Preparation And Anti-corrosion Properties Of Nano-attapulgite/Waterborne Epoxy Composite Emulsion

Preparations of high-performance waterborne resins become research focus in the field of anti-corrosion industry. Preparation of waterborne organic-inorganic composite materials is an important way to improve the performance of waterborne anti-corrosion resins. In this paper, the natural nanoattapulgite clay was modified by phytic acid through a hydrothermal process to prepare a series of functional nano-attapulgites. Nanoattapulgites could be fabricated into composite emulsions with waterborne epoxy resins to remedy the shortcomings of reunion and condensation in nanoparticles system. The nanoattapulgites, with good dispersion, compatibility, stability, have a broad application prospects in the field of waterborne anticorrosion coatings. The detailed content is listed as follows:(1) The natural nanoattapulgite was modified to prepare the functional nano-attapulgite particles through a facile hydrothermal process. The phytic acid was used as modifier and the pH values were adjusted by neutralizers. The temperature was kept as150℃in the hydrothermal process. By multiple comparison tests, we found that phytic acid concentration, reaction time and pH value of the system pH are key factors which affect the final micromorphology of the modified nanoattapulgite. So we could adjust these three influencing factors and prepare various nanoattapulgite with different morphologies and performances. The experimental results show that the formation mechanisms of the modified nano-attapulgites were different in neutral, alkaline and acidic conditions. In neutral and alkaline conditions, the attapulgite tended combination with phytic acid molecules and form spherical particles. However, the nanorod structures of attapulgite tend to combination with each other and the nanorods were enlonged and expanded. The modified nanoattapulgites could be fabricated into composite emulsions with waterborne epoxy resins. Compared with traditional epoxy emulsion, the hybrid emulsion had better corrosion protection efficiency and a substantial increase in the long-lasting protective effect of the metal substrate.(2) Waterborne acrylic modified epoxy anti-corrosion coatings were prepared. The ratios of film-forming resins, inhibitors and film coalescing aid on the performance of paints were discussed. It was found that the prepared waterborne acrylic modified epoxy coating have the best anti-corrosion performance and economic benefits as the coating with resin ratio of 2:1, corrosion inhibitor content of1%and film coalescing aid content ratio of4%. The modified nanoattapulgite particles significantly improved the corrosion resistance of the coatings. When the ratio of modified nanoattapulgites was10%, the coating not only has good mechanical properties but also show excellent durable corrosion resistance in the electrochemical tests.