微胶囊型钢筋阻锈剂的热稳定性与阻锈性研究

Study on Thermal Stability and Corrosion Resistance of Microencapsulated Corrosion Inhibitors for Reinforcement Steel

采用阻锈剂是钢筋混凝土结构阻止钢筋锈蚀的有效方式,而阻锈剂微胶囊化克服了传统阻锈剂易流失、毒性大、阻锈效能较低等缺点,提高其在混凝土中的稳定性并延缓释放,可以显著改善钢筋混凝土的耐久性.采用溶剂蒸发法和喷雾干燥法制备出一种具有氯离子和氢氧根离子共同响应效果的双层壁结构微胶囊,利用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、热重分析仪(TGA)和电化学测试对微胶囊的形貌、物相、热稳定性和阻锈性能进行了分析.研究结果表明:制备的单、双层壁微胶囊形貌良好,具有理想的核-壳结构和良好的热稳定性,芯材含量分别为53.2%、38.6%.通过模拟混凝土孔隙溶液的电化学测试,单层壁微胶囊在24 h内将芯材全部释放,双层壁微胶囊将时间延长到了80 d,具有更好的阻锈效果.

The use of corrosion inhibitors is an effective way to stop the corrosion of reinforced concrete structures.The microencapsulation of corrosion inhibitors overcomes the shortcomings of the traditional corrosion inhibitors,such as easy loss,high toxicity and low corrosion-inhibiting efficiency,improves the stability of corrosion inhibitors in concrete,and delays their release.It also significantly improves the durability of reinforced concrete.In this paper,double-layered microcapsules with the co-responsive effect of chloride and hydroxide ions were prepared by solvent evaporation and spray drying method.The morphology,physical phase,thermal stability,and corrosion-inhibiting properties of the microcapsules were analyzed by optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),thermogravimetric analysis(TGA)and electrochemical tests.The results show that the prepared single-layered microcapsules and double-layered microcapsules have good morphology,ideal core-shell structure,and good thermal stability,with 53.2%and 38.6%of core material content respectively.Through the electrochemical test of simulated concrete pore solution,the single-layered microcapsules released all the core material within 24 hours,and the double-layered microcapsules extended the time to 80 days with a better corrosion-inhibiting effect.