SUPERVISOR: Wolfgang GINDL-ALTMUTTER

PROJECT ASSIGNED TO: Jan JANESCH

Wood is a natural high performance material, with an outstanding high strength at low density. However, its range of applications as well as its time of application are limited, owing to its hygroscopic properties, susceptibility to UV light, and degradation by microorganisms. Although the surface plays a key role in the protection of wood, cheap, functional and long-term protection coatings are yet to be developed. This project addresses that gap. The functionalizations that will be carried out are divided into two groups, that were identified as most crucial towards the protection of wood: -    The low UV stability of wood and its resulting color change are not only undesired by the costumer – wood degradation due to light exposure also paves the way for its degradation by microorganisms and leads to the failure of overlying coatings. Metal oxide particles offer a solution to this problem. They effectively absorb UV light, but in contrast to “conventional” UV-stabilizers such as UVA and HALS, have the advantage of long-term stability. A transparent coating based on TiO2 particles has successfully been prepared in this project (see Figure 1). Its protective performance in terms of preserving the color of spruce wood is demonstrated in Figure 2.

-    Water is one of the most important factors regarding the degradation of wood. It affects all mechanical properties of the material, can lead to crack formation and material failure and forms the basis for fungi and mold growth. Because of this, the second subtopic is about increasing the water repellency of wood. Such superhydrophobic coatings on wood are definitely not a new thing. However, most published systems cannot withstand real world conditions. The focus of this project should therefore be on a good mechanical performance.
 

Figure 1: TiO2 particles at the surface of wood.

Figure 2: Spruce wood samples subjected to several coating cycles show a decrease in color change.