Plasticization and partial depolymerization of lignocellulosebased materials

PI: Anette Larsson, Chalmers 
Co-PI: Ulrica Edlund, KTH och Gunnar Westman, Chalmers
PhD Student: Åke Henrik-Klemens
Duration: 4 years, starting September 2021
Reference Group: Stora Enso, Tetra Pak, Lantmännen, BIM Kemi, Nouryon & Essity 

Intro                                                                                                                                                                                        
Lignin, hemicellulose, and cellulose are the main components in lignocellulose-based materials. Lignin consists of covalently linked aromatic monomers which form polymer chains that can be partially linear, branched, or cross-linked (1).  FibRe aims to develop lignocellulose-based thermoplastic materials. One way to increase the thermal deformability is to add plasticizers and decrease the glass transition temperature, Tg. Plasticization is achieved by increasing the free volume, between the polymer chain segments, and hence the chain mobility. Such swelling of the materials is mediated by the addition of plasticizers (external plasticizers) or by covalently attaching substituents to the polymer chains (internal plasticization). Cross-linking of polymers limits the swelling of the systems, and the swelling can thus be increased by reducing the number of cross-links in the polymers. It is known that cleavage of lignin backbone bonds (depolymerization), for instance by chemicals or radiation, can decrease the cross-linking of the lignin chains. (2,3# 

Objectives                                                                                                                                                                                

Scientific: Create thermoplastic lignocellulose-based materials by swelling the lignin-rich environments in the fibers by adding selected plasticizers. 
Create thermoplastic lignocellulose-based materials by swelling the lignin-rich environments in the fibers by adding selected plasticizers to the fibers, and by partially depolymerizing the lignin chains with chemicals or radiation, but not remove the created lignin fragments (as in traditional delignification). 

Technical: Enable a set of thermomechanical evaluation methods (e.g. DSC, DMA and melt-rheological) adapted to for evaluation of lignocellulosic materials thermoformability.
 
Describe how this project addresses the hypotheses in FibRe                                                                                  
Hypothesis 1 suggests that lignocellulose-based material can be thermoplastic by modifying the lignin-rich parts of the fiber structure. The proposed project aims to disapprove or strengthen this hypothesis.


                                                                             
 1 Goring, In ACS Symposium serie, Lignin 1989
 2 Brännvall, BioResources (2017), 12(1), 2081-2107.
 3 ​Liu et al Polymer Degradation and Stability (2017), 135, 54-60


Page manager Published: Wed 28 Sep 2022.