CSIC scientists have developed resin microcapsules containing corrosion inhibitors. This system allows the progressive and efficient release of the inhibitors, reducing both costs and environmental impact. This methodology can be applied on construction materials such as paint, coatings and, especially, reinforced concrete structures (RCS).

Above, a solution of the microcapsules. Below, morphology of the microcapsules in which its porous structure is visible (images: CSIC)The use of corrosion inhibitors is one of the most efficient protection methods to prevent corrosion and increase reinforced concrete structures (RCS) service life. However, these compounds are needed in high quantities. Also, the large economic cost, there is an environmental cost due to the contaminant nature of these compounds.

A scientific team of the CSIC has developed a technology for encapsulating anticorrosive agents in natural resins. The microcapsules obtained can be incorporated to the concrete mixture or similar.  Industrial partners from the construction, coatings and additives industry are being sought to collaborate through a patent licence agreement.

The microcapsule is formed by a resin coat and a core of corrosion inhibitors (combinations of hydroxides and nitrites from different metals). It has an intelligent release: the release of the corrosion inhibitors stars with the beginning of corrosion symptoms, not before. The release of the inhibitor is triggered when there are signs of corrosion, such as when there are changes in the pH of the surroundings or when aggressive agents are detected, such as chlorides and carbonates. The porous structure of the microcapsules allows the controlled release of the content, extending its action through service lifetime.

It has an intelligent release: the release of the corrosion inhibitors stars with the beginning of corrosion symptoms, not before.

This resin coating layer provides high resistance to the damage suffered during handling and storage processes before its use, as well as high stability once incorporated to the concrete mixture. The resin is not soluble in water, which avoids lixiviation of the encapsulated inhibitor found inside during kneading, drying and hardening of concrete.

Encapsulation reduces environmental impact and economic cost due to the reduction of the inhibitor amount used, compared to other methods. The manufacture process of the microcapsule is simple, fast and efficient (85% of the inhibitor encapsulated). The resins used are economic, renewable and environmentally friendly.

Contact:

Laura Redondo Gallego
Deputy Vice-Presidency
for Knowledge Transfer-CSIC
Tel.: +34 915681825
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