采用酸性磷酸酯作为掺杂剂对本征态聚苯胺(EB)进行掺杂,制备了可在聚氨酯丙烯酸酯中进行纳米分散的导电聚苯胺(ES),其分散粒径分布为60-765 nm之间,进而制备了不含重金属的紫外光固化聚苯胺防腐涂料.随着体系中导电聚苯胺含量从0.5 wt%增大5.0 wt%,粒径从60-100 nm增加到190-765 nm.导电聚苯胺含量增大,导致了ES发生团聚,从而粒径增大,进而降低防腐涂层的致密性.当ES含量为1.0wt%时,粒径在110-180 nm之间,防腐涂层在3.5 wt%的Na Cl水溶液中浸泡2400 h后,其0.1 Hz下的绝对阻抗值(|Z|0.1 Hz)仍高于1.0×10^Ωcm^2,同时45-50μm的防腐涂层在划叉中性盐雾试验中,500 h内没有出现起泡现象,且锈蚀宽度小于1 mm,表现出优异的防腐性能.
Conducting polyaniline was prepared using acidic phosphate( HPAA) as dopant of emeraldine base( EB),which can be nano-dispersed in the polyurethane acrylates,and ultraviolet cured polyaniline anticorrosion coating without any heavy metals was obtained. The surface drying time of this kind of anti-corrosion painting was only 3- 5 s under ultraviolet light. Particle size distribution of conductive polyaniline can be controlled from 60 nm to 765 nm,the particle size increased from 60- 100 nm to 190- 765 nm when the polyaniline loading in the coating increased from 0. 5 wt% to 5. 0 wt%,accompanied by the increase of porosity of anti-corrosion coating,the reason was due to the agglomeration of conducting polyanilines with increasing polyaniline content. The absolute impedance at 0. 1 Hz( | Z |0. 1 Hz) of the anti-corrosion coating with1. 0 wt% polyaniline content can maintain 1. 0 × 10^8Ωcm^2 after 2400 h immersion in 3. 5% Na Cl solution,where the ES particle size was 110- 180 nm. Moreover,for such anti-corrosion coating with 45- 50 μm thickness,though red rust was found after 300 h due to the red iron oxide from interaction between conductive polyaniline and mild steel,no blister was found in the coating after 500 h cross scratch neutral salt spray test,and the rusted frontier around the scratch was less than 1 mm,indicating its very nice anti-corrosion performance.