9. Synchrotron techniques as a tool to investigate wood pulping process

Facing the issues of environmental pollution by non-renewable fossil-based materials, research is demanded to find natural and renewable substitutions. For that wood can be a perfect candidate. Apart of its unique properties it has also a long history in research and material production. Use of a new type of high precision experimental techniques based on synchrotron radiation can bring new insights into wood structure and extraction processes.

Kraft cooking is a well-established method for extraction of lignin and hemicellulose from wood and is widely used in industry. Investigation of wood compositional and structural variations before and after experiment were studied by numerous techniques, and instrumentation limitations often do not permit in situ experiments. In this work we want to investigate how structure and composition of a single wood building block – wood cell, is changing during different steps of Kraft cooking by in situ WAXS measurements using a specially customized reactor. We will demonstrate experimental setup and some preliminary results for digestion of spruce in water at different temperature and pressure.

3D visualization of two connected wood cells at different steps of cooking is another challenge we addressed in this project. Usually, it is performed by 3D TEM tomography using resin embedding and fine sectioning of a wood chip to 100 nm thickness. To investigate the impact of sample preparation on visualized structure 3D nanotomogrpahy was performed on a single wood cell cut by cryo ultramicrotome.