Waterborne Epoxy Coatings Research Articles

Fabrication of BTA-loaded mesoporous silica-encapsulated ZSM-5 molecular sieve for enhancing anti-corrosion performance of waterborne epoxy coatings

Anti-corrosion coatings have been widely applied to protect metals against corrosion attacks. To improve the corrosive resistance, it is an effective way to employ porous materials loaded with corrosion inhibitors as fillers of coatings. One of the critical challenges is to advance the inhibitor loading capability of porous fillers. In this study, the mesoporous silica encapsulation is introduced on the ZSM-5 molecular sieves through the hydrolysis-condensation of tetraethyl orthosilicate (TEOS), followed by calcinated for removing the residual templates. The porous SiO2@ZSM-5 particles are used as micro-nano containers to load corrosion inhibitor benzotriazole (BTA). The morphologies, structures and BTA releasing behaviors are thoroughly investigated. Subsequently, the as-prepared BTA-SiO2@ZSM-5 particles serve as fillers for waterborne epoxy resin (WER) to fabricate BTA-SiO2@ZSM-5/WER composite coatings with long-term anti-corrosion property. The corrosive resistance behavior and mechanism are emphatically tested and analyzed. The results demonstrate that the introduction of mesoporous silica on the ZSM-5 molecular sieves significantly increases the specific surface area and pore volume, which is highly beneficial for improving the BTA loading capability of fillers as well as the anti-corrosion performance of coatings. Moreover, the great dielectric, mechanical and UV light-shielding properties of the composite coatings are confirmed. This study presents an effective and practical route for fabricating long-term anti-corrosive composite coatings.

High barrier and durable self-healing composite coating: Boron nitride combined with cyclodextrin for enhancing the corrosion protection properties of waterborne epoxy coating

In recent years, a great deal of research has been devoted to designing smart anti-corrosion coatings with diverse self-healing capabilities, effective passive barrier properties, and long-lasting protection. Herein, the tetraethyl orthosilicate (TEOS) was used as a pH response guardian encapsulated on a BTA-loaded β-cyclodextrin (β-CD) nanocavity shells (CD(BTA)@TEOS), which would be ineffective in acidic environments, thus causing the release of BTA. Meanwhile, the polydopamine (PDA) was coated on the hexagonal boron nitride (h-BN) nanosheets (h-BN@PDA) to enhance its dispersibility and provide reactive sites. Further, the h-BN@PDA-CD(BTA)@TEOS (BPCT) hybrids were synthesized by linking CD(BTA)@TEOS nanocavity shells and h-BN@PDA nanosheets through PDA and KH560 as bridging agents. The dispersion of BPCT in waterborne epoxy coating (WEC) can effectively fill the coating defects and prolong the diffusion path of corrosive media, showing excellent barrier properties due to the excellent barrier properties of h-BN@PDA nanosheets against corrosive media. Meanwhile, the excellent self-healing properties of the composite coating under corrosive conditions were mainly derived from the released BTA and stripped PDA in response to pH variation. The corrosion resistance of the composite coating was tested by electrochemical, salt spray tests and microscopic corrosion morphology, and the self-healing properties of the coating were demonstrated by scratch electrochemistry. The expiration time of the BPCT/WEC sample was extended by 15 d, the persistence time in the salt spray test increased by 100 h, and the self-healing properties appeared after 4 h of coating rupture compared to the control WEC. The results proved that the WEC loaded with BPCT nanocontainers had a high barrier effect along with self-healing function and durable corrosion resistance.

Dopamine monomer functionalized Ti3C2 nanosheets and their anticorrosion improvement for waterborne epoxy coatings

MXene is becoming more and more active in the field of anticorrosion coatings. In this work, Ti3C2 nanosheets were modified with dopamine monomer and then introduced into waterborne epoxy coatings (EP). Composite coatings with unmodified Ti3C2 nanosheets were also prepared for comparison. Anticorrosion properties of the coatings were evaluated via electrochemical impedance spectroscopy and salt spray tests in detail. Dopamine monomer was readily attached to Ti3C2 nanosheets via chemical bond and saturated at 0.075 mg/mg Ti3C2. The modified Ti3C2 (D-Ti3C2) showed slightly deteriorated dispersibility in water but better dispersibility in waterborne epoxy resin relative to unmodified Ti3C2. The impedance modulus of D-Ti3C2 coatings achieved four and two orders of magnitude enhancement compared with EP and unmodified Ti3C2 coatings, respectively. The addition of D-Ti3C2 reduced the water absorption of EP by 80% after a prolonged immersion process. Superior barrier ability and enhanced dispersion of D-Ti3C2 nanosheets were responsible for the efficient enhancement of the anticorrosion performance of waterborne epoxy resin coating.

Graphene Oxide-Hybridized Waterborne Epoxy Coating for Simultaneous Anticorrosive and Antibiofilm Functions

Multifunctional coatings with simultaneous antibacterial and anticorrosive properties are essential for marine environments, oil and gas industry, medical settings, and domestic/public appliances to preserve integrity and functionality of pipes, instruments, and surfaces. In this work, we developed a simple and effective method to prepare graphene oxide (GO)-hybridized waterborne epoxy (GOWE) coating to simultaneously improve anticorrosive and antibacterial properties. The effects of different GO filler ratios (0.05, 0.1, and 0.5, 1 wt%) on the electrochemical and antibacterial behaviors of the waterborne epoxy coating were investigated over short- and long-term periods. The electrochemical behavior was analyzed with salt solution for 64 days. The antibacterial effect of GOWE coating was evaluated with Shewanella oneidensis (MR-1), which is a microorganism that can be involved in corrosion. Our results revealed that concentrations as low as 0.1 wt% of the GO was effective performance than the waterborne epoxy coating without graphene oxide. This result is due to the high hydrophilicity of the graphene oxide fillers, which allowed great dispersion in the waterborne epoxy coating matrix. Furthermore, this study used a corrosion relevant bacterium as a model organism, that is, Shewanella oneidensis (MR-1), which is more relevant for real-word applications. This as-prepared GO-hybridized waterborne polymeric hybrid film provides new insight into the application of 2D nanomaterial polymer composites for simultaneous anticorrosive and antibacterial applications.

Understanding the role of epoxy emulsifiers in water-borne epoxy coatings with the aggregation-induced emission approach

Emulsifiers in water-borne epoxy coatings play an essential role in the performance of the coatings. They typically keep coating formulations well-dispersed. However, depending on the emulsifier type, quantity, and properties, the final coating will perform differently. The underlying role and mechanism for any emulsifier in a coating formulation is key to predicting the final properties of coatings. However, to study these two is challenging and not straightforward as coatings have several other contents. In this work, we employed the theory of aggregation-induced emission (AIE) to study the role of epoxy emulsifiers in water-borne coatings. AIE offers the advantages of change in the emission of the AIE luminogens (AIEgens) depending on their nanoscale environment to understand the interaction of materials with a fast, contactless, nondestructive, and visual means. In this work, AIEgens were grafted to epoxy emulsifier into the coating formulations to endow the coating with the fluorescent property, then used to study the coating interaction environment. The interaction between the components and the properties of fluorescent coating dispersions were studied in real-time by reading the fluorescent properties of the final coatings.

Self-assembly of zinc hydroxystannate on polyethyleneimine supported boron nitride to improve the flame protection properties of waterborne epoxy coatings

Herein, polyethyleneimine (PEI) was loaded on the surface of BN nanosheets to impart them a positive charge. Then, negatively charged zinc hydroxystannate (ZHS) nanoparticles were adsorbed on the surface of BN/PEI composites through electrostatic self-assembly to obtain a novel BN/PEI@ZHS nanoadditive (BP@ZHS). The contribution of BP@ZHS hybrids to the flame retardant properties of epoxy coatings (EP) was characterized by fire performance tests. The thermal insulation performance test results showed that the backside temperature of the BP@ZHS based epoxy (BP@ZHS/EP) fireproof coating remained the lowest value (172.1 ℃) after 60 min of burning. The BP@ZHS/EP sample exhibited the most excellent expansion characteristics (expansion height is 21.5 mm, expansion rate is 16.54) after calcination in a muffle furnace. The TGA experiments illustrated that BP@ZHS/EP had the largest amount (30.8%) of carbon residue due to its catalytic carbonization. Moreover, the smoke density rating (SDR, 46.8%) of BP@ZHS/EP was significantly lower than other samples due to the synergistic effect of BN and ZHS. The carbon residue analysis showed that zinc stannate and BN remained in the carbon framework, thereby improving the strength and thermal insulation effect of the char layer. The excellent fire resistance of BP@ZHS/EP can be mainly attributed to the high barrier effect of BN nanosheets and the multifunctional flame retardant effect of ZHS.

Layer-by-layer self-assembly of sodium alginate and zinc ions on the surface of graphene oxide to improve the fire protection ability of intumescent waterborne epoxy coatings

In this study, polyethyleneimine (PEI) was first adsorbed on the GO surface, resulting in a positively charged GO/PEI composite. Afterwards, SA and Zn2+ were loaded on the surface of GO/PEI through a facile route to obtain an organic-inorganic hybrids (GPS@Zn). Among them, the gas phase products of SA delayed the progress of the combustion reaction, while the catalytic carbonization of zinc oxide and the high barrier effect of GO effectively improved the thermal insulation efficiency of the char layer. The fire performance test results showed that the backside temperature of GPS@Zn/EP decreased to 161.2 °C after burning for 60 min. The swelling height and swelling ratio of GPS@Zn based EP remained at the highest value compared to the other samples. In addition, the residual char content of EP loaded GPS@Zn was as high as 31.2 %, which lays the foundation for its high thermal insulation performance. The PHRR, THR, SPR and TSP values of GPS@Zn/EP were 420.2 ± 13 kW/m2, 13.2 ± 0.6 MJ/m2,0.078 ± 0.05 m2/s and 1.87 ± 0.05 m2, respectively, which were significantly lower than the other samples, thus proving its best flame retardant and smoke suppressing properties. The carbon residue analysis confirmed that zinc oxide remained in the char layer, which was beneficial to the improvement of its thermal insulation performance and strength.

Tannic acid‐copper metal‐organic frameworks decorated graphene oxide for reinforcement of the corrosion protection of waterborne epoxy coatings

AbstractWaterborne anticorrosion coatings have aroused tremendous attention in the metal protection field due to their environmentally friendly properties. However, the limited barrier performance and poor resistance to corrosive species severely impede its practical applications. Herein, tannic acid‐copper metal‐organic framework (TA‐Cu) was first synthesized via oxidative coordination and then assembled with graphene oxide to obtain TA‐Cu‐decorated graphene oxide (TAG), which was utilized to improve the anticorrosion performance of waterborne epoxy (WEP) coatings. Electrochemical measurements demonstrated that the impermeability of WEP has been significantly enhanced with the incorporation of TAG. Meanwhile, local electrochemical impedance spectroscopy tests indicated that the corrosion reaction at defected region can be effectively suppressed, presenting an active anticorrosion function. The protection mechanisms are attributed to (1) TA‐Cu contributed to the dispersion of graphene oxide in WEP and impeded the intrusion of aggressive ions and (2) the coordination and adsorption of TA on steel inhibited the redox process and corrosion extension.

Silane functionalized plasma-treated boron nitride nanosheets for anticorrosive reinforcement of waterborne epoxy coatings

Boron nitride nanosheets (BNNSs) are a two-dimensional material with electrical insulation, thermal conductivity and excellent barrier properties, but they are easy to agglomerate and not easy to modify. To solve this problem, the OH-functionalized BNNSs were prepared in high yield (80.1%) by plasma treatment on the surface of boron nitride, and then was further silylated with 3-aminopropyltriethoxysilane (APTES) via the reaction of Si-O-H with -OH. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) proved that APTES successfully modified the surface of BNNSs through covalent bonding. The obtained BNNSs@APTES exhibited good compatibility with waterborne epoxy (WEP) resins. In addition, BNNSs@APTES/WEP composite coatings were applied on carbon steel, and their anticorrosion performance was investigated using electrochemical measurements. Results demonstrated that the incorporation of 0.8 wt% BNNSs@APTES significantly enhanced the corrosion resistance of WEP coatings via the improved barrier property.

Distinctive roles of graphene oxide, ZnO quantum dots, and their nanohybrids in anti-corrosion and anti-fouling performance of waterborne epoxy coatings

In this research, the amino-silane functionalized ZnO quantum dots (F-ZnO QDs), graphene oxide (F-GO), and their nanohybrids (F-GO@ZnO QDs) are used as effective nanofillers to improve the anti-corrosion and anti-fouling properties of waterborne epoxy coatings. The synthesized nanomaterials before and after silane functionalization are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Then, the nanocomposite waterborne epoxy coatings loaded with 0.1 wt% F-ZnO QDs, F-GO, and F-GO@ZnO QDs are prepared through solution mixing method. The effects of different nanofillers on the surface roughness, water contact angle, pull-off adhesion strength, fracture surface, and corrosion resistance of the nanocomposite coatings are considered. The results reveal that the uniformly dispersed F-GO@ZnO QDs in the fracture surface of the coating could provide the highest barrier and corrosion resistance on the steel substrates. Meanwhile, the nanocomposite coatings have higher water contact angle and higher adhesion strength to the substrates. The anti-bacterial and anti-fouling properties of the nanocomposite coatings have also been confirmed. The multifunctional performance of the epoxy/F-GO@ZnO QDs is assigned to the synergy effect between the GO, ZnO QDs, and amino-silane; exhibiting the importance of the nanohybrids to combine the advantages of different nanomaterials in one coating system.

A robust and eco-friendly waterborne anti-corrosion composite coating with multiple synergistic corrosion protections

Environmentally friendly waterborne coatings have received significant attention recently due to their lower volatile organic compounds (VOCs) emission than solvent-based coatings, but their practical applications are severely limited by poor barrier properties. Herein, a novel and robust waterborne OBN-PA-Zn-D/WEP anti-corrosion composite coating was successfully fabricated by utilizing hydroxyl-functionalized h-BN (OBN) nanosheets , phytic acid (PA), Zn 2+ and dicyandiamide. Due to the π-π interactions between OBN and organic-inorganic PA-Zn-D complex, the dispersibility of OBN-PA-Zn-D nanosheets was improved, which was beneficial for enhancing the physical barrier properties of OBN-PA-Zn-D/WEP composite coating. After adding dicyandiamide, the interface compatibility between OBN-PA-Zn-D nanosheets and the waterborne resin matrix was significantly improved, greatly reducing the defects inside the OBN-PA-Zn-D/WEP composite coating. In addition, PA and Zn 2+ formed protective layer in the defect area to inhibit the corrosion of anode and cathode . Therefore, under the effect of multiple synergistic corrosion protections , the eco-friendly waterborne OBN-PA-Zn-D/WEP composite coating exhibited unique anti-corrosion performance that was greatly improved compared with the conventional waterborne epoxy coatings . • A robust and eco-friendly waterborne anti-corrosion composite coating was prepared. • OBN-PA-Zn-D/WEP composite coating provided strong corrosion protection. • Physical barrier, corrosion inhibition and interface enhancement synergistically enhance anti-corrosion ability.

Functionalization of h-BN by the exfoliation and modification of carbon dots for enhancing corrosion resistance of waterborne epoxy coating

The amino-functionalized carbon dots (FCDs) were used as intercalators to exfoliate and modify the boron nitride for obtaining the FCDs/boron nitride nanosheets (BNNS) nanocomposite. The FCDs, BNNS and FCDs/BNNS were respectively dispersed into the waterborne epoxy (WEP) matrix to prepare the corresponding modified WEP coatings on the copper substrate through the spray coating method. Their micro/macro-morphologies, compositions, surface roughness, self-healing and corrosion resistance behaviors were comparatively researched. Electrochemical results and surface morphology observation show that WEP FCDs/BNNS coating possesses the optimal corrosion protection performance after 40 d immersion in 3.5 wt% NaCl solution. And the impedance value (4.97 × 105 Ω cm2) of WEP FCDs/BNNS coating is still about an order of magnitude higher than that of pure WEP coating (3.36 × 104 Ω cm2). In the WEP FCDs/BNNS coating system, BNNS as physical barrier extend the diffusion path of corrosive species and block inherent defects of the coating, thus slowing down the corrosion rate; FCDs as intercalators strip BNNS enhancing its physical barrier effect. Besides, FCDs can also act as the effective corrosion inhibitors, which could adsorb on the exposed or corroded copper surface and hinder the further corrosion. Their synergistic effects of physical barrier performance from BNNS and self-healing capability from FCDs endow the WEP composite coating with outstanding corrosion resistance.

Green construction of melamine phytate nanosheets for enhancing anti-corrosive performance of water-borne epoxy coatings

Green construction of melamine phytate nanosheets for enhancing anti-corrosive performance of water-borne epoxy coatings

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 Gr0.04–ZnO0.4, far more than pure epoxy with 6186 Ω cm2 after 7 days of immersion in electrolytes. Furthermore, the Gr0.04–ZnO0.4 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.

Gemini Surfactant-Assisted Preparation of Sulfonated Polyaniline Copolymer for Waterborne Epoxy Coating with Promising Anticorrosion and Antibacterial Performance

Gemini Surfactant-Assisted Preparation of Sulfonated Polyaniline Copolymer for Waterborne Epoxy Coating with Promising Anticorrosion and Antibacterial Performance

Gemini Surfactant-Assisted Preparation of Sulfonated Polyaniline Copolymer for Waterborne Epoxy Coating with Promising Anticorrosion and Antibacterial Performance

Gemini Surfactant-Assisted Preparation of Sulfonated Polyaniline Copolymer for Waterborne Epoxy Coating with Promising Anticorrosion and Antibacterial Performance

Effect of Curing Agent Dosage on Fire Resistance of Waterborne Epoxy Coating

The water-based epoxy fire retardant coating is formed by reaction curing, which not only has good anti-corrosion performance, but also has environmental protection and flame retardant performance, which is suitable for construction machinery painting or steel structure buildings. However, the curing and cross-linking process of water-based epoxy coatings is centered on the curing agent, which gradually diffuses into the epoxy resin particles. The curing agent molecules first contact the surface of the epoxy resin dispersed phase particles and undergo a cross-linking curing reaction. As the reaction progresses, the relative molecular weight and glass transition temperature of the epoxy resin on the particle surface gradually increase, so that the diffusion rate of the curing agent molecules into the particles gradually slows down, which means that the curing reaction inside the epoxy resin dispersed phase particles Less than its surface, resulting in a low internal crosslink density, and ultimately not all epoxy groups have the opportunity to interact with the activating groups of the curing agent. Therefore, this paper studies different proportions of waterborne epoxy emulsion and curing agent. The results show that when m (epoxy emulsion): m (curing agent) = 7:3, the fire resistance and comprehensive performance of the coating are the best.

Eco-friendly functionalization of hexagonal boron nitride nanosheets with carbon dots towards reinforcement of the protective performance of water-borne epoxy coatings

A h-BN@CDs/WEP coating shows superior corrosion protection under intact or damaged status owing to the improved barrier properties and interfacial bonding of the coating.

Optimal Preparation and Characterization of Self-Curing Concrete Containing Internal Superabsorbent Polymer and External Waterborne Epoxy Coating

Optimal Preparation and Characterization of Self-Curing Concrete Containing Internal Superabsorbent Polymer and External Waterborne Epoxy Coating

Synthesis of ultrathin α-zirconium phosphate functionalized with polypyrrole for reinforcing the anticorrosive property of waterborne epoxy coating

As a classical two-dimension nanomaterial, α-zirconium phosphate (α-ZrP) with outstanding barrier property and non-conductivity has great potential application in anticorrosion field. However, the thicker layer thickness and lack of long-term anticorrosion property limit the application of α-ZrP. In this work, α-ZrP with the diameter of about 500 nm was prepared and then exfoliated to enhance the dispersion in waterborne epoxy coatings(WEC). Then polypyrrole (PPy) was used to encapsulate the exfoliated α-ZrP (E-ZrP) to obtain final nanomaterial(PPy-ZrP). XRD, FTIR, EDS mapping, SEM, TEM were employed to characterize the as-prepared nanomaterials. WECs with those as-prepared nanomaterials were fabricated by spray and the anticorrosion performance of WECs were tested by electrochemical impedance spectroscopy(EIS) test and salt spray test. At the end of the EIS test (60 days of immersion in 3.5 wt% NaCl solution), the PPy-ZrP/WEC exhibited the highest value of |Z|0.01 Hz (4.5 × 107 Ω·cm2), which is about two orders of magnitude higher than blank WEC. During the EIS test period, PPy-ZrP/WEC displayed better corrosion resistance than other WECs. As a two-dimension nanosheet with good dispersion in WEC, PPy-ZrP provided outstanding barrier property for WEC. And the passivation effect of PPy further enhanced the corrosion resistance of WEC.