Resin Coatings Research Articles

Effects of MOFs-derived Ni@NC/CNT nanocomposites on impermeability and microwave absorption of modified epoxy resin coatings on cement-based materials

Human health and information security are harmed by electromagnetic wave (EMW) energy’s constant increase and various reflections. In this study, Metal-organic frameworks (MOFs) derived metal nickel@nitrogen-doped porous carbon/carbon nanotube (Ni@NC/CNT) nanocomposites with excellent EMW absorption performance were utilized to modify epoxy resin coatings on the cement-based materials. Surprisingly, when the dosage is 3 wt%, the cement-based materials coated with the modified epoxy resin coatings show outstanding permeability resistance and EMW absorption properties. The capillary water absorption coefficient and the chloride ion diffusion coefficient are 37.583 and 2.42 × 10-12 m2 s−1, which are 88.05% and 73.2% respectively lower than that of the uncoated specimen. The excellent EMW absorption performance was concretely manifested that the minimum reflection loss (RLmin) value is −45.76 dB, the effective absorption bandwidth (EAB) value is 12.88 GHz, and the effective practical application bandwidth (EPB) value is 15.04 GHz. Additionally, the modified epoxy resin coatings also exhibit exceptional thermal stability and mechanical properties, which are further analyzed with TGA and SEM results. These outstanding properties are attributed to the good compatibility between Ni@NC/CNT nanocomposites and epoxy resin, higher cross-linking densities, favorable nano-size effect, and the excellent EMW performance of Ni@NC/CNT nanocomposites. This work is extremely helpful for improving EMW absorption and other properties of epoxy resin coatings on cement-based materials.

Adhesion enhancement and protection of concrete against aggressive environment using graphite-Fe2O3 modified epoxy coating

This study aimed to improve the performance of epoxy resin coatings for protecting concrete structures from chemical corrosion and surface abrasion. The research involved incorporating Fe2O3 nanoparticles into a carbonaceous matrix in a two-part epoxy resin coating. Concrete slabs with the modified coating underwent accelerated ageing under harsh conditions. It was found that the nanomodified coatings showed a significant improvement in performance compared to unmodified coatings. The effect of the amount of composite added to the epoxy system was analyzed. Results show that adding 3 wt% of the synthesized Fe2O3 nanoparticles into a graphite carbonaceous matrix offered the most promising adhesion values. Moreover, adding 3 wt% of the composite into epoxy resin fulfilled a compromise between adhesion improvement and limiting solubility. Finally, it was found a reduction in the number of nanoparticles emitted after ageing. Overall, the incorporation of Fe2O3 nanoparticles into epoxy resin coatings shows potential for improving their performance and durability.

Preparation of polyaniline/cellulose nanofiber composites with enhanced anticorrosion performance for waterborne epoxy resin coatings

AbstractIn this work, polyaniline‐cellulose nanofiber (PANI‐CNF) nanocomposites were prepared by in‐situ polymerization of aniline on 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) oxidized CNFs. Fourier transform infrared spectroscopy and transmission electron microscope demonstrate the successful polymerization of aniline on CNFs. The PANI‐CNF nanocomposites were added as nanofillers to waterborne epoxy resin (WER) in different proportions. The composite coatings with different contents of PANI‐CNFs were prepared by fabricating the mixture on the Q235 steel sheets. The corrosion resistance of different coatings was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy. The results confirmed that composite coatings containing 0.5% PANI‐CNF exhibit the optimum anticorrosion behaviors and best corrosion resistance, which shows the lowest corrosion current density (1.788 × 10−7 A/cm−2) and highest corrosion potential (−0.458 V). In addition, PANI‐CNF can significantly enhance the anticorrosion performance of WER coatings and maintain a high value even after 40 days of immersion in NaCl solutions. The above performances are attributed to the synergistic effect of the barrier effects and the passivation mechanism. Therefore, the bio‐based composite materials developed in this work are promising in enhancing the corrosion protection of mild steel, which is essential for the sustainable development of waterborne coatings.

Synthesis of magnetic targeted delivery microcapsules and its anti-corrosion self-healing behavior in epoxy resin coatings

This study proposed a tung-oil based magnetic targeted delivery microcapsules (MDTMs) to enhance the efficiency of self-healing coatings (SHC). Magnetic particles were used as function particles and emulsifier in synthesis of microcapsules (MC). DSC, OM, SEM, TEM, VSM, NSS, EIS and SKP were used to characterize the compounds, structure, healing behavior and anti-corrosion performance. Results indicate that magnetically driven SHC (MD-SHC) reduces 50% migration path of the released tung oil, and increases the release rate of tung oil after the coating is mechanically damaged. SKP and EIS results suggest that the healing part has impressive anti-corrosion performance, scratches were filled with a large amount of tung oil in a short time, and the released tung oil had formed a complete oil film on scratches at 24 h with higher polarization resistance (Rp). Rp of MD-SHC (2.5 × 105–3.6 × 105 Ω cm2) is 2.0–2.8 times of that the SHC (1.1 × 105–1.8 × 105 Ω cm2). The enrichment in MD-SHC at the interface decreases bonding strength from 7 to 4.5 MPa as the mass additive of microcapsules reaches 15 wt.%. The current work proves the effectiveness of MD-SHC in improving self-healing ability.

Microstructures, absorption and adhesion evolution of FeCoCr/silicone resin coatings at elevated temperature

Heat-resistant magnetic microwave absorption coatings are vital important for the stealth safety of apparatus working at elevated temperature or electromagnetic compatibility of high density/power electronic devices. In this work, we proposed a heat-resistant coating with nanocrystalline FeCoCr micropowders as the absorbents and silicone resin as the matrix. The evolution of microstructure, absorption and adhesion of FeCoCr/silicone resin coatings were investigated after heat treatment at 400°C. The results show that the roughness of FeCoCr powders slightly increased due to the formation of nanoparticles, while their crystalline phase maintained body-centered cubic structure with grain size increasing from 10.8 nm to 18.1 nm after heat treatment. The saturated magnetization and coercivity of FeCoCr powders also increased after heat treatment. The adhesion of FeCoCr/silicone resin coatings exhibited sharp increase with the extension of heat treatment time, i.e., from 7.59 MPa at room temperature to 11.78 MPa after heat treatment at 400°C for 10 h; this phenomenon occurred due to the condense of FeCoCr-resin interfaces. The complex permittivity of the coating was reduced after heat treatment, while the complex permeability increased; this gave rise to enhancement of microwave absorption and showed the working potential of the FeCoCr/silicone resin coatings at elevated temperature.

Textured epoxy resin coatings for corrosion resistance

Textured epoxy resin coatings for corrosion resistance

Structural control of PEG-intercalating Na-bentonite and its influence on the properties of castor oil-based polyurethane coating

Although controlled-release fertilizer (CRF) is a safer and more efficient strategy to administer nutrients for plant growth, it is still a daunting task to reduce the cost and improve the degradability of the synthetic resin coatings. In this paper, an inorganic/organic composite coating for urea fertilizer was prepared from a biodegradable castor oil-based polyurethane (PU) filled with the layered Na-bentonite (Na-BT), which was ultrasonically treated by a series of green PEG surfactants. Synergistically influenced by various intercalation ability, cation-hosting ability and hydrophilicity of the PEGs, the porous structures of the modified Na-BT (MBT) fillers were simply tuned by varying the Mn molecular weights of the PEGs, resulting in the adjustable water swelling and mechanical properties of the MBT/PU composites. Moreover, it was confirmed that the water swelling property played a critical role in controlling the early stage of nutrient release, and the mechanical properties were important for the longevity of nutrient release from the CRFs. The best MBT/PU composite supported a CRF with a long-term release of 75 % in 38 days, which was much longer than the one based on pure PU (20 days).

Shrinkage stress of thermal cured epoxy resin reduced by addition of functional hollow microspheres

The shrinkage stress of thermal cured epoxy resin developed during curing process can cause low film adhesion strength, low dimensional accuracy and even coating films warping which severely reduce service lifetime of the coating. Therefore, there is growing interest in developing effective means to reduce the shrinkage stress. In this paper, we report the use of hollow microspheres prepared from Pickering emulsion droplets in the thermal cured epoxy resin formulations and the shrinkage stress due to resin solidification is monitored in real time to reveal the effect of hollow microspheres upon shrinkage stress of the resin. Epoxy group functionalized silica nanoparticles from the Stöber method are used as Pickering emulsion stabilizer and the emulsion droplets are polymerized to obtain hollow microspheres with controllable mechanical properties and surface morphologies. Due to the reactivity of the hollow microspheres, they can be incorporated into the epoxy resin coatings and the shrinkage stress is thus reduced with the addition of hollow microspheres. It is revealed that the shrinkage stress is reduced from 195.79 kPa to 140. 40 kPa with the addition of 12 wt% hollow microspheres and polydisperse hollow microspheres are more effective in shrinkage stress reduction. As the modulus of the hollow microspheres is reduced and elasticity is increased, the shrinkage stress of the coating film is also reduced from 181. 37 kPa to 157.42 kPa which is not achieved by hollow glass microspheres. The hollow microspheres are well dispersed in the resin matrices which doesn't undermine the basic mechanical properties of the coating such as adhesion and surface hardness.

Polydopamine/polyethyleneimine co-crosslinked graphene oxide for the enhanced tribological performance of epoxy resin coatings

• GO were co-crosslinking modified through an environmentally friendly, simple and low-cost process. • Dispersion and surface activity of GO were enhanced by the covalently cross-linked network. • Friction and wear rate of the EP coating reduced by 31.9% and 62.7%, respectively. • Formation of GO lubrication transfer film played the role in friction and wear reduction. To enhance the wear resistance of graphene oxide (GO) nano-filled epoxy resin (EP) coatings with excellent dispersion, GO were modified using a co-crosslinking strategy between polydopamine (PDA) and polyethyleneimine (PEI) through an environmentally friendly, simple and low-cost process. High-density amino-branched PEI and highly adhesive PDA formed covalent bond cross-links with GO (PDA/PEI-GO) through the Michael addition and Schiff base reactions. With the introduction of amino active sites, the PDA self-polymerization reaction time was significantly shorted from 24 h to 6 h. The covalently cross-linked network increased the lamellar spacing of GO and enhanced the interfacial bonds between the PDA/PEI-GO lamellae and EP matrix. Due to the improved dispersion and surface activity of GO, the PDA/PEI-GO nano-filled EP coating exhibited excellent wear resistance. Reciprocating friction with GCr15 stainless steel ball, the average friction coefficient and wear rate of the coating were reduced by 31.9% and 62.7%, respectively, compared to the pure EP coating. In addition, the wear mechanism of the PDA/PEI-GO/EP coating changed from adhesive and fatigue wear to abrasive wear, and it maintained good wear resistance by forming a GO lubrication transfer film on the counterpart surface. Therefore, this study may provide a new strategy for improving the dispersion of graphene in wear-resistant polymer materials for practical applications.

Amorphous cellulose edge-functionalized graphene oxide for anticorrosive reinforcement of waterborne epoxy coatings

Graphene oxide (GO) has been extensively used as a filler in anticorrosion coatings; however, it is still limited by its dispersity and interfacial compatibility in the coating matrix. In this study, amorphous cellulose (AC) edge-functionalized GO was fabricated by electrostatic self-assembly of negatively charged AC (NAC) and positively charged GO (NGO). The assembly structure was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), and further directly observed by high-resolution transmission electron microscopy (HRTEM). NAC enhanced the anticorrosion performance of NGO as a nano-filler in waterborne epoxy resin (WEP) coatings, because the NAC/NGO composite was well dispersed and had strong interfacial interactions with the matrix. Furthermore, even when the immersion time was 1024 h, impedance values of 2.0 wt% NAC/NGO@EP at the low-frequency (f = 0.1 Hz) was 8.955 × 108 Ω·cm2, which is three orders of magnitude higher than that of pure epoxy resin (EP). Thus, the developed method of amorphization and electrostatic self-assembly is suitable to fabricate composites of cellulose and other two-dimensional (2D) materials.

The thermal behavior and flame retardant performance of phase change material microcapsules with halloysite nanotube

Phase change material (PCM) has the potential to be added in coatings for energy-saving while the drawback of low thermal conductivity, poor thermal stability and flammability restrict its application. In this study, a novel halloysite nanotube (HNT) doped PCM (H-PCM) microcapsule was successfully prepared and applied in epoxy resin (EP) coatings (H-PCM-EP) to achieve temperature control. Many characteristics of the prepared PCM microcapsule were examined such as surface morphology, phase transformation performance and combustion data. The results indicated that the H-PCM microcapsule with a clear core-shell structure were successfully prepared. In comparison with the pristine PCM microcapsule, the H-PCM microcapsule had better thermostability and thermal conductivity. While the melting process of capric acid in H-PCM microcapsule advanced from 31.62 °C to 31.04 °C when compared with PCM microcapsule, which was considered as the bridge-like function of HNT. Moreover, the flammability and temperature control ability of H-PCM-EP were also investigated. The data of the peak heat release rate, total heat release, and total smoke release showed that the addition of HNT in PCM microcapsule can significantly reduce the influence of PCM in EP composites on fire hazards. Notably, the results of the small room model test and infrared thermal imager suggested that the application of H-PCM-EP can regulate inner room temperature and maintain a comfortable temperature range with less fluctuation. These properties will promote the application of the H-PCM microcapsule in temperature control coatings.

Interfacial Properties of Graphene Oxide/Epoxy Resin Coatings in Corrosive Environments

Graphene oxide/epoxy composite coatings have attracted much attention from researchers due to their excellent anti-corrosion properties. Graphene oxide as a two-dimensional nano-filler can enhance the overall properties of epoxy resin coatings. In the paper, models of graphene oxide/epoxy composite coatings with different permeation degrees are constructed respectively. The interfacial interaction between GO and epoxy resin and the adsorption properties of epoxy coating with metal are analyzed from an atomic perspective by molecular dynamics simulations. The results indicate that the interfacial adsorption effect of the epoxy coating on the protected metal is stronger than the interfacial bonding of GO on the epoxy resin matrix. Simulations of models with different degrees of permeation suggest that the permeation of the NaCl solution occupies the interfacial space and reduces the adhesion between the two interfaces.

Design and enhanced anticorrosion performance of a Zn5Mo2O11·5H2O/h-BN nanocomposite with labyrinth of nanopores.

Zinc molybdate (ZMO) is a safe and effective grafting material for anticorrosion. Herein, we reported the synthesis of ZMO/h-BN with the labyrinth of capillary pores owing to the in situ growth of ZMO on flake hexagonal boron nitride (h-BN) using the hydrothermal method. The special morphological structure provided a tortuous path for aggressive species to the steel substrate, which extended and blocked the transmission of aggressive species, enhancing the physical corrosion barrier performance. In addition, the capillary pores of ZMO contributed to the competitive adsorption of Cl- in an electrolyte and reduced the diffusion of aggressive species, thus further delaying the corrosion process. Moreover, the capture of oxygen by forming a B-O bond with h-BN and the formation of a molybdate passive film are beneficial for the inhibition of cathodic and anodic reactions. As verified by electrochemical impedance spectroscopy (EIS), the anticorrosion performance of ZMO/h-BN coating increased by 49.58% and 130.72% compared with ZMO and epoxy resin (EP) coatings after immersing in a NaCl aqueous solution (3.50 wt%) for 72 h. This coating matrix provides an avenue for molybdate-based corrosion remediation.

Preparation and anti-corrosion properties of 8-HQ@SiO2@AK/EP composite materials

Epoxy coatings are popular due to their strong adhesion, low cost, and superior thermal and electrical insulation. Unfortunately, surface defects in epoxy resin lead to surface cracks, limiting the long-term use of epoxy resin coatings in humid marine environments. In this study, modified kaolin (Kaolin) was added to an epoxy resin (EP) to enhance its corrosion resistance, and a silane coupling agent 3-aminopropyltriethoxysilane (APTES), tetraethyl orthosilicate (TEOS), and 8-hydroxyquinoline (8-HQ) were chosen as modifiers. This resulted in the composite 8-hydroxyquinoline/silica/amino kaolin (8-HQ@SiO2@AK), and the structural makeup, loading, hydrophobic characteristics, surface roughness, and corrosion resistance of 8-HQ@SiO2@AK and 8-hydroxyquinoline/silica/amino kaolin/epoxy resin composite coating (8-HQ@SiO2@AK/EP) was investigated. Based on these findings, the maximum contact angle of the hydrophobic composite coating was 88°, its roughness Ra was 3.09 nm, and the hardness and adhesion were unaltered compared to silica-modified kaolin/epoxy composite coatings (SiO2@AK/EP). The impedance modulus |Z|0.01 Hz of the composite was 3.662×109 Ω • cm2 after 30 days of immersion, which indicated significantly enhanced corrosion resistance.

Effect of polishing methods on the surface roughness of different temporary restorative materials

Aim: The purpose of this study was to evaluate the effects of different polishing methods on the surface roughness of temporary prosthetic restorations. Methodology: In this study, 200 specimens were obtained from Structur 2, Imident, FSM Duo CAD, and Han Temp Crown. All specimens were sanded with 400-, 800-, and 1000-grit silicon carbide. Next, the specimens were divided into five subgroups (n = 10). The specimens in first group were sanded with 1200-, 1600-, and 2000-grit silicon carbide sandpaper. The second group was polished with an aluminum oxide-containing disc. The third group was polished with a diamond-containing pad. A glaze bond was applied to the specimens in the fourth group. The fifth group was glazed with a coat of nano-filled resin. Then, the surface roughness of all specimens was measured with a profilometer. A two-way ANOVA test was performed using SPSS 20.0. Finally, the microstructures of the surfaces were examined by a scanning electron microscope at 5000× magnification. Results: Statistically significant results were obtained between the temporary materials and polishing methods in terms of surface roughness (p < 0.05). For the polishing method, the highest surface roughness values were observed in the control group (0.50 ± 0.15). The lowest surface roughness values were observed in the Equia Forte GC coat group (0.25 ± 0.10). Among the temporary crown materials, the highest roughness was observed in Imicryl specimens. (0.45 ± 0.17), while the least roughness was the polymethyl-methacrylate (PMMA) specimens (0.17 ± 0.10). Conclusion: Surface polishing and finishing procedures might positively affect the surface roughness of temporary materials. Furthermore, materials made via computer-aided design and computer-aided manufacturing (CAD-CAM) demonstrate structural advantages and may be preferable. How to cite this article: How to cite this article: Kavut İ, Uğur M, Tanrıkut ÖO. Effect of polishing methods on the surface roughness of different temporary restorative materials. Int Dent Res 2022;12(3):149-57. https://doi.org/10.5577/intdentres.2022.vol12.no3.7 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Enhanced wear resistance while maintaining transparency of epoxy resin coatings filled with novel one-dimensional magnesium borate hydroxide nanorods

Wear resistance and transparency are critical properties of polymer coatings. In this study, a novel nanocoating filler composed of one-dimensional inorganic magnesium borate hydroxide (MBH) nanorods was used to improve the wear resistance and transparency of epoxy resin (EP) coatings. After successfully synthesizing MBH nanorods, different amounts were added to EP coatings to prepare EP/MBH nanocomposites, denoted as ExMBH (x = 1, 5, and 10 wt% MBH). The transparency and wear resistance of the neat and MBH-filled EP coatings were estimated using optical transmittance and nanoscratch testing, respectively. The results indicate that E10MBH displays a transmittance of more than 85 % in the visible region and a low value in the UV region, resulting from the similar refractive indices of the MBH filler and EP. Additionally, the scratch recovery index and scratch hardness increase by 53 % and 22 %, respectively, while the plastic deformation energy decreases by 67 % compared to that of the neat EP coating. The E10MBH nanocoating presents excellent wear resistance due to the formation of a solid three-dimensional network structure between EP and MBH. This paper demonstrates an effective strategy for designing inorganic nanofillers to improve the mechanical durability and optical properties of EP nanocoatings.

Effect of SiO2-MWCNTs on Mechanical and Tribological Properties of Acrylic Silicone Resin Coating

Effect of SiO2-MWCNTs on Mechanical and Tribological Properties of Acrylic Silicone Resin Coating

Formulation of Drying and Non Drying Oil Alkyd Resin from Palm Oil (Elaesis guineensis jacq.) and Tuna Fish Oil (Thunnus sp.) toward Acid Number Value and Non Volatile Content as Surface Coating Resin

Resin is a polymer chemical substance that is made up of monomers from carbon and nitrogen. Alkyd resin, a surface coating resin, produced by polycondensation reaction between polybasic and polyhydric alcohols, modified with monobasic acids or their anhydrides, and drying oil at controlled temperatures. Alkyd resin is widely used in the paint and surface coating industries. The advantages of this resin are its strong chemical and thermal resistance, quick drying power, and inexpensive cost. Alkyd resins can be produced from natural oil (palm and tuna fish oil). Oil derived from palm and tuna fish is known as natural oil. Tuna fish oil includes 40.04 % oleic acid. The oleic content is suitable for use in the alcoholysis process in the production of alkyd resins. The major ingredients in this study were tuna fish oil and palm oil. The aim of this research is to determine the influence of a combination of palm oil:tuna fish oil ratio, amount of pthalic anhydride, and temperature of alcoholysis process on the value of acid number and non-volatile content of alkyd resin was investigated using a Completely Randomized Design (CRD).

Fundamental understanding of the thermal properties of amorphous epoxy resin coatings filled with quartz-feldspar powder sourced from quarry waste

In the present work, a novel coating modified with quartz-feldspar powder (QFP) was prepared in order to overcome the well-known technical problems related to the thermal behavior of epoxy resin (ER) coatings. The degradation of floor coatings is often caused by thermal shock and depends on the difference in the thermal expansion between the ER coating and the substrate. The thermal expansion is strongly related to the thermal gradient. Therefore, the specimens were tested using differential scanning calorimetry in order to analyze the regions of the viscoelastic behaviors, the glass transition temperature, the specific heat capacity, the slopes of heat capacity, and the energy required to change the temperature of the material. The application of QFP reduced the value and slope of the specific heat capacity of the composite. The modification of the coating inhibits the growth of temperature, which in turn can reduce the risk of delamination caused by thermal shock. It also improves the adhesion of the coating the concrete substrate. The novelty of the article involves a detailed description of the influence of QFP waste on the thermal behavior of ER, as well as its effect on the thermal shock degradation of industrial floor coatings.

Steady superlubricity achieved by epoxy resin composite coatings containing polydimethylsiloxane

Epoxy resin (EP) coatings have been widely applied in the field of surface protection engineering due to their high adhesion and good corrosion resistance, but the high friction and low wear resistance of pure EP coatings restrain their service life. Developing superior EP coatings with superlubricity and good antiwear performance is extensively desirable but remains to be a challenge yet. Here we for the first time report a superlubricious epoxy resin composite coating containing polydimethylsiloxane, PDMS (EP/PDMS) prepared by a facile solvent evaporation method. The PDMS was found to self-aggregate into nanoparticles in the epoxy resin matrix and leaded to the enhancement of tensile toughness of the epoxy resin coatings. The composite EP coatings containing PDMS performed steady superlubricity and high wear resistance when sliding against different bearing materials. Especially, an exceptionally and stable low friction coefficient of 0.007 was achieved by rotationally rubbing on the EP composite coating with a small content of 3.0 wt% against silicon nitride (Si3N4) ball in ambient air with a high relative humidity of 70 %, and the average wear rate of the EP/PDMS composite coating was as low as 2.76 × 10−7 mm3/N·m in spite of its low hardness.