Study on preparation and anticorrosive performance of a new high hydrophobic anticorrosive coating

Water-based anticorrosive coatings have poor water resistance, which easily lead to coating deterioration and metal corrosion. In order to improve the anticorrosion performance of waterborne coating, herein, the polytetrafluoroethylene/dimethyl siloxane/epoxy resin (PTFE/PDMS/EP) hydrophobic anticorrosive coating was prepared by layer-by-layer construction. The spatial structure and microscopic morphology of the hydrophobic coating were analyzed by XRD, FTIR, and SEM. The hydrophobicity and corrosion resistance of the composite coating were analyzed by hydrophobicity test, electrochemical polarization curve, hydrophobicity and corrosion resistance test of the mixed layer, Tafel polarization curves, and AC impedance spectrum. The results showed that the water contact angle of PTFE/PDMS/EP coating reached 141° and the protection efficiency of PTFE/PDMS/EP coating was 98.62%. After soaking for 7 days, the corrosion process still stays at the initial stage, which was mainly due to the good sealing and barrier properties and high anticorrosion efficiency of PTFE/PDMS/EP coating. The coating has high corrosion protection efficiency and long service life, which is of great significance to metal corrosion protection in harsh marine environments.     

用杜仲胶/碳纳米管改性环氧树脂制备导电防腐涂料及其性能

以杜仲胶(EUG)和环氧树脂(E-51)为涂层基质、碳纳米管为导电填料制备了导电防腐涂料,考察了 EUG用量对复合涂层导电性和耐腐蚀性的影响.采用差示扫描量热仪和动态热机械分析仪研究了复合涂层的热性能,用四探针测试仪研究了导电性能,分别通过电化学阻抗谱及盐雾测试和附着力测试研究了耐腐蚀性和附着力.结果表明,当EUG用量...     

Synergic enhancement of the anticorrosion properties of an epoxy coating by compositing with both graphene and halloysite nanotubes

The aim of this research was to improve the corrosion resistance of metal surfaces with polymer coatings. Both graphene and halloysite nanotubes (HNTs) were introduced together into the epoxy resin coating for the enhanced barrier protection of the metallic surface. The anticorrosion behaviors of different coatings were comparatively evaluated by the potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. The potentiodynamic polarization curves showed that the coating containing 0.5 wt % HNTs and 0.8 wt % graphene (H05G08EP) together had the most positive corrosion potential and the minimum corrosion current density. The EIS results revealed that graphene endowed the composite coatings with excellent electrochemical performance for anticorrosive purposes. The NSS tests indicated that H05G08EP endured the longest NSS time. These results suggest that H05G08EP had the best corrosion resistance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47562.     

氧化石墨烯改性环氧树脂涂料的制备及防腐性能

环氧树脂在溶剂蒸发过程中容易产生微孔,影响其防腐蚀性能。为了提高其对腐蚀介质的阻碍能力,本文采用密闭氧化法制备氧化石墨烯,再利用湿式转移法将氧化石墨烯水溶液分散在环氧树脂中,制备氧化石墨烯/环氧树脂防腐涂料。通过红外光谱（FTIR）、X射线衍射（XRD）和拉曼光谱（Raman）分析氧化石墨烯的结构变化,利用开路电位测试（OCP）、水接触角、腐蚀形貌和气体透过率分析氧化石墨烯/环氧树脂涂料的防腐性能。结果表明,氧化石墨烯/环氧树脂（GO/EP）涂料的开路电位和水接触角分别为0.181V和86.12°,与纯环氧树脂涂料相比,分别提高了0.066V和10.5°;当GO/EP浸泡在3.5%NaCl溶液中腐蚀20天后,表面仅产生了粗糙化,涂层稳定性好,屏障性能强;与EP涂层相比,GO/EP涂层的O₂和H₂O渗透率分别降低了51.2%和65.5%。     

AZ31镁合金表面防腐胶粘涂层的研制

胶粘涂层法是有效提高镁合金耐腐蚀性能的表面处理技术之一.以E-44环氧树脂、低分子量650#聚酰胺、云母氧化铁等为主要原料,制备了适用于AZ3l镁合金基体的防腐胶粘涂层.研究了填料含量对涂层外观、施工性和耐蚀性能的影响.结果发现,当填料质量分数为60%、涂层厚度为180～220μm时,防腐胶粘涂层具有良好的外观及施工性,附着力为1级,耐盐雾时间168 h.     

Incorporation of silica network and modified graphene oxide into epoxy resin for improving thermal and anticorrosion properties

In this study, the silica network and functionalized graphene oxide (GO) were incorporated into the epoxy coating systems, which was aimed to improve the thermal property and corrosion resistance of epoxy coatings. First, tetraethyl orthosilicate (TEOS) oligomers and epoxy hybrid was fabricated through sol–gel method. Then the (3-aminopropyl) triethoxysilane (APTES) modified graphene oxide (FGO) was added into the epoxy hybrid composite to obtain anticorrosion coatings. Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), Raman spectrum, and X-ray photoelectron spectrum were conducted to evaluate the structural information of GO and APTES modified GO nanosheets. The results indicated that the APTES successfully grafted onto the surface of GO sheets. Besides, TGA curves, electrochemical measurements and salt spray test were also carried out to characterize the thermal performance and corrosion resistance of GO based epoxy coatings. The TGA results revealed that the thermal performance of epoxy coating containing silica network and FGO nanofiller (ES/FGO) was significantly strengthened compared to pure epoxy. The initial degradation temperature of epoxy coating was increased from 300 to 343.7°C after incorporation of silica component and FGO. The EIS measurements demonstrated that the impedance modulus of ES/FGO was significantly higher than neat epoxy, which indicated that the corrosion resistance of epoxy was substantially strengthened after introduction of silica component and FGO. The corrosion rate and inhibition efficiency of epoxy composite coatings were also shifted from 1.237 × 10⁻⁷ mm/year and 76.6% (for neat epoxy) to 1.870 × 10⁻⁹ mm/year and 99.6% (for ES/FGO), respectively. The salt spray test also revealed that the silica and FGO can improve the corrosion resistance of epoxy coating. Additionally, the dispersion of GO sheets was also enhanced after the modification of APTES siloxane.     

纳米/微米复合二氧化钛改性聚氨酯涂层的耐腐蚀性能研究

以微米/纳米二氧化钛(TiO2)为复合填料制备了聚氨酯防腐涂层,采用电化学阻抗谱(EIS)评估含不同用量纳米TiO2涂层在0.5mol/L氯化钠溶液中的耐腐蚀性,结果表明,纳米二氧化钛能有效提高涂层的抗腐蚀能力,其适宜用量为1.0%～1.5%。热分析(包括DSC和TG)结果表明,在有大尺度填料存在的条件下,添加纳米二氧化钛对涂层的热稳定性影响不大。     

ATO/GO纳米复合材料的制备及抗静电防腐性能研究

以氧化石墨烯(GO)作为前体,通过氨丙基三乙氧基硅烷将氧化锡锑（ATO）锚定到氧化石墨烯片层上,制备得到氧化锡锑-氧化石墨烯纳米复合材料（ATO/GO）。通过XRD,XPS和SEM对其结构进行测试。并研究了ATO/GO含量对水性环氧涂料（AE）防腐及抗静电性能的影响。结果表明：随ATO/GO含量的增加,复合涂料表面电阻降低,ATO/GO含量大于3%时,表面电阻降低至108Ω以下,达到了抗静电的使用要求;当ATO/GO含量为3%时,漆膜水蒸气透过率降低至（62.13g/m2 h）,具有最低的腐蚀电流密度（Icorr=3.73E-9 A/cm2）和最高的腐蚀电压（Ecorr=-0.19926v）,防腐效率与空白样相比提高了99.95%。     

Tribological and corrosion performance of epoxy resin composite coatings reinforced with graphene oxide and fly ash cenospheres

In this work, a novel graphene oxide (GO)-fly ash cenospheres (FACs) hybrid fillers was introduced to improve the wear and corrosive resistance of epoxy resin (ER) composite coatings. The tribological behavior and the corrosion performance of three kinds of coatings (pure ER, GO/ER and GO-FACs/ER coatings) were studied and the reinforced mechanisms of coatings filled by different fillers were analyzed. The friction coefficient and wear rate of the ER coatings were decreased with the addition of GO-FACs hybrids. The scanning electron microscope images showed that the dispersibility and compatibility of GO-FACs hybrids were effectively improved compared with that of GO sheet. The water contact angle examination indicated that the hydrophobicity of the GO-FACs/ER coatings increased. The electrochemical impedance spectroscopy (EIS) results demonstrated that the GO-FACs/ER coatings have better anticorrosion performance compared with the pure ER coatings and the GO/ER coatings. The hydrophobic surface and the well dispersed fillers constitute the dual barrier to resist the corrosion medium.     

High performance corrosion protective DGEBA/polypyrrole composite coatings

Conducting polymers (CP) have been envisaged as nontoxic substitutes for chromates in corrosion protective coatings owing to their environmental stability, excellent corrosion resistant performances and good adhesion to metal substrate. Recent advancements in the field of corrosion protective coatings have therefore headed towards the utilization of conducting polymers as “smart corrosion inhibitors” in the formulation of eco-friendly anti-corrosive coatings. With the aim to develop a facile method for the synthesis of anti corrosive coating material having superior corrosion protective properties, the present work reports the corrosion studies of polypyrrole/DGEBA composite coatings on mild steel (MS). The coatings were characterized by physicochemical as well as physicomechanical studies while the corrosion protective performance was evaluated by chemical resistance in different corrosive media, corrosion rate and open circuit potential (OCP) measurements. The morphologies of corroded, coated, uncorroded and uncoated samples were investigated by SEM studies. The composite coatings were found to show far superior anti corrosive performance than PANI/epoxy coatings in acid, alkaline as well as saline environments.     

咪唑啉季铵盐缓蚀剂改性蒙脱土/水性环氧纳米复合涂料

以油酸、二乙烯三胺和氯化苄为原料,合成了油酸基咪唑啉季铵盐缓蚀剂。通过FTIR、¹HNMR对其结构进行了表征,并离子交换至钠基蒙脱土(DK0)层间,制备了缓蚀剂改性蒙脱土(QACDK0)。通过XRD、TGA和UV-Vis对其结构、组成及层间缓蚀剂释放性能进行了表征。结果表明,咪唑啉季铵盐缓蚀剂约占QACDK0质量的38.96%,并将蒙脱土层间距由1.28 nm(DK0)扩大至3.98 nm(QACDK0)。利用DLS及Zeta电位对添加有QACDK0的水性环氧树脂进行了稳定性测试,其Zeta电位为–27.8 m V,具有较高的稳定性。电化学阻抗谱(EIS)测试表明,在腐蚀介质中浸泡30 d后,基于QACDK0制备的清漆漆膜仍具有2.29×10⁸?·cm²的高阻抗,表明涂层具有较好的耐腐蚀性。并且在耐中性盐雾测试中,QACDK0对应的防腐色漆耐盐雾时间最长,验证了该涂层具有良好的耐盐雾性能。     

Anticorrosion reinforcement of waterborne polyacrylate coating with nano-TiO2 loaded graphene

Photocathodic protection coatings have been widely applied in various areas such as ship and architectural protection, or chemical industry. In this work, a composite of titanium dioxide loaded with reduced graphene oxide (RGO/TiO₂) was prepared and used as filler on waterborne polyacrylate (PA) coating to reinforce the metal protection against corrosion. Compared with the current filler of zinc phosphate used for anticorrosive coating, the photoelectrochemical properties of RGO/TiO₂-PA coating exhibit improved photocathodic protection under visible light illumination since RGO/TiO₂ composite has significant superiority in enhancing metal protection due to its dispersion, micropore blocking ability, and photoelectrochemical conversion performance. The mechanism of anticorrosion reinforcement of RGO/TiO₂-PA coating was hypothesized that graphene provides an extrabarrier layer to obstruct corrosive in dark condition and photocathodic protection under lighting. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48733.     

Fabrication of ZnO–GO hybrid for enhancement of chemically bonded phosphate ceramic coatings corrosion protection performance on AISI304L stainless steel

In this paper, a solvothermal method is used to prepare nano-sized zinc oxide-graphene oxide (ZnO–GO) hybrid, and the ZnO–GO hybrid is characterized by X-ray diffraction analysis, Raman, Fourier transform infrared spectroscopy, and scanning electron microscopy. In addition, chemically bonded phosphate ceramics coatings with different content of ZnO–GO hybrid are prepared on the stainless steel through the sol-gel method. The corrosion performance of the coatings is evaluated by electrochemical properties and the analysis of the surface and cross morphology of the coating. Results indicate ZnO–GO hybrid significantly enhances the compactness and corrosive behavior of the coating because the overlapping structure of GO flake improves the barrier performance of the coating. Besides, ZnO nanoparticles on the surface of GO can react with aluminum dihydrogen phosphate binder, in that case the adhesion between GO and the coating is improved.     

Preparation of transparent nanocomposites from UV‐ and thermo‐curable epoxyacrylate and graphene oxide for the application of corrosion protection coatings

In this study, we report UV‐ and thermo‐curable epoxyacrylate/graphene oxide (EA/GO) nanocomposites that present good transparency, excellent pencil hardness and promising improvement in corrosion protection. A dual‐curable EA oligomer with one terminal epoxide and one double bond at the other end was synthesized by reaction of diglycidyl ether of bisphenol‐A and acrylic acid. After mixing EA and GO with the curing agents and reactive diluent followed by UV cure and thermo‐cure, the resulting EA/GO films on a glass slide with GO loading up to 3 phr exhibited over 86% light transmittance. Furthermore, the pencil hardness was enhanced from 3H for EA to 6H for the EA/GO composite at 2 phr GO loading. The corrosion protection of the EA/GO coatings was evaluated by a potentiodynamic polarization technique and electrochemical impedance spectra. The corrosion potential (E_corr) of the EA/GO‐coated steel increased with increasing GO loading. Meanwhile, Nyquist and Bode plots indicated that the higher the GO content in the EA/GO coating was, the higher was the coating resistance and also the charge transfer resistance after immersion in salt solution. All these results proved that the GO had positive effects on enhancement of the corrosion resistance. The improved corrosion protection by the EA/GO coatings was mainly due to the enhanced hydrophobicity, the deviation of electron transfer and the increased tortuosity of the diffusion path. The improved corrosion protection and hardness together with the useful dual‐curability make the EA/GO nanocomposite a competitive candidate for corrosion protection coatings. © 2019 Society of Chemical Industry     

Investigation of the size effect of mica sheets on the anticorrosion behavior of UV-cured coatings

In this article, four different grades of mica sheets were used to investigate the influence of the size of mica sheet on the UV-curing process and the anticorrosion performance of UV-cured coatings. The dispersion of mica sheets in coating matrix was explored by viscosity and morphology measurements. The curing behavior of the composite coatings was studied by gel content and double bond conversion rate. The dispersing behavior of the mica sheets with different grades was investigated by SEM image and rheology measurement. And the anticorrosive performance of the UV-cured composite coatings was studied by electrochemical measurements and neutral salt spray tests. It was found that the curing degree of the UV-cured coating was not affected with incorporation of mica sheet as well as its size. Mica sheets with medium size (10 μm) could be more efficiently dispersed in UV-cured coating than other grades, which helps to form a denser filler pathway and suppresses the diffusion of corrosive agents into the coating matrix, leading to the lowest water adsorption and best anticorrosion performance. After 45 days of immersion in NaCl solution, the impedance modulus of the UV-cured composite coating with 10 μm mica sheets did not decrease and still maintained at the initial impedance value. After 1500 h's salt spray test, the corresponding coating remained intact without bubbling, peeling, corrosion, and other defects, whereas the coating with other grades of mica sheets all exhibited corrosion pits and blisters, demonstrating that the size of mica sheet played an important role in enhancing the anticorrosion performance of UV-cured coatings.     

氨基化GO/磺化聚苯胺改性水性环氧防腐涂料的制备与性能

以氯磺酸、苯胺和过硫酸铵为主要原料合成磺化聚苯胺（SPANI）,利用聚乙烯亚胺（PEI）还原GO,合成PG复合材料。利用GO上活性位点,将SPANI与PG结合,制备了SPG复合材料。利用SPG与水性环氧树脂共混制备水性环氧防腐涂料。通过FT-IR、XRD对SPG复合材料结构表征,结果表明,PEI上的氨基成功与GO结合,SPANI成功增加了PG的层间距;通过盐雾、电化学等实验对水性环氧涂层的防腐性能进行测定,并分析了涂层的物理性能。结果表明,当添加2wt%SPG时（添加量以环氧树脂和固化剂总质量为基准,下同）的水性环氧防腐涂层具有最优异的耐腐蚀性,腐蚀效率可达到99.19%,与纯EP相比,腐蚀电流密度从1080 nA?cm-2减小至307 nA?cm-2,腐蚀电压从-0.840mV升高至-0.347mV。     

Excellent corrosion protection performance of epoxy composite coatings filled with silane functionalized silicon nitride

Silicon nitride was firstly used as anticorrosive pigment in organic coatings. An effective strategy by combining inorganic fillers and organosilanes was used to enhance the dispersibility of silicon nitride in epoxy resin. The formed nanocomposites were applied to protect Q235 carbon steel from corrosion. The anticorrosive performance of modified silicon nitride with silane (KH-570) was investigated by electrochemical impedance spectroscopy (EIS), water absorption and pull-off adhesion methods. With the increase of immersion time, the corrosion resistance as well as adhesion strength of epoxy resin coating and unmodified silicon nitride coating decreased significantly. However, for the modified silicon nitride coating, the corrosion resistance and adhesion strength still maintained 5.7×10¹⁰ Ω cm² and 7.6 MPa after 2400-h and 1200-h immersion, respectively. The excellent corrosion resistance performance could be attributed to the chemical interactions between KH-570 functional groups and silicon nitride powders, which mainly came from the easy formation of Si-O-Si bonds. Furthermore, the modified silicon nitride coating formed a strong barrier to corrosive electrolyte due to the hydrophobic of modified silicon nitride powder and increased bonds.     

Electrodeposition of graphene oxide-hydroxyapatite composite coating on titanium substrate

In this work, graphene oxide (GO)/hydroxyapatite (HA) composite coatings were successfully prepared on titanium substrate by electrophoretic deposition technology. Subsequently, microstructure, phase composition, adhesion strength, hydrophilicity, corrosion resistance, bioactivity, antibacterial activity and biocompatibility of the coating were evaluated. The adhesion strength of coating increased by 76% from 6.46 MPa to 17.81 MPa with 0 wt% GO to 12 wt% GO and the corrosion rate of coating with 8 wt% GO was achieved at the minima of (1.493 × 10^-3mm/a). Biomineralization experiment indicated the excellent bioactivity of GO/HA composite coatings. The water contact angle of the composite coatings increased from 20.6°(0 wt% GO) to 38.1°(12 wt%GO). The antibacterial rates of coating with 5 wt% GO was 96.7%, while declined to 25% after thermal treatment. In-vitro L929 cell culture experiments indicated the composite coatings with 5 wt% GO exhibited good biocompatibility.     

Improved corrosion resistance based on APTES-grafted reduced sulfonated graphene/waterborne polyurethane coatings

In this work, reduced sulfonated graphene (RSG) containing free amine groups was prepared and modified by 3-aminopropyltriethoxysilane (APTES) and reduction by diethanolamine (DEA). In addition, waterborne polyurethane (WPU) composite coatings were prepared by adding RSG as an anticorrosive filler to WPU. From the results of Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM), it can be found that sulfonated graphene was modified with APTES and successfully reduced by DEA. The SEM images illustrated that RSG was uniformly doped in the WPU. With increasing RSG content, the hydrophobicity of the RSG/WPU films increased due to the strong covalent interaction between RSG and WPU. Finally, the corrosion resistance of the coating was characterized by polarization curves and salt spray tests.     

Synthesis and characterization of corrosion protective polyurethanefattyamide/silica hybrid coating material

For the first time, polyurethanefattyamide/silica [PULFAS] based organic-inorganic hybrid coatings were prepared at ambient temperature to combat the corrosion of mild steel. The coating material was synthesized in situ by the reaction of Linseed diol fattyamide (HELA) and tetraethoxy orthosilicate (TEOS, 20-30 phr) at 80 °C, followed by the addition of calculated amount of toluene-2,4-diisocyanate (TDI) in the reaction setup at room temperature. The formation of PULFAS was confirmed by FTIR spectral technique while morphology of the same was observed by optical micrography. The physico-mechanical properties of PULFAS coatings such as scratch hardness, impact resistance, bend test and gloss along with coating thickness were evaluated by standard methods. Thermal stability of PULFAS was investigated by thermogravimetric analysis (TGA). Curing behavior of PULFS was studied by differential scanning calorimetry (DSC). Corrosion resistance performance of the hybrid coatings was evaluated by potentio dynamic polarization (PDP) measurements in different corrosive environments at room temperature. Salt spray test of PULFAS coatings was carried out in 3.5 wt% NaCl solution. The corrosion protection mechanism of the same was also investigated. The results showed that PULFAS coatings exhibit good physico-mechanical properties with excellent performance against the corrosive environments.