LAUSR

Biocomposites were produced by equal channel angular pressing (ECAP) of wood particles with addition of polyethylenimine (PEI) to improve processability and binding performance. The highest flexural strength of ~ 50 MPa achieved in a fully densified bulk material is significantly greater than that displayed by many of the commercial biocomposite products processed from wood particles. Friction with the ECAP die walls played a very important role in the process. With high friction, the size and amount of cracks were minimalised, leading to higher flexural strength. On the other hand, low friction caused long cracks and damage to the wood cell structure. The optimum processing temperature range was 190–200 °C under high friction with enhanced deformability and crosslinking. Temperatures over 200 °C, however, should be avoided since excessive thermal degradation would occur. The outcome has further demonstrated the potential of ECAP for producing wood-particle based biocomposites.Graphical abstract