聚苯胺颗粒对水性环氧树脂涂层防腐性能的影响

以盐酸为掺杂剂、过硫酸铵为氧化剂、咪唑类离子液体为稳定剂，采用化学氧化聚合法合成了导电聚苯胺(PANI)颗粒，将其分散到水性环氧树脂(ER)中制成聚苯胺水性环氧防腐涂层，研究了聚苯胺颗粒对涂层防腐性能和机械性能的影响。结果表明，添加聚苯胺显著提高了水性环氧涂层的阻隔性能，信号频率f=0.01 Hz时，PANI/ER涂层的阻抗(|Z|f=0.01Hz)均高于纯ER涂层。添加5.0wt% PANI时ER涂层阻隔性能最好，浸泡0~168 h时|Z|f=0.01Hz稳定在约8.0×108 Ω?cm2，浸泡168 h后|Z|f=0.01Hz=7.5×108 Ω?cm2，远高于ER和其它PANI/ER体系。中性盐雾实验结果表明，聚苯胺赋予了涂层钝化腐蚀的能力，显著提高了涂层的防腐性能，且其添加量越高，防腐性能越好。弯曲和冲击实验结果表明，涂层的机械性能随聚苯胺含量增加先上升后降低，当聚苯胺添加量不超过5.0wt%时，涂层的机械性能优异，附着力和韧性均较好；PANI添加量增至7.0wt%时，ER涂层的脆性明显变大，机械性能下降。聚苯胺在水性环氧体系中的最宜添加量为5.0wt%，此时涂层的机械性能良好，综合防腐性能最优。

Effect of polyaniline particles on corrosion resistance of waterborne epoxy resin coatings

Conductive polyaniline (PANI) particles were synthesized by chemical oxidation polymerization using hydrochloric acid as dopant, ammonium persulfate as oxidant and imidazole ionic liquid as stabilizer. Polyaniline waterborne epoxy anticorrosive coating was prepared by dispersing as-prepared polyaniline into waterborne epoxy resin (ER). And the effects of polyaniline particles on the corrosion resistance and mechanical properties of the coating were studied. Electrochemical impedance spectroscopy (EIS) results of the coating showed that the addition of polyaniline significantly improved the barrier properties of the aqueous epoxy coating. The impedance (|Z|f=0.01Hz) of all PANI/ER coatings were higher than pure ER coating. ER coating had the best barrier performance when adding 5.0wt% PANI, the |Z|f=0.01Hz value during 0~168 h immersion was stable at around 8.0?108 Ω?cm2 and after immersion for 168 h was 7.5?108 Ω?cm2, which was much higher than ER and other PANI/ER systems. The neutral salt spray test showed that the addition of polyaniline imparted the coating of the ability to passivate corrosion, significantly improving the corrosion resistance of the coating. The higher the PANI amount, the better the corrosion resistance. The bending and impact tests showed that the mechanical properties of the coating increased first and then decreased with the increase of polyaniline content. When the addition amount of polyaniline did not exceed 5.0wt%, the mechanical properties of the coating were excellent and the adhesion and toughness were both very good. When the PANI addition amount increased to 7.0wt%, the brittleness of the ER coating was remarkably strong, and the mechanical properties were degraded. The optimum addition amount of polyaniline in the aqueous epoxy system was 5.0wt%. Under this condition, the mechanical properties of the coating were good and the comprehensive anticorrosion performance was optimal.