Journal of Metals, Materials and Minerals
Publication Date
2008-07-01
Abstract
Bricks were successfully modified by application of a chitosan coating in order to provide their surface with a water repellant character. The chitosan coating was prepared by depositing solutions of variable chitosan concentration (1% or 2.5% w/w) onto the brick surface and let to dry under ambient condition. In order to improve the water repellant property, the films were cross-linked with a 1% solution of sodium citrate, sodium sulfate or sodium tri - polyphosphate. The effect of the chitosan concentration on the morphology of the coating at the brick surface was observed by scanning electron microscope (SEM). It was found that the brick surface porosity can be completely covered by the 2.5% chitosan solution leading to the formation of a very smooth surface. The effect of the different cross-linking agents was evaluated by measuring the time needed for a 100 μL drop of water to penetrate through the chitosan coating into the bricks. Using this technique, it was shown that the citrate cross-linked films provide the best water resistance to the brick surface. This type of coating could be used in application where water resistant bricks are needed such as freeze/thaw cycles or in roof tile applications.
First Page
33
Last Page
37
Recommended Citation
Nilpairach, S and Dubas, S T.
(2008)
"Surface modification of bricks by chitosan coatings,"
Journal of Metals, Materials and Minerals: Vol. 18:
No.
1, Article 7.
Available at:
https://digital.car.chula.ac.th/jmmm/vol18/iss1/7