Water-based Epoxy Research Articles

Preparation of ZIF-67 composite MBI-modified Co-MOF material and its corrosion resistance to epoxy resin coating

Metal corrosion causes a lot of waste of resources, and the protection of metals from corrosion is becoming increasingly important. In this study, zeolite-imidazole (ZIF-67) was grown on the surface of Co-MOF for the first time by a one-step (complexation) method. 2-Mercaptobenzimidazole (MBI) was then loaded into the inner cavity of ZIF-67, resulting in the formation of a new composite material, Co-MOF@ZIF-67@MBI. The modified Co-MOF exhibits excellent interfacial compatibility with the water-based epoxy resin, and the Co-MOF@ZIF-67@MBI composite coating demonstrates robust anti-corrosion properties. Following a 60-day immersion period, the electrochemical experiment demonstrated that the corrosion resistance modulus of the Co-MOF@ZIF-67@MBI composite coating reached 108 Ω cm², indicating that the coating effectively enhanced the corrosion resistance of the coating and significantly extended the service life of the coating.

Multifunctional Ti3C2Tx-based epoxy composite coating towards intelligent response and corrosion/wear resistance

Questions remain about the unreasonable collocation of Ti3C2Tx and nanocontainers resulting in the performance degradation of multi-function Ti3C2Tx-based epoxy composite coating. Here, mesoporous SiO2 nanocontainers (SNT) containing both potassium thiocyanate and hexadecyl trimethyl ammonium bromide (CTAB) were loaded on MXene-based platform (SNT-on-MP) to achieve a novel epoxy coating (SNT-on-MP@EP) with the integrated functions of self-warning, self-healing, anti-corrosion and anti-wear. In the damaged area, the thiocyanate groups combined with Fe3+ ions to form a blood-red color display, and the formed coordination compound and CTAB as corrosion inhibitors were deposited on the metal substrate, thus showing intelligent response function. Besides, because of passive and active synergistic protection functions, the lowest-frequency impedance value of SNT-on-MP@EP maintained 5.74 × 107 Ω·cm2 after 4 weeks of exposure in salt water environment, which was increased by two orders of magnitude compared with pure epoxy coating. Under the reciprocating sliding friction, the wear rate of SNT-on-MP@EP reached 5.32 × 10−5 mm3/N·m, and was reduced by 58.29 %, owing to the formation of lubricant film at the friction interface and the enhancement of the deformation resistance of the coating. The reasonable collocation of SNT and Ti3C2Tx-based platform eliminated the problem of weak interaction between traditional inorganic nanocontainer and water-based epoxy coating, thus giving full play to the advantages of both.

Designing sandwich-structured IBP nanosheets with superior antioxidant property to enhance corrosion resistance, flame retardancy, and wear resistance for polymeric coatings

The rapid development of industrialization requires the advancement of multifunctional coatings. In this study, successful self-assembly of iron porphyrin on BP nanosheets resulted in the synthesis of IBP nanosheets with a sandwich structure. Characterization tests including SEM, XPS, SPM, and XRD confirmed the successful preparation of IBP nanosheets with robust structural stability and antioxidation. Subsequently, a water-based epoxy resin (WEP) coating containing IBP nanosheets was prepared. Test results revealed that the composite coating containing 0.4 wt.% IBP nanosheets exhibited outstanding anti-corrosion, wear-resistant, and flame-retardant properties. After 42 days of immersion in a 3.5 wt.% NaCl solution, the Rct value of the 4-IBP/WEP coating was 1.79 × 109 Ω cm2, surpassing the Pure WEP coating by more than 3 orders of magnitude. Additionally, the peak heat release rate (PHRR) and wear rate of the 4-IBP/WEP coating decreased by 19.29 % and 90.97 % compared to the Pure WEP coating. This research presents a novel idea for the utilization of BP nanosheets in multifunctional coatings.

Self-lubricating, self-healing and anti-corrosion coating with ultra-short run-in period

Mechanical equipment serves in harsh environments and always fails due to wear and corrosion, especially at the beginning of friction operation (run-in period). A lubricating, wear-resistant, corrosion-resistant, and self-repairing coating have been developed by combining MXene and polytetrafluoro-wax (PFW) with a water-based epoxy resin (EP). In the coating, MXene and PFW work together to form a moderately soft and hard transfer film, reducing the coefficient of friction from 0.236 to 0.009 and the run-in period from 1400 s to 7 s. In addition, the barrier properties of the MXene lamellar structure work synergistically with the phase-change capability of the PFW to provide self-healing and anti-corrosion properties. These coatings offer a new approach to the long-term protection of mechanical equipment.

Improvement of the anti-corrosion coating properties of waterborne epoxy resin with the incorporation of fluoropolymer-modified silica nanofillers

The objective of this research was to enhance the corrosion resistance and mechanical properties of silica nanoparticles modified by a fluoropolymer (polyhexafluorobutyl acrylate, PHFBA) by incorporating them into a waterborne epoxy resin (WEP) coating system. Initially, polyhexafluorobutyl acrylate (PHFBA)-modified silica nanoparticles were synthesized using a two-step method, involving the grafting of 3-(isobutylloxy) propyl trimethoxysilane (KH570) onto SiO2 to produce SiO2@KH570, followed by a random copolymerization of SiO2@KH570 with hexafluorobutyl acrylate (HFBA) to obtain the fluoropolymer-modified SiO2 (FxSiO2). Subsequently, the chemical structure and elemental composition of SiO2, as well as the prepared SiO2@KH570 and FxSiO2 nanoparticles, were comprehensively investigated. Moreover, FxSiO2/WEP composite coatings with different amounts of fluoropolymer-modified nanofillers and x-F5SiO2/WEP composite coatings with varying amounts of F5SiO2 nanofillers were prepared and characterized. The findings revealed that the functionalized FxSiO2 exhibits superior dispersion, interface, and size effects, significantly enhancing the overall performance of WEP coatings. Notably, when 0.1 wt% F5SiO2 nanofiller was incorporated, the resulting 0.1-F5SiO2/WEP composite coating demonstrated a considerable impedance modulus (1.171 × 108 Ω∙cm2), relatively low water absorption rate (about 11 % after 20 d of immersion in water), and robust mechanical properties: a tensile strength of 6.07 MPa and an elongation at break of 37.36 %. Moreover, the hardness and adhesion of the composite coating remain unaltered. Furthermore, after 20 days of salt spray testing, the electrochemical impedance still reached 8.765 × 106 Ω∙cm2, indicating a favorable long-term anti-corrosion capability. Consequently, the integration of fluoropolymer-modified nanoparticles in water-based epoxy resins holds great potential.

Waterborne epoxy composite coating containing N,S-doped carbon dots for enhancing corrosion resistance

In order to construct waterborne epoxy composite coating with enhanced anti-corrosive performance, the development of efficient additives with good compatibility with adhesive resin and good interaction with steel matrix is of significance. Herein, we adapted two heteroatom (N and S) doped carbon quantum dots, namely ACDs and LCDs, as eco-friendly anti-corrosion components to mix with water-based epoxy resin (WP) to prepare the CDs/WP composite coating. Compared with the ACDs/WP composite, the LCDs/WP composite exhibited a better performance because it contained more functional groups such as carboxyl and hydroxyl on the surface of LCDs, which not only made the system denser but also facilitated the multi-anchor coordination and adsorption on carbon steel. Following immersing in a 3.5 wt% NaCl solution for 28 d, the impedance modulus of LCDs/WP surpassed 109 Ω cm2, exhibiting approximately three orders of magnitude higher values compared to pure WP coatings. The inhibition efficiency was improved by 96.9%. The facile synthesis of LCDs coupled with excellent anti-corrosive properties of LCDs/WP composites, provides a new way for developing anti-corrosion coating materials.

Research on surface treatment technology for quickly improving the skid resistance of tunnel concrete pavement.

In order to solve the problem that the skid resistance of concrete pavement in tunnel deteriorates rapidly, which is easy to cause traffic accidents, the anti-skid rapid elevation technology of surface treatment is proposed. Wear tests were used to investigate the effects of concrete surface roughness, properties of modified emulsified asphalt binder and anti-skid fine aggregate type on long-term skid resistance of treated surfaces. The results show that the four coarsening methods of fine milling, milling, grooving and brooming can improve the skid resistance of concrete, and the skid resistance durability of fine milling and milling is better. The adhesive property of modified emulsified asphalt is the best when the content of water-based epoxy resin is 20%. In different aggregates, the anti-skid effect is better when silicon carbide is used as anti-skid aggregate and the particle size is 0.6mm:0.3mm = 2:3. The method of fine milling of concrete surface + spraying epoxy emulsified asphalt + spreading silicon carbide can effectively improve the anti-skid performance of the original concrete pavement, and the feasibility of the scheme is verified by the test road. The research results have a good reference value for improving the skid resistance of tunnel concrete pavement.

The Calcium Gluconate Filled Epoxy Waterborne Primer Coating for Marine Application

The synthesis of corrosion protection in the waterborne epoxy primer coating, which included calcium gluconate (CG), was synthesized. Various compositions of CG, ranging from 0 to 8 grams were applied to the carbon steel substrate using this water-based epoxy coating. The investigations included FTIR characterization, Tafel plot polarization, immersion, adhesion, and hardness tests. The presence of CG at 2868.88 cm-1, corresponding to calcium ion (Ca2+), was confirmed by the FTIR result, while the epoxy functional group was detected at 1506 cm-1. Furthermore, it was observed that the immersion test, hardness test, and adhesion test revealed that the highest formulation for corrosion inhibition was 8 g of CG, which also exhibited a lower corrosion rate of 0.262 mmpy, improved mechanical properties (4H), and 0 % area removed. The presence of CG, which facilitated interaction with the epoxy resin through coordination between gluconate ions and Ca2+ ions, was believed to be responsible for increasing the concentration of dissolved Ca2+ ions in the solution. This, in turn, enhanced the formation of Ca(OH)2 on the surface of the aluminium alloy, leading to corrosion inhibition. Ultimately, the utilization of CG as an anti-corrosive pigment resulted in a reduction of corrosive properties and an enhancement of mechanical properties in waterborne primer coatings.

Enhancement of anti-microbial corrosion properties through coatings incorporating S2− responsive TCS-MSNs@TA-FeIII nanofillers

In environments susceptible to microbiologically influenced corrosion (MIC), conventional coatings frequently lack antimicrobial properties, resulting in diminished corrosion protection. The direct incorporation of antimicrobial agents into coatings may lead to continuous leakage. In this study, we tackled this challenge by utilizing smart nanofillers known as TCS-MSNs@TA-FeIII, which form mesoporous silica nanoparticles (MSNs) encapsulated by tannic acid-Fe3+ and loaded with triclosan (TCS). These nanofillers exhibited responsiveness to variations in S2− concentration caused by sulfate-reducing bacteria's (SRB) metabolic activities, enabling controlled release of TCS within the low S2− concentration range of 0.05 to 3 mM. Additionally, we evaluated the antimicrobial and anti-corrosion properties of the coating after integrating it into a water-based epoxy coating within an SRB environment. The results showcased exceptional performance of the TCS-MSNs@TA-FeIII coating, characterized by the highest impedance modulus (3.19 × 106 Ω·cm2), lowest corrosion current density (2.04 × 10−8 A·cm−2), and remarkable antimicrobial efficacy. This study offers valuable insights into developing novel coatings with enduring MIC inhibition capabilities while also broadening the potential application range of organic coatings.

Tetraaniline-modified Co-MOF-PDA for anti-corrosive reinforcement of waterborne epoxy coating

The main aim of this study was to exploit the advantages of dopamine and tetraaniline (TA) to enhance the physical barrier properties and active anti-corrosion performance of composite coatings; in this study, the growth of polydopamine on the surface of Co-MOF enhanced its compatibility with waterborne epoxy, and Co-MOF-PDA-TA (MP-TA) was successfully synthesised by adding dopamine and tetraaniline via Michael addition, confirmed through characterisation methods such as Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. MP-TA can be added as a nanofiller additive to water-based epoxy coatings, and a detailed study on the corrosion resistance of the prepared composite coatings showed that the composite coating containing 0.50wt% MP-TA/WEC exhibits good anti-corrosion performance with an impedance modulus at low frequency (0.01 Hz) of 7.253 × 109 Ω cm2 because TA not only prolongs the time required for corrosion ions to reach the interface but also forms a passivation film on the steel surface. Moreover, the reduced TA can be oxidised to EB or even LEB by releasing two electrons, which further promotes the formation of a passivation film, providing a good pathway for the application of MP-TA as a multifunctional additive.

Fabrication of polyaniline/waste sugarcane bagasse composite fillers for excellent anti-corrosion protective coatings

Herein, biomass-based anti-corrosion composite fillers for water-based epoxy resin coatings, epoxy resin powder coatings, and efficient anticorrosive coatings were successfully prepared.

Mechanical Performance and Strengthening Mechanism of Polymer Concretes Reinforced with Carbon Nanofiber and Epoxy Resin

To address the issues of the brittleness, low tensile strength, insufficient bond strength, and reduced service life associated with ordinary cement concrete being used as a repair material, a water-based epoxy (WBE) and carbon-nanofiber-reinforced concrete composite repair material was designed, and the mechanical properties, bonding performance, and durability of the concrete modified using WBE and carbon fiber under various WBE contents were investigated and evaluated. In this paper, a self-emulsifying water-based epoxy curing agent with reactive, rigid, flexible, and water-soluble chains was obtained via chemical grafting, involving the incorporation of polyethylene glycol chain segments into epoxy resin molecules. The results demonstrated that a WBE has a contributing effect on improving the weak interfacial bond between the carbon fiber and concrete; moreover, the composite admixture of carbon fiber and WBE improves the mechanical properties and durability of concrete, in which the composite admixture of 1% carbon fiber and 10% WBE has the best performance. The flexural strength and chlorine ion permeability resistance of concrete were slightly reduced after more than 10% admixture, but bond strength, tensile strength, compressive strength, dry shrinkage resistance, and frost resistance were promoted. The addition of WBE significantly retards the cement hydration process while greatly improving the compactness and impermeability of the concrete. Furthermore, the combined effects of WBE and carbon fiber effectively prevented the generation and expansion of cracks. The interaction mechanism and microstructure evolution between the WBE, carbon fiber, and cement hydration were described by clarifying the mineral composition, organic–inorganic interactions, the evolution of the hydration products, and composite morphology at different scales. Carbon fiber and WBE exhibited synergistic effects on the tensile strength, ductility, and crack resistance of concrete. In the formed three-dimensional network structural system of concrete, the WBE formed an organic coating layer on the fiber surface and provided fiber protection as well as interfacial bonding reinforcement for the embedded cement particles.

Microzone characterization and corrosion resistance of water-based epoxysilane/Ti/Zr composite chemical conversion coating on multi-metals

A water-based epoxy silane and titanium/zirconium composite chemical conversion coating was prepared on the surfaces of 6061 aluminum alloy, 7075 aluminum alloy, and galvanized steel simultaneously. Our findings revealed that the composite chemical conversion coating exhibited the strongest anti-corrosion effect on multi-metals surfaces as the concentration of silane was 0.4 vol% and the conversion time was 90 s. The analysis showed that a notable deposition of TiO2 and ZrO2 in close proximity to intermetallic compounds, segregation phases enriched with copper, and inclusions. Notably, the formation of the composite chemical conversion coatings on the multi-metals surface primarily follows a synergistic mechanism involving adsorption, oxidation, and readsorption. Consequently, a crosslinked siloxane network structure is formed, which offers additional filling sites for surplus particles of Al2O3, TiO2, ZrO2, and Fe2O3.

Enhancing the carbonation and chloride resistance of concrete by nano-modified eco-friendly water-based organic coatings

To effectively improve the carbonation and chloride resistance of concrete with eco-friendly waterborne organic coatings, two nanomaterials (i.e., nano-SiO2 and nano-TiO2) were utilized to modify the water-based polyurethane and epoxy resin paints at dosages of 1 wt%, 2 wt%, and 3 wt%, and the coated concrete specimens were fabricated. Then, accelerated aging experiments of ultraviolet irradiation were conducted on the coated concrete specimens, followed by accelerated carbonation or Coulomb electric flux experiments. In addition, partial coating film samples were analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy. Results show that the application of water-based organic coatings can substantially improve the carbonation and chloride resistance of concrete. The two-component water-based epoxy resin coating exhibited a higher quality than the one-component water-based polyurethane coating, thus resulting in better improvement of the carbonation and chloride resistance of concrete. However, the anti-aging capability of water-based epoxy resin coating is lower than that of water-based polyurethane coating, resulting in the rapid decline of the carbonation or chloride resistance of coated concrete after ultraviolet aging. The addition of nano-SiO2 or nano-TiO2 to the water-based organic coating can reduce the defects in the coating, effectively improve the density of the coating, and further improve the carbonation and chloride resistance of the coated concrete, with average improvement ranges of 51–74 % and 24–27 %, respectively. Meanwhile, the addition of nano-SiO2 or nano-TiO2 can help reduce the damage of water-based coatings caused by ultraviolet irradiation, thereby improving the long-term carbonation and chloride resistance of coated concrete, among which the improvement effect of nano-TiO2 is higher than that of nano-SiO2.

Phytic acid oligomers as bio-based crosslinkers for epoxy and polyol resins

AbstractIn recent years, the chemical industry is not only striving to produce the best possible products for various applications, but the new products should ideally be based on renewable resources. The ideal case of "cradle to cradle" is generally not achievable in the coatings industry, as maximizing product life and preventing product degradation in the environment is usually one of the main goals of the coatings industry. Therefore, if the coatings industry wants to act sustainably, its efforts should be focused on renewable raw materials. This paper presents a process that makes the renewable raw material phytic acid easily accessible for conventional epoxy and polyol resin coating systems through hydrophobization- and oligomerization. Phytic acid, as a phosphorus reservoir in plants and with beneficial properties for corrosion protection and as a flame retardant, could be a new base for various coatings. In this work, a simple one-pot oligomerization of phytic acid with green mono- and difunctional alcohols is investigated. The aim of this work is to create a phytic acid hardener system based on renewable raw materials that can produce coatings with solvent-based epoxy and polyol binders as well as water-based epoxy binders. The successful reaction was observed by infrared, 1H-NMR, and 31P-NMR spectroscopy and the acid equivalent weight was determined by conductivity titration. The renewable curing agent was then used equivalently with different binder systems to prepare coatings. Crosslinking and glass transition temperature were monitored using oscillatory rheology. The coatings were applied to glass plates and the pendulum hardness was measured. A simple heating test followed by 31P-NMR and IR spectroscopy was also performed to demonstrate the stability of phytic acid under reaction conditions.

Synthesis and properties of a nonionic water-based epoxy curing agent

Owing to the requirement for environmental protection, water-based coatings have become a significant trend in the development of coatings. The water-based epoxy curing agent has also become a hot research topic. In this study, a B-A-B epoxy compound with a long hydrophobic alkyl chain connected to the intermediate nitrogen atom was synthesized at both ends of a molecule using ethylene glycol diglycidyl ether and 3,4-dimethoxyaniline as raw materials. Subsequently, the epoxy compound was sealed with triethylenetetramine. A nonionic, water-based epoxy resin curing agent with amino groups at both ends of the molecule was prepared. The target product structure was confirmed by infrared spectroscopy (IR), Mass spectrum (MS), and Nuclear magnetic resonance hydrogen spectroscopy (1H-NMR). Additionally, through three factors and three levels of orthogonal experimental design, the optimum experimental conditions were confirmed, the optimum yield was 82.83%. The thermogravimetric analysis (TGA) indicated that the monomer exhibited a significant weight loss in the temperature range of 320–450°C. The pencil hardness, flexibility, and impact resistance of the waterborne epoxy resin coating film prepared by the non-ionic water-based epoxy curing agent reached or exceeded those of similar products at China and foreign countries.

Experimental study of repairing rust-cracked reinforced concrete by electrophoresis deposition method

The rusting and cracking of reinforced concrete structures cost billions of dollars around the world every year, and there is a lack of targeted repair methods. In this study, we first put forward an electrophoretic deposition repair method using a high-performance colloid solution containing water-based cationic epoxy resin. The effect of electrophoretic deposition on rust-cracked reinforced concrete was studied. Then, the mesoscopic and microscopic morphologies of the repaired concrete surface, cracks, and defects at the interface of reinforced concrete were examined. Finally, the mechanism of electrodeposition was discussed, and the related reactions were summarized (ionization, electrolysis, electrophoresis, electrodeposition, electroosmosis, and curing reaction). The results show that electrophoretic deposition successfully increased the internal compactness, unconfined compressive strength, and split tensile strength of reinforced concrete, while greatly reducing the water absorption and the accelerated carbonation depth.

Enhancement of active anti-corrosion properties of waterborne epoxy resin by mussel bionic modified halloysite nanotube

Halloysite nanotube (HNT) is often used as a microcapsule loaded with corrosion inhibitors due to its cavity structure. However, the strong van der Waals forces between halloysite nanotubes can cause aggregation in organic coatings. Therefore, in this study, a new type of modified halloysite nano-filler (PDA@T-AHNT) was synthesized by a step-by-step method using the characteristics of self-polymerization of dopamine under an alkaline environment to achieve surface coating of halloysite nanotubes by polydopamine (PDA) to improve the dispersion of halloysite nanotubes in waterborne epoxy resin. UV-Vis was used to characterize the pH-responsive release properties of the modified nanofillers. Composite coatings were formed by adding PDA@T-AHNT into the water-based epoxy resin. FE-SEM was used to observe the morphology of the coatings, and EIS was used to test the electrochemical behavior of the coatings soaked in 3.5 wt% NaCl for 60 days to characterize the corrosion resistance of the coatings. The final results show that the 3 wt% PDA@T-AHNT composite coating (EPP-3) has the best corrosion resistance with a low-frequency impedance of 2.81 * 106 Ohm.cm2 after 60 days of immersion, which is much higher than the 1.45 * 106 Ohm.cm2of the pure epoxy resin coating (WEP). In conclusion, the results of this study demonstrated the application potential of PDA@T-AHNT nano-filler in corrosion protection of steel, especially in metal corrosion protection under acidic environment.

A Waterborne Epoxy Composite Coating with Smart Corrosion Resistance Based on 2-Phenylbenzimidazole-5-sulfonic Acid/Layered Double Hydroxide Composite

In this study, ZnAl-layered double hydroxide (ZnAl-LDH) was functionalized with 2-Phenylbenzimidazole-5-sulfonic acid (PBSA) to prepare ZnAl-PBSA-LDH using a simple one-step method. The electrochemical impedance spectroscopy (EIS) result of the solution phase demonstrated excellent corrosion inhibition performance of ZnAl-PBSA-LDH. Subsequently, 0.6 wt.% ZnAl-PBSA-LDH with shielding effects and active inhibition was incorporated into the water-based epoxy (WEP) for preparing the high-performance anti-corrosion coating (6-ZPL/WEP). The EIS test illustrated that the 6-ZPL/WEP coating maintained a high low-frequency impedance modulus (|Z0.01 Hz|) after 30 days of immersion, which is nearly two orders of magnitude higher compared to that of the blank coating. These results demonstrated that ZnAl-PBSA-LDH could efficiently improve the corrosion resistance of the WEP coating. Therefore, this study introduces new insights into the use of layered double hydroxides (LDHs) in the domain of anti-corrosion.

Effect of epoxy resin surface-modified techniques on recycled coarse aggregate and recycled aggregate concrete

The absorption of water by recycled coarse aggregates (RCAs) is significantly greater than that by natural coarse aggregates (NCAs), which affects the mechanical properties of recycled aggregate concrete (RAC). To mitigate this issue and enhance the mechanical strength of RCAs, a water-based epoxy resin was utilized to wrap an RCA, resulting in modified RCA (MRCA). Subsequently, MRCA and unmodified RCA (URCA) were mixed in various proportions and substituted for NCA in concrete, followed by performance evaluation. The experimental results showed that the MRCA absorbed 36.5% less water than did the RCA, and the compressive and tensile strengths of modified RAC (MRAC) were 11.3% and 4.2% greater than those of nature aggregate concrete (NAC) and 8.2% and 2.9% more than those of unmodified recycled aggregate concrete (URAC), respectively. This finding provides a strategy and possibility for the preparation of concrete using recycled aggregates.