Multifunctional coatings based on silicone matrix and propolis extract
The development of new green alternatives for anticorrosive and antifouling coatings is essential for the conservation of the environment. A coating with more than one functionality, for example both anticorrosion and antifouling is of great interest for cost reduction and for improved coating efficiency.
Increase of thermal stability
Fourier transform infrared (FTIR) and 13C nuclear magnetic resonance (13C NMR) analyses confirmed the presence of several compounds with active properties (e.g. polyphenols, cinnamic acid, ferulic acid, and diterpenes). The addition of propolis and TiO2 increased the thermal stability of the final coating while keeping the water contact angle of the silicone, near to 98°.
Antifouling efficiency over a longer period of time
Electrochemical impedance spectroscopy (EIS) experiments showed that the presence of propolis increased the anticorrosive properties, and bacterial experiments showed decreased adhesion of the gram-positive bacteria Staphylococcus aureus (ATCC 6538). Marine experiments also showed the excellent antifouling efficiency of the paint containing propolis over eleven months. The use of a natural pigment allied to a solvent free resin contributes to the formulation of more environmentally friendly paints.
The study is published in: Progress in Organic Coatings Volume 123, October 2018, Pages 223-231.
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