PI: Ulrica Edlund (KTH), Annelie Moldin (Lantmännen)
PhD Student/Postdoc: Nazmun Sultana
Duration: 1.5 years starting autumn 2021
The overarching aim of this project is to turn lignocellulosic biomass thermoplastic with as little
modification as possible. Wheat straw and softwood pulp are the two targeted lignocellulosic feedstocks. Lantmännen supplies fresh wheat straw cuttings from the field in-kind. A necessary start is hence to find a suitable method and the key parameters for converting the pristine straw into one or a few viable starting lignocellulosic materials with partly liberated fibres and/or softened cell walls, in analogy to the softwood pulps of different degrees of delignification also serving as starting materials in the centre projects. It is also necessary to thoroughly characterize the straw lignocellulose to develop an in-depth understanding of the morphology, chemistry, and process-structure relationships. When the straw lignocellulose is chemically modified to create a thermoplastic material, we need to compare the effects on structure and properties with the softwood pulp subjected to the same treatment to gain an in-depth understanding of how a specific treatment affects the structure.
Scientific: In-depth understanding of how to create a lignocellulosic fibre feedstock from straw that is feasible for making the material thermoplastic, based on the unique spatial and compositional structure of the straw tissue. Understanding structural and chemical relationships for how modification processes developed within the centre to induce thermoplasticity affects straw lignocellulose compared with softwood pulp.
Technical: Finding process parameters for the isolation of suitable lignocellulosic fibre feedstock from straw.
Enabling benchmarking of modification routes and finding parameter basis for upscaling for continued work in FibRe.
Description of how this project addresses the hypotheses in FibRe
FibRe aims to produce thermoplastic lignocellulose and presents two hypotheses for how to achieve the goal with minor modification:
Hypothesis 1: The thermoplastic material must be on the surface of fibres/fibril aggregates.
Hypothesis 2: The thermoplastic material must be within the fibre wall.
To be able to test and verify/falsify hypotheses 1 and 2 with wheat straw lignocellulose, such material must be created. This material must have sufficiently liberated fibres with accessible interphases and a suitable composition (which do not make subsequent thermoplasticisation impossible). The chemistry and morphology must be well understood. The characteristics of the pulping method in scale must be within the environmental boundary conditions of FibRe.