【作者】 王琪；

【导师】 李建丰；

【作者基本信息】 兰州交通大学 ， 材料科学与工程， 2023， 硕士

【摘要】 以钢筋为例的金属腐蚀问题日益严重,选用阻锈剂可以简便有效降低金属的腐蚀速率。有机聚合物阻锈剂作为一种阻锈剂的新发展趋势,具有多个吸附位点、更容易在金属表面形成多层薄膜、环境友好、更好的耐温性能等优点。但现存以聚合物作为阻锈剂的研究及文献腐蚀介质单一,有机聚合物材料存在产量问题、性价比不高,且目前对阻锈剂的研究囿于技术限制,对阻锈剂的具体阻锈机理研究还不够透彻。合成制备结构可控、价格低廉的阻锈剂并研究其在不同环境下的阻锈性能及机理具有巨大的研究空间和研究价值。本文从有机聚合物阻锈剂的分子结构特点出发,合成制备了两种有望具有金属腐蚀抑制作用的新型有机聚合物,分别将其应用于不同环境中对钢筋的腐蚀抑制研究中。通过腐蚀电位测量、电化学阻抗谱、Tafel极化曲线等电化学方式评价了有机聚合物的阻锈性能。利用扫描电子显微镜结合能谱仪的方法研究了钢筋在添加和未添加有机聚合物情况下的表面形貌和元素含量组成。最后利用量子化学计算和分子动力学模拟方法深入探讨了有机聚合物作为阻锈剂的作用机理。相关研究内容及结果如下:1.合成制备了聚[(2,7-双(3-(二甲氨基)丙基)萘二亚胺-4,9-二基)-alt-(9,9-双(3-N,N-二甲氨基-丙基)-9H-芴-2,7-二基)](PFN-NDIN),分子结构上由芳香烃、芴基和酰胺基等基团构成。通过电化学阻抗谱、Tafel极化曲线等电化学方式以及SEM-EDS等表面分析方法测试研究了PFN-NDIN在1 M HCl溶液中对Q235钢的阻锈效果。结果一致反映出PFN-NDIN的阻锈效率和浓度呈正比,且阳极和阴极都受到了抑制作用的影响,为混合型阻锈剂。PFN-NDIN在金属表面自发吸附,受物理吸附和化学吸附作用同时影响,可以对腐蚀产生明显抑制作用。2.在上述研究基础上,将PFN-NDIN置于模拟混凝土孔溶液体系中,研究其对HRB400钢的阻锈性能和阻锈机理。结果表明该条件下的阻锈效率虽不如盐酸体系,但模拟混凝土孔溶液体系中PFN-NDIN对钢筋仍具有良好的阻锈性能,加入该有机聚合物后电荷转移电阻值明显增加,它是一种有效的混合型阻锈剂,符合Langmuir单分子层吸附。同时验证了加入阻锈剂后钢筋的受腐蚀程度降低,PFN-NDIN在钢筋上的吸附作用主要是以芳烃基团向钢筋表面铁原子的空d轨道供电子的方式实现。3.合成制备了一种含有芳香环和氮原子的以芴基为主链的水溶性聚芴,即聚(9,9-双{3’-[(N,N-二甲基)-N-乙基铵}-丙基]-2,7-芴二溴化物)(PFBr)。研究发现该有机聚合物在1 M HCl溶液体系中对Q235钢的腐蚀抑制作用较好,加入400 ppm PFBr时阻锈效率最佳,可达96.37%;该物质可作为一种以阳极型为主的混合型阻锈剂。此外,钢表面对PFBr的吸附符合Langmuir等温吸附模型,同时发生物理和化学吸附。温度升高时金属界面/腐蚀溶液体系受到扰动,PFBr分子发生解吸,阻锈效率受到影响。PFBr在金属表面能够形成吸附膜,阻碍腐蚀反应的发生;其分子主要以芴基和溴原子作为化学吸附的活性位点,平行吸附于金属表面,以有利于最大程度覆盖金属表面并抑制腐蚀。更多还原

【Abstract】 The corrosion problem of metals,such as reinforcing steel,is becoming increasingly serious,and the selection of inhibitors can easily and effectively reduce the corrosion rate of metals.As a new trend of inhibitors,organic polymer inhibitors have the advantages of multiple adsorption sites,easier formation of multilayer films on metal surfaces,environmental friendliness,and better temperature resistance.However,the existing research and literature on polymers as corrosion inhibitors have a single corrosive medium,organic polymer materials have yield problems and are not cost-effective,furthermore,the current research on corrosion inhibitors is limited by technology,and the specific corrosion inhibiting mechanism of corrosion inhibitors has not been thoroughly studied.There is a huge research space and value for synthesizing and preparing corrosion inhibitors with controllable structure and low price so as to study their corrosion inhibiting performance and mechanism under different environments.In this paper,from the molecular structure characteristics of organic polymer inhibitors,two new organic polymers with promising metal corrosion inhibition effects were synthesized and prepared,which were applied to the corrosion inhibition studies on reinforcing steel in different environments.The corrosion inhibiting properties of the organic polymers were evaluated electrochemically by corrosion potential measurements,electrochemical impedance spectroscopy,and Tafel polarization curves.The surface morphology and elemental content composition of reinforcing steel with and without the addition of organic polymers were investigated using scanning electron microscopy combined with energy spectrometry.Finally,quantum chemical calculations and molecular dynamics simulations were used to explore the mechanism of organic polymers as corrosion inhibitors in depth.The relevant studies and results are as follows:1.Poly[(2,7-bis(3-(dimethylamino)propyl)naphthalenediimide-4,9-diyl)-alt-(9,9-bis(3-N,N-dimethylamino-propyl)-9H-fluorene-2,7-diyl)](PFN-NDIN)was synthesized and prepared,with a molecular structure consisting of aromatic hydrocarbon,fluorenyl and amide groups.The inhibiting effect of PFN-NDIN on Q235 steel in 1 M HCl solution was investigated by electrochemical methods such as electrochemical impedance spectroscopy,Tafel polarization curves and surface analysis tests such as SEM-EDS.The results consistently reflect that the corrosion inhibition efficiency of PFN-NDIN is proportional to the concentration,and both the anode and cathode are affected by the inhibition effect,which is a mixed type of inhibitor.PFN-NDIN spontaneously adsorbs on the metal surface and is affected by both physical and chemical adsorption,which can have a significant corrosion inhibition effect.2.Based on the above study,PFN-NDIN was placed in the simulated concrete pore solution system to study its rust inhibition performance and the mechanism of corrosion inhibition for HRB400 steel.The results show that although the corrosion inhibition efficiency is not as good as that of the hydrochloric acid system,PFN-NDIN still has good corrosion inhibition performance on the steel in the simulated concrete pore solution system,the charge transfer resistance value increases significantly after the addition of this organic polymer,and it is an effective hybrid type of corrosion inhibitor,which is consistent with Langmuir monomolecular layer adsorption.It is also verified that the corrosion exposure of the reinforcing steel is reduced after the addition of the inhibitor,and the adsorption of PFN-NDIN on the reinforcing steel is mainly achieved by the supply of electrons from the aromatic group to the empty d orbitals of the iron atoms on the surface of the reinforcing steel.3.A water-soluble polyfluorene containing aromatic ring and nitrogen atom with fluorene group as the main chain,namely poly(9,9-bis{3’-[(N,N-dimethyl)-Nethylammonium-propyl]-2,7-fluorene dibromide)(PFBr),was synthesized and prepared.The organic polymer shows good corrosion inhibition of Q235 steel in the 1 M HCl solution system,the corrosion inhibition efficiency can reach 96.37% with the addition of 400 ppm PFBr,and this material can be used as a hybrid corrosion inhibitor mainly of the anodic type.Furthermore,the adsorption of PFBr on the steel surface follows Langmuir isothermal adsorption model,with both physical and chemical adsorption occurring.PFBr forms an adsorption film on the metal surface and hinders the corrosion reaction,its molecules mainly use fluorene groups and bromine atoms as the active sites for chemisorption,and adsorb on the metal surface in parallel to facilitate maximum coverage of the metal surface and inhibit corrosion.更多还原