聚苯胺微乳液及其对水性防腐涂料防腐性能的影响

目的用不同酸掺杂的聚苯胺微乳液制备水性防腐涂料,提高马口铁表面涂层的耐腐蚀性能。方法采用扫描电子显微镜、傅立叶变换红外光谱和热重分析表征聚苯胺性能,通过动电位极化法及耐水性、耐盐雾和耐盐水实验检测聚苯胺微乳液水性防腐涂层的防腐性能,用铅笔硬度和划格法表征涂层的硬度和附着力。结果磷酸掺杂聚苯胺微乳液、本征态聚苯胺微乳液制备的水性防腐涂层都对马口铁起到良好保护作用。含有盐酸掺杂聚苯胺微乳液和不含聚苯胺微乳液的水性防腐涂层在浸泡过程中很快失去保护作用。掺杂态聚苯胺使马口铁表面钝化和屏蔽,本征态聚苯胺起机械屏蔽作用。通过把聚苯胺微乳液添加到水性防腐涂料中,发现涂层的硬度和附着力均没有发生明显下降,表明聚苯胺微乳液在水性防腐涂料中分散均匀,对涂层的性能影响较小。结论当水性防腐涂料中的聚苯胺质量分数为0.3%时,磷酸掺杂的聚苯胺微乳液具有最佳的耐腐蚀性能,其腐蚀电流密度Jcorr=7.359×10-7 A/cm2,腐蚀电位Ecorr=-0.527 V。

Polyaniline Microemulsion and Its Effects on Anticorrosion Property of Waterborne Anticorrosive Coatings

The work aims to improve corrsion resistance of coatings on tinplate surface by preparing waterborne anticorro-sive paints with different acids-doped polyaniline (PANI) microemulsion. Properties of PANI were characterized with scanning electronic microscopy, Fourier transform infrared spectrometer and thermal gravimetric analyzer. Corrosion resistance of the waterborne anticorrosive coatings to polyaniline microemulsion was detected in the method of potentiodynamic polarization and by performing water resistance, salt spray resistance and salt water resistance experiments. Hardness and adhesion of the coat-ings were characterized by using pencil hardness and cross-cut mothed. The waterborne anticorrosive coatings made from phosphoric acid-doped PANI microemulsion and eigenstate PANI microemulsion had favorable protective effect on the tinplate. However, the waterborne anticorrosive coatings with hydrochloric acid-doped PANI microemulsion and without PANI micro-emulsion lost protective effect quickly during the process of immersion. Doped PANI led to passivation and shield of the tinplate surface while the eigenstate PANI had the effect of mechanical shield. As polyaniline microemulsion was incorporated into the waterborne anticorrosive paints, the hardness and adhesion of coatings showed no obvious degradation, indicating that polyani-line microemulsion was dispersed uniformly in the waterborne anticorrosive paints, which had little effect on properties of the coatings. The phosphoric acid-doped PANI microemulsion exhibits the best corrosion resistance when the PANI mass fraction was 0.3% in waterborne anticorrosive paints. Corrosion current Jcorrreaches 7.359×10-7A/cm2and corrosion potential Ecorr reaches -0.527 V.