Wood particle size influence on water resistance and mechanical properties of thermally modified wood-polypropylene composites

The processing of wood produces large amounts and different types of wood residues. Currently, a part of these residues is used in the production of wood plastic composites (WPC). It is known that wood particle characteristics (size, length/diameter ratio, shape, etc.) significantly influence properties of WPC; however, for thermally modified wood, the information about these effects is limited. Therefore, the main objective of this research was to investigate how different size fractions of thermally modified wood particles influence mechanical and water resistance properties of WPC. The results showed that the particle size had a significantly smaller influence on the mechanical properties for WPC with thermally modified wood particles compared to WPC with unmodified wood particles. Additionally, the wood particle size had no effect on water absorption dynamics and ultimate water uptake in case of thermally modified wood particles. Finally, wood particle size did not affect changes in mechanical properties for re-dried WPC after 200 days of immersion in water.