Investigation of extractive types and proportions depending on the growth location and their influence on the adhesion
ExtractImpact (Investigation of extractive types and proportions depending on the growth location and their influence on the adhesion) is a 36-month research project, which will be carried out from 01 October 2020 to 31 October 2023 by the Wilhelm-Klauditz-Institut (WKI) at the Fraunhofer Institut for Wood Research and the Wood Chemistry Department at the Institute of Wood Sciences.
The quality of glued wood-based products depends on various factors. One of them is the content and type of wood extracts contained. These have an influence on the gluing process and in the worst case can worsen it. A dependence of the extractives on the growth location and genetics of the respective tree can be assumed, but there is a lack of correlation between the extract characteristics and the gluing properties. Knowing these influences is interesting and necessary with regard to wood processing and the production of wood-based products.
By the specific investigation of trees from extreme growth locations, this project will try to establish a correlation between location, genetics, extractive distribution and content and the resulting gluing quality.
- For this purpose, the extracts of the trees will be characterized. Five tree species from four (very different) growth sites each will be examined.
Against the background of the forest adaptation to climate change, hardwood in the form of the tree species beech and oak is also being integrated into this project.
- On the other hand, the influences of extract quantity and species on the utilization and bonding properties of five adhesives relevant in timber construction are investigated.
The knowledge of the site-related distribution of extractives should contribute in the long term to being able to carry out the raw material selection for glued wood products (e.g. glulam and cross laminated timber, veneer laminated timber, oriented strand board, etc.) in a more targeted manner. This concerns both the woods and the adhesives. The findings could also promote the new and further development of adhesive systems not only in load-bearing timber construction.
The results of the project should, on the one hand, promote the long-term substitution of softwood by hardwood and make it attractive for the construction sector. On the other hand, they could improve the quality of glued products in the future and thus contribute to safety for users and manufacturers.
01.10.2020 – 31.10.2023
Funding code: 2219WK33B3