed using an eco-synthesis approach, eliminating the need for halogenated compounds. The resulting AFG-doped PVA/Chitosan (PVA-Ch/AFG) polymer film exhibited promising properties for controlled delivery and biosensing applications. The investigation included assessing the swelling behaviour, dissolution percent, gel fraction, and mechanical properties of the polymer film. The swelling characteristics of PVA-Ch and PVA-Ch/AFG were found to be pH and temperature-dependent across various pH ranges (3, 5, 7, and 9). Interestingly, PVA-Ch/AFG demonstrated a stable swelling pattern at pH 5 and 7, unaffected by changes in chitosan concentration, indicating enhanced stability compared to PVA-Ch. The study also explored the use of PVA-Ch/AFG in a drug delivery system, revealing controlled release of the model antibiotic amphicillin, emphasizing its potential in medical applications. Furthermore, the eco-friendly synthesis route underscored the safety of PVA-Ch/AFG for use in food and medical applications. Biocompatibility assessments, including biodegradability studies and cytotoxicity tests on fibroblasts (3T3 cells), confirmed the safety profile of PVA-Ch/AFG. In conclusion, the study suggests that PVA-Ch/AFG holds promise for bio-sensing applications, offering a flexible and colorimetric platform capable of encapsulating, adsorbing, and desorbing biomolecules such as drugs and sensing compounds.

2D Nanomaterials Reinforced Organic Coatings for Marine Corrosion Protection: State of the Art, Challenges, and Future Prospectives

2D nanomaterials, with extraordinary physical and chemical characteristics, have long been regarded as promising nanofillers in organic coatings for marine corrosion protection. The past decade has witnessed the high-speed progress of 2D nanomaterial-reinforced organic composite coatings, and plenty of breakthroughs have been achieved as yet. This review covers an in-depth and all-around outline of the up-to-date advances in 2D nanomaterial-modified organic coatings employed for the marine corrosion protection realm. Starting from a brief introduction to 2D nanomaterials, the preparation strategies and properties are illustrated. Subsequently, diverse protection models based on composite coatings for marine corrosion protection are also introduced, including physical barrier, self-healing, as well as cathodic protection, respectively. Furthermore, computational simulations and critical factors on the corrosion protection properties of composite coatings are clarified in detail. Finally, the remaining challenges and prospects for marine corrosion protection based on 2D nanomaterials reinforced organic coatings are highlighted.

Natural chitosan-based carbon dots as an eco-friendly and effective corrosion inhibitor for mild steel in HCl solution

Polysaccharide chitosan and L-histidine were applied to synthesize chitosan-based carbon dots (CA-CDs) by a simple laser ablation method. After characterization of the CA-CDs by FT-IR, UV-vis, Raman, XRD, TEM, and XPS, the CA-CDs were introduced as an eco-friendly and high-performance corrosion inhibitor for mild steel (MS) in 1.0 M HCl solution. The inhibition action and mechanism of CA-CDs were determined by weight loss and electrochemical measurements, in combination with SEM, AFM, and XPS. The results show that CA-CDs as mixed-type inhibitors could effectively weaken the corrosion of MS in 1.0 M HCl solution, and their maximum inhibition efficiency reaches 97.4 % at 40 mg L-1. The adsorption behavior of CA-CDs well obeys the Langmuir adsorption isotherm containing both chemisorption and physisorption. The chemisorption mainly results from the multiple adsorption sites in the CA-CDs, and the physical adsorption is due to the blocking and barrier effect of CA-CD nanoparticles. Both adsorption behaviors were proposed to elucidate the corrosion inhibition mechanism of CA-CDs.

Functional Polymer Nanocomposites with Increased Anticorrosion Properties and Wear Resistance for Water Transport

Corrosive destruction and hydroabrasive wear is a serious problem in the operation of machine parts and water transport mechanisms. It is promising to develop new composite materials with improved properties to increase the reliability of transport vehicles. In this regard, the use of new polymer-based materials, which are characterized by improved anticorrosion properties and wear resistance, is promising. In this work, therefore, for the formation of multifunctional protective coatings, epoxy dian oligomer brand ED-20, polyethylene polyamine (PEPA) hardener, a mixture of nanodispersed compounds with a dispersion of 30-90 nm, fillers Agocel S-2000 and Waltrop with a dispersion of 8-12 μm, and particles of iron slag with a dispersion of 60-63 μm are used for the formation of multifunctional protective coatings. Using the method of mathematically planning the experiment, the content of additives of different physico-chemical natures in the epoxy binder is optimized to obtain fireproof coatings with improved operational characteristics. A mathematical model is developed for optimizing the content of components in the formation of protective anticorrosion and wear-resistant coatings for means of transport as a result of the complex effect of a mixture of nanodispersed compounds, iron scale, and Waltrop. Based on the mathematical planning of the experiment, new regularities of increasing the corrosion resistance and resources of the means of transport are established through the formation of four different protective coatings, which are tested for resistance to aggressive environments (technical water-CAS No. 7732-18-5, gasoline-CAS No. 64742-82-1, acetone-CAS No. 67-64-1, I-20A lubricant-CAS No. 64742-62-7, sodium solutions-CAS No. 1310-73-2, and sulfuric acid-CAS No. 7664-93-9) and hydroabrasive wear resistances. A study of the change in the permeability index in aggressive environments is additionally carried out, taking into account the rational ratio of dispersive fillers in the epoxy binder, which made it possible to create an effective barrier to the penetration of aggressive water molecules into the base. A decrease in the permeability of protective coatings by 2.0-3.3 times relative to the epoxy matrix is achieved. In addition, the wear resistance of the developed materials under the action of hydroabrasion is investigated. The relative resistance of the CM to the action of hydroabrasion was found by the method of materials and coatings testing on the gas-abrasive wear with a centrifugal accelerator. This method enables one to model the real process of the wear of mechanism parts under the hydroabrasive action. It is shown that the coefficient of the wear resistance of the developed materials is 1.3 times higher than that of the polymer matrix, which indicates the resistance of the composites to the influence of hydroabrasive environment. As a result, modified epoxy composite protective coatings with improved anticorrosion properties and wear resistance under hydroabrasive conditions are developed. It is established that the protective coating filled with particles of a mixture of nanodispersed compounds (30-90 nm), iron scale (60-63 μm), and Waltrop (8-12 μm) has the lowest permeability indicators. The permeability in natural conditions of such a coating during the time t = 300 days of the study is χ = 0.5%, which is 3.6 times less than the similar indicators of the epoxy matrix. It is substantiated that the protective coating filled with particles of a mixture of nanodispersed compounds (30-90 nm), iron scale (60-63 μm), and Agocel S-2000 (8-12 μm) is characterized by the highest indicators of wear resistance. The coefficient of wear resistance under the action of hydroabrasion of such a coating is K = 1.75, which is 1.3 times higher than the similar indicators of the original epoxy matrix.

Highly Orientated Sericite Nanosheets in Epoxy Coating for Excellent Corrosion Protection of AZ31B Mg Alloy

The growing demands for material longevity in marine environments necessitate the development of highly efficient, low-cost, and durable corrosion-protective coatings. Although magnesium alloys are widely used in the automotive and aerospace industries, severe corrosion issues still hinder their long-term service in naval architecture. In the present work, an epoxy composite coating containing sericite nanosheets is prepared on the AZ31B Mg alloy using a one-step electrophoretic deposition method to improve corrosion resistance. Due to the polyetherimide (PEI) modification, positively charged sericite nanosheets can be highly orientated in an epoxy coating under the influence of an electric field. The sericite-incorporated epoxy coating prepared in the emulsion with 4 wt.% sericite exhibits the highest corrosion resistance, with its corrosion current density being 6 orders of magnitude lower than that of the substrate. Electrochemical measurements and immersion tests showed that the highly orientated sericite nanosheets in the epoxy coating have an excellent barrier effect against corrosive media, thus significantly improving the long-term anti-corrosion performance of the epoxy coating. This work provides new insight into the design of lamellar filler/epoxy coatings with superior anticorrosion performance and shows promise in the corrosion protection of magnesium alloys.

Dopamine modified natural glucomannan as a highly efficient inhibitor for mild steel: Experimental and theoretical methods

In this work, Glucomannan was modified with dopamine to synthesize a new polysaccharide Schiff base (GAD). After confirmation of GAD by NMR and FT-IR spectroscopic methods, it was introduced as a sustainable corrosion inhibitor with excellent anti-corrosion action for mild steel in 0.5 M hydrochloric acid (HCl) solution. Employing electrochemical test, morphology measurement, and theoretical analysis, the anticorrosion performance of GAD on mild steel in 0.5 M HCl solution is determined. Maximum efficiency of GAD for suppressing the corrosion rate of mild steel at 0.12 g L^-1 reaches 99.0 %. After immersion in HCl solution for 24 h, the results from scanning electron microscopy indicate that GAD is firmly attached to the mild steel surface by making a protective layer. According to the X-ray photoelectron spectroscopy (XPS), FeN bonds existed on the steel surface indicate the presence of chemisorption between GAD and Fe to form stable complexes attracted to the active position on the mild steel. The effects of Schiff base groups on the corrosion inhibition efficiencies were also investigated. Moreover, the inhibition mechanism of GAD was further illustrated by the free Gibbs energy, quantum chemical calculation and molecular dynamics simulation.

High-compact MXene-based coatings by controllable interfacial structures

Titanium carbide (Ti₃C₂T_x) MXenes have been regarded as important functional fillers of organic coatings for anticorrosion. Various MXene-based composite coatings have been fabricated and investigated via a material modification strategy, enhancing the corrosion protection performance. However, the anticorrosion reliabilities of MXene-based composite coatings were thwarted by their disordered interfaces. Significantly, few reports discuss the influence of interface structures on the protection performance for the coatings. In this work, we confirm the exceptional anticorrosion performance of ordered MXene/epoxy composite (OMC) coatings via a reasonable interface strategy. The ordered interfacial structure can synergistically enhance the coating compactness while maximizing the infiltration paths of aggressive species. The obtained OMC coating is compact and shows a high impedance of 6.84 × 10⁹ Ohm cm², a high coating resistance of 6.08 × 10⁹ Ohm cm², an extremely low porosity of 0.77% and an extremely low breakpoint frequency of 0.18 Hz, at a low filler content of 0.5 wt%. Besides, the concept of specific impedance (SZ) is proposed to attest the superiority of the OMC coating. Furthermore, the galvanic corrosion effects of MXenes in epoxy coatings are systematically explored and confirmed for the first time. The highly ordered structure eliminates the corrosion promotion activity of the conductive MXene, and thus, endows the superior anticorrosion stability for the coating. This work provides an inspiration for constructing outstanding long-term MXene-based anticorrosion coatings via regulating the coating interface.

A review on antimicrobial mechanism and applications of graphene-based materials

In recent years, graphene and its derivatives, owing to their phenomenal surface, and mechanical, electrical, and chemical properties, have emerged as advantageous materials, especially in terms of their potential for antimicrobial applications. Particularly important among graphene's derivatives is graphene oxide (GO) due to the ease with which its surface can be modified, as well as the oxidative and membrane stress that it exerts on microbes. This review encapsulates all aspects regarding the functionalization of graphene-based materials (GBMs) into composites that are highly potent against bacterial, viral, and fungal activities. Governing factors, such as lateral size (LS), number of graphene layers, solvent and GBMs' concentration, microbial shape and size, aggregation ability of GBMs, and especially the mechanisms of interaction between composites and microbes are discussed in detail. The current and potential applications of these antimicrobial materials, especially in dentistry, osseointegration, and food packaging, have been described. This knowledge can further drive research that aims to look for the most suitable components for antimicrobial composites. The need for antimicrobial materials has seldom been more felt than during the COVID-19 pandemic, which has also been highlighted here. Possible future research areas include the exploration of GBMs' ability against algae.

In-Situ Catalytic Preparation of Two-Dimensional BCN/Graphene Composite for Anti-Corrosion Application

In-situ catalytic growth of two-dimensional materials shows great potential for metal surface protection because of the impermeability and strong interaction of the materials with metal surfaces. Two-dimensional hexagonal boron-carbon nitrogen (h-BCN) is composed of alternating boron, carbon, and nitrogen atoms in a two-dimensional honeycomb lattice, which is similar to graphene. The corrosion caused by defects such as grain boundary of two-dimensional materials can be weakened by dislocation overlap via the transfer method. However, two-dimensional composite films prepared using the transfer method have problems, such as the introduction of impurities and poor adhesion, which limit their corrosion resistance. In this study, a layer of BCN/Gr two-dimensional composite was directly grown on the surface of copper foil using the CVD in-situ catalysis method, and its anti-corrosion performance was characterized by electrochemical and salt spray experiments. The results showed that the directly grown two-dimensional composite had better adhesion to the substrate and the advantage of grain boundary dislocation, thus showing a better anti-corrosion capability.

Synergistically assembled graphene/ZnO composite to enhance anticorrosion performance of waterborne epoxy coatings

In this work, waterborne epoxy resin and graphene/ZnO (Gr/ZnO) were employed as the matrix and nanofiller to construct composite coatings with enhanced anticorrosive performance. The corrosion protection properties of the coatings were significantly improved by the dispersed Gr sheets, as well as the parallelly assembled ZnO nanoparticles. The most remarkable improvement was achieved by adding 0.04 wt% of Gr and 0.4 wt% of ZnO in the Waterborne Epoxy (WEP) coatings, where the highest impedance was 200 530 Ω cm² on Gr_0.04-ZnO_0.4, far more than pure epoxy with 6186 Ω cm² after 7 days of immersion in electrolytes. Furthermore, the Gr_0.04-ZnO_0.4 coatings and corresponding corrosion products immersed in a 3.5% NaCl solution for 30 days were also characterized, which could further reveal anticorrosion mechanisms of the graphene modified WEP coatings and the passivated effect of ZnO. Through the mechanism analysis, we also found that ZnO could be employed as the barrier reinforcement to improve the dispersibility of graphene in WEP coatings, and the parallel assembly of graphene occurs spontaneously, leading to remarkable improvement of anticorrosion properties.

Effect on the Surface Anticorrosion and Corrosion Protection Mechanism of Integrated Rust Conversion Coating for Enhanced Corrosion Protection

Here, a series of integrated rust conversion agents/coatings were synthesized by esterification reaction of 3,4,5-trihydroxybenzoic acid (GA) and triethanolamine (TE). The structural features, rust conversion ability, and corrosion resistance of the synthesized rust conversion agents/coatings were analyzed using the Fourier transform infrared tests, scanning electron microscopy tests, X-ray diffraction tests, and electrochemical measurements. It was found that when the mass ratio of TE and GA was 2:1, the synthesized rust conversion agent/coating has best rust conversion ability and anti-corrosion performance (i.e., corrosion current density 7.480 × 10^-7 A/cm²). In addition, different from the traditional coatings, the integrated rust conversion coating developed in this study combines the primer and topcoat of traditional coatings into one, which can significantly increase the on-site construction efficiency. Furthermore, a new rust conversion mechanism for the optimized rust conversion agent/coating was proposed. The phenolic hydroxyl functional groups in the rust conversion agent can well chelate with Fe²⁺/Fe³⁺ in the original rust layer and then form macromolecular compounds and dense chelating films inside the coating, which tightly wraps rust and also prevents the penetration and diffusion of corrosive medium, making them lose the opportunity to interact with each other.

Green modification of graphene dispersion with high nanosheet content, good dispersibility, and long storage stability

In this work, an easy, green, noncovalent surface modification of pristine graphene (GR) was carried out using a single-step method between sodium carboxymethyl cellulose (CMC) and pristine GR, resulting in the formation of a modified CMC-GR (CGR) dispersion with 15% nanosheet content, the first reported in water. Results obtained from thermogravimetry analysis (TGA), Raman spectroscopy, and atomic force microscopy (AFM) confirm that the CMC modifier is successfully decorated on the pristine GR surface. Analyses of transmittance spectrum, zeta potential and transmittance electron microscopy (TEM) images reveal that the modified CGR has a high degree of dispersion. More importantly, the pristine GR is insoluble, while the modified CGR-3, mixed with 1.1 wt% CMC modifier, is easily well dispersed in water and has good flowability, and no sedimentation is observed after more than 3 months.

Enhancement of absorption capacity, optical and non-linear optical properties of graphene oxide nanosheet

We studied the absorption capacity, optoelectronic and non-linear optical (NLO) properties of graphene oxide nanosheet (GON) and its doped derivatives with aluminum (-Al) atoms. The investigations have been performed using three functionals (B3LYP, B3LYP-D3 and ωB97XD) of the density functional theory (DFT) associated to the basis set 6-31+G(d,p). Aluminum atoms were incorporated into GON at different sites in order to search for suitable candidates that could lead to the enhancement of NLO properties and decrease the band gap value of pristine graphene oxide. As per our molecular investigations, several doped molecular design schemes based on push-pull models of GON were proposed. The best electronic and NLO configurations responses highlight the doped derivatives which were obtained by replacement of carbon atoms which support the functional groups present on the honeycomb lattice of GON with -Al atoms.

Influence of fluorinated graphene-modified epoxy coatings on the corrosion behaviour of 2024 aluminium alloy

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix. FG with different fluorine contents was obtained by reacting nitrogen trifluoride (NF₃) gas with GO and then incorporated into the EP matrix to fabricate the different composites. Through a series of characterization methods, the chemical composition and microstructures of FG were systematically analyzed, and its corrosion resistance was also studied. Results revealed that F atoms were bonded to the GO surface to form C–F covalent bonds, and an FG lamellar thickness less than 2 nm. The contact angle of the coatings increased with the incorporation of FG, and the coating resistance of FG2/EP coating was 3 orders of magnitude more than that of the EP coating after immersion for 4080 h. Thus, the incorporation of FG into epoxy matrix significantly enhanced its hydrophobic properties and barrier performance, which was beneficial to improving the long-term corrosion resistance of the coating.

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix.

Nanocomposite Cellulose Fibres Doped with Graphene Oxide and Their Biocidal Properties

The paper presents a method of obtaining composite cellulose fibres (CEL) doped with graphene oxide (GO) and the influence of GO nanoparticles on the structure and properties of the obtained fibres. Composite fibres (GO/CEL) were prepared using wet method from 5% CEL solutions in 1-ethyl-3-methylimidazolium acetate (EMIMAc) containing GO (0; 0.21; 0.50; 0.98; 1.97% w/w) dispersion in N,N-dimethylformamide (DMF). The fibres were coagulated in distilled water and methanol. Optical microscopy allowed us to demonstrate a good degree of GO additive dispersion in the CEL matrix. Surface morphology was examined by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR), which indicated interactions between the matrix and the additive. Strength tests have shown that GO/CEL fibres are characterised by high values of elongation at break (7.7–19.5%) and tenacity (~133–287 [MPa]). The obtained composite fibres are characterized by good biocidal properties against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphilococcus aureus), and fungi Candida albicans, and the resistance to microorganisms depends on the surface zeta potential value and the isoelectric point (IEP) of GO/CEL fibres.

Facile synthesis of Tb-decorated graphene oxide: electrochemical stability, hydrogen storage, and corrosion inhibition of Mg AZ13 alloy in 3.5% NaCl medium

Magnesium alloys have been broadly used due to their lightweight and high ductility. However, they are subject to corrosion which deteriorates their properties. To develop a novel corrosion inhibitor coating for Mg alloys, we performed functionalization of a graphene oxide (GO) matrix with Tb(iii) to improve the electrochemical behaviour and coating stability of a GO and Tb composite on the metal alloys in corrosive medium. The functionalized terbium GO material was characterized by microscopy, spectroscopy, and XRD techniques to confirm the non-covalent interactions on the active surface of the host material. The corrosion inhibition was found to be ca. 80% and electrochemical stability was observed to be high at a voltage of 900 mV. Computational studies also support the potential anti-corrosion applications of this material.

Active anti-corrosion of epoxy coating by nitrite ions intercalated MgAl LDH

Layered double hydroxide (LDH) with NO₂^- intercalation was successfully prepared via acidification oscillation and ion exchange. The nano-fillers were incorporated into the resin to prepare anti-corrosion coatings with the thickness of ca. 50 ± 5 μm. The electrochemical and self-repairing properties of the LDH-doped coatings were studied by EIS and LEIS. Results indicated that the addition of LDH loaded with nitrite induced obvious increased in the impedance of coating (from 4.64 × 10⁸ Ω cm² to 2.14 × 10¹⁰ Ω cm²) and improved the anticorrosion performance of the coating. In addition, the localized corrosion of coatings could be largely inhibited, and the released nitrite ions from LDH interlayers exhibited active anticorrosion functions. When LDH nanosheets were added to the coatings, the lamella structures improved the barrier performances of the coatings. At the same time, the excellent ion exchanges ability of LDH could be used as storage stations for chloride ions, and the release of nitrite ions could play an active anti-corrosion role. Both of them cooperated to synergistically improve the anti-corrosion performance of the coating.

Dispersity control and anti-corrosive performance of graphene oxide modified by functionalized nanosilica in waterborne polyurethane

Graphene oxide (GO) is expected to be used in the field of waterborne polyurethane (WPU) anti-corrosive coatings due to its excellent barrier property, but the poor dispersibility of GO limits its application. The hydrophilic modification of GO, although improving its dispersity, will greatly reduce its anti-corrosive property. Here, a new method is provided to avoid seeking an appropriate modifier blindly. Via the interaction between the epoxy group and amine group, the aminated GO (NGO) can be modified by (3-glycidyloxypropyl) trimethoxysilane (KH560) functionalized-silica (f-SiO₂) nanoparticles, while the f-SiO₂ is affected by KH560 due to its relatively hydrophobic alkyl side chain. Consequently, the hydrophobicity of the f-SiO₂ modified NGO (f-SGO) can be regulated just by adjusting the amount of KH560, thereby achieving the balance of excellent dispersibility and anti-corrosive performance of the f-SGO nanosheets in the WPU. The electrochemical impedance and potentiodynamic polarization results showed that the anti-corrosive performance of the WPU hybrid was greatly improved by adding the appropriate amount of f-SGO. This research provides a new idea for GO application in waterborne coatings.

The sandwich-like structures of polydopamine and 8-hydroxyquinoline coated graphene oxide for excellent corrosion resistance of epoxy coatings

A novel sandwich-like structure material was exploited for the fabrication of an effective corrosion resistance system. An environmentally friendly composite material was synthesized by installing 8-hydroxyquinoline (8-HQ) on the surface of graphene oxide (GO). In order to prevent leakage of corrosion inhibitor 8-HQ, GO/8-HQ was modified by polydopamine (PDA), denoted as GO/8-HQ/PDA. A sandwich-like structure (GO/8-HQ/PDA) enables long-term stable storage of corrosion inhibitor in the protective matrix. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were utilized to verify the sandwich-like structure of GO/8-HQ/PDA. The electrochemical tests in a 3.5 wt% NaCl solution showed that the addition of well-dispersed GO/8-HQ/PDA into epoxy system (GO/8-HQ/PDA-EP) remarkably improved corrosion protection of AZ31b magnesium alloy compared with pure epoxy (EP) coating. The sandwich structure protects the activity and structural integrity of the corrosion inhibitor (8-HQ). The corrosion inhibitor (8-HQ) of the GO/8-HQ/PDA sandwich structure cuts off the ion exchange between the metal alloy and the electrolyte solution, which hinders the electrochemical corrosion of the metal. A possible corrosion resistance mechanism of GO/8-HQ/PDA is fully discussed. This study provides feasibilities for the immobilization of corrosion inhibitors on the metal surface.

Improvement of Corrosion Resistance of Waterborne Polyurethane Coatings by Covalent and Noncovalent Grafted Graphene Oxide Nanosheets

The amphiphilic graphene derivative was prepared by covalent grafting of graphene oxide (GO) with isophorone diisocyanate and N,N-dimethylethanolamine and then noncovalent grafting of GO with sodium dodecylbenzenesulfonate. The results obtained from infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis, and X-ray diffraction analysis revealed that the short chains were successfully grafted onto the surface of GO. Subsequently, scanning electron microscopy and optical microscopy results showed that the modified GO (IP-GO) has the best dispersibility and compatibility than GO and reduced GO in the waterborne polyurethane matrix. The relationship between the corrosion resistance of composite coatings and the dispersibility of the graphene derivative and the compatibility of the graphene derivative with a polymer matrix were discussed. The anticorrosive properties were characterized by electrochemical impedance spectroscopy analysis and salt spray tests. Through a series of anticorrosion tests, it is concluded that the anticorrosion performance of a composite coating with 0.3 wt % IP-GO is significantly improved. The excellent anticorrosion performance is due to the perfect dispersion and good compatibility of IP-GO in waterborne polyurethane.

Reduced Graphene Oxide–Epoxy Grafted Poly(Styrene-Co-Acrylate) Composites for Corrosion Protection of Mild Steel

Reduced graphene oxide–epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through π–π electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 × 10−1 to 1.394 × 10−6 mm/a.

Improvement of self-cleaning waterborne polyurethane-acrylate with cationic TiO2/reduced graphene oxide

UV curable waterborne polyurethane acrylate (WPUA) with surfactant-modified TiO2/reduced graphene oxide (TiO2/rGO) nanocomposites were prepared and analyzed to improve their mechanical performance and self-cleaning ability. TiO2/rGO nanocomposites were prepared by a simple hydrothermal method with nano-TiO2 and graphene oxide, and modified with cationic surfactant (CTAB) to obtain a cationic TiO2/rGO (C-TiO2/rGO). Then, the obtained C-TiO2/rGO was incorporated into anionic waterborne polyurethane acrylate by in situ fabrication to obtain a composite emulsion (C-TiO2/rGO-WPUA). The results of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) showed that CTAB was successfully intercalated into TiO2/rGO, and TiO2 nanoparticles were evenly distributed on graphene sheets with good dispersibility. Compared to UV-cured neat WPUA and C-TiO2/rGO-WPUA, the mechanical properties and thermal stability of the composites were significantly improved. When the content of C-TiO2/rGO was 0.5%, the UV-cured composites had overall excellent performance. In particular, the WPUA composites exhibited good self-cleaning ability in photocatalysis. The photocatalytic degradation rate of methyl orange in 0.5% C-TiO2/rGO-WPUA reached 88.3% under 6 h visible light irradiation.