微胶囊技术在粘接涂层自修复中的应用

微胶囊技术是21世纪重点研究开发的高新技术之一,用途广泛。将其与粘接技术相结合,不仅增加产品的附加值更是获得新特性胶粘剂的新途径。本文简要介绍了微胶囊技术在粘接涂层自修复中的应用原理及研拓进展。指出了其未来研发的难点、方向。,     

Photoinduced healing of polyolefin dielectrics enabled by surface plasmon resonance of gold nanoparticles

Dielectrics with the capability to sustain large electric fields and to repair electrical damages rapidly are attracting for advanced insulation systems. Herein we demonstrate, for the first time, polymer blends with a co-continuous structure can heal electrical-breakdown-damage under laser illumination. Polymer blends consisting of polyethylene (PE) and poly(ethylene-co-vinyl acetate) (EVA) plus a small amount of gold nanoparticles (AuNPs) were prepared via a solvent-assisted approach. The co-continuous structure was obtained by controlling the mass ratio of PE/EVA to 50/50 wt %. The PE/EVA blend showed a relatively high dielectric strength of 215 kV mm⁻¹ at room temperature under a direct current electric field. The dielectric strength was slightly reduced to 202 kV mm⁻¹ by incorporating with 0.42 wt % of AuNPs. Importantly, after electrical breakdown, the AuNPs-filled blend films were able to restore their dielectric strength to 80% of the initial values by laser irradiation for seconds. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47158.     

High-performance self-healing anticorrosion epoxy coating based on microencapsulated epoxy-amine chemistry

Attributed to the merits of excellent material compatibility, healing performance, and long-term stability, the self-healing system based on microencapsulated epoxy-amine chemistry is a potentially practical self-healing system for both structural and functional materials. Herein, based on the microencapsulated epoxy-amine chemistry, a self-healing anticorrosion coating was successfully developed. This self-healing coating system was modeled theoretically to explore the factors that influence the crack filling and the self-healing anticorrosion function. The established quantitative relationship shows that the filling depth of the crack in the coating is proportional to the microcapsule parameters and coating thickness, but inversely proportional to the crack width. Based on the above theoretical model, the effects of various parameters on the anticorrosion performance were experimentally studied. The actual filling of small in-situ cracks (<100 μm) generated by impact damage was semi-quantitatively characterized using scanning electron microscopy (SEM). The filling behavior is consistent with the theoretical modeling. After being healed at room temperature for 2 days upon impact damage, the formulated self-healing coatings were subjected to accelerated corrosion tests in 10 wt% sodium chloride (NaCl) solution for 2 days to observe their anticorrosion behavior. Compared to the neat epoxy coating, all the formulated self-healing epoxy coatings show evident anticorrosion function. Good self-healing anticorrosion performance was achieved by adding 10.0 wt% microcapsules with a size of 100–150 μm to the coating with a thickness of 300 μm. The results of this investigation laid a theoretical and technical foundation for the further development of both the self-healing chemistry and the self-healing anticorrosion coating.     

Self-lubricating epoxy composite coating with linseed oil microcapsule self-healing functionality

Cured epoxy resins have poor abrasion resistance, which shortens the service life of the material. This work aims to improve the tribological properties of epoxy resins by coupling self-lubrication and auto-healing. In this study, linseed oil microcapsules with an average particle size of 38.57 μm and good thermal stability were successfully prepared by in situ polymerization. The effects of microcapsule content on the tribological, mechanical, and self-healing properties of the composite coatings were studied. It was demonstrated that the composite coating has outstanding self-lubricating properties. The coefficient of friction reduced from 0.634 (pure epoxy resin) to 0.0459 (epoxy resin with 10 wt.% linseed oil microcapsules). Wear rate reduced from 7.16 × 10⁻⁴ mm³/(N m) to 1.74 × 10⁻⁵ mm³/(N m). The self-lubricating mechanism of the coating was investigated by SEM and EDS, which indicated that the formation of uniform and continuous lubricating film on the surface of the friction pairs was the key to improving the wear resistance of the material. In addition, the linseed oil released after the microcapsules rupture can repair the abrasion marks by reacting with oxygen during the friction process. The dual-functional effect of linseed oil microcapsules prolongs the life of epoxy resin coating and expands its application range.     

多巴胺在防腐涂料中的研究进展

多巴胺在碱性环境下自聚合形成聚多巴胺,聚多巴胺具有很强的黏附性,能够黏附在几乎所有有机或无机材料表面,被研究者广泛关注.本文介绍了多巴胺的聚合机理,多巴胺改性纳米材料作为填料添加到环氧聚合物中,解决了纳米粒子团聚的问题,增强了复合材料与环氧树脂的化学交联密度,提高了涂层的耐腐蚀性能;另外,多巴胺还可以负载缓蚀剂制备微胶...     

SiC modified self-healing ytterbium disilicate materials for potential environmental barrier coating application

Environmental barrier coatings (EBCs) are crucial to the reliability and durability of SiC_f/SiC composite components seeking applications in hot sections of next-generation advanced aero-engines. The cracks initiated and developed in EBCs owing to various reasons during service greatly undermine their lifespans. To address this problem, in this work, silicon carbide (SiC) in the forms of particles and whiskers with various amounts have been introduced to ytterbium disilicate (Yb₂Si₂O₇), the mainstream EBC topcoat materials, so as to gain some self-healing potential. The results reveal that, the SiC inclusions in Yb₂Si₂O₇ in the presence of ytterbium monosilicate (Yb₂SiO₅) can trigger the following reactions. Specifically, SiC self-healing agents are oxidized to form viscous SiO₂, which actively reacts with Yb₂SiO₅ upon encountering it, forming Yb₂Si₂O₇. This has brought twofold beneficial effects including ① silicon supplementation of disilicate topcoat, whose silicon element tends to be “dragged out” by water vapor, leading to the deterioration of thermal mismatch; as well as ② crack self-healing resulting from the volume expansion induced by the above reactions. Then the two aspects of self-healing agents, namely the “promptness” and “sustainability,” have been discussed in detail. The former is unveiled to be more pertinent to the repairing of large cracks, whilst the latter is more relevant to the self-healing of tiny cracks at initiation or early stage of propagation. The current work sheds some lights on the design and development of more durable and robust EBCs with self-healing capability.     

电弧喷涂复合涂层防护技术在杭州九堡大桥上的应用

九堡大桥是杭州钱塘江上第八座跨江大桥,是国内首次采用整体顶推施工的空间异形结构的钢混拱桥,桥址处于高腐蚀强度的海洋气候环境。本文介绍了九堡大桥钢结构防腐方案设计,金属涂层及其厚度、封闭漆、中间漆和面漆的选择,电弧喷涂铝复合涂层寿命预测及其施工情况,旨在给国内类似大型钢结构工程的腐蚀防护方案设计提供借鉴。     

Graphene modified phosphate-based metal/ceramic composite coating for corrosion protection in the high-temperature marine environment

Graphene-modified phosphate-based metal/ceramic composite coatings were prepared for corrosion protection in the high-temperature marine environment. The morphology and structure of the coating were observed by SEM, and the high-temperature anticorrosion performance of the coating was analyzed by electrochemical measurement and salt spray-high temperature cycle test. The results showed that the addition of 0.1 wt% graphene could bridge the aluminum particles inside the composite coating and extend the sacrificial anode protection time of the coating in the 3.5 wt% NaCl solution from less than 4 days to more than 8 days, thus avoiding the local failure of the coating and improving the anticorrosion performance. Besides, the addition of graphene nanosheets at low content also enhanced the physical barrier effect of the coating and prolonged the penetration path of the corrosive medium without destroying the structure of the composite coating.     

Environmental studies of smart/self-healing coating system for steel

Smart/self-healing micro-capsulated inhibitor incorporated in epoxy primer before painting on a steel surface was evaluated for its corrosion protection effectiveness on exposure to ASTM D 5894 electrolyte in laboratory and natural tropical sea-shore environment. The “healant” inhibitor was industrial custom-made and non-chromate organic-based microcapsules which were mixed into the primer before applying a polyurethane topcoat layer on steel surface. The results indicate that the active components in ruptured embedded inhibitor microcapsules were released into an inflicted scribe primer and topcoat film on steel surface on exposure to inhibit development of an electrochemical cell. Undamaged surface film of the test and control specimens exposed in the environments demonstrated excellent corrosion-inhibition performance as reflected by both visual inspection and electrochemical impedance spectroscopy experimental data. The results obtained on the performance of self-healing inhibitors should provide an understanding of the fundamental material-property relationships of smart inhibitor coatings. And, thus, should facilitate the development of optimized paint compositions in order to extend the useful service life of steel-infrastructure applications.     

热浸镀锌层表面偏钒酸盐–氟锆酸复合转化膜的研究

在热浸镀锌层上获得了一层连续、致密的偏钒酸盐–氟锆酸复合转化膜。分析了工艺参数对膜层耐蚀性的影响,确定了成膜的最佳工艺条件为:NaVO3 5.0 g/L,H2ZrF6 6.0 g/L,pH=1.5,成膜时间20 min。采用扫描电镜、能谱仪研究了膜层的微观形貌和元素组成,通过中性盐雾试验及电化学方法测试了膜层的耐蚀性能。与未经处理的热浸镀锌层相比,偏钒酸盐–氟锆酸复合转化膜的盐雾腐蚀面积明显减少,电化学阻抗值显著增大,腐蚀电流密度大幅降低。当成膜时间为20 min时,试样表现出最佳的耐蚀性能,并超过了单纯偏钒酸盐转化膜。     

发光化学镍复合镀层(英文)

在90℃下,采用含有25 g/L硫酸镍,20 g/L次磷酸钠、35 g/L柠檬酸钠、0～6 g/t,卤磷酸钙和15 g/t.硫酸铵的镀液(pH 5.5),制备了基于卤磷酸钙的发光化学镍复合镀层.研究了镀液pH对复合镀层的沉积速率及卤磷酸钙含量的影响.采用硬度测量、磨损测试、腐蚀试验、紫外光谱,扫描电镜和X射线衍射对复合镀层进行了表征.在最佳卤磷酸钙质量浓度(4 g/L)下所得的复合镀层含77.59%(质量分数)镍、7.58%(质量分数)磷和14.83%(质量分数)卤磷酸钙.由于卤磷酸钙是硬质粒子,随着其嵌入量的增多,复合镀层的硬度增大.在存在卤磷酸钙的条件下,化学镍复合镀层的耐磨和耐蚀性能均显著提高.     

液相沉积法在304不锈钢上制备纳米二氧化钛涂层

采用液相沉积法在304不锈钢上制得外观均匀致密的纳米TiO2涂层,热处理后为锐钛矿晶型。这种纳米TiO2涂层的颜色和厚度随(NH4)2TiF6与H3BO3浓度比和沉积时间的变化而不同,其光电化学效应与防腐蚀性能都比溶胶–凝胶法所制备的TiO2薄膜差。     

硅烷改性环氧树脂自修复微胶囊的制备及应用

采用硅烷偶联剂γ-（2,3-环氧丙氧基）丙基三甲氧基硅烷（KH-560）对环氧树脂E-51进行改性,并以此为芯材,三聚氰胺-脲醛树脂（MUF）为壁材,原位聚合法合成微胶囊,探讨了微胶囊制备工艺,并用光学显微镜（OM）、扫描电子显微镜（SEM）、红外光谱仪（FTIR）、热重分析仪（TGA）等对其表面形貌、化学结构及热性能等进行了表征和测试;之后将改性后的微胶囊应用到自修复环氧树脂涂层中,考察了自修复涂层的力学性能和电化学性能。结果表明,当芯壁比为1.5：1、乳化剂质量分数为1.4%时,微胶囊为规则球形,表面粗糙、致密,大小均匀,平均粒径约为100μm,具有良好的热稳定性。当涂层中改性微胶囊质量分数为3%时,涂层的拉伸强度、弯曲强度、黏结强度及冲击强度均较高,且其较未改性微胶囊自修复涂层分别提高了14.9%、14.3%、16.0%和9.6%;与未改性微胶囊自修复涂层相比,改性微胶囊自修复涂层的电化学性能增强,且电化学阻抗值显著提高。     

纳米改性工业防腐蚀涂料的研制与应用

介绍了纳米改性工业防腐蚀涂料的制备工艺,包括纳米浓缩浆、纳米改性环氧封闭漆、纳米改性环氧云铁中间漆以及纳米改性含氟聚氨酯面漆等系列产品的制备与表征。测试结果表明,纳米材料在纳米浆及涂料中获得了良好分散,纳米改性复合涂层(即喷铝涂层+纳米改性环氧封闭漆+纳米改性云铁中间漆+纳米改性含氟聚氨酯面漆)的物理机械性能以及耐久性均得到显著提高,产品在实际工程应用中也取得了可喜成果。该纳米改性工业防腐蚀涂料具有良好的应用前景。     

锌-碳化硅复合镀层的制备及性能

以钢板为基体,在普通氯化物镀锌液中加入碳化硅制得Zn-SiC 复合镀层。研究了电流密度、温度以及 SiC、氯化铵的质量浓度对镀层耐蚀性和显微硬度的影响,得到制备 Zn-SiC 复合镀层的较佳工艺条件:电流密度 0.5～1.0 A/dm2,温度 20～25℃,SiC 10～11 g/L,氯化铵 250～260 g/L。在较佳工艺下,Zn-SiC 复合镀层中 SiC 的质量分数为 0.75%,耐蚀性优于纯锌镀层,镀层中 SiC 的存在有利于生成晶粒细小、致密且显微硬度较高的镀层。     

Efficiency improvement of silicon solar cells enabled by ZnO nanowhisker array coating

An efficient antireflection coating is critical for the improvement of silicon solar cell performance via increased light coupling. Here, we have grown well-aligned ZnO nanowhisker (NW) arrays on Czochralski silicon solar cells by a seeding-growth two-step process. It is found that the ZnO NWs have a great effect on the macroscopic antireflection effect and, therefore, improves the solar cell performance. The ZnO NW array-coated solar cells display a broadband reflection suppression from 500 to 1,100 nm, and the minimum reflectance smaller than 3% can easily be achieved. By optimizing the time of ZnO NW growth, it has been confirmed that an increase of 3% relatively in the solar cell efficiency can be obtained. These results are quite interesting for the application of ZnO nanostructure in the fabrication of high-efficiency silicon solar cells.     

Self-healing waterborne polyurethane coating by pH-dependent triggered-release mechanism

In this study, effect of high-loaded silica capsules with corrosion inhibitor on thermal degradation and self-healing properties of waterborne polyurethane (WPU) was investigated. Silica capsules were synthesized using an oil in water (O/W) microemulsion and WPU was prepared via the prepolymer method. Assembled capsules demonstrated pH dependent release of their core. Incorporating silica capsule as an inorganic component resulted to improve thermal and barrier properties of WPU coatings. WPU coating with 1% silica capsules demonstrated better barrier quality in corrosive media and adding more than that resulted a rapid deterioration in barrier properties. Furthermore, such coatings possess an excellent adhesive strength with steel substrate. Electrochemical impedance spectroscopy was used in corrosion monitoring and healing procedure. Moreover, capsule morphology and thermal degradation of the WPU coating has been investigated separately by scanning electron microscopy and thermal gravimetric analysis. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47082.     

镁合金表面自修复防护膜层的研究进展

对镁合金表面自修复防护膜层的研究进行了综述,通过介绍自修复膜层的作用机理、制备及性能特点,为设计镁合金表面自修复防护涂层提供参考。     

弱极化法测评大功率二次雾化电弧喷铝涂层的腐蚀防护寿命

利用弱极化原理,通过腐蚀速率测量仪测量大功率二次雾化电弧喷铝涂层的腐蚀电位和腐蚀电流密度,计算其深度腐蚀速率,时电弧喷铝涂层的防腐寿命进行评估,获得了不同厚度电弧喷铝涂层所对应的防护寿命,确定了具有不同防护寿命的复合涂层的最佳防腐设计方案.讨论了该法存在的问题.指出电弧喷铝复合涂层的防护寿命不仅取决于涂层系统的选择及其内在质量,而且与腐蚀环境和防腐蚀涂装质量、工程养护质量密切相关,应用中须根据已用工程金属涂层的实际防护寿命对其进行修正.     

片状锌粉在富锌涂料领域的应用及其技术发展趋势

介绍了国内外鳞片基富锌涂料的主要技术特点和发展状况:包括鳞片锌基粉末涂料、鳞片基水生无机富锌涂料、鳞片基醇溶无机富锌涂料和球片结合基富锌涂料.认为片锌基粉末涂料、片锌基水性/醇溶无机涂料及球片结合基富锌涂料等是这类涂料的发展方向.