Novel organic–inorganic hybrid coatings prepared by the sol–gel process: corrosion and mechanical properties

(Hyperbranched polyurethane‐urea)/[(3‐aminopropyl)triethoxysilane]‐ZnO (HBPUU‐APTES‐ZnO) hybrid coatings were synthesized using an inexpensive mixing technique by varying the APTES‐modified ZnO concentration. The mechanical and surface properties of the hybrid coating films were studied and compared with unmodified and modified ZnO. The corrosion, solvent and abrasion resistance show significant enhancement in HBPUU‐APTES‐ZnO hybrids and their properties are increased with increasing APTES‐ZnO concentration. This hybrid coating has opened up an opportunity for automotive topcoat application. Copyright © 2012 Society of Chemical Industry     

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.     

溶胶-凝胶/环氧杂化涂料的应用

溶胶-凝胶/环氧杂化涂料的配方已经进行了研究,杂化涂料具有更强的机械强度(如硬度),更加耐磨蚀。当固化温度提高到80℃,全部研究的杂化涂料都能通过湿性黏结试验,但在室温下固化时仅有部分的杂化涂料通过湿性黏结试验。多数杂化涂料在室温下固化时对水的敏感性问题尚待解决。     

固化剂对有机改性凹凸棒石/聚苯胺环氧树脂复合涂层性能的影响

固化剂对涂层的防腐、力学性能起着至关重要的作用.以环氧树脂为成膜物质,采用原位复合法在环氧树脂体系中合成有机改性凹凸棒石/聚苯胺(OAT/PAn)复合涂层,分别使用改性脂肪胺固化剂593、酚醛胺固化剂T-31以及聚酰胺固化剂650对上述涂层进行固化,讨论了不同种类固化剂对涂层的化学结构、防腐和力学性能以及耐水性能的影响.利用FTIR 对比了各涂层的固化结构,证明了三种固化剂均可使复合涂层固化;SEM结果表明,593固化剂固化涂层的致密性最好;电化学实验结果表明,593固化剂的固化涂层防腐性能最佳,腐蚀电位达到了Ecorr=-318 mV,腐蚀电流密度Icorr=1.193×10-6 A·cm-2;通过划格法评价了各涂层的附着力,发现593固化剂固化效果最好,附着力可达5B;对比浸泡168 h后涂层的耐水性发现,593固化剂耐水性最好.     

Organic–inorganic hybrid linseed oil‐based urethane oil wood coatings

To prepare alkoxysilane‐functionalized urethane oil (AFUO) using linseed oil, 3‐aminopropyltriethoxysilane (APTES) was first reacted with diisocyanate to obtain an NCO‐terminating oligomer. The reaction was continued by adding linseed oil glyceride to form an AFUO prepolymer. The auto‐oxidative drying coating was obtained after adding a metal dryer to the AFUO prepolymer. Urethane oil (UO) coating, as a control, was obtained by the same procedure as that for AFUO, but without containing alkoxysilane‐functional groups in the formation. Siloxane hybrid urethane oil (SHUO) wood coatings were prepared by mixing tetraethyl orthosilicate (TEOS) solutions, as an external crosslinking agent by sol–gel process, with the AFUO and UO coatings. We found that introducing of APTES into the molecular chains of the UO coating resulted in a film with superior impact and abrasion resistance, and it is the most efficient process to enhance the UO films. The addition of TEOS into AFUO coatings shortened the curing time and further improved the crosslinking density of the AFUO films; however, the physical properties like impact resistance, bending resistance, and gloss were even worse than AFUO films. Mixing of TEOS and UO coating also shorten the curing time and improved the heat resistance, lightfastness, and hardness of the UO coating. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44562.     

机械力表面改性对镁合金含铝涂层耐腐蚀性能影响的研究

在AZ91D镁合金表面涂覆含有铝粉的缩丁醛有机涂层，并对涂层表面进行机械力表面改性通过中性盐雾试验和W=5％的NaCl溶液浸泡试验研究了机械力表面改性和不同铝粉粒径对该涂层耐腐蚀性能的影响时涂层经机械力表面改性前后的微观形貌和NaCI溶液中的交流阻抗分踟进行了探讨结果表明，涂液中铝粉的粒径对涂层的耐蚀性有较大影响；该机械力表面改性处理可以增强有机涂层与基体的结合强度，提高涂层表面的致密程度．从而提高了涂层的耐腐蚀性能。     

Preparation of polyvinylpyrrolidone/graphene oxide/epoxy resin composite coatings and the study on their anticorrosion performance

Waterborne epoxy resin (EP) is often used as anticorrosive coating in the industrial field. However, small holes and gaps can be formed during the curing process. The corrosive medium easily penetrates the anticorrosive coating and corrodes the metal matrix. Herein, polyvinylpyrrolidone (PVP) and graphene oxide (GO) were doped into EP to improve the shielding and resistance to corrosive media. The composite coatings were prepared successfully by solution blending method. In the PVP/GO composite materials, original spatial structure of GO was changed and the composite was mainly combined by covalent bonding. The surface morphology of hybrid filler was flat and uniform, and the structural defects of GO was reduced. Compared with single-layer anticorrosive coating, the corrosion potential of PVP/GO/EP coating moved forward and the corrosion current density decreased. The ideal corrosion resistance of PVP/GO/EP composite coatings was mainly because agglomeration of GO sheet was obviously avoided after it was modified by PVP. Furthermore, the hybrid filler can be uniformly dispersed in the aqueous EP. It blocked the gaps and holes inside the coatings, which could contribute to form anticorrosive coatings.     

Corrosion protection by zirconia-based thin films deposited by a sol–gel spin coating method

This paper focuses on the structure and corrosion behavior of 316L stainless steel coated by inorganic ZrO₂, hybrid ZrO₂–PMMA, and combined inorganic–hybrid films. The coatings were deposited by a particulate sol–gel spin-coating route, using carboxymethyl cellulose as a nanoparticle dispersant. The electrochemical evaluations were conducted in a simulated body fluid, via potentiodynamic polarization and impedance spectroscopic experiments. According to the results, the hybrid coating presented a better corrosion protection compared to the inorganic coating, due to a lesser density of structural defects. However, the best corrosion resistance was found for a combined coating which consists of an inorganic bottom layer and a hybrid top layer, due to a desirable compromise of good adhesion and low defect density.     

Electrochemical and mechanical studies on influence of curing agents on performance of epoxy tank linings

Effect of different curing agents on the mechanical, chemical resistance and anticorrosive properties of tank linings based on phenolic + novolac epoxies has been studied. Proportion of two epoxies was chosen by monitoring the processing viscosity of the coating. Parts of hardener required for 100 g of the above resin (phr) was scrutinized using differential scanning calorimetry and flexibility measurements. As a result, five coatings were finalized and their mechanical properties were investigated by dynamic mechanical analyzer. Anticorrosive properties of these coatings were studied using electrochemical impedance measurements and neutral salt spray exposure test. Chemical resistance of these coatings was investigated by monitoring the weight change of the coating during immersion. Coatings cured with modified cycloaliphatic amine (amine value = 350), in spite of lower cross-link density, exhibited superior anticorrosive properties and reasonably good chemical resistance. Electrochemical impedance results correlated fairly well with actual solvent resistance property of the coating.     

以复配硅烷偶联剂为基料的无铬锌铝涂层的制备及性能研究

以复配乙烯基三乙氧基硅烷（ A151）、 γ-缩水甘油醚氧丙基三甲氧基硅烷（ KH560）水解液为粘接剂，制备了一种水性无铬锌铝涂层。通过扫描电镜（ SEM）、 X射线衍射仪（ XRD）、能谱仪（EDS）分析了涂层及腐蚀产物的微观形貌及成分；通过傅里叶红外分析仪（ FT-IR）研究了涂层的固化过程；通过盐水浸泡实验及电化学实验研究了涂层的耐蚀性能。实验结果表明：涂层，主要由 Al相、 Zn相、 AlSi9相、 Al0.403Si0.597相组成，其中鳞片状锌铝粉在涂层中交替层叠，延长了腐蚀介质进入金属基体的路径，起到了良好的屏蔽作用； Tafel曲线表明相较于裸钢，涂层具有更高的腐蚀电位，能够对金属基材起到良好的牺牲阳极保护作用；在 3.5% NaCl溶液浸泡试验中，随着时间的延长，锌铝涂层的腐蚀产物微观形态由初期的致密针状转变为松散的多孔结构。     

功能型环氧树脂基防腐涂层的研究进展

环氧树脂涂层因其优异的耐蚀性能、对金属表面良好的附着力而在金属防腐领域得到广泛应用。但涂层固化过程中会形成缺陷和孔洞，腐蚀介质可以直接接触到金属表面。为了开发出具有优良耐久性的防腐涂层，研究人员使用不同的方法和材料制备了多种环氧树脂防腐涂层。该文综述了纳米粒子改性环氧防腐涂层、超疏水型环氧防腐涂层、自修复型环氧防腐涂层、导电聚合物改性环氧防腐涂层及生物基材料改性环氧防腐涂层的制备及性能。但这5种防腐涂层各有局限性，未来应该探究出新的环氧防腐涂层，在提升涂层防腐性能的同时，兼顾其他性能，使环氧树脂基防腐涂层朝着功能化、智能化的方向发展。     

呋喃树脂—丙烯酸酯聚氨酯互穿网络防腐涂料的研究

呋喃树脂涂料具有优良的防腐蚀性能，但质地较脆，附着性较差。用丙烯酸酯聚氨酯对其改性，形成互穿网络（ＩＰＮ）结构，可提高涂层的柔韧性和附着性，同时保持其优良的防腐蚀性能。文中讨论了ＩＰＮ形成过程中两种交联反应时间的匹配方法和丙烯酸酯聚氨酯用量对涂料性能的影响，并比较了改性前后的涂料性能。     

Electrochemical and salt spray analysis of multilayer ormosil/conversion coating systems for the corrosion resistance of 2024-T3 aluminum alloys

The corrosion resistance characteristics of multilayer coating systems comprised of a conversion coating base layer and an organically modified silicate (ormosil) topcoat have been analyzed using salt spray and potentiodynamic polarization curve analyses. The effectiveness of the multilayer coating systems was found to depend on the presence of an electrochemically active species in the conversion coating and on the presence of a curing agent in the ormosil system. Multilayer coatings systems comprised of conversion coatings that contain active corrosion inhibitors were found to provide high degrees of corrosion protection. In all cases, the presence of the ormosil was found to enhance the corrosion resistance of the underlying conversion coating. The use of multilayer ormosil/conversion coating systems enhances the corrosion protection of 2024-T3 aluminum alloy by combining previously developed corrosion protection methods with emerging sol-gel technology. Environmental Institute, Stillwater, OK 74078.     

Advanced anticorrosion coatings prepared from polybenzoxazine/siloxane-containing epoxy resin

In this study, a new type of coating comprising benzoxazine and siloxane-containing epoxy (SiEP) resin was prepared by the thermal curing method. The FTIR (Fourier transform infrared) analysis not only confirmed the complete reaction between polybenzoxaine and SiEP resin after heat curing, but also found the hydrogen-bonding interactions between them. The addition of SiEP resin significantly enhanced the hydrophobicity and adhesion ability of the coating and greatly improved the water contact angles of the blend coatings (>108°), compared to that of the pristine PBa coating, which attributed to the introduction of a Si O Si network structure in the matrix. In addition, the corrosion resistance of the coating was tested though a series of electrochemical experiment. According to the results, the corrosion current values of the blend coatings decreased by about four orders of magnitude compared to that of the pristine carbon steel, and the corrosion protection efficiency of the blend coatings were >99%, indicating good application prospect of these blend coatings.     

Corrosion resistance performance of cerium doped silica sol–gel coatings on 304L stainless steel

The aim of this work is the synthesis and investigation of silane based organic–inorganic hybrid coatings, which can be used to improve the corrosion performance of steel structures subjected to a marine environment. The silane based sol–gel coatings were prepared by dip coating 304L stainless steel in a solution of organically modified silica sol made through hydrolysis and condensation of 3-glycidoxypropyl-trimethoxysilane (GPTMS) as precursor and bisphenol A (BPA) as a cross-linking agent in an acid catalyzed condition. The influence of the addition of cerium and the use of bisphenol A as a cross-linking agent on the microscopic features and morphology as well as on the corrosion resistance of the coatings were examined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), neutral salt spray tests, potentiodynamic polarization and electrochemical impedance techniques. Results show that cerium modified nano-hybrid coatings exhibit a superior corrosion inhibition performance to that displayed by silica hybrid coatings. Additionally, data showed that the bisphenol A as a cross-linking agent has a significant effect on the morphology and corrosion resistance of the cerium doped silica coating. Omitting the use of bisphenol A causes the creation of defects/cracks in the coating, thereby promoting diffusion of the aggressive electrolyte toward the substrate and decreasing the corrosion resistance of the coating.     

柔性环氧防腐涂料的制备

以聚醚聚氨酯改性环氧树脂和自制的固化剂为基料,添加适当的防锈颜填料及助剂,制备了一种柔性环氧防腐涂料,该涂料具有良好的机械性能、耐介质性能及防腐性能,而且涂层浸水后以及低温下的柔韧性保持率高,湿态附着力好。     

有机硅改性端羟基聚酯的合成

在二月桂酸二丁基锡的催化作用下,通过有机硅预聚体与端羟基聚酯的缩聚合成了系列有机硅改性聚酯。用傅里叶变换红外光谱分析了改性聚酯的结构。以钛酸四正丁酯为固化剂成膜后,检测了改性聚酯涂层耐热性、耐腐蚀性及机械性能。改性聚酯涂层具有良好的性能,按端羟基聚酯和有机硅树脂质量比1∶1改性后,涂层的附着力达1级,铅笔硬度达4 H,冲击强度大于50 kg.cm,可耐400~450℃的高温;涂层阻抗由2.8×107Ω.cm2提高到1.1×108Ω.cm2,腐蚀电位由-0.671 V增至-0.536 V,腐蚀电流密度由4.562×10-5A/cm2降至6.194×10-7A/cm2,极化电阻由4.812 kΩ/cm2提高到57.019 kΩ/cm2。     

耐保温层下腐蚀涂料的制备及性能研究

以环氧有机硅树脂改性酚醛环氧制备了一种耐保温层下腐蚀涂料,以 TGA（热重分析）、 DMA（动态力学分析）、 DSA（表面接触角分析）等对涂层性能进行评估,考察了树脂比例、固化剂种类、颜填料种类对涂层耐热性能、机械性能和防腐性能的影响。结果表明：环氧有机硅树脂与改性酚醛环氧的质量比为 4∶6 时可有效提高涂膜耐热性能;采用该树脂,以改性脂环胺为固化剂,片状云母氧化铁红为主颜料制备耐温涂料时,涂层具有良好的机械性能、耐热性能、耐腐蚀性能,并通过 250 ℃条件下耐保温层下循环腐蚀性能要求。     

聚硫改性环氧树脂涂料的初探

研究了聚硫改性环氧树脂涂料配方,讨论了聚硫固化的机理,通过实验表明,聚硫改性环氧树脂涂料有优异的附着力、柔韧性、耐腐蚀性和耐化学品、耐油性。