咪唑啉季铵盐缓蚀剂改性蒙脱土/水性环氧纳米复合涂料

Quaternary ammonium corrosion inhibitor modified montmorillonite/waterborne epoxy nanocoating

摘要:

以油酸、二乙烯三胺和氯化苄为原料,合成了咪唑啉季铵盐缓蚀剂。通过FT-IR、₁^H-NMR对季铵盐结构进行了表征。并将其离子交换至钠基蒙脱土(DK0)层间,制备缓蚀剂改性有机蒙脱土QACDK0。通过XRD,TGA和UV-Vis对QACDK0的结构、组成及层间缓蚀剂释放性能进行了表征,结果表明季铵盐缓蚀剂的插入使蒙脱土层间距由12.8 ?扩大到39.8 ?,蒙脱土中缓蚀剂负载量约为39.0 wt%。为研究在同种基质中使用不同纳米粘土对水性环氧涂层防腐性能的影响,将缓蚀剂改性有机蒙脱土、无机蒙脱土及市售普通有机改性蒙脱土加入到环氧树脂E-51中,通过相反转法制备了水性环氧树脂/蒙脱土纳米复合乳液。利用DLS和Zeta电位对环氧乳液的稳定性进行表征,其中咪唑啉季铵盐缓蚀剂改性蒙脱土/环氧乳液Zeta电位为-27.8 mV,稳定性最高。电化学阻抗谱(EIS)测试表明,在腐蚀介质中浸泡30天后,基于QACDK0制备的防腐清漆漆膜阻抗模值仍保持最高,具有2.29×10₈ ^Ohm.cm₂^的高阻抗值,表明季铵盐缓蚀剂的释放使涂层具有更好的主动防腐性能。在耐中性盐雾测试中,QACDK0对应的防腐色漆耐盐雾时间更长,验证了该涂层具有良好的耐盐雾性能。此外,该涂层表面平整致密,具有良好的阻隔性能。

Abstract:

Imidazoline quaternary ammonium salt corrosion inhibitor was synthesized from oleic acid, diethylenetriamine and benzyl chloride. The structure of quaternary ammonium salt was characterized by FT-IR, ₁^H-NMR. The ions were exchanged into the Na-montmorillonite (DK0) layer to prepare the corrosion inhibitor modified organic montmorillonite. The structure, composition and release properties of QACDK0 were characterized by XRD, TGA and UV-Vis. The results showed that the insertion of quaternary ammonium salt inhibitor increased the spacing of montmorillonite layers from 12.8 ? to 39.8 ?, and the load of inhibitor in montmorillonite was about 39.0 wt%. In order to study the effect of different nano-clay particles on the corrosion resistance of water-based epoxy coating, epoxy resin/montmorillonite composite emulsions were prepared by phase inverse method with the incorporation of QACDK0, DK0 and commercially available common organic montmorillonite blended with epoxy resin E-51. DLS and Zeta potential were used to characterize the stability of epoxy emulsion. The Zeta potential of imidazoline quaternary ammonium salt corrosion inhibitor modified montmorillonite/epoxy emulsion was -27.8 mV, indicating the highest stability. Electrochemical impedance spectroscopy (EIS) test demonstrated that after 30 days of immersion in corrosive medium, the impedance modulus of the anticorrosive coatings prepared based on QACDK0 remained the highest, with a high impedance value of 2.29×10₈ ^Ohm.cm₂^{, indicating that the release of quate}rnary ammonium salt corrosion inhibitor made the coatings have better active anticorrosive properties. In the test of neutral salt spray resistance, the grey coating containing pigment corresponding to QACDK0 salt spray resistance time, which verified that the coating has good salt spray resistance performance. In addition, the coating surface is flat and compact, which was beneficial to good barrier performance.