Waterborne Epoxy Research Articles

Chitosan-capped mesoporous silica nano/microcontainers for waterborne epoxy coating: Implications of size and textural properties modulated by synthesis route

Herein, the dependence of the performance of smart waterborne epoxy coating on the size and textural properties of intercalated nano/microcontainers is critically examined. Two routes were adopted to synthesize nano/microcontainers from similar starting materials resulting in nanocontainers and microcontainers with dissimilar textural properties. The containers were constructed based on mesoporous silica particles (MSPs) loaded with benzotriazole (BTA) and encased with chitosan (CTS) shell to obtain nanocontainers with a slightly crystalline core (C@B@MSP1) and microcontainers with amorphous core (C@B@MSP2), both demonstrating pH-responsiveness. The obtained containers were characterized using SEM, TEM/EDX, XRD, FTIR, TGA, XRD, N2 adsorption/desorption and UV-vis studies. These containers were incorporated into waterborne epoxy coating namely EP/CBS1 and EP/CBS2, respectively. Their performance was investigated in comparison to a reference coating EP/REF and coatings doped with commercial inhibitor zinc phosphate, EP/ZP. The surface morphology and adhesion of coatings were examined using OM, SEM and 3D profilometer. EIS measurements of scribed coating in 3.5 wt% NaCl solution for 48 h demonstrated high active corrosion resistance of EP/CBS1. However, EIS assessment of intact coatings for 30 d shows the dominance of EP/CBS2 with |Z|0.01 Hz value of 6.0×107 Ω cm2 after 30 d of exposure, a performance corroborated by salt spray test carried out for 50 d. Hence, driven by the large size and amorphous core of C@B@MSP2 which allows compatibility with the waterborne epoxy matrix, EP/CBS2 demonstrated a synergy between exceptional barrier properties and adequate active corrosion resistance implying their versatility. Therefore, in addition to inhibitor loading efficiency of containers, their sizes and compatibility of textural properties with the chosen polymer matrix is crucial for better performance as active carriers in waterborne anticorrosive coatings.

Influence of Construction Process on Aggregate Spalling Behavior on Ultrathin Waterborne Epoxy Resin Layer

The waterborne epoxy resin (WER) colored antiskid thin layer has been widely used in asphalt pavement to improve driving safety. The tectonic depth determines the antiskid performance of aparticle antiskid type thin layer. The spalling of aggregate from a thin layer may reduce the tectonic depth, thus damaging antiskid performance. The spreading process of aggregate on the WER binder surface plays an important role in the spalling behavior of the thin layer. Herein, the influence of spreading processes on the ceramic aggregate spalling behavior on the WER thin layer was investigated based on laboratory experiments. The abrasion and British Pendulum Number (BPN) tests were employed to evaluate the antispalling and antiskid properties of the WER thin layers with different amounts of WER mortar, coverage rates of first-spread aggregate, and spreading orders of coarse/fine aggregates. Moreover, the tectonic depths of the layers before/after the spalling test were also investigated. The results indicated that the optimal dosage of WER mortar is 2.8 kg/m2. The WER thin layer exhibited better anti-striping property when coarse ceramic aggregate was spread first. The first-spread coverage rate of the aggregate on the WER surface is 70%. The thin layer exhibited a superior antispalling performance according to the resulting scheme, with a spalling rate of 3.77%. The tectonic depth only decreased from 1.87 to 1.80 mm after the spalling test.

Ratio optimization and grouting effect of low-viscosity and high-flexibility polymer

A new waterborne epoxy resin (polymer) was studied as a potential grouting material to improve the conventional epoxy resin's high viscosity, brittleness and poor environmental performance. The polymer's formulation was meticulously tailored and optimized by adjusting the curing/hardening time, solid content, viscosity and mechanical properties. Concurrently, grouting tests and scanning electron microscope (SEM) were carried out to scrutinize the diffusion effects and microscopic morphology of three distinct grouted sands, employing polymer, superfine cement and sodium silicates as grouting materials. The results show that the polymer performance is optimal when the polymer ratio is CC-190. CC-190 exhibits a homogeneous composition with 100 % solid content. The initial viscosity of CC-190 stands at a mere 19.2 mPa·s and peak compressive strength of 10.8 MPa. The compression ratio (compression height/original height) and rebound rate (rebound height/original height) of CC-190 remain consistently above 35 % and 93 %, respectively. Grouting tests underscore that polymer outperforms superfine cement and sodium silicates in terms of diffusion distance and grouting volume. Microscopic examination of the grouted sands elucidates that the polymer engenders a sophisticated three-dimensional cross-linked skeletal network, effectively binding and encapsulating individual sand particles. This skeletal framework imparts robust binding forces, ensuring the structural integrity of the grouted sand when subjected to external forces.

Distinct photooxidation and interface degradation of waterborne epoxy resin coatings on mortar substrate affected by bulk water

Epoxy-based coatings are widely used in engineering but are prone to degrade under aggressive environmental actions, especially in hygrothermal environments. However, the degradation mechanisms of a coating-substrate system under coupled UV irradiation and bulk water remain insufficiently explored. Herein, we designed three parallel accelerated aging tests, including UV irradiation only, UV/flush, and UV/submerged, on a waterborne epoxy resin (WER) coating on cement mortar substrate. The chemical structure, micro-morphology, and hydrophilicity over aging time were comprehensively characterized by the tests of attenuated total reflectance Fourier transformation infrared spectrometer (ATR-FTIR), scanning electron microscopy (SEM), image analysis, water contact angle (WCA). Results show that the UV/flush environments induced more micro-pinholes on the WER outer surface than the neat UV photooxidation. The UV/ submerged environment led to a blistering rate over 24% after 60 d's exposure owing to the significant osmotic pressure built between the inner and outer surfaces of the WER coating. Additionally, the physicochemical and microstructure changes to the outer surface of WER also caused the changes of WCA. The osmotic, hydrolysis, and thermal stresses were evaluated to clarify the water-accelerated photooxidation and interface degradation mechanisms. These findings contribute to a deeper understanding of epoxy coating degradation mechanisms in response to environmental stressors, and offer insights for enhancing coating performance under varying conditions.

Development of waterborne epoxy-based resin incorporated with modified natural rubber latex for coating application

Water-based coating has gained much attention globally due to environmental issues. This work aims to develop a waterborne epoxy coating incorporated with modified natural rubber (NR) latex for improved performance. For this purpose, the NR latex was modified into three types of low molecular weight epoxidized natural rubber (LENR) latex. The waterborne epoxy resin was prepared by simply mixing the epoxy resin with an amine curing agent in water and various LENR latex contents (10 to 50 wt%). The waterborne epoxy/LENR blend was coated on a tin substrate and the cured coating demonstrated better adhesion and bending properties than the neat epoxy. Phase morphological properties displayed a rough surface with a heterogeneous surface structure of the dispersed rubber and epoxy matrix. Two glass transition temperatures were observed, corresponding to the rubber modifier and the epoxy matrix. The mechanical properties of the thermosetting epoxy/LENR blends were assessed, revealing a maximum increment in elongation ability by approximately 370% for adding 50 wt% LENR, compared to the neat epoxy. These results hold the potential avenue for utilizing NR-based material in the waterborne epoxy-based resin for coating applications. Furthermore, it contributes to the NR, a renewable and eco-friendly material, in the coating technology, embracing a sustainable future.

A surfactant-mediated dynamic protection strategy for 100% waterborne fabrication of durable superhydrophobic coatings

Waterborne preparation of superhydrophobic coatings now becomes strongly favored because of its environmental and health friendliness. However, the huge surface energy difference between low surface-energy components and water still poses a challenge for achieving their co-dispersion. Here, a surfactant-mediated protection strategy is proposed to achieve well dispersion of both SiO2 nanoparticles and perfluorosilane in water as well as block their conjugation, thereby fabricating a 100% waterborne F-FC-SiO2 suspension with high homogeneity and dispersion stability. During the painting and drying process, demulsification spontaneously triggers the deprotection and enables sufficient covalent conjugation between perfluorosilane and SiO2, thus achieving a superhydrophobic coating. This supramolecular protection/deprotection approach enables high compatibility of the F-FC-SiO2 suspension with versatile waterborne polymer emulsions (e.g., waterborne polyurethane, waterborne polysiloxane, and waterborne epoxy resin) to fabricate durable superhydrophobic coatings. The resulting composite coating can impart super-repellency to various substrates against aqueous solutions and multiple oils, displaying high antifouling and self-cleaning properties, as well as resistance to extreme mechanical abrasion and weathering. This work provides a promising approach for the convenient production of totally waterborne superhydrophobic coatings.

Rheological Properties and Modification Mechanism of Emulsified Asphalt Modified with Waterborne Epoxy/Polyurethan Composite.

In research aimed at improving the brittleness of WER (waterborne epoxy)-modified emulsified asphalt, commonly encountered issues are that the low-temperature performance of this type of asphalt becomes insufficient and the long curing time leads to low early strength. Matrix-emulsified asphalt was modified with WPU (waterborne polyurethane), WER, and DMP-30 (accelerator). Firstly, the performance changes of modified emulsified asphalt at different single-factor dosages were explored through conventional performance tests and assessments of its adhesion, tensile properties, and curing time. Secondly, based on a response surface methodology test design, the material composition of the composite-modified emulsified asphalt was optimized, and its rheological properties were analyzed by a DSR test and a force-ductility test. Finally, the modification mechanism was explored by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that WER can improve the adhesion strength of modified emulsified asphalt and greatly reduce elongation at break. WPU can effectively improve the elongation at break of composite-modified emulsified asphalt, but it has a negative impact on adhesion strength. DMP-30 mainly affects the curing time of modified emulsified asphalt; EPD (composite modification) can effectively improve the high-temperature rutting resistance of matrix-emulsified asphalt, and its low-temperature performance is significantly improved compared with WER-modified emulsified asphalt. The EPD modification process mainly consists of physical blending. In the case of increasing the curing rate, it is recommended that the contents of WER and WPU be lower than 10% and 6%, respectively, to achieve excellent comprehensive performance of the composite modification.

Polyaniline nanoparticles intercalated Ti3C2 MXene reinforced waterborne epoxy nanocomposites for electromagnetic wave absorption and anticorrosion coating applications

Ti3C2 MXene (TM) has great application potential in the field of wave absorption and corrosion resistance due to its unique performance, such as high specific surface area, high electrical conductivity, excellent mechanical and good chemical stability. However, it is difficult to obtain uniformly dispersed TM in the resin matrix due to rapid agglomeration behavior. It is difficult to obtain uniformly dispersed Ti3C2 MXene (TM) in the resin matrix due to rapid agglomeration behavior. Herein, a novel method is presented to improve the corrosion protection and dispersion of TM by polymerizing polyaniline (PANI) nanoparticles between layers. The waterborne epoxy (WEP) coating with PANI-TM had high mechanical properties including impact resistance, adhesion, and flexibility and wear resistance. The PANI-TM-WEP composites can effectively absorb more than 90 % of the electromagnetic waves and demonstrate a decreased glass transition temperature of WEP from 128.0 to 107.6 ℃. Moreover, the |Z|0.01Hz value of the PANI-TM0.5 % was 1.2369 × 106 Ω·cm2, which was one order of magnitude larger than WEP coating. The high-performance anticorrosion of PANI intercalated TM coating is attributed to the synergistic effect of impermeable TM nanosheets and passivation effect of PANI. Therefore, PANI-TM is a potential choice for applications in the fields of anticorrosion and microwave absorption.

Preparation and characterization of waterborne silicone modified epoxy resin

AbstractSilicone modified epoxy resin was synthesized with bisphenol‐A epoxy resin (E51) and dimethyldichlorosilane (DMDCS), and waterborne silicone modified epoxy resin (WSER) was prepared. The WSER emulsion exhibited good stability with particle size ranging from 0.5 to 2 μm. Compared with waterborne epoxy resin (WER) cured film, the water resistance of WSER cured film was enhanced by the excellent hydrophobicity of DMDCS. Furthermore, the WSER cured film with 6% DMDCS showed better mechanical properties, and Shore hardness and tensile strength of that were greatly increased. Moreover, the corrosion resistance and ultraviolet (UV) aging resistance of WSER cured film were obviously improved compared to WER cured film.Highlights Dimethyldichlorosilane (DMDCS) was employed to modify bisphenol‐A epoxy resin (E51). Waterborne silicone modified epoxy resin (WSER) was prepared by phase inversion method. WSER cured films did better than WER cured film in water resistance and mechanical properties. WSER cured films showed good corrosion resistance and ultraviolet aging resistance.

Investigating the effectiveness of graphene oxide and hydroxylated hexagonal boron nitride to improve the coating corrosion resistance from electrochemistry and simulation perspectives

The performance of GO and hydroxylated BN in improving the corrosion resistance of a water-borne epoxy coating was comparatively investigated to evaluate the relative excellence of two nanofillers. Electrochemical tests indicated that GO outperformed hydroxylated BN. The corrosion current density was further decreased to 3.48 × 10−6 A/cm2 and polarization resistance was increased to 8.67 × 104 Ω·cm2. The electrochemical reactivity was also most significantly decreased with incorporating GO. Without changing the coating structure, the superior performance of GO was attributed to its exceptional ability to capture water molecules as revealed by simulation results. The mass transfer process of water molecules within coatings was inhibited and the redox reactions during corrosion process were thereby effectively controlled.

Gallocyanine-mediated non-covalent functionalization and exfoliation of h-BN for efficient anticorrosion reinforcement of waterborne epoxy coating

Hexagonal boron nitride (h-BN) is commonly used to enhance the anti-corrosion of organic coatings due to its excellent barrier properties, dielectricity and mechanical robustness. However, the bulky h-BN tends to create poor dispersibility and interfacial compatibility problems with the resin matrix, leading to coating cracking and failure. H-BN nanosheets exfoliated by conventional methods only provide passive barrier effect with coatings at the initial stage of corrosion. Herein, we used a mussel-inspired non-covalent functionalization strategy, using the catechol groups and heteroaromatic ring structure of gallocyanine to achieve the functionalization and exfoliation of h-BN through ball milling, and obtained ultra-thin h-BN@G nanosheets. Remarkably, spare gallocyanine can further suppress the erosion, whose inhibition efficiency is 95.48 % at the concentration of 100 mg/L in 1 M HCl within 9 h. Typically, after 105 days of immersion in 3.5 wt% NaCl solution, the low-frequency impedance of h-BN@G/WEP coating is still as high as 1.45 × 109 Ω cm2, which is two orders of magnitude higher than that of the pure coating. The superior long-term anti-corrosion capacity can be ascribed to the triple protection of enhanced shielding property of desirable-exfoliated h-BN, passivation films adsorbed on the metal and coordination bonds formed between gallocyanine and the iron to resist the active corrosion. Our work offers an innovative idea for the functionalization and exfoliation of other lamellar materials, which can be applied to the implementation of long-lasting anti-corrosion coatings.

Attenuation Law of Performance of Concrete Anti-Corrosion Coating under Long-Term Salt Corrosion

In saline soil areas, the concrete piers of concrete bridges experience long-term corrosion, mainly caused by chloride salts due to alternating temperature changes. Waterborne concrete coatings are prone to failure in this aggressive salt environment. Implementing coating protection measures can improve the durability of concrete and enhance the service life of bridges. However, the effectiveness and longevity of coatings need further research. In this paper, three types of waterborne concrete anti-corrosion coatings were applied to analyze the macro and micro surface morphology under wet–dry cycles and long-term immersion conditions. Various indicators such as glossiness, color difference, and adhesion of the coatings were tested during different cyclic periods. The chloride ion distribution characteristics of the buried concrete coatings in saline soil, the macro morphology analysis of chloride ion distribution regions, and the micro morphology changes of the coatings under different corrosion times were also investigated. The results showed that waterborne epoxy coatings (ES), waterborne fluorocarbon coatings (FS), and waterborne acrylic coatings (AS) all gradually failed under long-term salt exposure, with increasing coating porosity, loss of internal fillers, and delamination. The chloride ion content inside the concrete decreased with increasing depth at the same corrosion time, while the chloride ion content at the same depth increased with time. The chloride ion distribution boundary in the cross-section of concrete with coating protection was not significant, while the chloride ion distribution boundary in the cross-section of untreated concrete gradually contracted towards the concrete core with increasing corrosion time. During the corrosion process in saline soil, the coatings underwent three stages: adherence of small saline soil particles, continuous increase in adhered material area, and multiple layers of uneven coverage by saline soil. The failure process of the coatings still required erosive ions to infiltrate the surface through micropores. The predicted lifespans of FS, ES, and AS coatings, obtained through weighted methods, were 2.45 years, 2.48 years, and 2.74 years, respectively, which were close to the actual lifespans observed in salt environments. The developed formulas effectively reflect the corrosion patterns of different resin-based coatings under salt exposure, providing a basis for accurately assessing the corrosion behavior and protective effectiveness of concrete under actual environmental factors.

Fabrication of High-Performance Asphalt Mixture Using Waterborne Epoxy-Acrylate Resin Modified Emulsified Asphalt (WEREA)

Existing research shows that using waterborne epoxy resin (WER) instead of emulsified asphalt as the binder for cold mix asphalt (CMA) can enhance the rutting resistance, high-temperature performance, fracture performance, and early performance of CMA. In order to eliminate the potential drawbacks such as insufficient strength and low-temperature performance of CMA during application, a novel method was proposed in this study for the preparation of waterborne epoxy-acrylate resin (WER), specifically tailored to modify emulsified asphalt, resulting in waterborne epoxy-acrylate resin emulsified asphalt (WEREA). The modification effect of WER on emulsified asphalt was evaluated through rheological tests and direct tensile tests. A modified design method based on the conventional Marshall design method was proposed to determine the optimal mix proportions, including the key parameters of specimen compaction and curing. The results revealed that the incorporation of WER led to a substantial improvement in the complex shear modulus and a concurrent decrease in the phase angle. When the temperature exceeded 60 °C, the phase angle exhibited a diminishing trend, indicative of a reduced viscosity as temperatures escalated. As the WER content increased, a decrease in the direct tensile strain rate was observed, accompanied by a substantial elevation in direct tensile strength. At various stress levels, the shear strain of WEREA decreases with increased content of WER, indicating that the incorporation of WER can enhance the hardness of emulsified asphalt and improve its deformation resistance. The results from MSCR tests indicate that WER could significantly improve the elasticity and hardness of emulsified asphalt, transitioning it from a viscoelastic material to an elastic material, thereby improving its deformation resistance, resistance to rutting, and high-temperature performance. The results of fatigue life are consistent with those of the amplitude sweep, both reflecting the improvement of resistance to deformation of emulsified asphalt by WER. This indicates that WER has a significant improving effect on the fatigue resistance of emulsified asphalt. Furthermore, the Marshall design tests further confirmed the advantages of WEREA in asphalt mixtures. The optimal preparation for the WEREA mixture was proposed as follows: double-sided compaction for 50 times each, aging at 60 °C for 48 h, optimal moisture content of 5.14%, cement content of 2.5%, and emulsion content of 8.4%. The optimal mix proportions identified through these tests yielded asphalt mixtures with significantly improved stability, reduced flow value, and enhanced rutting resistance compared to the hot-mix asphalt mixture (HMA) of AC-16. These findings suggest that WEREA has the potential to significantly enhance the durability and longevity of asphalt pavements. For future applications, it can be explored for use in producing cold recycled asphalt mixtures. In addition to designing the WEREA mixture according to AC-16 gradation, consideration can also be given to using a gradation with a smaller nominal maximum aggregate size for the application in the surface layer or ultra-thin wearing course.

The effect of anionic emulsifiers’ diversity and manufacturing processes on the stability and mechanical properties of the water-based epoxy-emulsified asphalt

Emulsified asphalt mixtures’ cold mix and paving features facilitate asphalt pavements in fulfilling dual-carbon and energy-saving demands. Anionic emulsifiers can enhance emulsion stability, ensure uniform dispersion of oil and water, possess good decompression viscosity, thickening, and lubricating properties, and maintain good stability under acidic conditions. Nevertheless, anionic emulsified asphalt is restricted in engineering applications due to problems like its storage stability. In this paper, eight anionic emulsifiers and two preparation procedures were chosen for stability tests. Through static tests, storage tests, sieve residue tests, and laser particle size tests, the impacts of emulsifiers on the storage stability and dispersion of asphalt were analyzed. Waterborne epoxy resin exhibits excellent adhesive properties, mechanical properties, chemical resistance, and heat stability. A fluorescence microscope test, static and storage test, laser particle size test, and cementation test were employed to explore the effects of different preparation processes and waterborne epoxy mixing ratios on emulsified asphalt’s storage stability, dispersion stability, and structural stability. The results showed that: (1) the emulsified asphalt prepared with the BWH-02 emulsifier exhibits the best storage stability, and blending with 20% of the waterborne epoxy modifier can notably enhance the bonding properties; (2) the shear strength of the BWH-02 waterborne epoxy emulsified asphalt prepared can reach 1.543 MPa, and the tensile viscosity can reach 0.848 MPa; (3), The emulsified asphalt prepared by the process of modification has better storage stability than that prepared by the side of the emulsification process. Moreover, the storage stability of emulsified asphalt prepared by emulsification and modification is superior to that of the emulsification and modification process. This research provides theoretical and technical support for popularizing and applying cold-mixed cold-paving asphalt mixtures.

Effects of Polymer-Curing Agent Ratio on Rheological, Mechanical Properties and Chemical Characterization of Epoxy-Modified Cement Composite Grouting Materials.

This study designs and uses water-borne epoxy resin (WBER) and curing agent (CA) to modify traditional cement-based grouting for tunnels. The purpose of this paper is to analyze the rheological and mechanical properties of composite grouting with different ratios of WBER and CA and analyze the modification mechanism by means of chemical characterization to explore the feasibility of WBER as a high-performance modifier for tunnel construction. The composite grouting is prepared by mixing cement paste with polymer emulsion. A series of experiments was carried out to investigate the effects of WBER and CA, including the slump test, viscosity, rheological curve, setting time, bleeding rate, grain size distribution, zeta potential, compressive and splitting tensile strength, X-ray diffraction(XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM), on the composite grout. The results show that WBER improves grout fluidity, which decreases in combination with CA, while also reducing the average particle size of the composite grout for a more rational size distribution. Optimal uniaxial (38.9%) and splitting tensile strength (48.7%) of the grout are achieved with a WBER to CA mass ratio of 2:1. WBER accelerates cement hydration, with the modification centered on the reaction between free Ca2+ and polymer-OH, significantly enhancing the strength, fluidity, and stability of the polymer-modified composite grout compared to traditional cement-based grouting.

Improvement of the Abrasion and Corrosion Resistance of a Waterborne Epoxy Coating by α-ZrP@PTA-Ce(III) with Dual Corrosion Inhibition Effects.

The introduction of poly(tannic acid) (PTA) and cerium ion [Ce(III)] on the surface of α-zirconium phosphate (α-ZrP) endowed the α-ZrP@PTA-Ce(III)/waterborne epoxy composite coating with enhanced corrosion protection and wear resistance performances. The successful preparation of α-ZrP@PTA-Ce(III) was confirmed through X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectra. PTA improved the compatibility between α-ZrP@PTA-Ce(III) and the waterborne epoxy resin due to the presence of organic groups from tannic acid. The wear resistance test indicated that the incorporation of α-ZrP@PTA-Ce(III) effectively reduced the coefficient of friction and the wear rate. Electrochemical impedance spectroscopy was used to analyze the corrosion protection performance of unbroken coatings and the self-healing ability of scratched coatings. The incorporation of α-ZrP@PTA-Ce(III) improved the protection performace distinctly. In addition, α-ZrP@PTA-Ce(III) endowed the composite coating with dual corrosion inhibition effects, originating from the PTA film, to prevent the penetration of corrosive media and a dense film that came from the Ce(III) cation. The waterborne epoxy system with enhanced corrosion and wear resistance in this paper broadens the application of α-ZrP.

Preparation and performance characterization of waterborne epoxy resin modified asphalt emulsion for tack coat

In order to eliminate the possible drawbacks of waterborne epoxy resin (WER) generated by the phase inversion method and the chemical modification method, this study prepared WER using a novel method, i.e., epoxy resin was introduced into the molecular structure of aqueous acrylic resin; after the combination of epoxy resin and the aqueous dispersion process, the aqueous epoxy acrylic resin can be prepared. Waterborne epoxy resin modified emulsified asphalt (WEREA) was then prepared for the application of a tack coat material. Fourier Transform Infrared Spectroscopy (FTIR) test was conducted to explore the possible reactions between the compositions. A rheology test, direct tension test, pull-off bonding test, and oblique shear test were also conducted. Results indicated that in the FTIR test, a new peak around 1732 cm−1 was formed due to the reaction between the carboxyl functional group in WER and the amino group in curing agent to form an ester bond. The incorporation of WER led to an elevation in the complex modulus and a simultaneous reduction in the phase angle of WEREA. When the temperature was larger than 60 °C, the phase angle showed a decreased trend, indicating the material became less viscous due to the increased temperature, illustrating thermosetting characteristics of epoxy resin. As the content of waterborne epoxy resin (WER) increased, there was an observed decrease in the direct tensile rate, coupled with a concurrent increase in direct tensile strength. When the ratio of emulsified asphalt and WER was 1:0.6, the tensile strength of WEREA increased by 811% in contrast to the specimen without the inclusion of WER. There existed different optimal WER contents for the pull-off strength tests conducted on different substrates. For asphalt concrete substrate and steel slab substrate, the optimum ratio of emulsified asphalt to WER + curing agent was 1:0.4, and 1:0.8 was the optimum ratio for the cement concrete substrate. When the ratio between emulsified asphalt and the combination of WER along with the curing agent was 1:0.4 (WEREA-4), the oblique shear strength obtained the maximum value, which was increased by 18.7% in contrast to WEREA-0.

Study on the restoration of glass slides dating back to the 1940s

The Museum of Sun Yat-sen University houses a collection of antique glass slides dating back to the 1940s. These historical artifacts not only serve as a record of the past but also bring history to life. During extended storage, the emulsion layer on glass slides may harden and become brittle, leading to cracking and buckling. This study suggests a method to enhance the physical property of the emulsion layer by using a combination of nonionic surfactant isomeric alcohol ethoxylates eight (TO-8) and waterborne epoxy resin (WER). We investigated the microscopic action mechanism of the two on the emulsion layer of glass slides using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), water contact angles, and other techniques. Our study revealed that TO-8 can significantly eliminate the spherulitic crystal structure of the emulsion layer, as well as improve its softness and hydrophilicity. The addition of the WER ensures that the cracking and warping of the emulsion layer film is fully corrected, resulting in a flat surface. Additionally, the size of the emulsion layer film remains stable even after wetting. The WER has minimal impact on the image information of glass slides. The emulsion layer of the glass slides, restored using the softening protection solutions developed in this study, showed almost full recovery of image information. This research holds significant theoretical and practical value for repairing cracked and warped emulsion layers on glass slides.

Preparation and Characterization of Graphene Oxide/Carbon Nanotube/Polyaniline Composite and Conductive and Anticorrosive Properties of Its Waterborne Epoxy Composite Coatings.

The organic coating on the surface is common and the most effective method to prevent metal materials from corrosion. However, the corrosive medium can penetrate the metal surface via micropores, and electrons cannot transfer in the pure resin coatings. In this paper, a new type of anticorrosive and electrically conductive composite coating filled with graphene oxide/carbon nanotube/polyaniline (GO/CNT/PANI) nanocomposites was successfully prepared by in situ polymerization of aniline (AN) on the surface of GO and CNT and using waterborne epoxy resin (WEP) as film-forming material. The structure and morphology of the composite were characterized using a series of characterization methods. The composite coatings were comparatively examined through resistivity, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and salt spray tests. The results show that the GO/CNT/PANI/WEP composite coating exhibits excellent corrosion resistance for metal substrates and good conductivity when the mass fraction of GO/CNT/PANI is 3.5%. It exhibits a lower corrosion current density of 4.53 × 10-8 A·cm-2 and a higher electrochemical impedance of 3.84 × 106 Ω·cm2, while only slight corrosion occurred after 480 h in the salt spray test. The resistivity of composite coating is as low as 2.3 × 104 Ω·cm. The composite coating possesses anticorrosive and electrically conductive properties based on the synergistic effect of nanofillers and expands the application scope in grounding grids and oil storage tank protection fields.

Tri-source integrated adenosine triphosphate complexed copper ions anchored to boron nitride surfaces for enhancing flame protection of waterborne epoxy coatings

The abundant C, P, and N elements in the structure of adenosine triphosphate (ATP) can act as carbon, acid, and gas sources, and thus can be used as an efficient intumescent flame retardant. Here, a layer of polydopamine (PDA) with polyhydroxyl groups was firstly loaded on the surface of BN to provide a bridging effect for the surface modification of BN. Then, ATP-Cu was immobilized on the BN surface by complexation of ATP with Cu2+, resulting in an efficient inorganic-organic-metal composite flame retardant (BNP@ATP-Cu). This composite flame retardant effectively combined the high barrier effect of BN, the high swelling property of ATP and the catalytic carbon formation activity of Cu2+. The experimental results revealed that the EP loaded with BNP@ATP-Cu showed the lowest backside temperature (171.2 °C), indicating the highest thermal barrier effect. Moreover, BNP@ATP-Cu/EP exhibited the most significant swelling characteristics (22.7 mm, 17.46) and smoke suppression effect (42.8 %). In contrast, the carbon residue of BNP@ATP-Cu/EP (30.8 %) was significantly higher than that of the other coated samples, which was related to the combined effect of BN and ATP-Cu. The above relevant results fully demonstrated the effectiveness of the composite flame retardants in improving the fire resistance of epoxy coatings.