PI: Marianne Liebi and Aleksandar Matic
PhD Student/Postdoc: Linnea Björn
Duration: 48 months starting from Jan 2020
To replace fossil-based plastics, there have been huge efforts in transforming biomass to degradable bioplastics. One approach is to introduce chemical modifications in lignin and/or cellulose to achieve thermoplastic material properties. In order to investigate the success of a specific chemical modification, material properties such as tensile strength and thermal properties are traditionally investigated. Even though the material properties are directly linked to the structure of the material, these techniques only give indirect information of the location of the modifications. Other techniques that are commonly used to confirm chemical modifications are FTIR and NMR. These techniques provide information on the bulk properties in the material, but in order to get full insight of the location and effect of chemical modifications, high spatial resolution is essential. In this project, we aim to use and develop advanced X-ray techniques for the characterization of structure and chemical composition with high resolution. X-ray imaging with focused X-ray beams can be used to collect scattering as well as spectroscopic information point by point, aiming for spatial resolutions of 50 nm or beyond. The main focus has so far been on using scanning Small- and Wide Angle X-ray Scattering (SAXS/WAXS) as well as Scanning Transmission X-ray Microscopy (STXM). The Scanning SAXS/WAXS have been used to determine structural changes after processing, for example how the degree of orientation of cellulose is affected by chemical modification. The STXM has been used to get chemical information of modified cellulose with a high spatial resolution of >30 nm.
Scientific: Use advanced X-ray methods to investigate how chemical modifications combined with processing affects lignocellulose materials ranging from centimeter to Angstrom length scales.
Technical: Develop a method portfolio with focus on advanced X-ray techniques including sample preparation and data analysis.
Description of how this project addresses the hypotheses in FibRe__________________________________________
The two hypothesis of Fib:Re are strongly connected to where chemical modifications are happening in the fibers/fibril aggregates. The goal is to develop a characterization platform in order to spatially resolved structural and chemical information on different length scales. Structural and chemical characterization with high resolution can be used to address if chemical modifications should be located on the surface of the fibers or within the fiber wall, what is the minimal degree of modification needed to achieve thermoplasticity as well as correlate processing conditions with structural changes inside the material.