Philipp Scheibe, M.Sc.
Aging of renewable raw materials
For the effective and durable use of wood and other lignocellulose-based materials in civil engineering as well as recycling of old wood, a comprehensive understanding of the property changes by aging effects is essential. The macroscopic and thereby the relevant properties for civil engineering are the result of various parameters from the molecular to the macroscopic scale. Up to now aging studies on the molecular level were primary focused on the field of paper-based objects. On the other hand the aging of wood is often quantified by mechanical test methods. However these tests have high variances caused by their chemism and cellular structure. The aging behavior of wood on the molecular level is clearly less investigated and understood. The limited insight is due to the complex chemical composition of lignocellulose and the difficult accessibility of the single components. The underlying molecular degradation mechanism are responsible for a number of phenomena, for example the gray coloring of wood which was exposed to weathering.
The investigation of the aging behavior of wood contains mainly the chemical and mechanical-physical aging by naturally or simulated environmental conditions. Due to the natural variability and the limited assessment of the original properties of aged wood a simulation of the environmental conditions is potentially the better method for the investigation of the aging of wood. Additionally there are inconsistent statements in the literature in many cases about the property changes of old wood.
The objective of the project is, besides a comprehensive literature research, the development of methods and models for the explanation and quantification of aging of wood as well as a prediction of the properties in relation for the application in civil engineering. Further, experiments should be designed and carried out to provide the required data for the models.