聚苯胺涂层的改性与耐蚀性能研究

发布时间：2018-05-27 10:17

本文选题：聚苯胺 + 改性　；参考：《上海电力学院》2016年硕士论文

【摘要】：聚苯胺(PANI)因单体价廉易得、掺杂机制独特、制备简单等优点,在腐蚀防护中备受关注。通常采用化学氧化法制备聚苯胺,将其与环氧树脂混合,涂覆于防护基体表面。或是采用电化学聚合,在金属表面制备聚苯胺膜。但前者制备的涂层中聚苯胺难溶、易团聚、加工性差。后者聚苯胺结构多孔、屏蔽作用较弱、附着力欠缺。由此可见单一聚苯胺涂层并非金属防腐的理想选择。改性聚苯胺复合涂层将成为拓展聚苯胺在腐蚀领域应用的研究重点。因此采用无机物或有机聚合物改性聚苯胺,提高其粘附力、改善分散性、增强耐蚀稳定性具有极其重要的实际意义和应用价值。本文采用共混法分别制备Mn_2O_3改性PANI复合涂层、Zn S改性PANI复合涂层。采用电化学法制备PVP改性PANI复合涂层。通过改性,增强PANI涂层的性能,主要研究成果如下:(1)采用共混法成功制得不同质量比的Mn_2O_3/PANI,将其涂覆于Q235碳钢表面制备复合涂层。研究不同添加量的Mn_2O_3对改性PANI复合涂层的润湿性及防腐蚀性能的影响。结果表明,Mn_2O_3的加入,使PANI涂层具有更好的疏水性。当Mn_2O_3在复合材料中的质量分数为10%时,Mn_2O_3均匀填入PANI的间隙之中,颗粒结合紧密,防腐性能达到最佳。且在3.5%Na Cl中浸泡37天,其接触角仍能达到114.5°。(2)采用共混法成功制得不同质量比的纳米Zn S改性PANI复合物,将其涂覆于Q235碳钢表面制备复合涂层。研究不同添加量的Zn S对PANI的电导率及复合材料防腐蚀性能的影响。结果表明Zn S的加入,能显著提高PANI的电导率。纳米Zn S改性PANI复合材料中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,防腐性能最优。在3.5%Na Cl溶液中浸泡1周后,复合涂层的保护效率高达99.9%。浸泡1个月后复合涂层的表面形貌发生变化,仍为致密的保护膜。相比于PANI涂层,对应的自腐蚀电位正移172m V,腐蚀电流密度由4.05×10-8A·cm-2降低为4.57×10-9A·cm-2。(3)采用循环伏安法在304不锈钢(304SS)表面沉积不同质量比的PVP-PANI薄膜。实验结果表明,与PANI涂层相比,PVP-PANI涂层在0.1mol/LKOH溶液中能为304SS提供更好的保护。少量的PVP可以显著改善PANI的团聚现象,但对提高PANI的电导率无明显作用。当PVP在混合溶液中的质量分数为1%时,其防腐性能最优。在0.1mol/LKOH溶液中浸泡1h后,与浸泡前相比,1%PVP-PANI/SS发生明显变化,其表面生成更加致密的网状交联薄膜,且接触角为138.6°。这种结构能有效阻挡腐蚀性离子和腐蚀产物的渗透,为304不锈钢提供更好的物理屏蔽作用。对应电极的腐蚀电位相较304不锈钢,正移约620m V,腐蚀电流密度降低近三个数量级,保护效率高达99.7%。
[Abstract]:Polyaniline polyaniline (pani) has attracted much attention in corrosion protection due to its advantages of low cost, unique doping mechanism and simple preparation. Polyaniline is usually prepared by chemical oxidation, mixed with epoxy resin and coated on the surface of protective matrix. Polyaniline film was prepared on metal surface by electrochemical polymerization. However, Polyaniline in the coating prepared by the former is insoluble, easy to agglomerate and poor processability. The latter has porous structure, weak shielding and poor adhesion. This shows that the single Polyaniline coating is not an ideal choice for metal anticorrosion. The modified Polyaniline composite coating will become the focus of research on the application of Polyaniline in corrosion field. Therefore, it is of great practical significance and application value to use inorganic or organic polymer to modify Polyaniline, to improve its adhesion, to improve its dispersion and to enhance its corrosion resistance and stability. In this paper, Mn_2O_3 modified PANI composite coatings and Zn S modified PANI composite coatings were prepared by blending method. PVP modified PANI composite coating was prepared by electrochemical method. The main research results are as follows: 1) mn _ 2O _ 2O _ 3 / PANI with different mass ratio was successfully prepared by blending method, and the composite coating was prepared on the surface of Q235 carbon steel. The effect of different amount of Mn_2O_3 on wettability and corrosion resistance of modified PANI composite coating was studied. The results show that the addition of Mn2O3 makes the PANI coating more hydrophobic. When the mass fraction of Mn_2O_3 in the composite material is 10, Mn-2O3 is evenly filled into the gap of PANI, the particles are tightly bonded and the anticorrosive property is the best. After immersion in 3.5%Na Cl for 37 days, the contact angle could still reach 114.5 掳. 2) Nano-ZnS modified PANI composites with different mass ratios were successfully prepared by blending method, and the composite coatings were prepared on Q235 carbon steel surface. The effects of different amount of ZnS on the conductivity of PANI and the corrosion resistance of composites were studied. The results show that the conductivity of PANI can be improved by adding ZnS. ZnS and PANI were uniformly dispersed in nano-ZnS modified PANI composites, and their corrosion resistance was improved significantly. When the mass ratio of ZnS and PANI is 1:1, the anticorrosive property is the best. After immersion in 3.5%Na Cl solution for 1 week, the protective efficiency of the composite coating was 99.9%. After soaking for one month, the surface morphology of the composite coating changed and remained a dense protective film. Compared with PANI coating, the corrosion current density was reduced from 4.05 脳 10 ~ (-8) A cm-2 to 4.57 脳 10 ~ (-9) A cm ~ (- 2. 3) by cyclic voltammetry. The PVP-PANI films with different mass ratios were deposited on 304 stainless steel (304SS) surface by cyclic voltammetry. The experimental results show that the PVP-PANI coating can provide better protection for 304SS in 0.1mol/LKOH solution than that of PANI coating. A small amount of PVP could significantly improve the aggregation of PANI, but had no effect on the conductivity of PANI. When the mass fraction of PVP in mixed solution is 1%, the anticorrosive property of PVP is optimal. After being immersed in 0.1mol/LKOH solution for 1 h, the PVP-PANI- / SS had obvious change compared with that before soaking, and the surface of PVP-PANI- / SS was more dense, and the contact angle was 138.6 掳. This structure can effectively block the penetration of corrosive ions and corrosion products and provide better physical shielding for 304 stainless steel. Compared with 304 stainless steel, the corrosion potential of the corresponding electrode is about 620mV, the corrosion current density is reduced by nearly three orders of magnitude, and the protection efficiency is as high as 99.7%.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG174.46;O633.21

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