聚苯胺原位聚合改性氧化石墨烯制备复合涂层及其耐腐蚀性能研究

目的 提高聚苯胺(PANI)涂层的腐蚀防护性能,并明确其防腐机理.方法 通过原位聚合的方法,采用PANI对氧化石墨烯(GO)进行功能化修饰,并对其在GO表面的生长状态进行调控.利用傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、拉曼光谱仪(Raman)和场发射高分辨扫描电镜(FESEM),对功能化GO的结构和形貌进行表征和分析;然后将其引入到聚苯胺涂层中,制备PANI/GO复合涂层.采用电化学阻抗谱(EIS)详细研究PANI涂层以及不同的PANI/GO复合涂层对不锈钢基材的腐蚀防护效应,并对其耐腐蚀机制进行探讨.结果 PANI均匀地生长在GO片层上,其结构与形貌可以通过控制苯胺的添加量进行有效调控,且PANI的原位聚合促进了GO的片层剥离及舒展,改善了其分散性以及与涂层间的相容性.与单一PANI涂层相比,PANI/GO复合涂层的稳定开路电压值较大,且当苯胺与GO的质量比为5︰1时,获得的功能化GO的分散效果最佳,对聚苯胺涂层的腐蚀防护性能增强效果最为显著.此时复合涂层表现出最大的容抗弧直径,且电化学阻抗谱拟合后的电荷转移电阻最大,双电层电容最小.结论 PANI涂层本身可以在金属表面形成具有屏蔽作用的保护层,但其非致密的形态结构及腐蚀环境下的分子构型变化损害了涂层的腐蚀防护性能.通过功能结构化GO的复合,尤其是在GO分散性最佳的状态下,可有效提高涂层的致密性和抗渗透性,并且可抑制因质子反应导致的分子构型变化对涂层结构的破坏,从而增强涂层的腐蚀防护性能.     

聚苯胺膜/不锈钢复合双极板的耐蚀性和导电性

目的在316L不锈钢(SS)表面沉积聚苯胺(PANI)薄膜,制备PANI/316L SS复合材料双极板,提高316LSS在质子交换膜燃料电池工作环境下的耐腐蚀性能和导电性能。方法采用循环伏安法,在0.1 mol/L苯胺单体与0.2 mol/L H2SO4组成的水溶液中,在316L SS基体上电化学聚合PANI薄膜。采用SEM观察表面形貌,采用FTIR和Raman分析PANI官能团结构,采用XPS分析PANI膜中元素组成和化学键合状态。采用开路电位(OCP)、极化曲线和电化学阻抗谱(EIS)研究PANI/316L SS腐蚀性能。采用四探针技术研究PANI膜的导电性。结果 SEM观察显示PANI膜为纤维状堆积物。红外光谱发现苯环、醌环和S==O伸缩振动,拉曼光谱发现掺杂态的半醌自由基C—N+·,确定合成的PANI具有中间氧化态结构。XPS分析表明,聚合过程发生了质子酸掺杂,"对阴离子"(SO42-)进入PANI分子链中,掺杂度为3%～4%。电化学测试表明,PANI/316L SS的OCP为0.15～0.25 V,PANI使316L SS腐蚀倾向降低,随着Cl-浓度的升高,腐蚀电流密度增大。结论在酸性含Cl-介质中,PANI/316L SS体系耐蚀性好,膜/基界面处保护性氧化膜Fe2O3和Cr2O3的形成,使PANI/316L SS体系耐腐蚀性能提高。在制备条件下,PANI膜厚度介于146～315μm之间,电导率范围为1.33～8.91 S/cm。     

湿固化型石墨烯改性重防腐涂料的性能研究

目的 为延长如输电塔架等金属构件的服役期限，制备一种湿固化型石墨烯改性重防腐涂料，并测试表征和分析漆膜的防腐性能和作用机制。方法 以湿气固化型聚氨酯树脂为主要成膜物，铝鳞片代替传统锌粉为主要防腐填料，石墨烯为改性剂搭配形成复合导电填料体系，借助定位排列剂等助剂制备了湿固化型石墨烯改性重防腐涂料。通过沉降测试、结合强度测试、水接触角测试、电化学测试、扫描电镜（SEM）分析、耐中性盐雾实验等手段，对涂层的常规理化性能、防腐蚀性能及微观形貌进行了表征分析，并探讨了石墨烯-铝鳞片复合填料防护体系的防腐蚀作用机理。结果 定位剂有助于提高涂料的分散性和稳定性，经过石墨烯改性后，重防腐涂层的结合强度、耐盐水性、耐候性等常规理化性能明显提升，固含超过70%，达到高固含的环保要求；水接触角增至115°，涂层疏水性有效改善；中性耐盐雾试验进行1000 h时涂层划痕处有明显的腐蚀迹象，但表面未发生起泡、剥落等缺陷，单边扩蚀小于2 mm，石墨烯质量分数为0.8%的涂层性能达到最佳，耐盐雾时间达5000 h以上，此时涂层湿结合强度仍达到8.3 MPa，电化学腐蚀速率仅为0.011 673 mm/a，耐腐蚀性能优异。结论 石墨烯-铝鳞片复合防护体系的力学性能、机械封闭和阴极保护功能优异，属于一种底面合一的涂料，适用于湿热工业-海洋大气环境的腐蚀防护工作。     

聚苯胺长效防腐水性环保涂料的研制及性能研究

采用原位化学合成法制备对甲苯磺酸掺杂的聚苯胺/二氧化硅复合材料,并用红外光谱、扫描电镜和透射电镜表征其结构,以合成的聚苯胺/二氧化硅为功能组分,丙烯酸水性乳液为成膜物质,制成水性环保防腐涂料。用电化学测试技术研究复合水性防腐涂料对碳钢基材的防护效果。结果表明,复合水性防腐涂料使金属基体的腐蚀电位正移,具有较好的钝化效果,增强了耐蚀性。     

聚苯胺/不锈钢双极板在H2SO4中腐蚀性能的变化规律

目的提高质子交换膜燃料电池(PEMFC)双极板的耐蚀性。方法采用循环伏安法,在316L不锈钢(SS)表面电合成导电聚苯胺(PANI)膜,制备PANI/316L SS复合双极板。用红外光谱确定PANI官能团结构,用扫描电镜观察表面形貌,用X射线光电子能谱研究PANI膜成分和键合状态。用0.2 mol/L H2SO4模拟PEMFC腐蚀环境,采用极化曲线研究PANI/316LSS耐腐蚀性能,采用开路电位(OCP)和电化学阻抗谱(EIS),研究PANI/316L SS在长期浸泡过程中的腐蚀行为的变化规律。结果 PANI膜具有中间氧化态结构,呈现纤维堆积形貌。XPS结果表明,PANI膜中含有C、N、S和O等元素,聚合过程中"对阴离子"SO42-通过"掺杂"进入PANI分子链。涂覆PANI薄膜的316L SS腐蚀电位提高了0.17 V,长期浸泡过程中,OCP介于0.19～0.32 V之间,说明PANI/316L SS的腐蚀倾向降低。浸泡初期,OCP增大对应于膜/基界面处钝化膜的形成;浸泡中期,OCP下降/上升与钝化膜的溶解/修复有关;浸泡后期,OCP持续下降源于钝化膜的溶解。EIS的Nyquist图由高频端容抗弧和低频端扩散尾构成。结论随着浸泡时间延长,PANI膜被氧化,导致"对阴离子"SO_4~(2-)从PANI中发生"脱掺杂",使膜电阻增加,容抗弧半径增大。浸泡82天,PANI/316L SS体系仍具有良好的耐腐蚀性能。     

三种导电防腐涂层的耐蚀性能研究

分别制备聚苯胺改性石墨烯、纳米粒子改性石墨烯和石墨/炭黑复合物三种导电防腐涂料,并将其分别涂覆在Q235钢表面制备导电防腐涂层接地材料。采用接触角仪、电化学阻抗谱、Tafel极化曲线和光学显微镜,研究了该上述涂层在酸性土壤模拟液中的腐蚀性能。结果表明:三种导电防腐涂层均具有优良的防腐性能和较大的接触角。纳米粒子改性石墨烯涂层和聚苯胺改性石墨烯涂层防腐效果大于石墨/炭黑复合导电涂层。纳米粒子改性石墨烯涂层和聚苯胺改性石墨烯涂层的保护效率分别高达92.09%和91.44%。     

纳米ZnS增强聚苯胺复合涂层的性能研究

采用水热法制备纳米Zn S,与化学氧化法制备的聚苯胺(PANI)按不同比例混合,制得纳米Zn S改性PANI复合物,将其涂覆于Q235碳钢表面制备复合涂层。采用SEM,AFM,XRD和FTIR表征纳米Zn S改性PANI复合涂层的表面形貌和结构,利用动电位极化和EIS研究复合涂层浸泡在3.5%(质量分数)Na Cl溶液中的腐蚀电化学行为。结果表明,纳米Zn S改性PANI复合涂层中Zn S和PANI二者均匀分散,显著提高其耐蚀性能。当Zn S和PANI的质量比为1∶1时,性能最优,在3.5%Na Cl溶液中浸泡7 d,复合涂层的保护效率高达99.9%;浸泡30 d后复合涂层的表面形貌发生变化,仍为致密的保护膜,对基底材料具有较好的保护作用,使其免受溶液离子的侵蚀。     

不锈钢表面聚苯胺纳米纤维/改性氧化石墨烯/水性环氧复合涂层的制备与防护性能研究

在氧化石墨烯纳米片(GO)改性的基础上,于非盐酸介质中采用原位共聚法合成了聚苯胺纳米纤维/改性氧化石墨烯复合材料(PANI-F/CTGO),将其作为防腐增效组分引入到水性环氧聚合物乳液(WEP)中构建复合涂料.采用电化学方法和盐雾实验研究了涂料在加速腐蚀条件下对不锈钢的腐蚀防护作用,对腐蚀产物结构进行了分析.复合材料中...     

Service Performance Evaluation of Graphene Modified Heavy Anticorrosive Coating on the Surface of Transmission Tower under Harsh Marine Atmosphere Corrosive EnvironmentEI北大核心CSCD

目前国家电网输电铁塔普遍采用镀锌钢进行施工建设,钢材表面镀锌层可以抑制基体腐蚀,保障输电铁塔长期安全服役。但在沿海地区的苛刻海洋工业大气腐蚀环境中,输电铁塔表面镀锌层易发生快速腐蚀失效。研制一种低表面处理石墨烯改性重防腐涂料体系,包括低表面处理石墨烯防腐底漆、环氧石墨烯阻隔中间漆和聚氨酯耐候面漆。通过实验室性能测试、 环境考核试验和示范工程涂装,对其服役性能进行综合评价。结果表明：研制的石墨烯改性重防腐涂料具有良好的隔水性和低表面处理施工性能,复合涂层耐盐雾性能超过 5 000 h,耐循环老化 4 200 h 后漆膜完整。在国网宁波供电公司北坞 2321 线 10 级输电铁塔示范涂装 54 个月后,石墨烯改性重防腐涂层光泽度降低,漆膜变色 1 级,百格附着力在 0~1 级,拉拔附着力 8.56~11.37 MPa。根据室内模拟加速试验和实际工程服役性能测试结果,研制的石墨烯改性重防腐涂料对输电铁塔在苛刻海洋大气腐蚀环境下的综合防护寿命可达 10 年以上。研究了石墨烯改性重防腐涂料体系的实际服役性能,实现在苛刻海洋大气腐蚀环境中对输电铁塔的长效腐蚀防护,为电网设施的长期腐蚀防护提供可靠途径。     

超疏水化合物在金属腐蚀与防护领域的应用进展

近年来,随着现代工业不断发展,金属材料的应用日趋广泛,同时金属材料的腐蚀问题也受到大家的广泛关注.超疏水化合物因其优良的化学特性而被应用于金属腐蚀防护领域.介绍了超疏水化合物在金属基底进行防护的原理,综述了近年来常用于制备超疏水表面的方法,如通过氟化物、硬脂酸类化合物、长链的烷基或者是硅烷基等疏水性物质对低表面能的化合物进行改性,构建出具有低表面能的超疏水表面.超疏水化合物与有机金属框架化合物(MOFs)、缓蚀剂以及微胶囊3种特殊的具有防腐特性的物质,可通过协同作用对金属基体进行防护:(1)利用一些疏水性化合物对具有特殊的表面特性的有机金属框架化合物(MOFs)纳米材料进行改性,制造出超疏水表面;(2)通过一些长链疏水性化合物对缓蚀剂进行改性,以提高其疏水性能,进而可获得更优异的防腐效果;(3)具有自修复功能的微胶囊与疏水性化合物,通过协同作用发挥其最佳防腐性能.最后对超疏水化合物在金属腐蚀与防护领域的应用前景进行了展望.     

Corrosion inhibition performance of polymer-alloy bilayer coatings: electropolymerised polyaniline and electrodeposited ZnNi with different layer orders

Polyaniline (PANI) conducting polymer coatings have been obtained galvanostatically with various current densities (from 0·1 to 0·4 mA cm^?2) and ZnNi alloy coatings have been obtained galvanostatically at 30 mA cm^?2 current density. Corrosion protection performances of monolayered PANI and ZnNi alloy coatings and multi-layered ZnNi/PANI and PANI/ZnNi coatings on st-37 low carbon mild steel (MS) have been investigated by an open circuit potential method, Tafel extrapolation method and electrochemical impedance method in 3·5 wt-% NaCl solution. In addition, the surface morphology of the coatings has been characterised by using scanning electron microscopy (SEM). Synthesising PANI films between two metal layers provided better corrosion protection to the steel. MS/PANI/ZnNi layer formation exhibited the biggest corrosion protection performance among all layer formations of the films and protected MS for up to 72 h.     

Ni~(2+)掺杂电合成聚苯胺膜的耐腐蚀性能

利用电化学测试技术、扫描电子显微镜(SEM)和X射线衍射仪(XRD)对在苯胺-硫酸电解液体系中加入Ni2+改性的电化学合成聚苯胺膜(PANI)性能进行了研究。结果表明,采用恒电流法制备聚苯胺膜(PANI)时,Ni2+的加入使PANI膜的形貌由不规则片状转变为纤维状,改性后PANI膜的交流阻抗明显增大,膜的腐蚀电流降低,10%HCl点滴腐蚀时间达320 s,中性盐雾实验36 h未见锈蚀。     

Research Progress of Modified Polyaniline in Anticorrosive CoatingsEI北大核心CSCD

聚苯胺因其可逆的氧化还原特性在金属腐蚀与防护领域具有广阔的应用前景,目前有关改性聚苯胺对涂层附着力、阻隔性能以及钝化机理的研究比较零散,缺乏系统总结。通过对单一聚苯胺分散性差、疏水性弱等缺陷的分析,报道近年来改性聚苯胺在防腐涂料领域中的研究思路和研究进展,比较不同条件下改性策略的优劣,归纳聚苯胺结构与涂层耐腐蚀性之间存在的联系。进一步论证柔性、疏水基团取代聚苯胺有利于提升涂层抗渗性,改变掺杂剂以及与纳米氧化物、石墨烯等原位聚合制备复合填料也是提升涂层防腐性能的有效途径。展望该行业未来研究和发展的趋势,可为今后聚苯胺的改性工作提供理论指导。     

Electrochemical behavior of mild steel coated by polyaniline doped with organic sulfonic acids

A comparison of electrochemical behavior was made of coatings of pure undoped PANI cast from solution and this coating after doping as a film on the substrate. These were also compared to coatings of pure PANI/sulfonic acids adducts formed from the outset in the doped state through casting from xylene or chloroform solutions. The results obtained allowed to assume that the formation of protective iron oxide layers occurs mainly during the coating of pure undoped PANI (emeraldine base). During the doping stage a modification of these layers obviously proceeds leading to a change of the corrosion currents of the whole coating system. As a consequence, the formation of pure doped PANI coatings by casting doped PANI from solutions cannot give as good of results as does the two stage process.     

Influence of tungstate ion dopants in corrosion protection behavior of polyaniline coating on mild steel

Electropolymerization of polyaniline (PANI) and polyaniline‐tungstate (PANIW) coatings on mild steel were successfully performed using cyclic voltammetry technique. Processes were carried out in aqueous electrolyte solutions of 0.3 M oxalic acid + 0.1 M aniline and 0.3 M oxalic acid + 0.1 M aniline + 0.001 M sodium tungstate dehydrate. Corrosion protection of PANI and PANIW coatings was evaluated with the help of open circuit potential (E_ocp) monitoring and electrochemical impedance spectroscopy (EIS) methods. All the results reveal the influence of additional doping agent (i.e., tungstate) in corrosion protection behavior of PANI coating.     

A study on mechanism of corrosion protection of polyaniline coating and its failure

Polyaniline (PANI) coatings were electrochemically deposited on substrates of stainless steel and platinum in solutions of 0.2 M H₂SO₄ and 0.1 M aniline by cyclic voltammetry. The corrosion protection of the PANI coatings and their failure were investigated in 0.2 M H₂SO₄ solution. It was observed that the corrosion protection ability of the coating to steel substrate was increased with the increase of the coating thickness. The corrosion protection ability was mainly attributed to the passivating effect of PANI due to its oxidizing ability in its emeraldine state. During its operation, the PANI coating in emeraldine state tended to gradually lose its corrosion protection ability. This gradual failure of the PANI coating, but faster than expected, was confirmed to be related to a gradual reduction of the emeraldine PANI and a gradually increased resistance between the PANI coating and the stainless steel substrate. These findings lead to a new mechanism for the corrosion protection of PANI coating and its failure.     

Dependence of the corrosion performance of polyaniline films applied on stainless steel on the nature of electropolymerisation solution

Polyaniline (PANI) films were deposited under cyclic voltammetric conditions on 304L stainless steel by aniline electropolymerisation from acidic and slightly basic solutions containing respectively the followed support-electrolytes: H₂C₂O₄ and KNO₃.It was found that the film produced in oxalic acidic medium was more conductive than that obtained in potassium nitrate one.The PANI coatings corrosion performances in 0.5 M NaCl were investigated and compared using standard electrochemical methods, electrochemical impedance spectroscopy (EIS) and SEM analysis.The highest corrosion resisting efficiency was obtained for PANI_nitrate which exhibited a significant physical barrier property against the attack of corrosive products. However, the corrosion protection of conductive PANI_oxalic coating was related to its catalytic behavior.     

Polyaniline acrylic coatings for corrosion inhibition: the role played by counter-ions

The interest in providing new corrosion protection systems for different metals and metal alloys is related to restrictions to the use of chromium (VI) compounds owing to their environmental problems. This work presents the electrochemical behavior of a polymeric blend formed by camphorsulphonate or phenylphosphonate-doped polyaniline (PANI) and poly(methyl methacrylate) used for iron corrosion protection in sulphuric acid solutions with or without chloride ions. Results indicate that these blends act by a two-step protection mechanism. First, a redox reaction between Fe and PANI takes place leading to PANI reduction and concomitant anion release. Then, iron cations form a passivating complex with the PANI doping anion (camphorsulphonate or phenylphosphonate) that simultaneously acts as a second physical barrier to avoid penetration of aggressive ions. So, considering these processes, it is possible to conclude that PANI is an anion reservoir, which can release anions in a smart way when damage is produced on the surface of the coating.     

Inhibition of steel corrosion by polyaniline coatings

Polyaniline (PANI) coatings were electrosynthesised on steel samples (13% and 4.44% Cr) using sulphuric and phosphoric acids as supporting electrolytes. Protective properties of PANI coatings in the supporting electrolytes were investigated by monitoring the open-circuit potential vs. time, and by applying electrochemical impedance spectroscopy. PANI layers have been found to provide corrosion protection. Thicker PANI layers at 530 mV vs. Ag/AgCl (3 mol dm⁻³ KCl) exhibit pure capacitive behaviour at low frequencies, and in addition a small resistance at high frequencies. Thinner layers at 530 mV exhibit a much higher resistance attributed to a higher degree of PANI-free electrode surface and/or to a significant amount of PANI transformed from emeraldine to leucoemeraldine form. The layer deposited in a phosphate solution appears to have better protective properties than the layer deposited in a sulphate solution. Therefore, PANI from phosphate solution was tested also in 0.1 mol dm⁻³ HCl. However, in the chloride-containing solution, the time of protection was significantly shorter.     

Corrosion protection of aluminum alloy by epoxy coatings containing polyaniline modified graphene additives

In the study, polyaniline/reduced‐graphene oxide (PANI‐RGO) composites, fabricated by loading 2, 5, and 8wt% graphene oxide, was prepared by in‐situ emulsion polymerization and reduction. They are characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. Epoxy coatings adding PANI and PANI‐RGO composites were coated on the surface of AA5083 Al alloy. The anticorrosion performance of the coatings is measured by electrochemical impedance spectroscopy and potentiodynamic polarization curve in 3.5wt% NaCl solution. The results demonstrate that the epoxy/PANI‐RGO coating exhibits a better protection against AA5083 alloy corrosion compared with the epoxy/PANI coating. Enhancement of the passivation performance of PANI was obtained by the addition of RGO into epoxy/PANI coating system.